US20230165600A1 - Devices and methods for removing material from a patient - Google Patents
Devices and methods for removing material from a patient Download PDFInfo
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- US20230165600A1 US20230165600A1 US18/103,169 US202318103169A US2023165600A1 US 20230165600 A1 US20230165600 A1 US 20230165600A1 US 202318103169 A US202318103169 A US 202318103169A US 2023165600 A1 US2023165600 A1 US 2023165600A1
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- Prior art keywords
- filament
- container element
- catheter
- clot
- distal opening
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B17/22—Implements for squeezing-off ulcers or the like on the inside of inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones; Calculus removers; Calculus smashing apparatus; Apparatus for removing obstructions in blood vessels, not otherwise provided for
- A61B17/221—Gripping devices in the form of loops or baskets for gripping calculi or similar types of obstructions
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B17/00234—Surgical instruments, devices or methods, e.g. tourniquets for minimally invasive surgery
- A61B2017/00358—Snares for grasping
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B17/22—Implements for squeezing-off ulcers or the like on the inside of inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones; Calculus removers; Calculus smashing apparatus; Apparatus for removing obstructions in blood vessels, not otherwise provided for
- A61B17/22031—Gripping instruments, e.g. forceps, for removing or smashing calculi
- A61B2017/22034—Gripping instruments, e.g. forceps, for removing or smashing calculi for gripping the obstruction or the tissue part from inside
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B17/22—Implements for squeezing-off ulcers or the like on the inside of inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones; Calculus removers; Calculus smashing apparatus; Apparatus for removing obstructions in blood vessels, not otherwise provided for
- A61B17/221—Gripping devices in the form of loops or baskets for gripping calculi or similar types of obstructions
- A61B2017/2215—Gripping devices in the form of loops or baskets for gripping calculi or similar types of obstructions having an open distal end
Definitions
- This disclosure relates generally to the field of surgery, and more specifically to the field of interventional radiology. Described herein are devices and methods for removing material from a patient.
- the present invention is directed to devices and methods for removing material from a blood vessel.
- the devices and methods are used to capture and remove material from the cerebral vasculature.
- the device includes a capture element which is collapsed and loaded into a delivery catheter which is advanced to a vascular location. The capture element is then deployed in a position to receive and contain material for removal.
- a clot retrieving element (such as a stent retriever) may be used to engage the material to be removed and assist in moving the material into the capture element.
- the capture element is contained within a chamber (which may be a lumen) in the delivery catheter when advanced through the vasculature.
- the capture element has a distal opening at a distal end and a sidewall extending proximally from the distal opening. The distal opening is moved to an open position to receive the material.
- the distal opening defines a perimeter which is used to define aspects of the invention described below.
- a first filament is coupled to the capture element to manipulate the capture element.
- the capture element is released from the chamber by moving the capture element to a position outside the chamber.
- the capture element may be moved out of the chamber by manipulating the delivery catheter and/or the capture element.
- the first filament When the capture element is released, the first filament may support the open position of the distal opening.
- the first filament may have a predetermined shape which supports the open position.
- the predetermined shape may extend around at least 120 degrees, at least 150 degrees or at least 260 degrees, around the distal opening in the open position when viewed along a longitudinal axis defined by the capture element.
- the predetermined shape of the first filament may form a first concave portion (facing the longitudinal axis) which supports and moves the distal opening to the open position when the capture element is released.
- the first concave portion may generally lie in a plane which forms an angle with the first arm of 45-135 degrees in an unbiased position. When the capture element is closed, the plane forms an angle with the first arm of 135-180 degrees.
- the concave portion has a shape larger than an unbiased shape of the distal opening so that the concave portion biases the distal opening toward the open position.
- the concave portion may be restrained by the open position of capture element so that the concave portion biases the distal opening toward the open position.
- the first filament may be coupled to the delivery catheter so that the first filament moves proximally relative to the capture element when the capture element moves to the released position and when the capture element is closed.
- Manipulation of the first filament with the delivery catheter provides advantages over systems that require the tension element to extend out of the patient (such as lower tension force required at the proximal end resulting in lower forces exerted on blood vessels through which the tension element extends).
- the first filament may also extend out of the patient and be manipulated independent of the delivery catheter without departing from numerous aspects of the present invention.
- the capture element is moved to a closed position in which the distal opening is reduced in size to prevent the material from escaping through the distal opening as the capture element is removed and/or moved into the delivery catheter or another catheter or sheath for removal from the patient.
- the distal opening may be closed by tensioning the first filament.
- the first filament may have a first arm and a second arm which are both tensioned.
- the first and second arms may extend from the first and second ends of the concave portion, respectively.
- the first filament When the capture element and first filament are advanced through the blood vessel, the first filament may have a first leading portion which extends from the distal end of the capture element within the delivery catheter.
- the first leading portion may have a length (which may form a first loop) which extends from the distal end of the capture element at least 30%, or at least 50%, of an effective diameter of the perimeter of the distal opening in the open position when moving to the open position.
- the first leading portion may be free of attachments to the capture element and may extend distally at least 1.5 mm from the distal end of the capture element as the capture element is released (and while the distal opening is moving toward the open position).
- the term “loop” as it pertains to the leading portion does not require a closed loop and merely requires a segment having both ends extending outwardly from the distal end of the delivery element.
- the effective diameter is the equivalent diameter of a circle having the same area as the distal opening (the area circumscribed by the perimeter) or other reference area or cross-section.
- the first filament may be positioned at a relatively distal location when advanced through the vasculature by the delivery catheter.
- the first filament defines a working length which is the length of the first filament positioned within 10 cm of the distal end of the capture element.
- the working length of the first filament includes the first arm, the second arm and the concave portion but may include just one arm in some embodiments and may omit the concave portion in without departing from the scope of the invention.
- the working length of the first filament changes by less than 70% of the effective diameter of the distal opening in the open position when the capture element moves from the collapsed position to the released position.
- the first filament (and optionally the first leading portion) may also engage an inner surface of the sidewall of the capture element when the filament moves to the released position.
- the first filament may also apply (exert) an outward force to the inner surface of the sidewall over a longitudinal length of at least 2 cm and may contact the inner surface through an angle of at least 180 degrees when viewed along the longitudinal axis.
- the concave portion When the capture element is closed by tensioning the first and second arms, the concave portion is deformed to reduce the size of the distal opening.
- the concave portion may be elastically deformed when and may be formed of a superelastic material deformed into a superelastic state.
- the effective diameter of the distal opening may reduce in size by at least 80% when moving to the closed position (and may be no more than 1 mm in the closed position).
- Tensioning the first filament may also invert a portion of the sidewall at the distal end. Inverting of the sidewall also moves the distal opening proximally to a position surrounded by the sidewall. The sidewall may resist inverting so that a radially inward force is exerted on the inverted portion which is transmitted through the sidewall to bias the distal opening toward the closed position.
- the sidewall of the capture element may also include an expandable portion.
- the expandable portion may be at least 10 mm long and within 10 mm from the distal end of the capture element.
- the expandable portion may exert a radially outward force on the vessel wall when tensioning the first filament to close the capture element.
- the expandable portion may be naturally biased outward due to the physical properties and shape of the sidewall.
- the first filament may move and/or assist the sidewall and distal opening to the open position.
- the expandable portion may be expanded by the first filament beyond an unbiased shape so that an effective diameter of the expandable portion increases by at least 10%. Stated another way, when the capture element is moved to the closed position the first filament is tensioned to exert an outward force on the expandable portion and may increase a radially outward force on the vessel wall by at least 10%.
- the sidewall of the capture element may also have a distal portion which reduces in length when the capture element is closed. The distal portion may extend 10 mm from the distal end and reduces in length longitudinally by at least 20% when the capture element moves to the closed position. The distal portion may also expand in accordance with the expandable portion described below.
- the first concave portion may form a closed loop with only the first arm extending from the closed loop.
- a second filament is coupled to the capture element.
- the second filament may have all features, aspects and uses as the first filament and all such features, aspects and uses are incorporated for the second filament.
- the second filament may have a second leading portion which may have any of the characteristics, features and uses of the first leading portion of the first filament.
- the second filament may be coupled to the first filament and may even be being integrally formed with the first filament.
- the first concave portion and a second concave portion formed by the second filament may each extend 90-180 degrees when the capture element is in the open position.
- FIG. 1 illustrates an embodiment of the device in an isometric view.
- FIG. 2 A illustrates a first embodiment of the filament predetermined shape.
- FIG. 2 B illustrates a second embodiment of the filament predetermined shape.
- FIG. 2 C illustrates a third embodiment of the filament predetermined shape.
- FIG. 2 D illustrates a fourth embodiment of the filament predetermined shape.
- FIG. 2 E illustrates a first embodiment of the filament predetermined shape.
- FIG. 2 F illustrates a first embodiment of the filament predetermined shape.
- FIG. 2 G illustrates a first embodiment of the filament predetermined shape.
- FIG. 2 H illustrates a first embodiment of the filament predetermined shape.
- FIG. 2 I illustrates a first embodiment of the filament predetermined shape.
- FIG. 2 J illustrates a first embodiment of the filament predetermined shape.
- FIG. 2 K illustrates a first embodiment of the filament predetermined shape.
- FIG. 3 illustrates a detailed view of the distal end of the container element.
- FIG. 4 A illustrates an intermediate catheter within a vessel which includes a clot.
- FIG. 4 B illustrates a microcatheter traversing the clot.
- FIG. 4 C illustrates the microcatheter retracted and a clot engagement element engaged with the clot.
- FIG. 4 D illustrates the intermediate catheter retracted and a constraining catheter in place.
- FIG. 4 E illustrates the constraining catheter beginning to be retracted and the container element partially deployed.
- FIG. 4 F illustrates the constraining catheter further retracted and the container element further deployed.
- FIG. 4 G illustrates the constraining catheter further retracted and the container element further deployed.
- FIG. 4 H illustrates the constraining catheter fully retracted and the container element fully deployed.
- FIG. 4 I illustrates the clot engagement element and clot partially retracted into the container element.
- FIG. 4 J illustrates the clot engagement element and clot fully retracted into the container element.
- FIG. 4 K illustrates the distal end of the container element partially closed.
- FIG. 4 L illustrates the distal end of the container element further closed.
- FIG. 4 M illustrates the distal end of the container element inverted.
- FIG. 4 N illustrates the distal end of the container element further inverted.
- FIG. 4 O illustrates the microcatheter and clot engagement element retracted.
- FIG. 4 P illustrates the constraining catheter and container element beginning to be retracted from the vessel.
- FIG. 5 A illustrates a detailed view of the distal end of the container element open.
- FIG. 5 B illustrates a detailed view of the distal end of the container element partially closed.
- FIG. 5 C illustrates a detailed view of the distal end of the container element further closed.
- FIG. 5 D illustrates a detailed view of the distal end of the container element inverted.
- FIG. 5 E illustrates a detailed view of the distal end of the container element further inverted.
- FIG. 6 A illustrates an embodiment of the device with an aspiration catheter.
- FIG. 6 B illustrates the aspiration catheter advanced toward the clot.
- FIG. 6 C illustrates the clot drawn toward the aspiration catheter.
- FIG. 6 D illustrates the aspiration catheter and clot retracted into the container element.
- FIG. 6 E illustrates the distal end of the container element partially closed.
- FIG. 6 F illustrates the distal end of the container element further closed.
- FIG. 6 G illustrates the distal end of the container element inverted.
- FIG. 6 H illustrates the distal end of the container element further inverted.
- FIG. 7 A illustrates a constraining catheter
- FIG. 7 B illustrates a filament advancing out of the constraining catheter.
- FIG. 7 C illustrates the filament further advanced out of the constraining catheter.
- FIG. 7 D illustrates a container element advancing out of the constraining element.
- FIG. 7 E illustrates the filament forming an open distal end of the container element.
- FIG. 7 F illustrates the container element further advanced out of the constraining element.
- FIG. 7 G illustrates the container element further advanced out of the constraining element.
- FIG. 8 A illustrates an embodiment with an askew plane filament perimeter in a constraining catheter.
- FIG. 8 B illustrates an embodiment with an askew plane filament perimeter deployed from a constraining catheter.
- FIG. 9 A illustrates an embodiment of part of the invented device within a simulated vessel.
- FIG. 9 B illustrates the distal end of the container element partially closed and retracted.
- FIG. 9 C illustrates the distal end of the container element further closed and retracted.
- FIG. 9 D illustrates the distal end of the container element further closed and retracted.
- FIG. 9 E illustrates the container element with the distal end of the device substantially closed.
- FIG. 9 F illustrates a perspective view of the container element.
- FIG. 10 A illustrates an embodiment of the container element inside an intermediate catheter.
- FIG. 10 B illustrates the container element with the intermediate catheter retracted and the distal opening closed.
- FIG. 10 C illustrates the container element with the intermediate catheter retracted and the distal opening open.
- FIG. 11 A illustrates a vessel with a clot and an intermediate catheter inside the vessel.
- FIG. 11 B illustrates a microcatheter extending from the intermediate catheter and a guidewire traversing the clot.
- FIG. 11 C illustrates the microcatheter traversing the clot.
- FIG. 11 D illustrates the guidewire removed from the patient.
- FIG. 11 E illustrates a stent retriever inserted into the microcatheter and traversing the clot.
- FIG. 11 F illustrates the microcatheter retracted and the stent retriever capturing the clot.
- FIG. 11 G illustrates the intermediate catheter and microcatheter removed from the patient.
- FIG. 11 H illustrates an intermediate catheter inserted into the vessel with the container element inside the intermediate catheter.
- FIG. 11 I illustrates the intermediate catheter retracted and the container element in an open configuration inside the vessel.
- FIG. 11 J illustrates the stent retriever and clot pulled within the container element.
- FIG. 11 K illustrates the container element in a closed configuration.
- FIG. 12 A illustrates an embodiment of the device with a filament catheter with the distal opening in an open position.
- FIG. 12 B illustrates an embodiment of the device with a filament catheter with the distal opening in a closed position.
- FIG. 13 A illustrates an embodiment of the device with a flap in the open position.
- FIG. 13 B illustrates an embodiment of the device with a flap in the partially closed position.
- FIG. 13 C illustrates an embodiment of the device with a flap in the closed position.
- FIG. 13 D illustrates an embodiment of the device with multiple flaps in the open position.
- FIG. 14 A illustrates an embodiment of the device with a filament excess length in the constrained position.
- FIG. 14 B illustrates an embodiment of the device with a filament excess length in the deployed position.
- FIG. 14 C illustrates an embodiment of the device with a filament excess length in the closed position.
- a device 2 to contain and remove material from a blood vessel is shown.
- the device 2 includes a container element 4 , a first filament 6 , and a constraining catheter 8 .
- the device 2 is shown in a generally deployed configuration with the container element 4 unrestricted by the constraining catheter 8 and the first filaments is not under significant tension.
- the various configurations and procedural steps of the device 2 will be described in greater detail below. Aspects of the present invention are described with reference to a single or limited number of embodiments, however, it is understood that all features, aspects and methods are incorporated into all applicable embodiments described herein even though not expressly mentioned or set forth.
- the container element 4 has a vessel diameter portion 10 and a small diameter portion 12 with a proximal funnel area 14 between them.
- the container element 4 is connected to the first filament 6 toward a distal end 16 and the constraining catheter 8 toward a proximal end 18 .
- the connection of the first filament 6 toward the distal end is configured such that when proximal tension is applied to the first filament 6 , a distal opening 20 of the container element 4 reduces in size from an open position of FIG. 5 A to a closed position of FIG. 5 E and may also move proximally as described below.
- the open position defines a perimeter of the distal opening 20 .
- the constraining catheter 8 may slide axially along the length of the container element 4 and is configured to constrict the container element 4 and position the container element 4 within a chamber 22 (which may be a lumen 24 ). As will be shown in the images below, as the constraining catheter 8 slides distally over the container element 4 , the container element 4 constricts and enters the constraining catheter 8 to load the container element 4 within the constraining catheter 8 for delivery through the vasculature. The entirety of the container element 4 may fit within the constraining catheter 8 .
- the container element 4 is configured to extend out of the constraining catheter 8 and may expand as defined by its unrestricted shape to deploy the container element 4 at or near the desired location to remove material.
- the container element 4 has a lumen 7 through which a clot retrieval device may be passed as detailed herein.
- the constraining catheter 8 is advanced through a blood vessel with the container element 4 positioned in the chamber 22 and held in the collapsed position.
- the container element 4 has a sidewall 26 extending proximally from the distal opening 20 which surrounds and contains the material.
- the first filament 6 is coupled to the container element 4 to manipulate the container element 4 as described herein.
- the first filament 6 is also in a collapsed position when the container element 4 is collapsed within the chamber 22 of the constraining catheter 8 .
- the first filament 6 may include a first arm 28 coupled to a first end 32 of a concave portion 34 and a second arm 30 coupled to a second end 36 of the concave portion 34 .
- the concave portion 34 faces a longitudinal axis LA defined by the container element 4 .
- the longitudinal axis LA follows the geometry of the container element 4 at a geometric center of the sidewall 26 and may take any shape such as curved or segmented linear sections and may be substantially by the shape of the vasculature rather than an unbiased shape of the container element 4 in use.
- the concave portion 34 may support the open position of the distal opening 20 as described in further detail below.
- the container element 4 and first filament 6 may be advanced through the blood vessel with the first filament 6 having a first leading portion 38 which extends from the distal end 16 of the container element 4 in the collapsed position.
- the first leading portion 38 may have a length L which extends from the distal end 16 of the container element 4 by at least 30%, or at least 50%, of an effective diameter ED of a perimeter P of the distal opening 20 in the open position.
- the first leading portion 38 may be free of attachments to the container element 4 and may extend distally at least 1.5 mm from the distal end 16 of the container element 4 in the collapsed position.
- the first leading portion 38 may form a first loop 40 which extends beyond the distal end 16 of container element 4 .
- the container element 4 may also be advanced through the vasculature with the first filament 6 defining a working length WL which is positioned at a relatively distal location when collapsed.
- the working length WL is defined as the length of the first filament 6 positioned within 10 cm of the distal end 16 of the container element 4 .
- the working length WL may include the combined length of the first arm 28 , the second arm 30 and the concave portion 34 within 10 cm of the distal end 16 .
- the working length WL of the first filament 6 changes by less than 70% of the effective diameter ED of the distal opening 20 in the open position when the container element 4 moves from the collapsed position to the released position.
- the working length WL may be about 11.5 cm in the collapsed position and about 11.5 cm when the distal opening 20 is open.
- the first leading portion 38 and working length WL both contribute to reducing the required length of the first filament 6 that must be drawn distally as part the working length WL to release the container element 4 .
- the required length of the first filament 6 to be drawn distally may be further reduced by coupling the first filament 6 to the constraining catheter 8 so that the first filament 6 moves proximally with the constraining catheter 8 relative to the container element 4 when releasing the container element 4 and when closing the distal opening 20 .
- Coupling the first filament 6 (specifically the first and second arms 28 , 30 ) to the constraining catheter 8 in this manner further reduces the required length of the first filament 6 that must be manipulated since the first filament 6 needn't extend completely out of the patient like many conventional devices.
- the first filament 6 may also be independent of the constraining catheter 8 and extend out of the patient without departing from numerous aspects of the present invention.
- the container element 4 is moved to a released position outside the chamber 22 by moving the container element 4 , the constraining catheter 8 or both.
- the first filament 6 may move to the released position while the distal opening 20 simultaneously moves to the open position as the container element 4 is moved/positioned outside of the chamber 22 .
- Simultaneous release of the sidewall 26 and opening of the distal opening 20 may be accomplished by coupling the first filament 6 (specifically the proximal end of the first and second arms 28 , 30 ) to the constraining catheter 8 as described above.
- the distal opening 20 may be separately opened using the first filament 6 or some other structure after the container element 4 has been released without departing from numerous aspects of the invention.
- the open position may be achieved in any suitable manner in accordance with the present invention although aspects of the present invention provide for the first filament 6 to support the open position as now described.
- the first filament 6 may be positioned and coupled to the container element 4 so that the natural unbiased shape (such as the shape of the concave portion 34 ) supports the open position of the distal opening 20 .
- the first filament 6 may have a predetermined shape 46 which defines a filament perimeter 48 which supports the open position of the container element 4 .
- the predetermined shape 46 may extend around at least 120 degrees, at least 150 degrees or at least 260 degrees, around the distal opening 20 in the open position when viewed along the longitudinal axis LA. Stated another way, the first filament 6 may form the first concave portion 34 (oriented facing the longitudinal axis LA) which supports and moves the distal opening 20 to the open position when the container element 4 is released.
- the concave portion 34 has a shape larger than an unbiased shape of the distal opening 20 so that the concave portion 34 biases the distal opening 20 toward the open position.
- the concave portion 34 may be restrained by the open position of container element 4 so that the concave portion 34 biases the distal opening 20 toward the open position.
- the first leading portion 38 may form the predetermined shape such as the concave portion 34 .
- the first concave portion 34 may generally lie in a plane P which forms an angle A with the first arm 28 of 45-135 degrees in an unbiased position as shown in FIG. 9 A . When the container element 4 is closed, the plane P forms the angle A with the first arm 28 of 135-180 degrees.
- the first concave portion 34 may also form a closed loop 50 which moves the distal opening 20 toward the open position when the container element 4 is in the released position as shown in FIG. 9 A .
- the first leading portion 38 may move into the container element 4 and form the concave portion 34 or, alternatively, move into the container element 4 and engage an inner surface 52 of the container element 4 .
- the first filament 6 may apply an outward force to the inner surface 52 of the sidewall 26 over a longitudinal length of at least 2 cm of the container element 4 in the released position which may help anchor the device 2 when the material is moved into the container element 4 through the distal opening 20 .
- the first filament 6 may also apply the outward force to the inner surface 52 over an angular extent of at least 180 degrees when viewed along the longitudinal axis LA.
- the first filament 6 (such as the first and second arms 28 , 30 ) may also be substantially straight and may not apply an outward force to the sidewall 26 without departing from numerous aspects of the invention.
- a clot engaging element 58 (which may engage in any suitable manner such as mechanical or suction engagement) is used to engage and, if necessary, dislodge the material to be removed.
- the material is then passed through the distal opening 20 and into the container element 4 by manipulating the clot engaging element 58 , the container element 4 , the first filament 6 or any combination thereof.
- the container element 4 is closed by tensioning the first filament 6 (such as the first arm 28 and second arm 30 ).
- the distal opening 20 may reduce in size from the open position so that the effective diameter ED is reduced by at least 80%. Stated another way, the effective diameter ED in the closed position may be no more than 1 mm.
- the concave portion 34 may also be deformed when the first filament 6 is tensioned to close the distal opening 20 .
- the first filament 6 (such as the concave portion 34 ) may be formed of a superelastic material which is elastically deformed when the distal opening 20 is closed.
- the concave portion 34 may also be plastically deformed or may be a simple tension element without departing from aspects of the invention.
- the sidewall 26 of the container element 4 may also include an expandable portion 60 which may expand into engagement with the vessel 80 when the distal opening 20 is closed.
- the expandable portion 60 may be at least 10 mm long and within 10 mm from the distal end 16 of the container element 4 .
- the expandable portion 60 may exert a radially outward force on the vessel wall when the container element 4 is closed by tensioning the first filament 6 .
- the expandable portion 60 may be expanded beyond an unbiased shape by the first filament 6 , for example, an effective diameter ED of the sidewall 26 along the expandable portion 60 may increase by at least 10% compared to an unbiased condition. Stated another way, when the container element 4 is moved to the closed position the first filament 6 causes an outward force on the expandable portion 60 which increases a radially outward force on the vessel wall by at least 10%.
- the sidewall 26 of the container element 4 may also have a distal portion DP which reduces in length when the container element 4 is closed.
- the distal portion DP may extend 10 mm from the distal end 16 and reduces in length longitudinally by at least 20% when the container element 4 moves to the closed position.
- the distal portion DP may also expand in accordance with the expandable portion 60 and be fully or partially coextensive with the expandable portion 60 .
- the first filament 6 may also move proximally when the distal opening 20 is closed and may also move the distal opening 20 proximally as shown in FIGS. 9 A- 9 F .
- the first filament 6 may be coupled to the constraining catheter 8 so that the first filament 6 is manipulated by the constraining catheter 8 and moves proximally with the constraining catheter 8 relative to the container element 4 when the container element 4 is released and when it is closed. In this manner, the first filament 6 is manipulated by the constraining catheter 8 which provides the advantages described herein such as a reduced length of the first filament 6 and possibly reduced forces on the vessel 80 when tensioning the first filament 6 .
- the sidewall 26 When the distal opening 20 is closed, the sidewall 26 may form an inverted IP portion which also moves the distal opening 20 to a position surrounded by the sidewall 26 (when viewed along the longitudinal axis LA). The sidewall 26 may also apply a radially inward force on the inverted portion IP (which is transmitted through the sidewall 26 ) to bias the distal opening 20 toward the closed position. The distal opening 20 may also invert when moving to the closed position or may remain uninverted with a small portion of the distal end of the sidewall 26 .
- the device 2 may also include a second filament 6 A coupled to the container element 4 as shown in FIG. 2 K wherein the same or similar reference numbers refer to the same or similar features as the first filament and all relevant features are incorporated here as previously mentioned.
- the second filament 6 A may have a second leading portion 42 which distally extends beyond the distal end 16 of the container element 4 in the collapsed position.
- the second leading portion 42 extends at least 1.5 mm from the distal end 16 of the container element 4 .
- the second leading portion 38 A has a length which extends from the distal end 16 of the container element 4 which is at least 30%, and may be at least 50%, of an effective diameter of the perimeter of the distal opening 20 in the open position.
- the second filament 6 A may be coupled to the first filament 6 and may even be being integrally formed with the first filament 6 .
- the second filament 6 A may form a second concave portion 34 A when the container element 4 is in the open position.
- the second concave portion 34 A also moves the distal opening 20 toward the open position.
- the first concave portion 34 and the second concave portion 34 A may each extend 90-180 degrees when the container element 4 is in the open position and viewed along the longitudinal axis LA.
- the container element 4 may be of any number of constructions.
- the container element 4 may be a radially expandable element, such as a braid, laser cut stent, woven structure, or the like.
- the container element 4 may be a non-compliant flexible bag or fabric such as a PET or PTFE materials.
- the container material may be a compliant material such as a polyurethane, silicone, or the like that may stretch and expand as materials are pulled into it.
- the container material may be a combination of multiple constructions.
- the container element 4 may have a bag construction in certain areas and a braid construction in other areas.
- the container element 4 is a frame with an attached membrane or fabric.
- the frame may be comprised of a nitinol or stainless steel or plastic component that expands radially once delivered out of the constraining catheter 8 .
- the frame may be a nitinol tube that is laser cut and shape set to expand when not constrained.
- a fabric such as a PTFE graft material or any other membrane material, may be connected to the frame to either provide local flow arrest and contain the clot once it is within the container element 4 or both.
- the container element 4 may be combination of a braid and a frame element. For example, a small wire braid may extend over a frame structure, possibly on both the inner and outer surfaces of the frame structure.
- the container element 4 is a braided wire construction.
- the braid wires may be nitinol, stainless steel, cobalt chromium, plastic, such as PET, or any other suitable material.
- the braid wire may contain radiopaque elements that allow it to be visualized under fluoroscopy such as a nitinol wire with a platinum core.
- the container element 4 may have connected markers that enable visualization.
- the number of wires in the braid may be between 12 to 128 wires or between 32-64 wires.
- the braid angle may be between 100-200 degrees or between 120-160 degrees.
- the braid wires may be between 0.0001′′-0.0050′′ in diameter or between 0.0005′′-0.0020′′.
- the braid wires may be non-circular and may be oval, flat, or rectangular ribbons.
- the braided geometry may allow the container element 4 to act like a Chinese finger trap where it decreases in diameter when it is elongated and increases in diameter when it is compressed. This may provide advantages such as allowing the device 2 to reduce in size when it is pulled out of the body and also secure itself against the vessel 80 when compressive loads are placed on portions of it such as through the filaments.
- the container element 4 has a predetermined shape 46 which is the unrestricted and unbiased shape that it naturally takes when no other components are restricting its movement at a given temperature.
- the predetermined shape 46 may be different shapes at different temperatures and as used herein shall be defined at normal body temperature.
- the container element 4 may be a braided construction comprised of Nitinol wire.
- the Nitinol braid may be given a predetermined shape 46 through a shape setting heat treatment where the container element 4 has a defined unrestricted shape.
- the container element 4 is configured such that in an unrestricted shape it may expand to close the vessel size.
- the container element 4 may be configured to expand to a diameter between 4 mm and 10 mm. Assuming an MCA has an average inner diameter of 4 mm, the container element 4 expands until it touches the intimal wall of the vessel 80 . If the container element 4 is designed such that it expands to a diameter of 6 mm in air then it may provide a small to moderate amount of radial pressure on the wall of the vessel. By changing the unconstrained diameter of the container element 4 , the amount of radial force exerted on the vessel may be modulated. Additionally, the radial expansion force may be adjusted by altering the characteristics of the container element 4 .
- MCA middle cerebral artery
- the container element 4 is a braided construction
- the following parameters may be changed to increase or decrease the desire radial force on the vessel: braid angle, number of braided ends, braid material, braid wire diameter, braid wire cross sectional profile, braid coating, etc.
- the desired radial force may be different for different vessels and different anatomical locations.
- the container element 4 has varying diameters or cross-sectional profiles along its length.
- the unconstrained diameter may be 8 mm in one or more locations and may be 4 mm in one or more locations.
- the cross sectional profile of the container element 4 may not be generally circular as is shown.
- the cross-sectional profile may be ovular, triangular, rectangular, or any other profile and may vary along the axial length of the container element 4 .
- the profile may be general elliptical with the semi-major axis in intimal contact with the vessel 80 and the semi-minor axis not in contact with the vessel 80 .
- the cross-sectional profile may be circular with the entire circumference not in contact with the vessel wall. Any number of different shapes and configurations may be contemplated.
- the container element 4 may not be a fully tubular structure meaning that container element 4 may represent a rolled-up surface that may or may not connect to itself.
- the container element 4 may be comprised of a laser cut pattern on a flat sheet of material that is then rolled to form a substantially circular shape but in which the two rolled edges may or may not connect to each other.
- the container element 4 has a distal opening 20 toward its distal end that allows for the passing of materials into the container element 4 from the distal direction.
- the distal opening 20 may be configured such that in an unrestricted shape it is the same diameter as the sidewall 26 of the container element 4 .
- the distal opening 20 defines a distal opening perimeter 64 along the rim of the distal opening 20 .
- the distal opening 20 may be larger or smaller than the sidewall 26 of the container element 4 when it is unrestricted such that the distal end 16 of the container element 4 tapers outward or inward.
- the distal opening 20 may have a cross-sectional area which is roughly the same as the cross-sectional area of the vessel 80 it is within. For example, in a 5 mm vessel 80 the cross-sectional area of the container element 4 may be between 10-30 mm2 or between 18-22 mm2 in a deployed configuration.
- the size of the distal opening 20 of the container element 4 may defined partially by the shape and size of the filament perimeter 48 48 as well.
- the filament perimeter 48 may be such that it imparts an inward or an outward radial force on the distal opening 20 of the container element 4 .
- the filament 6 may impart an inward radial force in some locations and an outward radial force in other locations.
- the container element 4 is a flexible bag material and the filament perimeter 48 fully defines the distal opening 20 size and shape.
- the container element 4 When fully deployed the container element 4 may have a length of 1 cm-30 cm depending on the application. In a MCA application, the container element 4 may be between 4 cm-16 cm or 5 cm-10 cm. Standard stent retrievers are 3 cm-5 cm in length. Therefore, if the clot engagement element is a similar length, in order to fully capture and contain the clot engagement element, the length of the container element 4 may be on the order of 7 cm. However, as will be shown, the clot engagement element does not necessarily need to be fully captured by the container element 4 . In any event, assuming a length of 7 cm of the container element 4 when unconstrained, the container element 4 may have a length of 14 cm when it is within the constraining element. This is commonly called foreshortening where the length of the container element 4 increases as it is radially constrained.
- the container element 4 may have features which provide partial or full local flow arrest within the vessel such as a coating 108 .
- the coating 108 may be a dipped or spayed coating 108 such as silicone.
- the silicone may be between 0.0001′′-0.0050′′ thick or between 0.0005′′-0.0010′′ thick.
- the silicone can provide a local flow arrest within the vessel 80 by covering portions of the braid so that blood flow is limited. Additionally, a coating 108 may provide further advantages of keeping the clot material that is captured by the device 2 better contained.
- the container element 4 may be covered along its entire length such that when it is deployed within the vessel 80 blood flow stops within the vessel 80 as blood cannot pass through the container element 4 which is in intimal contact with the vessel 80 .
- the coating 108 may cover only a portion of the container element 4 such as the proximal funnel such that the full or partial cross section of the vessel is blocking blood flow. In other embodiments the coating 108 may be over the entire container element 4 .
- the braid windows or space between the braid wires may be so small that they provide local flow arrest or reduced flow. For example, if the braid windows are small enough it may provide local flow arrest without needing to be covered. In some embodiments it may be desirable to allow certain components of blood to pass through the braid such that the braid acts as a filter to substantially reduce blood flow but not fully arrest it.
- the container element 4 may include more than one coating 108 .
- the container element 4 may have a hydrophilic coating 108 such as PTFE or other coating material to reduce friction of the container element 4 as it slides within the constraining catheter 8 .
- the coatings 108 may be applied to the outer surfaces of the container element 4 to facilitate deployment of the container element 4 or may be applied to the inner surface 52 to facilitate movement of other components such as microcatheter 74 through the lumen of the container element 4 .
- the coating 108 may a drug coating to deliver an active pharmaceutical ingredient (API) to the vessel or local anatomy. This may include drugs such as tissue plasminogen activator (tPa). These may be separate or in addition to a coating 108 that provides flow arrest such as a silicone coating.
- the container element 4 may have a silicone coating 108 which provides flow arrest and additionally have a hydrophilic coating to provide lubricity.
- Local flow arrest may advantageously encourage retrograde collateral flow from the vessel such that the clot 78 is at a reduced risk of distal embolization since the flow may be reversed.
- it may allow for injection of contrast through a portion of the device 2 such as through the container element 4 or through the constraining catheter 8 which may facilitate identification of the thrombus within the vessel since there is no flow to carry the contrast away.
- the device 2 may be used to inject therapeutic agents such as tissue plasminogen activator (tPa).
- the proximal end 18 of the container element 4 may reduce down to a small diameter portion 12 .
- the small diameter portion 12 is defined by a predetermined shape of the container element 4 .
- the shape set configuration of the container element 4 may include the small diameter portion 12 at its proximal end 18 .
- the small diameter portion 12 may not necessarily be defined by a predetermined shape 46 but instead defined by the constraint of the constraining catheter 8 .
- the small diameter portion 12 may be sized to fit within the inner lumen 24 of the constraining catheter 8 .
- the inner diameter of the small diameter portion 12 may also be sized to allow for the passage of catheters and wires within it.
- Microcatheters 74 which are used to deploy stent retrievers may be on the order of 0.010′′-0.040′′ outer diameter.
- Aspiration catheters which are used to grab clots through aspiration may be on the order of 0.020′′-0.070′′ outer diameter. Therefore, the inner diameter of the small diameter portion 12 may be on the order of 0.010′′-0.080′′ or may be on the order of 0.025′′-0.060′′. This may allow other components to pass through the lumen of the container element 4 before and after the container element 4 is deployed.
- the proximal end 18 of the container element 4 may continue through the constraining catheter 8 and out of the patient where it can be manipulated to change its relative position to the constraining catheter 8 and filaments.
- the proximal end of the container element 4 may transition to a catheter or other suitable structure which is capable of moving the container element 4 forward and backward axially or rotationally.
- the catheter portion of the container element 4 may extend from out of the patient and may be manipulated either by the user, a delivery mechanism, or robotically.
- the proximal end 18 of the container element 4 may be connected to a vacuum source such that aspiration may be achieved through the lumen of the container element 4 . As will be shown in subsequent description, the aspiration may be used to draw clots into the container element 4 and otherwise prevent distal blood flow.
- the constraining catheter 8 may be comprised of any number of materials and constructions which exist in the field of catheters.
- the constraining catheter 8 may be a stainless steel braid reinforced catheter with a PTFE inner liner and a Pebax outer jacket. Any number of other suitable constructions and materials may exist.
- the construction and materials of the constraining catheter 8 may vary along its length to achieve the desired stiffness and force transmission.
- the constraining catheter 8 may be ideally delivered through an intermediate catheter 72 which has been placed in the cerebral artery.
- the inner diameter of intermediate catheters 72 used in thrombectomy procedures is typically on the order of 0.04′′-0.08′′.
- the outer diameter of the constraining catheter 8 may be on the order of 0.04′′-0.08′′ or 0.05′′-0.06′′.
- the inner diameter of the constraining catheter 8 may be sized to allow the passage of catheters and wires within it which are delivered distally including the container element 4 . Therefore, the inner diameter of the constraining catheter 8 may be on the order of 0.010′′-0.080′′ or may be on the order of 0.025′′-0.060′′.
- the constraining catheter 8 may have a flared or constricted distal end 16 which facilitates the movement of the container element 4 into and out of the constraining catheter 8 .
- the diameter of the distal end 16 of the constraining catheter 8 may be flared by 0.001′′-0.020′′ such that container element 4 is easily retracted into the constraining catheter 8 by the tapered section.
- the constraining catheter 8 may extend out of the patient and can be manipulated by the user relative to the other components to guide the device 2 through the motions described in detail herein.
- the constraining catheter 8 may be the same as the intermediate catheter 72 such that there is only one catheter.
- the constraining catheter 8 may be connected to a portion of the filament 6 or filaments such that a proximal movement of the constraining catheter 8 relative to the container element 4 not only deploys the container element 4 but may also cause the distal opening 20 of the container element 4 to close by way of placing tension on the filament 6 as the constraining catheter 8 retracts. This will be described in greater detail below.
- the filament 6 has the first arm 28 and the second arm 30 extending through the inner lumen of the container element 4 and connected at the filament perimeter 48 toward the distal end 16 of the container element 4 .
- the filament 6 may extend through the assembly and out of the patient such that it can be manipulated by the user, a deployment mechanism, or robotically.
- the filament 6 may connect to a different component within the device 2 such as the constraining catheter 8 such that the motion of the constraining catheter 8 relative to the container element 4 may apply or remove tension from the filament 6 .
- the filament 6 may be a monofilament 6 wire or may be any number of other constructions.
- the filament 6 may be small coil made of any of the materials listed herein.
- the filament 6 may be a suture material such as a polypropylene or polyester.
- the material and construction of the filament 6 may vary along the length of the filament 6 and need not necessarily be the same along its entire length.
- the material is a round wire, whereas in other embodiments the snare may be a coil or a filament 6 of any number of cross-sections such as rectangular, ovular, sheet, or the like.
- the cross-sectional shape and area of the snare filament 6 may vary along the length of the snare.
- the filament 6 is constructed of multiple materials. For instance, a portion of the filament 6 may be flexible like a suture while other portions are elastic like Nitinol.
- the filament 6 is a piece of Nitinol wire that is 0.0005′′-0.0100′′ or 0.001′′-0.004′′ in diameter.
- the filament 6 may be stainless steel, tungsten, cobalt chromium, plastic, or any other suitable material.
- the filament 6 may be shape set to have a predetermined shape such as a circle at the filament perimeter 48 .
- FIG. 2 A- 2 H various predetermined shapes 46 of the filament 6 are shown. This is not intended to be an exhaustive list of any possible shape but merely to show the variety of shapes which one could configure the filament 6 to.
- a filament 6 with a round filament perimeter 48 is shown.
- the filament perimeter 48 may be generally circular or ovular.
- the filament perimeter 48 transitions to a first arm 28 and a second arm 28 through a filament 6 bend.
- the first arm 28 and a second arm 28 extend roughly perpendicularly from a plane defined by the filament perimeter 48 .
- the filament perimeter 48 may be at about the location of the distal opening 20 on the container element 4 and therefore the filament perimeter 48 may define a profile that is roughly the same as the inner surface of the vessel 80 .
- the filament perimeter 48 is about 330-360 degrees in circumference such that the first arm 28 and second arm 30 are in close proximity.
- the filament perimeter 48 defines an arc that has an included circumference which is less and may be on the order of 200-330 degrees such that there is a gap between the filament bends 54 for the first arm 28 and the second arm 30 .
- the filament perimeter 48 defines an arc that has an included circumference which is on the order of 360-540 degrees such that there is an overlap of the filament perimeter 48 .
- the filament perimeter 48 defines a plane that is not substantially perpendicular to the longitudinal axis of the vessel 80 .
- Filament perimeter 48 is an oval that defines a plane which is askew to the central axis of the vessel 80 .
- the filament bends 54 are at a proximal portion of the filament perimeter 48 and in FIG. 2 E the filament bends 54 are at a distal portion of the filament perimeter 48 .
- the filament perimeter 48 has a nipple 102 feature on its profile.
- the nipple 102 feature may facilitate the closing of the distal opening 20 when the filament 6 is in tension by providing a specific location where the filament 6 can bend to a tight radius which may allow the distal opening 20 to close tightly.
- the filament perimeter 48 has an undulating profile 104 that can facilitate the weaving into and out of the container element 4 looped ends 106 .
- the filament perimeter 48 defines an arc that has an included circumference of 70-200 degrees such that the filament perimeter 48 only circumscribes a portion of the distal opening 20 .
- the first arm 28 and second arm 30 are joined at a filament junction 100 which is close to the filament perimeter 48 .
- FIG. 1 the first arm 28 and second arm 30 are joined at a filament junction 100 which is close to the filament perimeter 48 .
- filaments 6 are joined at a filament junction 100 which is proximally further away from the filament perimeter 48 .
- FIG. 2 K there are two separate filament 6 elements which have individual filament perimeters 48 .
- Each of the two filaments has a first arm 28 and a second arm 30 .
- This embodiment may have less off axis loading of the container element 4 when the filaments 6 are placed in tension such that the distal opening 20 may remain generally concentric as it closes. Any number of other filament 6 configurations and shapes may be contemplated.
- the filament 6 may only have a first arm 28 and the filament perimeter 48 may terminate part way through the circumference.
- the end of the filament perimeter 48 may be connected to a part of the container element 4 .
- the distal end of each filament 6 may form a hook that is looped around the distal edge of the container element 4 such that there are a series of pull wires which can be activated independently or in conjunction with one another to place the distal end 16 of the container element 4 in tension.
- the filament 6 may have a predetermined shape 46 that is generally straight wire and which is constrained to one of the shapes shown in FIG. 2 A- 2 K by the shape of the distal end 16 of the container element 4 .
- the filament 6 may be threaded through the container element 4 and therefore held in a shape that resembles one of the shapes shown in FIGS. 2 A- 2 K by nature of being connected to the container element 4 .
- the container element 4 may be connected to the filament 6 in any number of ways.
- the distal end 16 of the container element 4 may be wrapped around the filament 6 and adhered to itself through the use of heat sealing or adhesives or any other suitable method.
- the filament 6 may weave through portions of the container element.
- the container element 4 may include a laser cut stent structure.
- the stent may include features such as holes at the distal end which are configured for the filament 6 to weave through.
- the container element 4 is a braided structure and the filament 6 may weave through the braid or looped ends 106 near or at the distal end 16 of the container element 4 .
- the distal opening perimeter 62 and the filament perimeter 48 may be generally the same in some configurations such as when the device 2 is deployed and in an open configuration. In other configurations such as the constrained or closed configuration, the distal opening perimeter 62 and filament perimeter 48 are different shapes and lengths.
- FIG. 3 a detailed view of the distal end 16 of an embodiment of the container element 4 is shown.
- the container element 4 is constructed of braided wires.
- the wires may double back on themselves as shown by terminating at one end of the container element 4 with looped ends 106 .
- the braided wires may form looped ends 106 by being wrapped around posts during manufacturing and then braiding the wires back over the already created braid. In this way, the looped ends 106 provide an atraumatic end within the vessel and also provide a location where the filament 6 can be woven through.
- the filament perimeter 48 may be woven through these braided looped ends 106 so that as the filament 6 is tensioned, it constricts the distal opening 20 of the container element 4 like a purse string or draw string.
- the filament 6 may weave through back and forth through each of the looped ends 106 or may weave through every other looped end 106 or any weave pattern. For example, the filament 6 may weave through only 4 locations of the braided looped ends 106 at 90 degrees apart from each other. The weave characteristics may dictate the friction necessary to open the distal opening 20 of the container element 4 once it is deployed.
- the filament perimeter 48 can wrap around 360 degrees at the distal end.
- the filament 6 can cross over itself and wrap around between 360 and 720 degrees.
- the filament 6 may only wrap around 90 to 360 degrees so that only a portion of the distal end 16 of the container element 4 has the filament 6 wrapping around.
- the filament 6 is only attached to a small section of the container element 4 such as a one or two looped ends 106 .
- the filament 6 may also only have a single wire returning proximally from the distal end 16 .
- the filament 6 may form a loop at the distal end 106 but may connect back to itself such that two filaments 6 are not required to constrict the distal end 16 .
- Any number of filaments 6 may be used and connected to the container element 4 and may be actuated independently or in conjunction.
- the first arm 28 and the second arm 30 may weave through sections of the container element 4 along the axial length of the container element 4 . This may keep the arms 28 , 30 constrained to the sidewall 26 of the container element 4 such that they do not get in the way of other components which are moving within the container element 4 . Additionally, keeping the filament 6 constrained to the sidewall 26 of the container element 4 may facilitate the closure of the distal opening 20 by directing the force applied to the distal opening 20 in a radial direction rather than a proximal direction. In other embodiments, the first arm 28 and the second arm 30 do not weave through the side wall 26 of the container element 4 and are left free. In this embodiment, they may be configured through a predetermined shape 46 to remain biased against the sidewall 26 or may be configured to take any number of other shapes.
- the container element 4 and filament 6 are configured such that when they are deployed the container element 4 is unrestricted and the filament 6 is not under a significant amount of proximal tension.
- the distal opening 20 of the container element 4 is open and positioned to receive clot 78 material from the distal direction.
- the distal opening perimeter and filament perimeter 48 may be generally the same shape and length in this position.
- tension is then applied to the filament 6
- the filament perimeter 48 and distal opening 20 may begin to move proximally.
- the distal opening 20 is configured to constrict and close as additional tension is applied to the filament 6 . In this manner, the closure of the distal opening 20 is actuated by the tension applied to the filament 6 .
- the distal opening perimeter P may reduce in length as the looped ends of the braid get closer together while the filament perimeter 48 is the same fixed length. However, the amount of the filament perimeter 48 that the distal opening perimeter 62 occupies is less. For example, in the deployed configuration the distal opening perimeter 62 may overlap with about 60% to 100% or 80% to 100% of the filament perimeter 48 . In the closed configuration, the distal opening perimeter 62 may overlap with about 1% to 30% or 5% to 15% of the filament perimeter 48 . The filament perimeter 48 has remained the same fixed length but its shape has changed and only a portion of it has the distal opening perimeter 62 overlapping.
- the opening of the distal opening 20 may be actuated by the removal of tension from the filament 6 .
- the filament 6 may return to its predetermined shape 46 and likewise the container element 4 may return to its unrestricted predetermined shape.
- the distal opening 20 may return to an open position.
- the distal opening 20 once the distal opening 20 is closed by means of applying tension to the filament 6 , the distal opening 20 will not open upon release of the tension to the filament 6 . In this manner the device 2 locks into a generally closed distal opening 20 once tension is applied and even the removal of the tension does not allow the distal opening 20 to open.
- the filament perimeter 48 may be located substantially away from the distal end 16 of the container element 4 .
- the filament 6 may be woven through any section of the container element 4 along its axial length.
- the filament perimeter 48 may not necessarily be woven through any feature on the container element 4 .
- the filament perimeter 48 may exist primarily on the outer surface of the container element 4 and may simply pinch the outside of the braid at a given location along the axial length of the container element 4 instead of constricting it like a purse string.
- the first arm 28 and second arm 28 may still enter the inner lumen of the container element 4 by threading through a portion of the container element 4 .
- the distal opening 20 and distal opening perimeter 62 may be defined by the location of the filament perimeter 48 or may be defined by the distal end 16 of the device 2 .
- filament 6 is generally described herein as a snare type mechanism that cinches the distal opening 20 of the container element 4
- the container element 4 may contain one or more flaps 88 at its distal end that are connected to one or more filaments.
- the one or more flaps 88 may be folded inward by tensioning the filaments so that the flaps collapse and restrict the distal opening 20 .
- twisting mechanisms may be used to constrict the distal opening 20 of the container element 4 .
- the distal end 16 of the container element 4 may be held generally stationary while the body of the container element 4 is twisted clockwise. In this manner the distal end 16 of the container element 4 may constrict and close the distal opening 20 .
- Any number of other closure mechanisms may be contemplated.
- FIG. 4 A- 4 P a first embodiment of the device 2 is shown.
- an intermediate catheter 72 is shown within a vessel which contains a clot.
- the intermediate catheter 72 may be any standard size such as between 0.010′′ to 0.500′′ OD or between 0.050′′ and 0.110′′ outer diameter depending on the anatomical location it will be used. It may be comprised of any typical materials used for such catheters, such as Pebax, polyimide, PEEK, multi-layer braided composite, or any other suitable material or composition.
- the vessel shown may be a cerebral artery such as the middle cerebral artery (MCA) or any other vessel within the body of a human or animal.
- MCA middle cerebral artery
- the size of the intermediate catheter 72 may depend on the size of the vessel 80 and the expanded size of the container element 4 as will be shown. Larger vessels 80 often will require larger catheter sizes while smaller vessels 80 often will require smaller catheter sizes.
- the intermediate catheter 72 is placed proximal of the clot 78 and in a position to deploy other parts of the invented device 2 .
- a microcatheter 74 has traversed the clot 78 .
- the microcatheter 74 may be any suitable size such as 0.010′′ to 0.080′′.
- a guidewire or other such element Prior to traversing the clot 78 with the microcatheter 74 , a guidewire or other such element may be included and used to guide the microcatheter 74 across the clot. In some embodiments a guidewire may be required while in other embodiments a guidewire is not necessary. If a guidewire is used, it will often be withdrawn once the microcatheter 74 traverses the clot and the clot engagement element may then be inserted into the microcatheter 74 while it is traversing the clot. This places the clot engagement element 58 across the clot 78 so that it is in an optimal location when the microcatheter 74 is withdrawn.
- the microcatheter 74 is withdrawn and a clot engagement element 58 is left behind and engages with the clot.
- the clot engagement element 58 may be a stent retriever type design as shown but it may also be any other element suitable for pulling a clot proximally.
- the clot engagement element 58 has a series of struts or interwoven elements that expand radially outward when it is not constrained which allow it to engage with the clot 78 and pull it proximally when the clot engagement element 58 is retracted.
- the clot engagement element 58 is a balloon that is inflated distally to the clot 78 such that as it retracts, it pulls the clot 78 proximally with it.
- the clot engagement element 58 is a Nitinol wire with a convoluted shape such that when it is deployed it likewise engages with the clot 78 and secures itself in different areas of the clot. Any number of other clot engagement elements 58 may be contemplated.
- the intermediate catheter 72 is withdrawn, exposing a constraining catheter 8 which constrains the container element 4 .
- the intermediate catheter 72 can constrain the container element 4 such that when it is retracted, as will be shown with the constraining catheter 8 , the container element 4 is deployed.
- the constraining catheter 8 with the container element 4 is within the intermediate catheter 72 during the navigation and delivery of the microcatheter 74 while in other embodiments it is advanced into position within the intermediate catheter 72 at some point between navigation and after the clot engagement element 58 has been deployed.
- FIGS. 4 E- 4 H show a container element 4 being deployed within the vessel.
- the constraining catheter 8 begins to be retracted and the distal end 16 of the container element 4 is deployed.
- the initial deployment steps of the filament perimeter 48 and distal end 16 of the container element 4 will be shown in greater detail in FIGS. 7 A- 7 G .
- the container element 4 has a relatively consistent unconstrained diameter of 3 mm-6 mm and is sized such that when deployed within an MCA, it is uniformly in contact with the vessel wall.
- the container element 4 is partially deployed and a filament perimeter 48 exists at the distal end 16 of the container element 4 .
- the plane formed by the filament perimeter 48 is generally perpendicular to the longitudinal axis of the vessel 80 .
- the container element 4 is more deployed out of the constraining catheter 8 .
- the container element 4 may be actively expanded with the use of balloons, shape memory materials such as nitinol that transition at a given applied temperature, or any other means.
- the constraining catheter 8 may be fully retracted before the container element 4 is actively expanded in the vessel.
- the filament perimeter 48 comes out of the constraining catheter 8 and automatically expands to the vessel 80 with the container element 4 open. In some embodiments the filament perimeter 48 may come out of the constraining catheter 8 in a fully or partially closed configuration and then may be opened once in place.
- the container element 4 is more deployed as the constraining catheter 8 is further retracted.
- the constraining catheter 8 is retracted to deploy the container element 4 .
- the container element 4 may be advanced out of the constraining catheter 8 .
- the axial length of the container element 4 is significantly longer when it is within the constraining catheter 8 . Therefore, as the container element 4 is deployed by retracting the constraining catheter 8 , the proximal end of the container element 4 must be advanced if the distal end of the distal end 16 of the container element 4 is to stay in a fixed location.
- the container element 4 may be in contact with the vessel 80 when it is deployed it may be advantageous to keep any areas which are contacting the vessel 80 stationary so as not to injure the vessel 80 . Therefore, a retraction of the constraining catheter 8 may be accompanied by an advancing of the proximal end 18 of the container element 4 .
- FIG. 4 H the container element 4 is shown in a fully deployed state.
- the constraining catheter 8 has been retracted far enough that a proximal funnel area 14 of the container element 4 is exposed.
- the proximal funnel area 14 may be a predetermined shape that the container element 4 has at the proximal end 18 of its vessel diameter portion 10 .
- the proximal funnel area 14 tapers the vessel diameter portion 10 to the smaller diameter portion 12 that fits within the constraining catheter 8 . It should be noted that a proximal funnel area 14 may not be required since the container element 4 may naturally come out of the constraining catheter 8 in a funnel shape as it is being deployed. As will be discussed the proximal funnel area 14 may provide local flow arrest in the vessel 80 .
- the user may select the length of the container element 4 to deploy. For example, in the case of capturing small clots only 1 ⁇ 4-1 ⁇ 2 of the vessel diameter portion 10 of the container element 4 may be deployed. Other times in the case of longer clots 78 , the full length of the vessel diameter portion 10 may be deployed. The amount of container element 4 may be selectable by the user.
- the microcatheter 74 may remain within the device 2 or it may be removed from the patient at any point during the procedure.
- the microcatheter 74 is a mono-rail catheter that allows it to be removed while keeping the clot engagement element in place.
- the microcatheter 74 remains in place and may be used in subsequent steps to sheath the clot engagement element 58 once the clot is captured within the container element 4 .
- the clot engagement element 58 with the clot 78 is withdrawn toward the distal opening 20 of the container element 4 .
- the distal end 16 of the container element 4 may be flared outward, either by its predetermined shape or by a radial force from the filament perimeter 48 , so that the clot engagement element 58 enters smoothly and does not get stuck on any part of the container element 4 as it enters.
- the distal end 16 of the container element 4 may be constricted partially.
- the clot engagement element 58 has been withdrawn so that it is entirely within the container element 4 .
- Some embodiments of the clot engagement element 58 may leave components outside of the container element 4 .
- One critical aspect is that most or all of the clot 78 that will be withdrawn from the patient is within the container element 4 even though pieces of the clot engagement element 58 may remain outside of the container element 4 .
- the clot engagement element 58 may be a balloon that pulls the clot 78 into the container element 4 but itself does not go fully within the container element 4 .
- portions of the clot engagement element 58 , guidewire, microcatheter 74 , or any other structure may remain distal to the distal opening 20 .
- distal opening 20 when the distal opening 20 is fully or mostly closed, devices may be navigated beyond the distal end of the distal opening.
- the distal opening 20 after retracting a clot engagement element 58 with a clot 78 into the container element 4 , the distal opening 20 may be disclosed as described herein but with a portion of the clot engagement element 58 remaining distal.
- the user may then use a microcatheter 74 to constrict the clot engagement element 58 again and advance the microcatheter beyond the distal opening 20 .
- a clot engagement element 58 may be used again to engage with additional pieces of clot 78 which were not retracted the first time.
- Such an embodiment can be used when the clot engagement element 58 is a stent retriever or an aspiration catheter 76 .
- the distal opening 20 can be opened by releasing tension on the filament 6 and the additional clot 78 material can be retracted within the containing element 4 . This process may be repeated as many times as necessary and may be useful in removing significant amounts of clot 78 or in instances where only fragments of the clot 78 can be engaged.
- FIGS. 5 A- 5 E the distal end 16 of the container element 4 and filament perimeter 48 are shown in greater detail during the closure of the distal opening 20 .
- FIG. 5 E the container element 4 is shown with the distal opening 20 in the open configuration where the clot engagement element 58 can be withdrawing into the container element 4 .
- the distal opening 20 of the container element 4 begins to close.
- a proximal tension is applied to the first arm 28 or second arm 30 or both.
- the tension can be equal across the arms 28 , 30 or can be different. In some embodiments only the first arm 28 is tensioned while in other embodiments both arms are tensioned.
- the tension in the filament 6 imparts a proximally directed force on the distal end 16 of the container element 4 . This may be translated into a compressive load on the container element 4 .
- the filament perimeter 48 begins to move proximally and change shapes.
- the braided structure may be designed to increase in diameter when it is constricted and decrease in diameter when it is lengthened.
- the container element 4 may expand radially. At some point the radially expansion may be constrained by the vessel 80 and the container element 4 may then impart a radially outward force on the vessel 80 .
- the container element 4 may not substantially expand when it is placed under a compressive load but rather may directly impart a radially outward force. In some embodiments only a portion of the container element 4 such as the distal end 16 may expand radially and impart a radially outward force while in other embodiments a substantial amount of the container element 4 may do so.
- the outward force may facilitate in securing at least a portion of the container element 4 to the vessel 80 and prevent it from moving proximally. In this manner, the tension applied to the filament 6 may secure the container element 4 distally to the vessel 80 such that the distal opening 20 can be closed.
- the container element 4 is not constrained and secured by the vessel 80 , there must be a component or components which impart a reaction force to support the distal end while the distal opening 20 is closing. In some embodiments this may be the container element 4 itself which may have structures and frames to support a compressive load. This may be true in the case of a framed configuration of the container element 4 . Alternatively, additional catheters or support structures may provide a reaction force to hold the distal end while the distal opening 20 is closed. In some embodiment which will be shown in greater detail below, the filament 6 may be supported by a filament catheter 82 which can provide such a function.
- An advantage of the braided structure of the container element 4 described herein is that the device 2 can be very flexible and no stiff or rigid components are required because it is secured to the vessel 80 itself and only when tension is applied to the filament 6 .
- FIG. 5 B a closer view of the distal end 16 is shown with the filament perimeter 48 beginning to constrict the distal opening 20 .
- the filament perimeter 48 remains a fixed length is moving proximally such that the distal opening perimeter 62 is decreasing in length.
- the looped ends 106 of the braid are being constricted like a purse string with a pull wire.
- the distal opening perimeter 62 is occupying a smaller portion of the filament perimeter 48 as more tension is applied.
- FIGS. 4 L and 5 C additional tension is applied to the filament 6 and the distal opening 20 is constricted further.
- the distal end 16 of the container element 4 and the filament perimeter 48 have moved further proximally.
- FIGS. 4 M and 5 D the filament perimeter 48 and distal opening 20 have moved further proximally such that they are within the sidewall 26 of the container element 4 .
- the distal opening perimeter 62 now occupies a small portion of the original filament perimeter 48 at its very distal end.
- the container element 4 has inverted as the filament perimeter 48 moves proximally and a portion of the container element 4 is secured by the vessel 80 .
- FIGS. 4 N and 5 E the filament perimeter 48 and distal opening 20 have moved even further proximally.
- the filament perimeter 48 has changed shapes from the predetermined shape 46 to an elongated loop due to the tension across the elements.
- the distal opening 20 is generally concentric with the vessel 80 while in other embodiments the distal opening 20 may be of axis or angled in any manner determined by the applied forces.
- the cross sectional area of the distal opening when it is in the closed configuration may be between 0-1.0 mm2 or between 0.01-0.2 mm2.
- the distal opening 20 must be mostly closed to prevent any parts of the clot 78 from coming out of the container element 4 .
- the distal opening 20 is formed by the space between the looped ends 106 of the braided container element 4 . In the closed configuration, the looped ends 106 are bunched up close together such that the effective distal opening perimeter 62 of the distal opening 20 is significantly reduced from the open shape.
- the circumference of the distal opening 20 when the container element 4 is deployed may be between 10 mm-20 mm or between 14 mm-17 mm.
- the circumference may be between 0.01 mm-5 mm or between 0.5 mm-2 mm.
- the distal opening perimeter 62 is now only occupied by part of the filament perimeter 48 which has been tensioned and so the majority of the filament perimeter 48 is now proximal to the distal opening 20 .
- the shape of the distal opening 20 configuration in this shape is not necessarily circular and in fact is likely not circular. The shape may be like a horseshoe or half-moon or any portion of an arc or bent wire.
- FIG. 5 E the distal end 16 of the container element 4 is shown inverted such that it has move further proximally within the container element 4 itself.
- the tension in the filament 6 has pulled the distal end 16 proximally and secured the distal opening 20 closed.
- the filaments 6 are connected to the constraining catheter 8 such that the constraining catheter 8 can be further retracted and the filaments 6 can close at the distal end 16 .
- the user only needs to retract one component, in this case the constraining catheter 8 , in order to deploy the container element 4 and then continue to retract it in order for the distal opening 20 to constrict.
- FIGS. 4 J- 4 N show the constraining catheter 8 moving proximally as the filament 6 is placed in tension indicating such a configuration. This may provide advantages for the user interface and simplicity of the device 2 .
- the clot engagement element 58 or the intermediate catheter 72 may be connected similarly to the filament 6 to perform a similar function as described above.
- a handpiece may exist outside of the body which handles the relative movements of the catheters and elements.
- a syringe type motion or a trigger type motion by the user may cause the device 2 to go through its relative motions as described herein. In this manner the user does not have to think about which component to move but rather can just activate a simple interface to move through the various stages.
- the clot engagement element 58 has been removed from the body leaving the majority of the clot 78 behind in the container element 4 . In some embodiments this step is not performed and the clot engagement element 58 can remain in position relatively to the container element 4 as the entire device 2 is removed from the body.
- the device 2 begins to be removed from the body by pulling it proximally.
- the container element 4 is a braid that decreases in diameter as it is placed under tension.
- the container element 4 therefore stretches as shown and can be further pulled into other catheters if necessary.
- the clot 78 is fully contained within the container element 4 and will not distally embolize as it is retracted.
- the container element 4 and device 2 may be stretched as much as necessary to remove it from the body.
- the filament 6 is pulled taut and the distal opening 20 of the container element 4 is constricted, it does not significantly open again even if the tension in the filament 6 is reduced or removed.
- the distal opening 20 of the container element 4 may automatically open once the filament 6 is relaxed. In some embodiments, after the device 2 is removed from the body it may be opened and the device 2 may be used again for additional clots 78 and foreign bodies.
- FIGS. 6 A- 6 H an alternative embodiment of the device 2 is shown.
- the clot engagement element 58 is an aspiration catheter 76 rather than a stent retriever.
- the container element 4 has been deployed in the vessel but no microcatheter 74 or stent retriever necessarily traverse the clot.
- an aspiration catheter 76 exists within the lumen of the device 2 and may be advanced.
- the aspiration catheter 76 may be comprised of any of the materials or constructions known to one skilled in the art of catheters.
- the outer diameter may be on the order of 0.02′′ to 0.080′′ and sized to fit within the lumen of the container element 4 .
- the aspiration catheter 76 may be connected to a vacuum source external or internal to the patient that provides suction to the distal end of the aspiration catheter 76 .
- the aspiration catheter 76 can be used for aspirating blood such that it flows in a proximal or retrograde manner within the cerebral artery. Additionally, the suction in the aspiration catheter 76 can be used to engage and remove clots 78 or foreign bodies.
- the aspiration catheter 76 is advanced distally toward the clot 78 .
- suction applied to the clot 78 may pull the clot 78 toward the aspiration catheter 76 or alternatively the aspiration catheter 76 may be advanced all the way to the clot 78 before suction is applied.
- the aspiration catheter 76 is withdrawn into the container element 4 with the clot 78 such that the clot 78 is contained within the container element 4 .
- the clot 78 may be in multiple pieces or may break apart during the aspiration and retraction.
- the aspiration catheter 76 may be extended distally multiple times from the container element 4 and engage with new pieces of clot 78 .
- the clot 78 can be retracted into the container element 4 and can then be dislodge from the aspiration catheter 76 by releasing the suction or providing a positive pressure through the aspiration catheter 76 to dislodge the clot 78 .
- the distal opening 20 of the container element 4 can be partially closed as described herein and used as a method of keeping the clot 78 within the container element 4 while allowing the aspiration catheter 76 to be distally extended again to engage with another piece of clot 78 .
- the filament 6 is tensioned and the distal opening 20 begins to close and may retract proximally.
- the filament 6 is further tensioned and the distal opening 20 closes further.
- the aspiration catheter 76 could be advanced distally to extend out of the container element 4 and engage with another clot 76 .
- a guidewire or microcatheter 74 may be left distal to the distal opening 20 so that the aspiration catheter 76 can traverse through the distal opening 20 .
- the distal opening 20 Before pulling the new clot 78 into the container element 4 , the distal opening 20 may be opened as needed by releasing tension on the filament 6 .
- Aspiration may be applied through the container element 4 to keep any loose clot fragments within the container element 4 while the distal opening 20 is partially or fully open.
- the distal opening 20 is inverted within the container element 4 .
- the distal opening 20 is further inverted and moved proximally along with the filament perimeter 48 .
- a separate aspiration catheter 76 is not necessary.
- the aspiration can be applied to the lumen of the container element 4 such that flow is directed in from the distal opening 20 .
- the container element 4 can be positioned just proximal to the clot 78 so that when aspiration is applied, the clot 78 is suctioned into the container element 4 .
- aspiration may be applied to any of the elements.
- a vacuum source may be fluidly connected to the constraining catheter 8 , container element 4 , microcatheter 74 , aspiration catheter, intermediate catheter 72 , or any other component.
- FIG. 7 A- 7 G an embodiment of the device 2 is shown with the container element 4 deploying out of a constraining catheter 8 in greater detail.
- a constraining catheter 8 is shown with a distal end.
- the constraining catheter 8 may be a separate catheter or may be an intermediate catheter 72 or any other catheter within the device 2 .
- the container element 4 begins to deploy.
- a first leading portion 38 of the filament(s) 6 begins to exit the constraining catheter 8 as shown in a ‘bunny ears’ configuration.
- bunny ears is intended to describe the shape shown in FIG. 7 B- 7 D , however this term should not be limiting to other shapes or configurations which may accomplish the same thing.
- FIG. 7 A a constraining catheter 8 is shown with a distal end.
- the constraining catheter 8 may be a separate catheter or may be an intermediate catheter 72 or any other catheter within the device 2 .
- the container element 4 begins to deploy.
- a first leading portion 38 of the filament(s) 6 begins to exit the constraining catheter 8 as
- the first leading portion 38 of the filament 6 exit the constraining catheter 8 more and begin to fold outward.
- the first leading portion 38 forms a first loop 40 that resembles a bunny ear.
- a second leading portion 42 may also exist and move with the first leading portion 38 .
- the braid of the container element 4 begins to deploy as shown. As the distal end 16 of the container element 4 begins to open slightly, the length of the filament 6 within the first loop 40 begins to become the filament perimeter 48 at the distal end.
- FIG. 7 E the container element 4 is further deployed and the distal end has opened up substantially from its constrained shape within the constraining catheter 8 .
- FIG. 7 G the container element 4 is mostly deployed.
- the filament perimeter 48 at the distal end 16 of the container element 4 is in the open configuration and the arms 28 , 30 run on the inside surface of the container element 4 and into the constraining catheter 8 .
- the clot engagement element 58 could be pulled into the container element 4 at the distal end 16 .
- the ‘bunny ears’ shape of the filaments may be important because it is one embodiment in which the container element 4 may be deployed with an open distal end 16 .
- ‘bunny ears’ refers to a specific aspect of the leading portion 38 and all combinations and features shall be shared without indispensable features from either. That is, all features of the ‘bunny ears’ needn't include a closed loop 50 nor more than one for those features to be used with any aspect of the leading portion 38 independently. Stated another way, the terms may be interchangeable without impugning any necessity of one or the other or any feature of one to the other by necessity.
- the distal opening 20 is much smaller than when it is open after being deployed.
- the distal opening 20 when it is within the constraining catheter 8 , the distal opening 20 may be 1.0 mm in diameter versus when it is deployed and open it may be 5.0 mm in diameter. In this example, this represents a 5 ⁇ increase in diameter and circumference. Therefore, since the filament perimeter 48 extends around the circumference of the container element 4 , the length of the filament 6 at the distal end 16 has to similarly increase by 5 ⁇ . In some embodiments, the filament 6 at the distal end 16 can simply grow in length by pulling more filament 6 distally. However, the force required to pull more filament 6 distally may be significant compared to the opening force of the container element 4 .
- the container element 4 is a shape set braid that has a nominal 5 mm diameter then it will have a given radial force trying to open the distal end once it is deployed from a 1 mm constraining catheter 8 .
- this force may not be enough to pull more filament 6 distally especially if the device 2 is long or curved due to anatomical constraints. Therefore, the distal end 16 may not open fully when it is deployed unless another consideration is given for the increase in filament 6 length at the distal end.
- the ‘bunny ears’ keep an amount of excess filament length at the distal end 16 of the container element 4 . Therefore, when the container element 4 is deployed, the filament perimeter 48 at the distal end 16 can form an open circular shape.
- the filament 6 is shape set to a predetermined shape 46 such as a circle.
- the 90 degree filament bend 54 where the filament 6 transitions from the filament perimeter 48 to the arms 28 , 30 going back along the longitudinal length of the device 2 does not move substantially relative to the container element 4 when the device 2 is deployed versus when it is constrained.
- the length of the filament perimeter 48 instead transforms into the ‘bunny ears’ shape and is then constrained by the constraining catheter 8 with leading portions 38 extending distally from the end of the container element 4 .
- the shape set profile of the filament 6 perimeter can include features which encourage the ‘bunny ears’ shape or a similar shape.
- the filament perimeter 48 may be primarily a circle but may additionally have small nipples 102 extending radially outward defined by the loop pathway as shown in FIGS. 2 F and 2 G . This may provide a specific place for the ‘bunny ears’ to bend when they are constrained within the constraining catheter 8 .
- FIGS. 7 A- 7 G show a ‘bunny ears’ shape, any number of other shapes may be contemplated such as a single loop, several loops, or any other shape that takes up the filament length when it is constrained.
- the excess amount of filament 6 length is folded or bunched up in any number of other locations.
- FIGS. 14 A- 14 C an embodiment of such a device 2 is shown.
- a container element 4 is shown in a constrained configuration.
- a constraining catheter 8 is not shown, it can be appreciated that the container element 4 is radially constrained within a catheter.
- the distal opening 20 of the container element 4 is relatively small.
- the filament perimeter 48 has a generally circular predetermined shape 46 when unconstrained but in the constrained configuration shown the filament perimeter 48 has an elongated loop shape.
- the filament perimeter 48 extends along a given length of the longitudinal axis LA of the container element 4 that is roughly one half of the circumference of the filament perimeter 48 when it is unconstrained. For example, if the diameter of the filament perimeter 48 is 5 mm, the longitudinal length of the filament perimeter 48 when stretched as shown may be about 6 mm-9 mm.
- the distal arm 98 transitions to a region of filament excess length 96 which is folded into the constraining catheter 8 and then transitions to a filament proximal arm 94 .
- the filament excess length 96 is folded and stored within the constraining catheter 8 so that when the filament perimeter 48 expands to its unconstrained shape, the filament excess length 96 can be utilized.
- FIG. 2 B the container element 4 and filament perimeter 48 have been deployed out of the constraining catheter 8 .
- the filament perimeter 48 now extends a very short length of the longitudinal axis LA of the container element 4 .
- the filament perimeter 48 may extend only about 0 mm-3 mm or 0.25 mm-1 mm.
- the filament junction 100 advances distally by about the difference between the longitudinal length of the filament perimeter 48 in the constrained shape and the longitudinal length of the filament 6 in the deployed shape. For example, this might be about 1 mm-9 mm or 3 mm-6 mm.
- the filament excess length 96 may then unfold and allows the extension of the filament distal arm 98 without substantial movement of the filament proximal arm 94 .
- the folded filament excess length 96 enables the frictional force of pulling the filament distal arm 98 to be minimized since the filament proximal arm 94 , which extends through additional components and potentially tight turns, does not need to move substantially. Therefore, the radial opening forces of the filament 6 or the container element 4 , or both, do not need to overcome a large frictional force and may still achieve their open deployed position.
- the folded filament excess length 96 may exist at any location within any of the catheters but may be optimally applied within the container element 4 and more optimally toward the distal end 16 of the container element 4 and as explained elsewhere herein.
- FIG. 14 shows that the excess length may be along the distal portion and formed by a first fold and a second fold forming a flat z-shaped portion for the filament excess length 96 .
- the device 2 is shown in a closed configuration as the proximal arm 28 is placed in tension.
- the filament excess length 96 may unbend more than is shown in the figure, but it should be noted that the shape of the filament 6 in the closed configuration is unique and different from the shape of the filament 6 in the constrained position.
- the filament perimeter 48 shape when the container element 4 is in the constraining catheter 8 is different than the shape of the filament perimeter 48 when the distal opening 20 is closed.
- the filament perimeter 48 therefore goes through at least 3 unique shapes.
- the filament perimeter 48 forms a circumference of the distal opening 20 that is generally circular.
- the filament perimeter 48 may be at or close to its predetermined shape 46 at this point.
- the filament perimeter 48 when the filament 6 is in tension and the distal opening 20 is closed, the filament perimeter 48 resembles an elongated loop or stretched rubber band where the distal end of the filament perimeter 48 forms a small circumference of the distal opening 20 which may or may not be circular.
- the filament perimeter 48 transitions between these three shapes during the normal use of the device 2 .
- the first and third shapes are unique meaning that the shape of the filament perimeter 48 when the container element 4 is in the constraining catheter 8 is not necessarily the same as when the distal opening 20 is closed.
- the filament perimeter 48 generally forms a plane.
- the plane may be a perpendicular plane 66 which is perpendicular to the longitudinal axis LA of the container element 4 as shown in FIGS. 4 A- 4 P , or the plane may be askew to the longitudinal axis LA.
- the plane is tilted by an askew angle 64 of about 30 degrees from the perpendicular plan 66 .
- the filament perimeter 48 forms an ellipse or similar shape and has a distal section at one apogee and a proximal section at the other apogee.
- having an askew distal end opening may provide advantages for guiding the clot engaging element 58 into the container element 4 .
- the distal end 16 of the container element 4 with its crown of looped ends is also askew to its longitudinal axis LA while in other embodiments the filament perimeter 48 is simply threaded through the braid of the container element 4 at an angle while the distal end is still perpendicular to the longitudinal axis LA.
- the amount that the snare is askew to the perpendicular plane 66 may be between 2-60 degrees or between 10-30 degrees.
- the closed shape may look similar to other embodiments shown and described herein. Meaning, the shape of the filament perimeter 48 in the closed configuration is not necessarily the same as the shape of the filament perimeter 48 in the constrained configuration.
- the filament perimeter 48 does not define a single plane and instead may be a more complex three-dimensional shape.
- the filament perimeter 48 may have portions that are askew to the longitudinal axis LA of the container element 4 and other portions that are askew in a different angle or orientation.
- the filament perimeter 48 may have protrusions that extend proximally or distally.
- the filament perimeter 48 is not constrained by a single plane.
- FIGS. 9 A- 9 F the closure of the distal opening 20 of the container element 4 is shown in greater detail.
- the container element 4 is within a 5 mm vessel.
- the clot 78 and clot engagement elements 58 are not shown but would be within the container element 4 during this step.
- the distal end 16 of the container element 4 is generally open such that it could receive the clot engagement element 58 to be pulled into the container element 4 .
- the filament perimeter 48 is in an open shape and there may be little or no tension in the arms 28 , 30 .
- FIG. 9 D the filaments arms 28 , 30 are pulled further proximally and the distal opening 20 of the container element 4 moves proximally as well and even folds back within itself.
- FIG. 9 E the distal end 16 is folded back even further. This may be required in some embodiments while in other embodiments less tension is required on the arms 28 , 30 .
- a critical aspect is that the clot 78 particles do not escape the container element 4 .
- FIG. 9 F the container element 4 is shown removed from a vessel 80 with the distal end constricted. As can be seen there is generally no opening at the distal opening to allow further embolization of the clot 78 .
- the filament 6 is effectively closing the distal opening 20 as a purse string so that all the looped ends 106 of the braid are close together.
- a filament catheter 82 is included in the device 2 .
- a filament catheter 82 can provide several advantages. First, it can provide axial support to the device 2 as the filament 6 is being cinched. The support may hold the distal end 16 of the device 2 in a fixed position during the distal opening 20 closure. Second, it can facilitate in the deployment and retraction of the container element 4 in the vessel. In the configurations where the container element 4 is a braid, the filament 6 catheter can be used to stretch the braid and thereby reduce its diameter by applying a distally acting tension on the braid. Third, it can keep the arms 28 , 30 constrained as they are inside or outside of the container element 4 .
- FIG. 10 A shows the filament catheter 82 within the intermediate catheter 72 and the distal opening 20 in the closed configuration.
- the container element 4 is completely within the intermediate catheter 72 in this configuration and the intermediate catheter 72 can be advanced to the target vessel 80 in this configuration.
- the filament catheter 82 is shown external to the container element 4 .
- the filament catheter 82 could be within the lumen of the container element 4 .
- FIG. 10 B the intermediate catheter 72 has been retracted while the filament catheter 82 remained in the same location.
- the filament catheter 82 can be advanced while the intermediate catheter 72 remains in the same location.
- the filament perimeter 48 is distal to the end of the intermediate catheter 72 and is still in the closed configuration with the proximal end of the container element 4 still within the intermediate catheter 72 .
- the amount of closure of the distal opening 20 can be less or more than what is shown.
- the distal opening 20 can be closed more so that the container element 4 at the filament perimeter 48 touches itself and forms a full or partial seal at the distal opening 20 .
- FIG. 10 C the filament 6 has been advanced and the distal opening 20 is in the open configuration.
- the filament perimeter 48 is opened to approximately the size of the vessel diameter and the container is therefore opened as well.
- FIGS. 11 A- 11 F show a series of steps that is similar to what may be currently practiced in thrombectomy procedures.
- a clot 78 is shown in a vessel 80 such as a middle cerebral artery.
- An intermediate catheter 72 has been advanced to the target vessel 80 as shown.
- a microcatheter 74 has been advanced and a guidewire 84 has been advanced so that it traverses the clot 78 .
- FIG. 11 C the microcatheter 74 follows the guidewire 84 and traverses the clot 78 .
- Contrast may be injected through the microcatheter 74 at these steps to confirm its location with fluoroscopy.
- the guidewire 84 is removed from the microcatheter 74 in FIG. 11 D .
- a clot engagement element 58 such as a stent retriever is inserted into the microcatheter 74 until its tip extends distally from the end of the microcatheter 74 .
- the microcatheter 74 is retracted and the stent retriever expands into the clot 78 and grabs it so that it can be pulled with the stent retriever.
- the stent retriever is now pulled along with the microcatheter and intermediate catheter 72 . They can be pulled through the vessel and into a silicon balloon catheter in the carotid. While this can remove the clot it can also create fragmentation and distal embolization of the clot as described above.
- FIGS. 11 G- 11 K show the use of an embodiment of part of the invented device 2 and method which can reduce the problems associated with just pulling the clot engagement element 58 and bare non-covered clot 78 out through the vessel 80 .
- the intermediate catheter 72 and microcatheter 74 are removed, leaving the stent retriever behind in the vessel 80 with the clot 78 .
- Monorail type catheters e.g. Rapid Exchange
- the intermediate catheter 72 can be left in place proximal to the clot 78 and the stent retriever.
- the device 2 can be fed into the existing intermediate catheter 72 and the remaining steps of the described procedure can be followed.
- a new intermediate catheter 72 or the pre-existing intermediate catheter 72 with the device 2 is inserted onto the stent retriever wire and advanced to the target vessel.
- a monorail style catheter may be used.
- the stent retriever wire is inserted through a hole at the proximal end of the container element such that the wire extends through the lumen of the container element 4 .
- the hole may be significantly larger such that the container element 4 does not come to a closed end like a wind sock.
- the filament 6 is within the intermediate catheter 72 and is in the closed configuration.
- the intermediate catheter 72 is retracted and the container element 4 is opened in the vessel 80 .
- the filament perimeter 48 expands manually or automatically such that it approximates the vessel 80 inner diameter.
- the container element 4 or filament 6 significantly reduces or occludes blood flow through the vessel to further prevent distal embolization of the clot.
- the full or partial occlusion of the vessel may additionally prevent the need for aspiration or a silicone balloon catheter in the carotid artery.
- the container element 4 may only slightly limit the blood flow.
- the filament perimeter 48 and distal opening 20 may open more or less than is shown.
- the filament perimeter 48 can be opened to provide a positive radial force on the vessel 80 and further ensure flow arrest.
- the stent retriever and clot 78 are pulled through the distal opening 20 and into the container element 4 . Since the filament perimeter 48 may approximate the diameter of the target vessel 80 , it acts like a funnel that the stent retriever and clot 78 are pulled into. The clot 78 is fully within the container element 4 .
- the container element 4 is connected to the filament catheter 82 along some portion of its length. For example, the proximal end of the container element 4 may be connected to the filament catheter 82 so it is not free floating. Alternatively, the entire length of the container element 4 may be connected or integrated into the filament catheter 82 .
- the filament perimeter 48 at the end of the device 2 is closed by pulling the arms 28 , 30 .
- the distal opening 20 of the container element 4 is therefore approximated and clot 78 is fully contained within the container element 4 .
- the device 2 with the clot 78 can be pulled from the vessel 80 and there may be a reduced likelihood of distal embolization since the clot is contained. The device 2 may then be withdrawn from the patient.
- FIGS. 12 A and 12 B alternative embodiments of the device 2 are shown.
- the filaments 6 are on the outside of the container element 4 in these embodiments and additionally are routed within a filament catheter 82 .
- the filament catheter 82 can hold the distal end 16 of the container element 4 in place as the tension is applied to the filaments 6 and the distal opening 20 is closed. Additionally, the filament catheter 82 can provide tension on the distal end 16 of the container element 4 such that the container element 4 can be stretched by pulling the proximal end of the container element 4 while holding the filament catheter 82 stationary or by pushing the distal end 16 of the container element 4 with the filament catheter 82 while holding the proximal end stationary or some combination therein.
- the filament catheter 82 may be comprised of any suitable catheter or tube material, such as nitinol, stainless steel, Pebax, PEEK, braided polyimide composite, or any other suitable construction.
- the filament catheter 82 can be a closed wound coil.
- FIGS. 10 - 11 and FIG. 12 show similar devices having features which are incorporated for each other. For example, both show the containing element 4 being free of attachments to the constraining catheter 8 and that the intermediate catheter 72 has the secondary lumen with the first filament 6 extending through the secondary lumen. Further still, both devices show the intermediate catheter 72 positioned in the lumen 24 of the constraining catheter 8 with the intermediate catheter 72 being movable relative to the constraining catheter 8 so that relative motion can move the containing element 4 to the released position (such as moving the intermediate catheter 72 distally relative to the constraining catheter 8 ).
- the devices 2 do differ in some respects in that the device 2 of FIGS. 10 and 11 is free of attachments to the intermediate catheter 72 while in FIG. 12 the containing element 4 is coupled to the intermediate catheter 72 for a length of at least 5 mm.
- FIGS. 10 - 12 show embodiments where the filament 6 may include the features of any of the other embodiments described herein.
- the filament 6 may having the leading portion which will still emerge from the constraining catheter 8 in the manner describe above even though the container element 4 is not attached to the constraining catheter 8 .
- a feature such as the inverted portion is not implicitly included in the embodiment of FIG. 10 A- 10 C while the features of the closed position would be implicitly included in the embodiments of FIGS. 10 - 12 .
- FIG. 13 A- 13 B an embodiment of the device 2 and method are shown.
- a container element 4 is shown with a distal opening 20 .
- the container element 4 may be braided construction, stent construction, framed cage construction, or any other suitable structure.
- the container element 4 is generally tubular and has a distal end with a distal opening 20 as well as at least one flap 88 .
- the flap 88 is a piece which extends distally past the distal opening 20 and has a flexing area 86 .
- a filament 6 is attached to the flap 88 at the filament 6 connection.
- the filament 6 may be a wire such as a stainless steel, nitinol, plastic, or suture.
- the filament 6 may be connected to the flap 88 by a connection 90 as shown or by welding, heat bonding, mechanical swaging, or any other suitable process.
- the flap 88 is in an unactuated state and there is minimal tension on the arm 28 . Therefore, the distal opening 20 is generally open and may receive clots 78 or other material through the distal opening 20 .
- tension may be applied to the arm 28 . The tension creates a force on the flap 88 that causes it to bend about the flexing area 86 .
- FIG. 13 B the flap 88 is rotated about 30 degrees and is thereby partially closing the distal opening 20 .
- FIG. 13 A the flap 88 is rotated about 30 degrees and is thereby partially closing the distal opening 20 .
- the flap 88 may be comprised of the same material as the container element 4 (integrally formed). Alternatively, the flap 88 may be a separate component that is connected to the container element 4 at the flexing area 86 .
- the connection may be a hinged connection (such as a living hinge) such that the flap 88 is primarily free to rotate about the flexing area 86 .
- a more rigid material may be applied to the flap 88 so that it does not crumple when the arm 28 is in tension. This may include adding fabric or plastic to the flap 88 .
- an alternative embodiment is shown with more than one flap 88 .
- Three flaps 88 are shown each with their own filament 6 but any number of other flaps 88 may be contemplated such as between 1 to 10 flaps or 2 to 4 flaps.
- the filaments 6 may be tensioned at the same time or individually. Thus, any number of folding patterns may be contemplated.
- the flaps 88 may act like anatomical valve flaps which meet at the longitudinal axis LA of the container element 4 .
- the flaps 88 do not need to be symmetric necessarily and can each be unique shapes.
- the shape of the flap 88 may be designed so that when all the flaps 88 are closed, the distal opening 20 of the container element 4 is mostly covered and materials within the container element 4 are trapped in place.
- aspiration may additionally be applied within the device 2 to further assist in capturing the clot 78 .
- the aspiration may be connected to the intermediate catheter 72 , constraining catheter 8 , container element 4 , or filament 6 catheter.
- the pieces of the clot 78 may be sucked into the container element 4 .
- the aspiration reverses the blood flow so that it goes proximally. This may be useful especially in embodiments where the device 2 provides local flow arrest so that the suction only comes from the distal side of the clot 78 and ensures that even if the clot 78 breaks apart it will not distally embolize.
- the aspiration could be applied during certain steps in the procedure outlined above such as when the clot engagement element 58 is being deployed and then retracted into the container element 4 .
- the use of aspiration may obviate the need for the clot engagement element 58 .
- Aspiration may be used to suck the clot 78 into the container element 4 without using a separate retriever.
- an agitator mechanism may be used to break up the clot and the aspiration then sucks the broken up pieces into the container element 4 .
- the agitator may be mechanical such as a spinning or axially sliding element that contacts the clot and breaks it into smaller pieces that can be sucked up.
- the agitator may be vibratory or ultrasonic such that the clot breaks apart.
- Aspiration may be achieved with the use of a syringe or a vacuum source connected to the device 2 .
- the aspiration catheter 76 has a connected morcellating tip that is capable of breaking up clots 78 .
- the aspiration catheter 76 can pull the clot 78 into the container element 4 and then the distal opening 20 can be closed.
- the morcellating tip can be used to emulsify or break down the clot into smaller pieces which can be sucked through the aspiration catheter 76 .
- the distal opening 20 can be opened and the aspiration catheter 76 can be advanced to engage with still more clot 78 . This process can be repeated any number of times. In some embodiments the same procedure is used for a stent retriever.
- the container element 4 may not have an active closing element such as the filament 6 described herein but instead may be passively closed.
- the container element 4 may be shape set such that it is a long tube as shown in the figures but at the distal end 16 the container element 4 may funnel back to a constricted shape when it is deployed.
- a separate frame element may be used to actively hold the container element 4 open when it is ready to accept the clot engagement element 58 being retracted within the container element 4 .
- the frame can be moved axially to allow the container element 4 to constrict back to its shape set profile. This may allow the opening and closing of the distal end 16 of the container element 4 by sliding a frame element distally and proximally.
- the device 2 may contain all or only a portion of the devices described herein.
- the device 2 may include a clot engagement element 58 such as a stent retriever or aspiration catheter.
- the device 2 may only include the container element 4 and filament 6 and the device 2 may be used with an existing off-the-shelf available stent retriever.
- the container element 4 and filament 6 may be sized to accept such a retriever.
- the device 2 may be inserted into the body after the stent retriever has been deployed and captured the clot. In this way it is a stand-alone system for capturing the clot that includes using other clot engagement elements. Any number of other configurations of the devices described herein are contemplated.
- the device 2 can have a variety of shapes and sizes serving as a platform for any type of thrombectomy, embolectomy, or foreign body, calculi or tissue removal in any part of the body or vessel.
- the device 2 may provide proximal support for placement of distal devices such as rheolytic catheters, suction devices, graspers, balloons such as a Fogarty balloon, wire snares, stent retrievers, etc. for any size tube or vessel including arteries, veins, ureters, airways, bile ducts, and hollow viscous for retrieval of material.
- peripheral blood clots may be likewise removed with such a system.
- Any number of other suitable applications may use such a device 2 for contained removal of a tissue, foreign body, calculi or other objects within a tubular contained space or even within non-tubular or non-contained spaces.
- filament used herein may be interchangeably used with snare, wire, ribbon, coil, elongate member, or any other suitable term.
- catheter is used to describe an elongate member with a distal and proximal end with a lumen extending there through.
- intermediate catheter, constraining catheter, filament catheter, guide catheter, and micro catheter may often be used interchangeably.
- container element may often be interchangeably used with bag, containing element, container element, pouch, or any other suitable term.
- the terms cinching, closing, constraining, collapsing, constricting, snaring, or any other suitable term may often be used interchangeably.
- the terms constraining, restricting, containing, or constricting may also often be used interchangeably.
- the term filament perimeter may be used interchangeably with concave portion.
Abstract
A containing element is used to capture material in a blood vessel for removal. The containing element is positioned within a constraining catheter while it is advanced through the blood vessel. A filament is coupled to the containing element which assists in opening and/or closing the containing element.
Description
- This application is a continuation of U.S. patent application Ser. No. 16/790,268, filed Feb. 13, 2020, and titled “Devices and Methods for Removing Material From a Patient”; which is a continuation of U.S. patent application Ser. No. 16/443,820, filed Jun. 17, 2019, now U.S. Pat. No. 10,624,659, and titled “Devices and Methods for Removing Material From a Patient”; which is a continuation of PCT/US2019/021943, filed Mar. 12, 2019, and titled “Devices and Methods for Removing Material From a Patient”; which claims the priority benefit of each of U.S. Provisional Patent Application No. 62/641,948, filed Mar. 12, 2018, titled “Treatment Device and Method” and U.S. Provisional Patent Application No. 62/793,498, filed Jan. 17, 2019, titled “Treatment Device and Method”, all of which are incorporated herein by reference in their entirety.
- All publications and patent applications mentioned in this specification are herein incorporated by reference in their entirety, as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference in its entirety.
- This disclosure relates generally to the field of surgery, and more specifically to the field of interventional radiology. Described herein are devices and methods for removing material from a patient.
- Minimally invasive endovascular techniques have come to the forefront in the safe and expeditious use of embolectomy devices for thromboembolic clot extraction. Currently employed devices generally extract the clot using a combination of balloons, graspers, aspiration, and wire retrievers. These devices attempt to remove the clot in vivo by attaching to it and then pulling it through the vascular lumen and out of the body. With these devices the thrombus is typically not fully contained and if fragments of the clot break away, they may become new emboli in the blood stream. That is to say that existing devices typically maintain partial or full exposure of the thrombus within the vascular lumen and when clot extraction is attempted the “bare thrombus” can pose a threat of fragmentation or partial clot dislodgement which can predispose a patient to inadvertent distal embolization, non-target territory embolization or incomplete thrombus extraction.
- Additionally, in order to limit the blood flow in the clotted vessel during clot removal, many procedures utilize a variety of flow arrest techniques such as balloon-assisted proximal vessel occlusion to minimize antegrade flow in an effort to exclude distal clot fragmentation during clot extraction. Mechanical or assisted suction techniques are oftentimes utilized simultaneously via the balloon flow arrest catheter to capture any potential embolic debris during clot extraction. However, complete flow arrest in the brain arteries is often difficult due to extensive intracranial collaterals (e.g. Circle of Willis), limiting the efficacy and utility of proximal flow arrest and suction in the carotid circulation. Even limited blood flow can create a significant risk of clot fragmentation and distal migration of clot during extraction.
- Completely encasing the clot captured within the stent-retriever by isolating the thromboembolism and excluding it from the vascular flow channel would eliminate or markedly reduce the risk of embolization.
- The present invention is directed to devices and methods for removing material from a blood vessel. In a specific application, the devices and methods are used to capture and remove material from the cerebral vasculature. The device includes a capture element which is collapsed and loaded into a delivery catheter which is advanced to a vascular location. The capture element is then deployed in a position to receive and contain material for removal. A clot retrieving element (such as a stent retriever) may be used to engage the material to be removed and assist in moving the material into the capture element.
- The capture element is contained within a chamber (which may be a lumen) in the delivery catheter when advanced through the vasculature. The capture element has a distal opening at a distal end and a sidewall extending proximally from the distal opening. The distal opening is moved to an open position to receive the material. The distal opening defines a perimeter which is used to define aspects of the invention described below.
- A first filament is coupled to the capture element to manipulate the capture element. When the capture element is positioned at or near the location where the material is to be removed, the capture element is released from the chamber by moving the capture element to a position outside the chamber. The capture element may be moved out of the chamber by manipulating the delivery catheter and/or the capture element.
- When the capture element is released, the first filament may support the open position of the distal opening. For example, the first filament may have a predetermined shape which supports the open position. The predetermined shape may extend around at least 120 degrees, at least 150 degrees or at least 260 degrees, around the distal opening in the open position when viewed along a longitudinal axis defined by the capture element. The predetermined shape of the first filament may form a first concave portion (facing the longitudinal axis) which supports and moves the distal opening to the open position when the capture element is released. The first concave portion may generally lie in a plane which forms an angle with the first arm of 45-135 degrees in an unbiased position. When the capture element is closed, the plane forms an angle with the first arm of 135-180 degrees.
- Stated another way, the concave portion has a shape larger than an unbiased shape of the distal opening so that the concave portion biases the distal opening toward the open position. The concave portion may be restrained by the open position of capture element so that the concave portion biases the distal opening toward the open position.
- When the capture element is released and the distal opening is open, the material is then engaged (with a clot engaging element such as a stent retriever) and passed through the distal opening and into the capture element. The first filament may be coupled to the delivery catheter so that the first filament moves proximally relative to the capture element when the capture element moves to the released position and when the capture element is closed. Manipulation of the first filament with the delivery catheter provides advantages over systems that require the tension element to extend out of the patient (such as lower tension force required at the proximal end resulting in lower forces exerted on blood vessels through which the tension element extends). Of course, the first filament may also extend out of the patient and be manipulated independent of the delivery catheter without departing from numerous aspects of the present invention.
- Once the material is contained within the capture element, the capture element is moved to a closed position in which the distal opening is reduced in size to prevent the material from escaping through the distal opening as the capture element is removed and/or moved into the delivery catheter or another catheter or sheath for removal from the patient. The distal opening may be closed by tensioning the first filament. The first filament may have a first arm and a second arm which are both tensioned. The first and second arms may extend from the first and second ends of the concave portion, respectively. Further aspects of the present invention will now be described with reference to the various positions of the first filament and the capture element and the basic method steps described above.
- When the capture element and first filament are advanced through the blood vessel, the first filament may have a first leading portion which extends from the distal end of the capture element within the delivery catheter. The first leading portion may have a length (which may form a first loop) which extends from the distal end of the capture element at least 30%, or at least 50%, of an effective diameter of the perimeter of the distal opening in the open position when moving to the open position. The first leading portion may be free of attachments to the capture element and may extend distally at least 1.5 mm from the distal end of the capture element as the capture element is released (and while the distal opening is moving toward the open position). The term “loop” as it pertains to the leading portion does not require a closed loop and merely requires a segment having both ends extending outwardly from the distal end of the delivery element. As used herein, the effective diameter is the equivalent diameter of a circle having the same area as the distal opening (the area circumscribed by the perimeter) or other reference area or cross-section.
- The first filament may be positioned at a relatively distal location when advanced through the vasculature by the delivery catheter. The first filament defines a working length which is the length of the first filament positioned within 10 cm of the distal end of the capture element. The working length of the first filament includes the first arm, the second arm and the concave portion but may include just one arm in some embodiments and may omit the concave portion in without departing from the scope of the invention. The working length of the first filament changes by less than 70% of the effective diameter of the distal opening in the open position when the capture element moves from the collapsed position to the released position.
- The first filament (and optionally the first leading portion) may also engage an inner surface of the sidewall of the capture element when the filament moves to the released position. The first filament may also apply (exert) an outward force to the inner surface of the sidewall over a longitudinal length of at least 2 cm and may contact the inner surface through an angle of at least 180 degrees when viewed along the longitudinal axis.
- When the capture element is closed by tensioning the first and second arms, the concave portion is deformed to reduce the size of the distal opening. The concave portion may be elastically deformed when and may be formed of a superelastic material deformed into a superelastic state. The effective diameter of the distal opening may reduce in size by at least 80% when moving to the closed position (and may be no more than 1 mm in the closed position).
- Tensioning the first filament (specifically the first and second arms) may also invert a portion of the sidewall at the distal end. Inverting of the sidewall also moves the distal opening proximally to a position surrounded by the sidewall. The sidewall may resist inverting so that a radially inward force is exerted on the inverted portion which is transmitted through the sidewall to bias the distal opening toward the closed position.
- The sidewall of the capture element may also include an expandable portion. The expandable portion may be at least 10 mm long and within 10 mm from the distal end of the capture element. The expandable portion may exert a radially outward force on the vessel wall when tensioning the first filament to close the capture element. The expandable portion may be naturally biased outward due to the physical properties and shape of the sidewall. Alternatively, the first filament may move and/or assist the sidewall and distal opening to the open position.
- The expandable portion may be expanded by the first filament beyond an unbiased shape so that an effective diameter of the expandable portion increases by at least 10%. Stated another way, when the capture element is moved to the closed position the first filament is tensioned to exert an outward force on the expandable portion and may increase a radially outward force on the vessel wall by at least 10%. The sidewall of the capture element may also have a distal portion which reduces in length when the capture element is closed. The distal portion may extend 10 mm from the distal end and reduces in length longitudinally by at least 20% when the capture element moves to the closed position. The distal portion may also expand in accordance with the expandable portion described below.
- In some embodiments, the first concave portion may form a closed loop with only the first arm extending from the closed loop. In other embodiments a second filament is coupled to the capture element. The second filament may have all features, aspects and uses as the first filament and all such features, aspects and uses are incorporated for the second filament. For example, the second filament may have a second leading portion which may have any of the characteristics, features and uses of the first leading portion of the first filament. The second filament may be coupled to the first filament and may even be being integrally formed with the first filament. The first concave portion and a second concave portion formed by the second filament may each extend 90-180 degrees when the capture element is in the open position.
- The foregoing is a summary, and may be limited in detail. The above-mentioned aspects, as well as other aspects, features, and advantages of the present technology are described below in connection with various embodiments, with reference made to the description, claims and accompanying drawings.
-
FIG. 1 illustrates an embodiment of the device in an isometric view. -
FIG. 2A illustrates a first embodiment of the filament predetermined shape. -
FIG. 2B illustrates a second embodiment of the filament predetermined shape. -
FIG. 2C illustrates a third embodiment of the filament predetermined shape. -
FIG. 2D illustrates a fourth embodiment of the filament predetermined shape. -
FIG. 2E illustrates a first embodiment of the filament predetermined shape. -
FIG. 2F illustrates a first embodiment of the filament predetermined shape. -
FIG. 2G illustrates a first embodiment of the filament predetermined shape. -
FIG. 2H illustrates a first embodiment of the filament predetermined shape. -
FIG. 2I illustrates a first embodiment of the filament predetermined shape. -
FIG. 2J illustrates a first embodiment of the filament predetermined shape. -
FIG. 2K illustrates a first embodiment of the filament predetermined shape. -
FIG. 3 illustrates a detailed view of the distal end of the container element. -
FIG. 4A illustrates an intermediate catheter within a vessel which includes a clot. -
FIG. 4B illustrates a microcatheter traversing the clot. -
FIG. 4C illustrates the microcatheter retracted and a clot engagement element engaged with the clot. -
FIG. 4D illustrates the intermediate catheter retracted and a constraining catheter in place. -
FIG. 4E illustrates the constraining catheter beginning to be retracted and the container element partially deployed. -
FIG. 4F illustrates the constraining catheter further retracted and the container element further deployed. -
FIG. 4G illustrates the constraining catheter further retracted and the container element further deployed. -
FIG. 4H illustrates the constraining catheter fully retracted and the container element fully deployed. -
FIG. 4I illustrates the clot engagement element and clot partially retracted into the container element. -
FIG. 4J illustrates the clot engagement element and clot fully retracted into the container element. -
FIG. 4K illustrates the distal end of the container element partially closed. -
FIG. 4L illustrates the distal end of the container element further closed. -
FIG. 4M illustrates the distal end of the container element inverted. -
FIG. 4N illustrates the distal end of the container element further inverted. -
FIG. 4O illustrates the microcatheter and clot engagement element retracted. -
FIG. 4P illustrates the constraining catheter and container element beginning to be retracted from the vessel. -
FIG. 5A illustrates a detailed view of the distal end of the container element open. -
FIG. 5B illustrates a detailed view of the distal end of the container element partially closed. -
FIG. 5C illustrates a detailed view of the distal end of the container element further closed. -
FIG. 5D illustrates a detailed view of the distal end of the container element inverted. -
FIG. 5E illustrates a detailed view of the distal end of the container element further inverted. -
FIG. 6A illustrates an embodiment of the device with an aspiration catheter. -
FIG. 6B illustrates the aspiration catheter advanced toward the clot. -
FIG. 6C illustrates the clot drawn toward the aspiration catheter. -
FIG. 6D illustrates the aspiration catheter and clot retracted into the container element. -
FIG. 6E illustrates the distal end of the container element partially closed. -
FIG. 6F illustrates the distal end of the container element further closed. -
FIG. 6G illustrates the distal end of the container element inverted. -
FIG. 6H illustrates the distal end of the container element further inverted. -
FIG. 7A illustrates a constraining catheter. -
FIG. 7B illustrates a filament advancing out of the constraining catheter. -
FIG. 7C illustrates the filament further advanced out of the constraining catheter. -
FIG. 7D illustrates a container element advancing out of the constraining element. -
FIG. 7E illustrates the filament forming an open distal end of the container element. -
FIG. 7F illustrates the container element further advanced out of the constraining element. -
FIG. 7G illustrates the container element further advanced out of the constraining element. -
FIG. 8A illustrates an embodiment with an askew plane filament perimeter in a constraining catheter. -
FIG. 8B illustrates an embodiment with an askew plane filament perimeter deployed from a constraining catheter. -
FIG. 9A illustrates an embodiment of part of the invented device within a simulated vessel. -
FIG. 9B illustrates the distal end of the container element partially closed and retracted. -
FIG. 9C illustrates the distal end of the container element further closed and retracted. -
FIG. 9D illustrates the distal end of the container element further closed and retracted. -
FIG. 9E illustrates the container element with the distal end of the device substantially closed. -
FIG. 9F illustrates a perspective view of the container element. -
FIG. 10A illustrates an embodiment of the container element inside an intermediate catheter. -
FIG. 10B illustrates the container element with the intermediate catheter retracted and the distal opening closed. -
FIG. 10C illustrates the container element with the intermediate catheter retracted and the distal opening open. -
FIG. 11A illustrates a vessel with a clot and an intermediate catheter inside the vessel. -
FIG. 11B illustrates a microcatheter extending from the intermediate catheter and a guidewire traversing the clot. -
FIG. 11C illustrates the microcatheter traversing the clot. -
FIG. 11D illustrates the guidewire removed from the patient. -
FIG. 11E illustrates a stent retriever inserted into the microcatheter and traversing the clot. -
FIG. 11F illustrates the microcatheter retracted and the stent retriever capturing the clot. -
FIG. 11G illustrates the intermediate catheter and microcatheter removed from the patient. -
FIG. 11H illustrates an intermediate catheter inserted into the vessel with the container element inside the intermediate catheter. -
FIG. 11I illustrates the intermediate catheter retracted and the container element in an open configuration inside the vessel. -
FIG. 11J illustrates the stent retriever and clot pulled within the container element. -
FIG. 11K illustrates the container element in a closed configuration. -
FIG. 12A illustrates an embodiment of the device with a filament catheter with the distal opening in an open position. -
FIG. 12B illustrates an embodiment of the device with a filament catheter with the distal opening in a closed position. -
FIG. 13A illustrates an embodiment of the device with a flap in the open position. -
FIG. 13B illustrates an embodiment of the device with a flap in the partially closed position. -
FIG. 13C illustrates an embodiment of the device with a flap in the closed position. -
FIG. 13D illustrates an embodiment of the device with multiple flaps in the open position. -
FIG. 14A illustrates an embodiment of the device with a filament excess length in the constrained position. -
FIG. 14B illustrates an embodiment of the device with a filament excess length in the deployed position. -
FIG. 14C illustrates an embodiment of the device with a filament excess length in the closed position. - In
FIG. 1 , adevice 2 to contain and remove material from a blood vessel is shown. Thedevice 2 includes acontainer element 4, afirst filament 6, and a constrainingcatheter 8. Thedevice 2 is shown in a generally deployed configuration with thecontainer element 4 unrestricted by the constrainingcatheter 8 and the first filaments is not under significant tension. The various configurations and procedural steps of thedevice 2 will be described in greater detail below. Aspects of the present invention are described with reference to a single or limited number of embodiments, however, it is understood that all features, aspects and methods are incorporated into all applicable embodiments described herein even though not expressly mentioned or set forth. - The
container element 4 has avessel diameter portion 10 and asmall diameter portion 12 with aproximal funnel area 14 between them. Thecontainer element 4 is connected to thefirst filament 6 toward adistal end 16 and the constrainingcatheter 8 toward aproximal end 18. The connection of thefirst filament 6 toward the distal end is configured such that when proximal tension is applied to thefirst filament 6, adistal opening 20 of thecontainer element 4 reduces in size from an open position ofFIG. 5A to a closed position ofFIG. 5E and may also move proximally as described below. The open position defines a perimeter of thedistal opening 20. The constrainingcatheter 8 may slide axially along the length of thecontainer element 4 and is configured to constrict thecontainer element 4 and position thecontainer element 4 within a chamber 22 (which may be a lumen 24). As will be shown in the images below, as the constrainingcatheter 8 slides distally over thecontainer element 4, thecontainer element 4 constricts and enters the constrainingcatheter 8 to load thecontainer element 4 within the constrainingcatheter 8 for delivery through the vasculature. The entirety of thecontainer element 4 may fit within the constrainingcatheter 8. As the constrainingcatheter 8 is then moved proximally relative to thecontainer element 4, thecontainer element 4 is configured to extend out of the constrainingcatheter 8 and may expand as defined by its unrestricted shape to deploy thecontainer element 4 at or near the desired location to remove material. Thecontainer element 4 has alumen 7 through which a clot retrieval device may be passed as detailed herein. - The constraining
catheter 8 is advanced through a blood vessel with thecontainer element 4 positioned in thechamber 22 and held in the collapsed position. Thecontainer element 4 has asidewall 26 extending proximally from thedistal opening 20 which surrounds and contains the material. Thefirst filament 6 is coupled to thecontainer element 4 to manipulate thecontainer element 4 as described herein. Thefirst filament 6 is also in a collapsed position when thecontainer element 4 is collapsed within thechamber 22 of the constrainingcatheter 8. Thefirst filament 6 may include afirst arm 28 coupled to afirst end 32 of aconcave portion 34 and asecond arm 30 coupled to asecond end 36 of theconcave portion 34. Theconcave portion 34 faces a longitudinal axis LA defined by thecontainer element 4. As used herein, the longitudinal axis LA follows the geometry of thecontainer element 4 at a geometric center of thesidewall 26 and may take any shape such as curved or segmented linear sections and may be substantially by the shape of the vasculature rather than an unbiased shape of thecontainer element 4 in use. Theconcave portion 34 may support the open position of thedistal opening 20 as described in further detail below. - The
container element 4 andfirst filament 6 may be advanced through the blood vessel with thefirst filament 6 having a first leadingportion 38 which extends from thedistal end 16 of thecontainer element 4 in the collapsed position. The first leadingportion 38 may have a length L which extends from thedistal end 16 of thecontainer element 4 by at least 30%, or at least 50%, of an effective diameter ED of a perimeter P of thedistal opening 20 in the open position. The first leadingportion 38 may be free of attachments to thecontainer element 4 and may extend distally at least 1.5 mm from thedistal end 16 of thecontainer element 4 in the collapsed position. The first leadingportion 38 may form afirst loop 40 which extends beyond thedistal end 16 ofcontainer element 4. - The
container element 4 may also be advanced through the vasculature with thefirst filament 6 defining a working length WL which is positioned at a relatively distal location when collapsed. The working length WL is defined as the length of thefirst filament 6 positioned within 10 cm of thedistal end 16 of thecontainer element 4. For example, the working length WL may include the combined length of thefirst arm 28, thesecond arm 30 and theconcave portion 34 within 10 cm of thedistal end 16. In an aspect of the invention, the working length WL of thefirst filament 6 changes by less than 70% of the effective diameter ED of thedistal opening 20 in the open position when thecontainer element 4 moves from the collapsed position to the released position. In a specific embodiment, the working length WL may be about 11.5 cm in the collapsed position and about 11.5 cm when thedistal opening 20 is open. - The first leading
portion 38 and working length WL both contribute to reducing the required length of thefirst filament 6 that must be drawn distally as part the working length WL to release thecontainer element 4. The required length of thefirst filament 6 to be drawn distally may be further reduced by coupling thefirst filament 6 to the constrainingcatheter 8 so that thefirst filament 6 moves proximally with the constrainingcatheter 8 relative to thecontainer element 4 when releasing thecontainer element 4 and when closing thedistal opening 20. Coupling the first filament 6 (specifically the first andsecond arms 28, 30) to the constrainingcatheter 8 in this manner further reduces the required length of thefirst filament 6 that must be manipulated since thefirst filament 6 needn't extend completely out of the patient like many conventional devices. Of course, thefirst filament 6 may also be independent of the constrainingcatheter 8 and extend out of the patient without departing from numerous aspects of the present invention. - The
container element 4 is moved to a released position outside thechamber 22 by moving thecontainer element 4, the constrainingcatheter 8 or both. Thefirst filament 6 may move to the released position while thedistal opening 20 simultaneously moves to the open position as thecontainer element 4 is moved/positioned outside of thechamber 22. Simultaneous release of thesidewall 26 and opening of thedistal opening 20 may be accomplished by coupling the first filament 6 (specifically the proximal end of the first andsecond arms 28, 30) to the constrainingcatheter 8 as described above. Alternatively, thedistal opening 20 may be separately opened using thefirst filament 6 or some other structure after thecontainer element 4 has been released without departing from numerous aspects of the invention. Thus, the open position may be achieved in any suitable manner in accordance with the present invention although aspects of the present invention provide for thefirst filament 6 to support the open position as now described. - The
first filament 6 may be positioned and coupled to thecontainer element 4 so that the natural unbiased shape (such as the shape of the concave portion 34) supports the open position of thedistal opening 20. For example, thefirst filament 6 may have a predeterminedshape 46 which defines afilament perimeter 48 which supports the open position of thecontainer element 4. Thepredetermined shape 46 may extend around at least 120 degrees, at least 150 degrees or at least 260 degrees, around thedistal opening 20 in the open position when viewed along the longitudinal axis LA. Stated another way, thefirst filament 6 may form the first concave portion 34 (oriented facing the longitudinal axis LA) which supports and moves thedistal opening 20 to the open position when thecontainer element 4 is released. Stated yet another way, theconcave portion 34 has a shape larger than an unbiased shape of thedistal opening 20 so that theconcave portion 34 biases thedistal opening 20 toward the open position. Stated still another way, theconcave portion 34 may be restrained by the open position ofcontainer element 4 so that theconcave portion 34 biases thedistal opening 20 toward the open position. The first leadingportion 38 may form the predetermined shape such as theconcave portion 34. The firstconcave portion 34 may generally lie in a plane P which forms an angle A with thefirst arm 28 of 45-135 degrees in an unbiased position as shown inFIG. 9A . When thecontainer element 4 is closed, the plane P forms the angle A with thefirst arm 28 of 135-180 degrees. The firstconcave portion 34 may also form a closed loop 50 which moves thedistal opening 20 toward the open position when thecontainer element 4 is in the released position as shown inFIG. 9A . - When the
container element 4 is opened by thefirst filament 6, the first leadingportion 38 may move into thecontainer element 4 and form theconcave portion 34 or, alternatively, move into thecontainer element 4 and engage aninner surface 52 of thecontainer element 4. Furthermore, thefirst filament 6 may apply an outward force to theinner surface 52 of thesidewall 26 over a longitudinal length of at least 2 cm of thecontainer element 4 in the released position which may help anchor thedevice 2 when the material is moved into thecontainer element 4 through thedistal opening 20. Thefirst filament 6 may also apply the outward force to theinner surface 52 over an angular extent of at least 180 degrees when viewed along the longitudinal axis LA. The first filament 6 (such as the first andsecond arms 28, 30) may also be substantially straight and may not apply an outward force to thesidewall 26 without departing from numerous aspects of the invention. - Once the
distal opening 20 is in the open position, a clot engaging element 58 (which may engage in any suitable manner such as mechanical or suction engagement) is used to engage and, if necessary, dislodge the material to be removed. The material is then passed through thedistal opening 20 and into thecontainer element 4 by manipulating theclot engaging element 58, thecontainer element 4, thefirst filament 6 or any combination thereof. - After the material to be removed is contained within the
container element 4, thecontainer element 4 is closed by tensioning the first filament 6 (such as thefirst arm 28 and second arm 30). Thedistal opening 20 may reduce in size from the open position so that the effective diameter ED is reduced by at least 80%. Stated another way, the effective diameter ED in the closed position may be no more than 1 mm. - The
concave portion 34 may also be deformed when thefirst filament 6 is tensioned to close thedistal opening 20. The first filament 6 (such as the concave portion 34) may be formed of a superelastic material which is elastically deformed when thedistal opening 20 is closed. Theconcave portion 34 may also be plastically deformed or may be a simple tension element without departing from aspects of the invention. - The
sidewall 26 of thecontainer element 4 may also include anexpandable portion 60 which may expand into engagement with thevessel 80 when thedistal opening 20 is closed. Theexpandable portion 60 may be at least 10 mm long and within 10 mm from thedistal end 16 of thecontainer element 4. Theexpandable portion 60 may exert a radially outward force on the vessel wall when thecontainer element 4 is closed by tensioning thefirst filament 6. Theexpandable portion 60 may be expanded beyond an unbiased shape by thefirst filament 6, for example, an effective diameter ED of thesidewall 26 along theexpandable portion 60 may increase by at least 10% compared to an unbiased condition. Stated another way, when thecontainer element 4 is moved to the closed position thefirst filament 6 causes an outward force on theexpandable portion 60 which increases a radially outward force on the vessel wall by at least 10%. - The
sidewall 26 of thecontainer element 4 may also have a distal portion DP which reduces in length when thecontainer element 4 is closed. The distal portion DP may extend 10 mm from thedistal end 16 and reduces in length longitudinally by at least 20% when thecontainer element 4 moves to the closed position. The distal portion DP may also expand in accordance with theexpandable portion 60 and be fully or partially coextensive with theexpandable portion 60. - The
first filament 6 may also move proximally when thedistal opening 20 is closed and may also move thedistal opening 20 proximally as shown inFIGS. 9A-9F . Thefirst filament 6 may be coupled to the constrainingcatheter 8 so that thefirst filament 6 is manipulated by the constrainingcatheter 8 and moves proximally with the constrainingcatheter 8 relative to thecontainer element 4 when thecontainer element 4 is released and when it is closed. In this manner, thefirst filament 6 is manipulated by the constrainingcatheter 8 which provides the advantages described herein such as a reduced length of thefirst filament 6 and possibly reduced forces on thevessel 80 when tensioning thefirst filament 6. - When the
distal opening 20 is closed, thesidewall 26 may form an inverted IP portion which also moves thedistal opening 20 to a position surrounded by the sidewall 26 (when viewed along the longitudinal axis LA). Thesidewall 26 may also apply a radially inward force on the inverted portion IP (which is transmitted through the sidewall 26) to bias thedistal opening 20 toward the closed position. Thedistal opening 20 may also invert when moving to the closed position or may remain uninverted with a small portion of the distal end of thesidewall 26. - The
device 2 may also include a second filament 6A coupled to thecontainer element 4 as shown inFIG. 2K wherein the same or similar reference numbers refer to the same or similar features as the first filament and all relevant features are incorporated here as previously mentioned. The second filament 6A may have a second leadingportion 42 which distally extends beyond thedistal end 16 of thecontainer element 4 in the collapsed position. The second leadingportion 42 extends at least 1.5 mm from thedistal end 16 of thecontainer element 4. The second leading portion 38A has a length which extends from thedistal end 16 of thecontainer element 4 which is at least 30%, and may be at least 50%, of an effective diameter of the perimeter of thedistal opening 20 in the open position. - The second filament 6A may be coupled to the
first filament 6 and may even be being integrally formed with thefirst filament 6. The second filament 6A may form a second concave portion 34A when thecontainer element 4 is in the open position. The second concave portion 34A also moves thedistal opening 20 toward the open position. The firstconcave portion 34 and the second concave portion 34A may each extend 90-180 degrees when thecontainer element 4 is in the open position and viewed along the longitudinal axis LA. - Specific aspects of components of the invention are now described and these aspects, features, and method steps are incorporated into all applicable embodiments even though not expressly provided as mentioned above.
- The
container element 4 may be of any number of constructions. In some embodiments, thecontainer element 4 may be a radially expandable element, such as a braid, laser cut stent, woven structure, or the like. In other embodiments, thecontainer element 4 may be a non-compliant flexible bag or fabric such as a PET or PTFE materials. In other embodiments, the container material may be a compliant material such as a polyurethane, silicone, or the like that may stretch and expand as materials are pulled into it. In still other embodiments, the container material may be a combination of multiple constructions. For example, thecontainer element 4 may have a bag construction in certain areas and a braid construction in other areas. - In some embodiments the
container element 4 is a frame with an attached membrane or fabric. The frame may be comprised of a nitinol or stainless steel or plastic component that expands radially once delivered out of the constrainingcatheter 8. For example, the frame may be a nitinol tube that is laser cut and shape set to expand when not constrained. A fabric, such as a PTFE graft material or any other membrane material, may be connected to the frame to either provide local flow arrest and contain the clot once it is within thecontainer element 4 or both. In some embodiments, thecontainer element 4 may be combination of a braid and a frame element. For example, a small wire braid may extend over a frame structure, possibly on both the inner and outer surfaces of the frame structure. - In some embodiments the
container element 4 is a braided wire construction. The braid wires may be nitinol, stainless steel, cobalt chromium, plastic, such as PET, or any other suitable material. The braid wire may contain radiopaque elements that allow it to be visualized under fluoroscopy such as a nitinol wire with a platinum core. Alternatively, thecontainer element 4 may have connected markers that enable visualization. The number of wires in the braid may be between 12 to 128 wires or between 32-64 wires. The braid angle may be between 100-200 degrees or between 120-160 degrees. The braid wires may be between 0.0001″-0.0050″ in diameter or between 0.0005″-0.0020″. Alternatively, the braid wires may be non-circular and may be oval, flat, or rectangular ribbons. The braided geometry may allow thecontainer element 4 to act like a Chinese finger trap where it decreases in diameter when it is elongated and increases in diameter when it is compressed. This may provide advantages such as allowing thedevice 2 to reduce in size when it is pulled out of the body and also secure itself against thevessel 80 when compressive loads are placed on portions of it such as through the filaments. - In some embodiments, the
container element 4 has a predeterminedshape 46 which is the unrestricted and unbiased shape that it naturally takes when no other components are restricting its movement at a given temperature. Thepredetermined shape 46 may be different shapes at different temperatures and as used herein shall be defined at normal body temperature. For instance, thecontainer element 4 may be a braided construction comprised of Nitinol wire. The Nitinol braid may be given apredetermined shape 46 through a shape setting heat treatment where thecontainer element 4 has a defined unrestricted shape. In some embodiments, thecontainer element 4 is configured such that in an unrestricted shape it may expand to close the vessel size. For example, in applications of the middle cerebral artery (MCA), thecontainer element 4 may be configured to expand to a diameter between 4 mm and 10 mm. Assuming an MCA has an average inner diameter of 4 mm, thecontainer element 4 expands until it touches the intimal wall of thevessel 80. If thecontainer element 4 is designed such that it expands to a diameter of 6 mm in air then it may provide a small to moderate amount of radial pressure on the wall of the vessel. By changing the unconstrained diameter of thecontainer element 4, the amount of radial force exerted on the vessel may be modulated. Additionally, the radial expansion force may be adjusted by altering the characteristics of thecontainer element 4. For example, if thecontainer element 4 is a braided construction, the following parameters may be changed to increase or decrease the desire radial force on the vessel: braid angle, number of braided ends, braid material, braid wire diameter, braid wire cross sectional profile, braid coating, etc. The desired radial force may be different for different vessels and different anatomical locations. In some embodiments, thecontainer element 4 has varying diameters or cross-sectional profiles along its length. For instance, the unconstrained diameter may be 8 mm in one or more locations and may be 4 mm in one or more locations. In addition, the cross sectional profile of thecontainer element 4 may not be generally circular as is shown. The cross-sectional profile may be ovular, triangular, rectangular, or any other profile and may vary along the axial length of thecontainer element 4. For example, in some locations the profile may be general elliptical with the semi-major axis in intimal contact with thevessel 80 and the semi-minor axis not in contact with thevessel 80. In other locations the cross-sectional profile may be circular with the entire circumference not in contact with the vessel wall. Any number of different shapes and configurations may be contemplated. - In other embodiments, the
container element 4 may not be a fully tubular structure meaning thatcontainer element 4 may represent a rolled-up surface that may or may not connect to itself. For example, thecontainer element 4 may be comprised of a laser cut pattern on a flat sheet of material that is then rolled to form a substantially circular shape but in which the two rolled edges may or may not connect to each other. - The
container element 4 has adistal opening 20 toward its distal end that allows for the passing of materials into thecontainer element 4 from the distal direction. Thedistal opening 20 may be configured such that in an unrestricted shape it is the same diameter as thesidewall 26 of thecontainer element 4. Thedistal opening 20 defines adistal opening perimeter 64 along the rim of thedistal opening 20. In other embodiments, thedistal opening 20 may be larger or smaller than thesidewall 26 of thecontainer element 4 when it is unrestricted such that thedistal end 16 of thecontainer element 4 tapers outward or inward. If thecontainer element 4 is tapered outward at thedistal end 16 of thecontainer element 4 it may facilitate the smooth entrance of materials into thecontainer element 4 and reduce the likelihood of clots from getting dislodged from the components which are retracting them. If thecontainer element 4 is tapered inward at thedistal end 16 of thecontainer element 4 it may facilitate the closing of thecontainer element 4 when thefilament 6 is tensioned as will be discussed in more detail below. Thedistal opening 20 may have a cross-sectional area which is roughly the same as the cross-sectional area of thevessel 80 it is within. For example, in a 5mm vessel 80 the cross-sectional area of thecontainer element 4 may be between 10-30 mm2 or between 18-22 mm2 in a deployed configuration. The size of thedistal opening 20 of thecontainer element 4 may defined partially by the shape and size of thefilament perimeter 48 48 as well. For example, thefilament perimeter 48 may be such that it imparts an inward or an outward radial force on thedistal opening 20 of thecontainer element 4. In other embodiments, thefilament 6 may impart an inward radial force in some locations and an outward radial force in other locations. In some embodiments, thecontainer element 4 is a flexible bag material and thefilament perimeter 48 fully defines thedistal opening 20 size and shape. - When fully deployed the
container element 4 may have a length of 1 cm-30 cm depending on the application. In a MCA application, thecontainer element 4 may be between 4 cm-16 cm or 5 cm-10 cm. Standard stent retrievers are 3 cm-5 cm in length. Therefore, if the clot engagement element is a similar length, in order to fully capture and contain the clot engagement element, the length of thecontainer element 4 may be on the order of 7 cm. However, as will be shown, the clot engagement element does not necessarily need to be fully captured by thecontainer element 4. In any event, assuming a length of 7 cm of thecontainer element 4 when unconstrained, thecontainer element 4 may have a length of 14 cm when it is within the constraining element. This is commonly called foreshortening where the length of thecontainer element 4 increases as it is radially constrained. - The
container element 4 may have features which provide partial or full local flow arrest within the vessel such as acoating 108. In the embodiments where thecontainer element 4 is a braid, thecoating 108 may be a dipped or spayedcoating 108 such as silicone. The silicone may be between 0.0001″-0.0050″ thick or between 0.0005″-0.0010″ thick. The silicone can provide a local flow arrest within thevessel 80 by covering portions of the braid so that blood flow is limited. Additionally, acoating 108 may provide further advantages of keeping the clot material that is captured by thedevice 2 better contained. For example, thecontainer element 4 may be covered along its entire length such that when it is deployed within thevessel 80 blood flow stops within thevessel 80 as blood cannot pass through thecontainer element 4 which is in intimal contact with thevessel 80. In some embodiments, thecoating 108 may cover only a portion of thecontainer element 4 such as the proximal funnel such that the full or partial cross section of the vessel is blocking blood flow. In other embodiments thecoating 108 may be over theentire container element 4. Alternatively, in the embodiments where thecontainer element 4 is a braid, the braid windows or space between the braid wires may be so small that they provide local flow arrest or reduced flow. For example, if the braid windows are small enough it may provide local flow arrest without needing to be covered. In some embodiments it may be desirable to allow certain components of blood to pass through the braid such that the braid acts as a filter to substantially reduce blood flow but not fully arrest it. - The
container element 4 may include more than onecoating 108. In some embodiments, thecontainer element 4 may have ahydrophilic coating 108 such as PTFE or other coating material to reduce friction of thecontainer element 4 as it slides within the constrainingcatheter 8. Thecoatings 108 may be applied to the outer surfaces of thecontainer element 4 to facilitate deployment of thecontainer element 4 or may be applied to theinner surface 52 to facilitate movement of other components such asmicrocatheter 74 through the lumen of thecontainer element 4. In other embodiments, thecoating 108 may a drug coating to deliver an active pharmaceutical ingredient (API) to the vessel or local anatomy. This may include drugs such as tissue plasminogen activator (tPa). These may be separate or in addition to acoating 108 that provides flow arrest such as a silicone coating. For example, thecontainer element 4 may have asilicone coating 108 which provides flow arrest and additionally have a hydrophilic coating to provide lubricity. - Local flow arrest may advantageously encourage retrograde collateral flow from the vessel such that the
clot 78 is at a reduced risk of distal embolization since the flow may be reversed. In addition, it may allow for injection of contrast through a portion of thedevice 2 such as through thecontainer element 4 or through the constrainingcatheter 8 which may facilitate identification of the thrombus within the vessel since there is no flow to carry the contrast away. Alternatively, thedevice 2 may be used to inject therapeutic agents such as tissue plasminogen activator (tPa). - The
proximal end 18 of thecontainer element 4 may reduce down to asmall diameter portion 12. In some embodiments, thesmall diameter portion 12 is defined by a predetermined shape of thecontainer element 4. For example, if thecontainer element 4 is constructed of Nitinol the shape set configuration of thecontainer element 4 may include thesmall diameter portion 12 at itsproximal end 18. In other embodiments, thesmall diameter portion 12 may not necessarily be defined by apredetermined shape 46 but instead defined by the constraint of the constrainingcatheter 8. Thesmall diameter portion 12 may be sized to fit within theinner lumen 24 of the constrainingcatheter 8. The inner diameter of thesmall diameter portion 12 may also be sized to allow for the passage of catheters and wires within it.Microcatheters 74 which are used to deploy stent retrievers may be on the order of 0.010″-0.040″ outer diameter. Aspiration catheters which are used to grab clots through aspiration may be on the order of 0.020″-0.070″ outer diameter. Therefore, the inner diameter of thesmall diameter portion 12 may be on the order of 0.010″-0.080″ or may be on the order of 0.025″-0.060″. This may allow other components to pass through the lumen of thecontainer element 4 before and after thecontainer element 4 is deployed. - The
proximal end 18 of thecontainer element 4 may continue through the constrainingcatheter 8 and out of the patient where it can be manipulated to change its relative position to the constrainingcatheter 8 and filaments. In some embodiments, the proximal end of thecontainer element 4 may transition to a catheter or other suitable structure which is capable of moving thecontainer element 4 forward and backward axially or rotationally. The catheter portion of thecontainer element 4 may extend from out of the patient and may be manipulated either by the user, a delivery mechanism, or robotically. Theproximal end 18 of thecontainer element 4 may be connected to a vacuum source such that aspiration may be achieved through the lumen of thecontainer element 4. As will be shown in subsequent description, the aspiration may be used to draw clots into thecontainer element 4 and otherwise prevent distal blood flow. - Returning to
FIG. 1 , there is also shown a constrainingcatheter 8. The constrainingcatheter 8 may be comprised of any number of materials and constructions which exist in the field of catheters. In some embodiments the constrainingcatheter 8 may be a stainless steel braid reinforced catheter with a PTFE inner liner and a Pebax outer jacket. Any number of other suitable constructions and materials may exist. The construction and materials of the constrainingcatheter 8 may vary along its length to achieve the desired stiffness and force transmission. In the example of a MCA application, the constrainingcatheter 8 may be ideally delivered through anintermediate catheter 72 which has been placed in the cerebral artery. The inner diameter ofintermediate catheters 72 used in thrombectomy procedures is typically on the order of 0.04″-0.08″. Therefore, the outer diameter of the constrainingcatheter 8 may be on the order of 0.04″-0.08″ or 0.05″-0.06″. The inner diameter of the constrainingcatheter 8 may be sized to allow the passage of catheters and wires within it which are delivered distally including thecontainer element 4. Therefore, the inner diameter of the constrainingcatheter 8 may be on the order of 0.010″-0.080″ or may be on the order of 0.025″-0.060″. The constrainingcatheter 8 may have a flared or constricteddistal end 16 which facilitates the movement of thecontainer element 4 into and out of the constrainingcatheter 8. For example, the diameter of thedistal end 16 of the constrainingcatheter 8 may be flared by 0.001″-0.020″ such thatcontainer element 4 is easily retracted into the constrainingcatheter 8 by the tapered section. - The constraining
catheter 8 may extend out of the patient and can be manipulated by the user relative to the other components to guide thedevice 2 through the motions described in detail herein. In some embodiments, the constrainingcatheter 8 may be the same as theintermediate catheter 72 such that there is only one catheter. In some embodiments, the constrainingcatheter 8 may be connected to a portion of thefilament 6 or filaments such that a proximal movement of the constrainingcatheter 8 relative to thecontainer element 4 not only deploys thecontainer element 4 but may also cause thedistal opening 20 of thecontainer element 4 to close by way of placing tension on thefilament 6 as the constrainingcatheter 8 retracts. This will be described in greater detail below. - Returning to
FIG. 1 , there is also shown thefilament 6. Thefilament 6 has thefirst arm 28 and thesecond arm 30 extending through the inner lumen of thecontainer element 4 and connected at thefilament perimeter 48 toward thedistal end 16 of thecontainer element 4. Thefilament 6 may extend through the assembly and out of the patient such that it can be manipulated by the user, a deployment mechanism, or robotically. Alternatively, thefilament 6 may connect to a different component within thedevice 2 such as the constrainingcatheter 8 such that the motion of the constrainingcatheter 8 relative to thecontainer element 4 may apply or remove tension from thefilament 6. Thefilament 6 may be amonofilament 6 wire or may be any number of other constructions. For example, thefilament 6 may be small coil made of any of the materials listed herein. Alternatively, thefilament 6 may be a suture material such as a polypropylene or polyester. The material and construction of thefilament 6 may vary along the length of thefilament 6 and need not necessarily be the same along its entire length. In some embodiments the material is a round wire, whereas in other embodiments the snare may be a coil or afilament 6 of any number of cross-sections such as rectangular, ovular, sheet, or the like. Additionally, the cross-sectional shape and area of thesnare filament 6 may vary along the length of the snare. In some embodiments, thefilament 6 is constructed of multiple materials. For instance, a portion of thefilament 6 may be flexible like a suture while other portions are elastic like Nitinol. In some embodiments, thefilament 6 is a piece of Nitinol wire that is 0.0005″-0.0100″ or 0.001″-0.004″ in diameter. Alternatively, thefilament 6 may be stainless steel, tungsten, cobalt chromium, plastic, or any other suitable material. Thefilament 6 may be shape set to have a predetermined shape such as a circle at thefilament perimeter 48. - Turning now to
FIG. 2A-2H , variouspredetermined shapes 46 of thefilament 6 are shown. This is not intended to be an exhaustive list of any possible shape but merely to show the variety of shapes which one could configure thefilament 6 to. InFIG. 2A , afilament 6 with around filament perimeter 48 is shown. Thefilament perimeter 48 may be generally circular or ovular. Thefilament perimeter 48 transitions to afirst arm 28 and asecond arm 28 through afilament 6 bend. Thefirst arm 28 and asecond arm 28 extend roughly perpendicularly from a plane defined by thefilament perimeter 48. As will be shown, thefilament perimeter 48 may be at about the location of thedistal opening 20 on thecontainer element 4 and therefore thefilament perimeter 48 may define a profile that is roughly the same as the inner surface of thevessel 80. InFIG. 2A , thefilament perimeter 48 is about 330-360 degrees in circumference such that thefirst arm 28 andsecond arm 30 are in close proximity. InFIG. 2B , thefilament perimeter 48 defines an arc that has an included circumference which is less and may be on the order of 200-330 degrees such that there is a gap between the filament bends 54 for thefirst arm 28 and thesecond arm 30. InFIG. 2C , thefilament perimeter 48 defines an arc that has an included circumference which is on the order of 360-540 degrees such that there is an overlap of thefilament perimeter 48. InFIGS. 2D and 2E , thefilament perimeter 48 defines a plane that is not substantially perpendicular to the longitudinal axis of thevessel 80.Filament perimeter 48 is an oval that defines a plane which is askew to the central axis of thevessel 80. The application of this embodiment will be described in greater detail in subsequent figures. InFIG. 2D , the filament bends 54 are at a proximal portion of thefilament perimeter 48 and inFIG. 2E the filament bends 54 are at a distal portion of thefilament perimeter 48. InFIG. 2F , thefilament perimeter 48 has anipple 102 feature on its profile. Thenipple 102 feature may facilitate the closing of thedistal opening 20 when thefilament 6 is in tension by providing a specific location where thefilament 6 can bend to a tight radius which may allow thedistal opening 20 to close tightly. InFIG. 2G , thefilament perimeter 48 has an undulatingprofile 104 that can facilitate the weaving into and out of thecontainer element 4 looped ends 106. InFIG. 2H , thefilament perimeter 48 defines an arc that has an included circumference of 70-200 degrees such that thefilament perimeter 48 only circumscribes a portion of thedistal opening 20. InFIG. 2I , thefirst arm 28 andsecond arm 30 are joined at afilament junction 100 which is close to thefilament perimeter 48. InFIG. 2J , they are joined at afilament junction 100 which is proximally further away from thefilament perimeter 48. In these embodiments, there may only be asingle filament 6 which extends proximally and therefore needs to be placed in tension. InFIG. 2K , there are twoseparate filament 6 elements which haveindividual filament perimeters 48. Each of the two filaments has afirst arm 28 and asecond arm 30. This embodiment may have less off axis loading of thecontainer element 4 when thefilaments 6 are placed in tension such that thedistal opening 20 may remain generally concentric as it closes. Any number ofother filament 6 configurations and shapes may be contemplated. In some embodiments thefilament 6 may only have afirst arm 28 and thefilament perimeter 48 may terminate part way through the circumference. In such an embodiment, the end of thefilament perimeter 48 may be connected to a part of thecontainer element 4. In other embodiments, there may be two ormore filaments 6 that connect to thedistal end 16 of thecontainer element 4. The distal end of eachfilament 6 may form a hook that is looped around the distal edge of thecontainer element 4 such that there are a series of pull wires which can be activated independently or in conjunction with one another to place thedistal end 16 of thecontainer element 4 in tension. In other embodiments, thefilament 6 may have a predeterminedshape 46 that is generally straight wire and which is constrained to one of the shapes shown inFIG. 2A-2K by the shape of thedistal end 16 of thecontainer element 4. For example, thefilament 6 may be threaded through thecontainer element 4 and therefore held in a shape that resembles one of the shapes shown inFIGS. 2A-2K by nature of being connected to thecontainer element 4. - The
container element 4 may be connected to thefilament 6 in any number of ways. In some embodiments where thecontainer element 4 is a fabric or bag material, thedistal end 16 of thecontainer element 4 may be wrapped around thefilament 6 and adhered to itself through the use of heat sealing or adhesives or any other suitable method. Alternatively, thefilament 6 may weave through portions of the container element. In some embodiments, thecontainer element 4 may include a laser cut stent structure. The stent may include features such as holes at the distal end which are configured for thefilament 6 to weave through. In some embodiments, thecontainer element 4 is a braided structure and thefilament 6 may weave through the braid or looped ends 106 near or at thedistal end 16 of thecontainer element 4. Thedistal opening perimeter 62 and thefilament perimeter 48 may be generally the same in some configurations such as when thedevice 2 is deployed and in an open configuration. In other configurations such as the constrained or closed configuration, thedistal opening perimeter 62 andfilament perimeter 48 are different shapes and lengths. - In
FIG. 3 , a detailed view of thedistal end 16 of an embodiment of thecontainer element 4 is shown. Thecontainer element 4 is constructed of braided wires. The wires may double back on themselves as shown by terminating at one end of thecontainer element 4 with looped ends 106. For example, at one end of thecontainer element 4, the braided wires may form looped ends 106 by being wrapped around posts during manufacturing and then braiding the wires back over the already created braid. In this way, the looped ends 106 provide an atraumatic end within the vessel and also provide a location where thefilament 6 can be woven through. Thefilament perimeter 48 may be woven through these braided looped ends 106 so that as thefilament 6 is tensioned, it constricts thedistal opening 20 of thecontainer element 4 like a purse string or draw string. Thefilament 6 may weave through back and forth through each of the looped ends 106 or may weave through every other loopedend 106 or any weave pattern. For example, thefilament 6 may weave through only 4 locations of the braided looped ends 106 at 90 degrees apart from each other. The weave characteristics may dictate the friction necessary to open thedistal opening 20 of thecontainer element 4 once it is deployed. It may be advantageous to reduce the friction between thefilament 6 and braid by limiting the number of woven looped ends 106 so that the radial expansion force of thecontainer element 4 can easily overcome the friction of thefilament 6 expanding as it opens. In some embodiments thefilament perimeter 48 can wrap around 360 degrees at the distal end. In other embodiments thefilament 6 can cross over itself and wrap around between 360 and 720 degrees. In still other embodiments thefilament 6 may only wrap around 90 to 360 degrees so that only a portion of thedistal end 16 of thecontainer element 4 has thefilament 6 wrapping around. In still other embodiments, thefilament 6 is only attached to a small section of thecontainer element 4 such as a one or two looped ends 106. Thefilament 6 may also only have a single wire returning proximally from thedistal end 16. Thefilament 6 may form a loop at thedistal end 106 but may connect back to itself such that twofilaments 6 are not required to constrict thedistal end 16. Any number offilaments 6 may be used and connected to thecontainer element 4 and may be actuated independently or in conjunction. - In some embodiments, the
first arm 28 and thesecond arm 30 may weave through sections of thecontainer element 4 along the axial length of thecontainer element 4. This may keep thearms sidewall 26 of thecontainer element 4 such that they do not get in the way of other components which are moving within thecontainer element 4. Additionally, keeping thefilament 6 constrained to thesidewall 26 of thecontainer element 4 may facilitate the closure of thedistal opening 20 by directing the force applied to thedistal opening 20 in a radial direction rather than a proximal direction. In other embodiments, thefirst arm 28 and thesecond arm 30 do not weave through theside wall 26 of thecontainer element 4 and are left free. In this embodiment, they may be configured through apredetermined shape 46 to remain biased against thesidewall 26 or may be configured to take any number of other shapes. - The
container element 4 andfilament 6 are configured such that when they are deployed thecontainer element 4 is unrestricted and thefilament 6 is not under a significant amount of proximal tension. In this condition, thedistal opening 20 of thecontainer element 4 is open and positioned to receiveclot 78 material from the distal direction. The distal opening perimeter andfilament perimeter 48 may be generally the same shape and length in this position. When tension is then applied to thefilament 6, thefilament perimeter 48 anddistal opening 20 may begin to move proximally. Thedistal opening 20 is configured to constrict and close as additional tension is applied to thefilament 6. In this manner, the closure of thedistal opening 20 is actuated by the tension applied to thefilament 6. The distal opening perimeter P may reduce in length as the looped ends of the braid get closer together while thefilament perimeter 48 is the same fixed length. However, the amount of thefilament perimeter 48 that thedistal opening perimeter 62 occupies is less. For example, in the deployed configuration thedistal opening perimeter 62 may overlap with about 60% to 100% or 80% to 100% of thefilament perimeter 48. In the closed configuration, thedistal opening perimeter 62 may overlap with about 1% to 30% or 5% to 15% of thefilament perimeter 48. Thefilament perimeter 48 has remained the same fixed length but its shape has changed and only a portion of it has thedistal opening perimeter 62 overlapping. - In some embodiments the opening of the
distal opening 20 may be actuated by the removal of tension from thefilament 6. As tension is removed, thefilament 6 may return to itspredetermined shape 46 and likewise thecontainer element 4 may return to its unrestricted predetermined shape. As such thedistal opening 20 may return to an open position. In other embodiments, once thedistal opening 20 is closed by means of applying tension to thefilament 6, thedistal opening 20 will not open upon release of the tension to thefilament 6. In this manner thedevice 2 locks into a generally closeddistal opening 20 once tension is applied and even the removal of the tension does not allow thedistal opening 20 to open. - In other embodiments the
filament perimeter 48 may be located substantially away from thedistal end 16 of thecontainer element 4. For instance, rather than weaving thefilament 6 through the looped ends of the braid thefilament 6 may be woven through any section of thecontainer element 4 along its axial length. In some embodiments, thefilament perimeter 48 may not necessarily be woven through any feature on thecontainer element 4. For example, thefilament perimeter 48 may exist primarily on the outer surface of thecontainer element 4 and may simply pinch the outside of the braid at a given location along the axial length of thecontainer element 4 instead of constricting it like a purse string. In such an embodiment, thefirst arm 28 andsecond arm 28 may still enter the inner lumen of thecontainer element 4 by threading through a portion of thecontainer element 4. Thedistal opening 20 anddistal opening perimeter 62 may be defined by the location of thefilament perimeter 48 or may be defined by thedistal end 16 of thedevice 2. - While
filament 6 is generally described herein as a snare type mechanism that cinches thedistal opening 20 of thecontainer element 4, any other types and closures mechanisms may be contemplated. For example, thecontainer element 4 may contain one ormore flaps 88 at its distal end that are connected to one or more filaments. The one ormore flaps 88 may be folded inward by tensioning the filaments so that the flaps collapse and restrict thedistal opening 20. In other embodiments, twisting mechanisms may be used to constrict thedistal opening 20 of thecontainer element 4. For example, thedistal end 16 of thecontainer element 4 may be held generally stationary while the body of thecontainer element 4 is twisted clockwise. In this manner thedistal end 16 of thecontainer element 4 may constrict and close thedistal opening 20. Any number of other closure mechanisms may be contemplated. - Turning now to
FIG. 4A-4P , a first embodiment of thedevice 2 is shown. InFIG. 4A , anintermediate catheter 72 is shown within a vessel which contains a clot. Theintermediate catheter 72 may be any standard size such as between 0.010″ to 0.500″ OD or between 0.050″ and 0.110″ outer diameter depending on the anatomical location it will be used. It may be comprised of any typical materials used for such catheters, such as Pebax, polyimide, PEEK, multi-layer braided composite, or any other suitable material or composition. The vessel shown may be a cerebral artery such as the middle cerebral artery (MCA) or any other vessel within the body of a human or animal. The size of theintermediate catheter 72 may depend on the size of thevessel 80 and the expanded size of thecontainer element 4 as will be shown.Larger vessels 80 often will require larger catheter sizes whilesmaller vessels 80 often will require smaller catheter sizes. Theintermediate catheter 72 is placed proximal of theclot 78 and in a position to deploy other parts of the inventeddevice 2. - In
FIG. 4B , amicrocatheter 74 has traversed theclot 78. Themicrocatheter 74 may be any suitable size such as 0.010″ to 0.080″. Prior to traversing theclot 78 with themicrocatheter 74, a guidewire or other such element may be included and used to guide themicrocatheter 74 across the clot. In some embodiments a guidewire may be required while in other embodiments a guidewire is not necessary. If a guidewire is used, it will often be withdrawn once themicrocatheter 74 traverses the clot and the clot engagement element may then be inserted into themicrocatheter 74 while it is traversing the clot. This places theclot engagement element 58 across theclot 78 so that it is in an optimal location when themicrocatheter 74 is withdrawn. - In
FIG. 4C , themicrocatheter 74 is withdrawn and aclot engagement element 58 is left behind and engages with the clot. Theclot engagement element 58 may be a stent retriever type design as shown but it may also be any other element suitable for pulling a clot proximally. In the embodiment shown, theclot engagement element 58 has a series of struts or interwoven elements that expand radially outward when it is not constrained which allow it to engage with theclot 78 and pull it proximally when theclot engagement element 58 is retracted. In other embodiments, theclot engagement element 58 is a balloon that is inflated distally to theclot 78 such that as it retracts, it pulls theclot 78 proximally with it. In still other embodiments, theclot engagement element 58 is a Nitinol wire with a convoluted shape such that when it is deployed it likewise engages with theclot 78 and secures itself in different areas of the clot. Any number of otherclot engagement elements 58 may be contemplated. - In
FIG. 4D , theintermediate catheter 72 is withdrawn, exposing a constrainingcatheter 8 which constrains thecontainer element 4. In some embodiments there is no need for a constrainingcatheter 8 and theintermediate catheter 72 can constrain thecontainer element 4 such that when it is retracted, as will be shown with the constrainingcatheter 8, thecontainer element 4 is deployed. In some embodiments, the constrainingcatheter 8 with thecontainer element 4 is within theintermediate catheter 72 during the navigation and delivery of themicrocatheter 74 while in other embodiments it is advanced into position within theintermediate catheter 72 at some point between navigation and after theclot engagement element 58 has been deployed. - In
FIGS. 4E-4H show acontainer element 4 being deployed within the vessel. InFIG. 4E , the constrainingcatheter 8 begins to be retracted and thedistal end 16 of thecontainer element 4 is deployed. The initial deployment steps of thefilament perimeter 48 anddistal end 16 of thecontainer element 4 will be shown in greater detail inFIGS. 7A-7G . - In the embodiment shown in
FIGS. 4E-4H , thecontainer element 4 has a relatively consistent unconstrained diameter of 3 mm-6 mm and is sized such that when deployed within an MCA, it is uniformly in contact with the vessel wall. InFIG. 4E , thecontainer element 4 is partially deployed and afilament perimeter 48 exists at thedistal end 16 of thecontainer element 4. The plane formed by thefilament perimeter 48 is generally perpendicular to the longitudinal axis of thevessel 80. - In
FIG. 4F , thecontainer element 4 is more deployed out of the constrainingcatheter 8. As is shown, when thecontainer element 4 comes out of the constrainingcatheter 8 it self-expands against thevessel 80. In other embodiments, thecontainer element 4 may be actively expanded with the use of balloons, shape memory materials such as nitinol that transition at a given applied temperature, or any other means. For example, in some embodiments the constrainingcatheter 8 may be fully retracted before thecontainer element 4 is actively expanded in the vessel. Thefilament perimeter 48 comes out of the constrainingcatheter 8 and automatically expands to thevessel 80 with thecontainer element 4 open. In some embodiments thefilament perimeter 48 may come out of the constrainingcatheter 8 in a fully or partially closed configuration and then may be opened once in place. - In
FIG. 4G , thecontainer element 4 is more deployed as the constrainingcatheter 8 is further retracted. In some embodiments, the constrainingcatheter 8 is retracted to deploy thecontainer element 4. In other embodiments, thecontainer element 4 may be advanced out of the constrainingcatheter 8. In still other embodiments there may be a combination of retracting the constrainingcatheter 8 and advancing thecontainer element 4. In fact, as shown the axial length of thecontainer element 4 is significantly longer when it is within the constrainingcatheter 8. Therefore, as thecontainer element 4 is deployed by retracting the constrainingcatheter 8, the proximal end of thecontainer element 4 must be advanced if the distal end of thedistal end 16 of thecontainer element 4 is to stay in a fixed location. Since thecontainer element 4 may be in contact with thevessel 80 when it is deployed it may be advantageous to keep any areas which are contacting thevessel 80 stationary so as not to injure thevessel 80. Therefore, a retraction of the constrainingcatheter 8 may be accompanied by an advancing of theproximal end 18 of thecontainer element 4. - In
FIG. 4H , thecontainer element 4 is shown in a fully deployed state. The constrainingcatheter 8 has been retracted far enough that aproximal funnel area 14 of thecontainer element 4 is exposed. Theproximal funnel area 14 may be a predetermined shape that thecontainer element 4 has at theproximal end 18 of itsvessel diameter portion 10. Theproximal funnel area 14 tapers thevessel diameter portion 10 to thesmaller diameter portion 12 that fits within the constrainingcatheter 8. It should be noted that aproximal funnel area 14 may not be required since thecontainer element 4 may naturally come out of the constrainingcatheter 8 in a funnel shape as it is being deployed. As will be discussed theproximal funnel area 14 may provide local flow arrest in thevessel 80. In some embodiments, the user may select the length of thecontainer element 4 to deploy. For example, in the case of capturing small clots only ¼-½ of thevessel diameter portion 10 of thecontainer element 4 may be deployed. Other times in the case oflonger clots 78, the full length of thevessel diameter portion 10 may be deployed. The amount ofcontainer element 4 may be selectable by the user. - As shown in
FIG. 4H , themicrocatheter 74 may remain within thedevice 2 or it may be removed from the patient at any point during the procedure. In some embodiments, themicrocatheter 74 is a mono-rail catheter that allows it to be removed while keeping the clot engagement element in place. In other embodiments, themicrocatheter 74 remains in place and may be used in subsequent steps to sheath theclot engagement element 58 once the clot is captured within thecontainer element 4. - In
FIG. 4I theclot engagement element 58 with theclot 78 is withdrawn toward thedistal opening 20 of thecontainer element 4. As theclot engagement element 58 reaches thedistal opening 20 of thecontainer element 4 it enters thecontainer element 4. Thedistal end 16 of thecontainer element 4 may be flared outward, either by its predetermined shape or by a radial force from thefilament perimeter 48, so that theclot engagement element 58 enters smoothly and does not get stuck on any part of thecontainer element 4 as it enters. Alternatively, thedistal end 16 of thecontainer element 4 may be constricted partially. - In
FIG. 4J , theclot engagement element 58 has been withdrawn so that it is entirely within thecontainer element 4. Some embodiments of theclot engagement element 58 may leave components outside of thecontainer element 4. One critical aspect is that most or all of theclot 78 that will be withdrawn from the patient is within thecontainer element 4 even though pieces of theclot engagement element 58 may remain outside of thecontainer element 4. For example, theclot engagement element 58 may be a balloon that pulls theclot 78 into thecontainer element 4 but itself does not go fully within thecontainer element 4. In some embodiments, portions of theclot engagement element 58, guidewire,microcatheter 74, or any other structure may remain distal to thedistal opening 20. In this manner, when thedistal opening 20 is fully or mostly closed, devices may be navigated beyond the distal end of the distal opening. For example, after retracting aclot engagement element 58 with aclot 78 into thecontainer element 4, thedistal opening 20 may be disclosed as described herein but with a portion of theclot engagement element 58 remaining distal. The user may then use amicrocatheter 74 to constrict theclot engagement element 58 again and advance the microcatheter beyond thedistal opening 20. In this manner, aclot engagement element 58 may be used again to engage with additional pieces ofclot 78 which were not retracted the first time. Such an embodiment can be used when theclot engagement element 58 is a stent retriever or anaspiration catheter 76. Thedistal opening 20 can be opened by releasing tension on thefilament 6 and theadditional clot 78 material can be retracted within the containingelement 4. This process may be repeated as many times as necessary and may be useful in removing significant amounts ofclot 78 or in instances where only fragments of theclot 78 can be engaged. - In
FIGS. 5A-5E , thedistal end 16 of thecontainer element 4 andfilament perimeter 48 are shown in greater detail during the closure of thedistal opening 20. InFIG. 5E , thecontainer element 4 is shown with thedistal opening 20 in the open configuration where theclot engagement element 58 can be withdrawing into thecontainer element 4. - In
FIG. 4K , thedistal opening 20 of thecontainer element 4 begins to close. In the embodiment shown, a proximal tension is applied to thefirst arm 28 orsecond arm 30 or both. The tension can be equal across thearms first arm 28 is tensioned while in other embodiments both arms are tensioned. The tension in thefilament 6 imparts a proximally directed force on thedistal end 16 of thecontainer element 4. This may be translated into a compressive load on thecontainer element 4. During the proximal loading of thefilament 6, thefilament perimeter 48 begins to move proximally and change shapes. Additionally, thedistal end 16 of thecontainer element 4 anddistal opening 20 begin to move proximally as a result of the proximal force applied through thefilaments 6. The braided structure may be designed to increase in diameter when it is constricted and decrease in diameter when it is lengthened. In the embodiments where thecontainer element 4 is of a woven or braided construction, as thedistal end 16 of thecontainer element 4 moves proximally it may expand radially. At some point the radially expansion may be constrained by thevessel 80 and thecontainer element 4 may then impart a radially outward force on thevessel 80. In some embodiments where thecontainer element 4 is already in close approximation with thevessel 80 thecontainer element 4 may not substantially expand when it is placed under a compressive load but rather may directly impart a radially outward force. In some embodiments only a portion of thecontainer element 4 such as thedistal end 16 may expand radially and impart a radially outward force while in other embodiments a substantial amount of thecontainer element 4 may do so. The outward force may facilitate in securing at least a portion of thecontainer element 4 to thevessel 80 and prevent it from moving proximally. In this manner, the tension applied to thefilament 6 may secure thecontainer element 4 distally to thevessel 80 such that thedistal opening 20 can be closed. If thecontainer element 4 is not constrained and secured by thevessel 80, there must be a component or components which impart a reaction force to support the distal end while thedistal opening 20 is closing. In some embodiments this may be thecontainer element 4 itself which may have structures and frames to support a compressive load. This may be true in the case of a framed configuration of thecontainer element 4. Alternatively, additional catheters or support structures may provide a reaction force to hold the distal end while thedistal opening 20 is closed. In some embodiment which will be shown in greater detail below, thefilament 6 may be supported by afilament catheter 82 which can provide such a function. An advantage of the braided structure of thecontainer element 4 described herein is that thedevice 2 can be very flexible and no stiff or rigid components are required because it is secured to thevessel 80 itself and only when tension is applied to thefilament 6. - In
FIG. 5B , a closer view of thedistal end 16 is shown with thefilament perimeter 48 beginning to constrict thedistal opening 20. As can be seen, thefilament perimeter 48 remains a fixed length is moving proximally such that thedistal opening perimeter 62 is decreasing in length. The looped ends 106 of the braid are being constricted like a purse string with a pull wire. Thedistal opening perimeter 62 is occupying a smaller portion of thefilament perimeter 48 as more tension is applied. - In
FIGS. 4L and 5C , additional tension is applied to thefilament 6 and thedistal opening 20 is constricted further. Thedistal end 16 of thecontainer element 4 and thefilament perimeter 48 have moved further proximally. InFIGS. 4M and 5D , thefilament perimeter 48 anddistal opening 20 have moved further proximally such that they are within thesidewall 26 of thecontainer element 4. Thedistal opening perimeter 62 now occupies a small portion of theoriginal filament perimeter 48 at its very distal end. Thecontainer element 4 has inverted as thefilament perimeter 48 moves proximally and a portion of thecontainer element 4 is secured by thevessel 80. InFIGS. 4N and 5E , thefilament perimeter 48 anddistal opening 20 have moved even further proximally. Thefilament perimeter 48 has changed shapes from thepredetermined shape 46 to an elongated loop due to the tension across the elements. In some embodiments, thedistal opening 20 is generally concentric with thevessel 80 while in other embodiments thedistal opening 20 may be of axis or angled in any manner determined by the applied forces. - The cross sectional area of the distal opening when it is in the closed configuration may be between 0-1.0 mm2 or between 0.01-0.2 mm2. The
distal opening 20 must be mostly closed to prevent any parts of theclot 78 from coming out of thecontainer element 4. Thedistal opening 20 is formed by the space between the looped ends 106 of thebraided container element 4. In the closed configuration, the looped ends 106 are bunched up close together such that the effectivedistal opening perimeter 62 of thedistal opening 20 is significantly reduced from the open shape. For example, if thedevice 2 is used in a cerebral artery application and deployed into a vessel with a 5 mm diameter, the circumference of thedistal opening 20 when thecontainer element 4 is deployed may be between 10 mm-20 mm or between 14 mm-17 mm. When thedistal opening 20 is transitioned to a closed configuration, the circumference may be between 0.01 mm-5 mm or between 0.5 mm-2 mm. Thedistal opening perimeter 62 is now only occupied by part of thefilament perimeter 48 which has been tensioned and so the majority of thefilament perimeter 48 is now proximal to thedistal opening 20. The shape of thedistal opening 20 configuration in this shape is not necessarily circular and in fact is likely not circular. The shape may be like a horseshoe or half-moon or any portion of an arc or bent wire. - In
FIG. 5E , thedistal end 16 of thecontainer element 4 is shown inverted such that it has move further proximally within thecontainer element 4 itself. The tension in thefilament 6 has pulled thedistal end 16 proximally and secured thedistal opening 20 closed. - In some embodiments the
filaments 6 are connected to the constrainingcatheter 8 such that the constrainingcatheter 8 can be further retracted and thefilaments 6 can close at thedistal end 16. In such an embodiment, the user only needs to retract one component, in this case the constrainingcatheter 8, in order to deploy thecontainer element 4 and then continue to retract it in order for thedistal opening 20 to constrict.FIGS. 4J-4N show the constrainingcatheter 8 moving proximally as thefilament 6 is placed in tension indicating such a configuration. This may provide advantages for the user interface and simplicity of thedevice 2. In some embodiments, theclot engagement element 58 or theintermediate catheter 72 may be connected similarly to thefilament 6 to perform a similar function as described above. In other embodiments, a handpiece may exist outside of the body which handles the relative movements of the catheters and elements. For example, a syringe type motion or a trigger type motion by the user may cause thedevice 2 to go through its relative motions as described herein. In this manner the user does not have to think about which component to move but rather can just activate a simple interface to move through the various stages. - In
FIG. 4O , theclot engagement element 58 has been removed from the body leaving the majority of theclot 78 behind in thecontainer element 4. In some embodiments this step is not performed and theclot engagement element 58 can remain in position relatively to thecontainer element 4 as theentire device 2 is removed from the body. - In
FIG. 4P , thedevice 2 begins to be removed from the body by pulling it proximally. In the embodiment shown, thecontainer element 4 is a braid that decreases in diameter as it is placed under tension. Thecontainer element 4 therefore stretches as shown and can be further pulled into other catheters if necessary. At this point theclot 78 is fully contained within thecontainer element 4 and will not distally embolize as it is retracted. Thecontainer element 4 anddevice 2 may be stretched as much as necessary to remove it from the body. In some embodiments, once thefilament 6 is pulled taut and thedistal opening 20 of thecontainer element 4 is constricted, it does not significantly open again even if the tension in thefilament 6 is reduced or removed. This may be caused by a locking mechanism in thedevice 2 that locks thefilament perimeter 48 closed or may be simply due to friction within the system that prevents thefilament perimeter 48 from opening once it is closed. Alternatively, thedistal opening 20 of thecontainer element 4 may automatically open once thefilament 6 is relaxed. In some embodiments, after thedevice 2 is removed from the body it may be opened and thedevice 2 may be used again foradditional clots 78 and foreign bodies. - In
FIGS. 6A-6H , an alternative embodiment of thedevice 2 is shown. In this embodiment, theclot engagement element 58 is anaspiration catheter 76 rather than a stent retriever. InFIG. 6A , thecontainer element 4 has been deployed in the vessel but nomicrocatheter 74 or stent retriever necessarily traverse the clot. Instead, anaspiration catheter 76 exists within the lumen of thedevice 2 and may be advanced. Theaspiration catheter 76 may be comprised of any of the materials or constructions known to one skilled in the art of catheters. The outer diameter may be on the order of 0.02″ to 0.080″ and sized to fit within the lumen of thecontainer element 4. Theaspiration catheter 76 may be connected to a vacuum source external or internal to the patient that provides suction to the distal end of theaspiration catheter 76. Theaspiration catheter 76 can be used for aspirating blood such that it flows in a proximal or retrograde manner within the cerebral artery. Additionally, the suction in theaspiration catheter 76 can be used to engage and removeclots 78 or foreign bodies. - In
FIG. 6B , theaspiration catheter 76 is advanced distally toward theclot 78. InFIG. 6C , suction applied to theclot 78 may pull theclot 78 toward theaspiration catheter 76 or alternatively theaspiration catheter 76 may be advanced all the way to theclot 78 before suction is applied. InFIG. 6D , theaspiration catheter 76 is withdrawn into thecontainer element 4 with theclot 78 such that theclot 78 is contained within thecontainer element 4. In some embodiments, theclot 78 may be in multiple pieces or may break apart during the aspiration and retraction. In such cases, theaspiration catheter 76 may be extended distally multiple times from thecontainer element 4 and engage with new pieces ofclot 78. Theclot 78 can be retracted into thecontainer element 4 and can then be dislodge from theaspiration catheter 76 by releasing the suction or providing a positive pressure through theaspiration catheter 76 to dislodge theclot 78. Alternatively, thedistal opening 20 of thecontainer element 4 can be partially closed as described herein and used as a method of keeping theclot 78 within thecontainer element 4 while allowing theaspiration catheter 76 to be distally extended again to engage with another piece ofclot 78. - In
FIG. 6E , thefilament 6 is tensioned and thedistal opening 20 begins to close and may retract proximally. InFIG. 6F , thefilament 6 is further tensioned and thedistal opening 20 closes further. In this state, theaspiration catheter 76 could be advanced distally to extend out of thecontainer element 4 and engage with anotherclot 76. In such embodiments, a guidewire ormicrocatheter 74 may be left distal to thedistal opening 20 so that theaspiration catheter 76 can traverse through thedistal opening 20. Before pulling thenew clot 78 into thecontainer element 4, thedistal opening 20 may be opened as needed by releasing tension on thefilament 6. Aspiration may be applied through thecontainer element 4 to keep any loose clot fragments within thecontainer element 4 while thedistal opening 20 is partially or fully open. InFIG. 6G , thedistal opening 20 is inverted within thecontainer element 4. InFIG. 6H , thedistal opening 20 is further inverted and moved proximally along with thefilament perimeter 48. - In some embodiments, a
separate aspiration catheter 76 is not necessary. The aspiration can be applied to the lumen of thecontainer element 4 such that flow is directed in from thedistal opening 20. Thecontainer element 4 can be positioned just proximal to theclot 78 so that when aspiration is applied, theclot 78 is suctioned into thecontainer element 4. In any of the embodiments described herein aspiration may be applied to any of the elements. For example, a vacuum source may be fluidly connected to the constrainingcatheter 8,container element 4,microcatheter 74, aspiration catheter,intermediate catheter 72, or any other component. - Turning now to
FIG. 7A-7G , an embodiment of thedevice 2 is shown with thecontainer element 4 deploying out of a constrainingcatheter 8 in greater detail. InFIG. 7A , a constrainingcatheter 8 is shown with a distal end. As mentioned, the constrainingcatheter 8 may be a separate catheter or may be anintermediate catheter 72 or any other catheter within thedevice 2. InFIG. 7B , thecontainer element 4 begins to deploy. A first leadingportion 38 of the filament(s) 6 begins to exit the constrainingcatheter 8 as shown in a ‘bunny ears’ configuration. The term bunny ears is intended to describe the shape shown inFIG. 7B-7D , however this term should not be limiting to other shapes or configurations which may accomplish the same thing. InFIG. 7C , the first leadingportion 38 of thefilament 6 exit the constrainingcatheter 8 more and begin to fold outward. The first leadingportion 38 forms afirst loop 40 that resembles a bunny ear. A second leadingportion 42 may also exist and move with the first leadingportion 38. InFIG. 7D , the braid of thecontainer element 4 begins to deploy as shown. As thedistal end 16 of thecontainer element 4 begins to open slightly, the length of thefilament 6 within thefirst loop 40 begins to become thefilament perimeter 48 at the distal end. InFIG. 7E , thecontainer element 4 is further deployed and the distal end has opened up substantially from its constrained shape within the constrainingcatheter 8. At this point, most of the length of thefilaments 6 that was previously within the ‘bunny ears’ shape has become thefilament perimeter 48 of wire at thedistal end 16 of thecontainer element 4. There is no significantexcess filament 6 length at thedistal end 16 of thecontainer element 4 and thedistal end 16 of thecontainer element 4 has been deployed in a primarily open configuration, not a constricted configuration. InFIG. 7F , thecontainer element 4 is further deployed. - In
FIG. 7G , thecontainer element 4 is mostly deployed. Thefilament perimeter 48 at thedistal end 16 of thecontainer element 4 is in the open configuration and thearms container element 4 and into the constrainingcatheter 8. At this point, theclot engagement element 58 could be pulled into thecontainer element 4 at thedistal end 16. - The ‘bunny ears’ shape of the filaments may be important because it is one embodiment in which the
container element 4 may be deployed with an opendistal end 16. As used herein, ‘bunny ears’ refers to a specific aspect of the leadingportion 38 and all combinations and features shall be shared without indispensable features from either. That is, all features of the ‘bunny ears’ needn't include a closed loop 50 nor more than one for those features to be used with any aspect of the leadingportion 38 independently. Stated another way, the terms may be interchangeable without impugning any necessity of one or the other or any feature of one to the other by necessity. When thecontainer element 4 is within the constrainingcatheter 8, thedistal opening 20 is much smaller than when it is open after being deployed. For example, when it is within the constrainingcatheter 8, thedistal opening 20 may be 1.0 mm in diameter versus when it is deployed and open it may be 5.0 mm in diameter. In this example, this represents a 5× increase in diameter and circumference. Therefore, since thefilament perimeter 48 extends around the circumference of thecontainer element 4, the length of thefilament 6 at thedistal end 16 has to similarly increase by 5×. In some embodiments, thefilament 6 at thedistal end 16 can simply grow in length by pullingmore filament 6 distally. However, the force required to pullmore filament 6 distally may be significant compared to the opening force of thecontainer element 4. For example, if thecontainer element 4 is a shape set braid that has a nominal 5 mm diameter then it will have a given radial force trying to open the distal end once it is deployed from a 1mm constraining catheter 8. However, this force may not be enough to pullmore filament 6 distally especially if thedevice 2 is long or curved due to anatomical constraints. Therefore, thedistal end 16 may not open fully when it is deployed unless another consideration is given for the increase infilament 6 length at the distal end. The ‘bunny ears’ keep an amount of excess filament length at thedistal end 16 of thecontainer element 4. Therefore, when thecontainer element 4 is deployed, thefilament perimeter 48 at thedistal end 16 can form an open circular shape. This is particularly relevant in embodiments where thefilament 6 is shape set to apredetermined shape 46 such as a circle. The 90degree filament bend 54 where thefilament 6 transitions from thefilament perimeter 48 to thearms device 2 does not move substantially relative to thecontainer element 4 when thedevice 2 is deployed versus when it is constrained. The length of thefilament perimeter 48 instead transforms into the ‘bunny ears’ shape and is then constrained by the constrainingcatheter 8 with leadingportions 38 extending distally from the end of thecontainer element 4. In some embodiments the shape set profile of thefilament 6 perimeter can include features which encourage the ‘bunny ears’ shape or a similar shape. For example, thefilament perimeter 48 may be primarily a circle but may additionally havesmall nipples 102 extending radially outward defined by the loop pathway as shown inFIGS. 2F and 2G . This may provide a specific place for the ‘bunny ears’ to bend when they are constrained within the constrainingcatheter 8. ThoughFIGS. 7A-7G show a ‘bunny ears’ shape, any number of other shapes may be contemplated such as a single loop, several loops, or any other shape that takes up the filament length when it is constrained. - In other embodiments, the excess amount of
filament 6 length is folded or bunched up in any number of other locations. InFIGS. 14A-14C , an embodiment of such adevice 2 is shown. InFIG. 14A , acontainer element 4 is shown in a constrained configuration. Although a constrainingcatheter 8 is not shown, it can be appreciated that thecontainer element 4 is radially constrained within a catheter. As shown thedistal opening 20 of thecontainer element 4 is relatively small. There is afilament 6 with afilament junction 100 as also described inFIGS. 2I and 2J , such that there is asingle arm 28 extending proximally from thefilament perimeter 48. Thefilament perimeter 48 has a generally circularpredetermined shape 46 when unconstrained but in the constrained configuration shown thefilament perimeter 48 has an elongated loop shape. Thefilament perimeter 48 extends along a given length of the longitudinal axis LA of thecontainer element 4 that is roughly one half of the circumference of thefilament perimeter 48 when it is unconstrained. For example, if the diameter of thefilament perimeter 48 is 5 mm, the longitudinal length of thefilament perimeter 48 when stretched as shown may be about 6 mm-9 mm. Thedistal arm 98 transitions to a region offilament excess length 96 which is folded into the constrainingcatheter 8 and then transitions to a filamentproximal arm 94. As will be shown, thefilament excess length 96 is folded and stored within the constrainingcatheter 8 so that when thefilament perimeter 48 expands to its unconstrained shape, thefilament excess length 96 can be utilized. InFIG. 2B , thecontainer element 4 andfilament perimeter 48 have been deployed out of the constrainingcatheter 8. Thefilament perimeter 48 now extends a very short length of the longitudinal axis LA of thecontainer element 4. For example, thefilament perimeter 48 may extend only about 0 mm-3 mm or 0.25 mm-1 mm. As a result, thefilament junction 100 advances distally by about the difference between the longitudinal length of thefilament perimeter 48 in the constrained shape and the longitudinal length of thefilament 6 in the deployed shape. For example, this might be about 1 mm-9 mm or 3 mm-6 mm. Thefilament excess length 96 may then unfold and allows the extension of the filamentdistal arm 98 without substantial movement of the filamentproximal arm 94. The foldedfilament excess length 96 enables the frictional force of pulling the filamentdistal arm 98 to be minimized since the filamentproximal arm 94, which extends through additional components and potentially tight turns, does not need to move substantially. Therefore, the radial opening forces of thefilament 6 or thecontainer element 4, or both, do not need to overcome a large frictional force and may still achieve their open deployed position. The foldedfilament excess length 96 may exist at any location within any of the catheters but may be optimally applied within thecontainer element 4 and more optimally toward thedistal end 16 of thecontainer element 4 and as explained elsewhere herein. The features related to the working length WL may be combined in any subset of features as being related aspects of the invention and all such combinations and sub-combinations are expressly provided as further aspects of the present invention. For example, it is expressly provided even though not explicitly stated that the foldedfilament 6 is positioned within 10 mm of the distal end so that all features describe above concerning the working length are equally applicable to the foldedfilament 6. As another example,FIG. 14 shows that the excess length may be along the distal portion and formed by a first fold and a second fold forming a flat z-shaped portion for thefilament excess length 96. InFIG. 14C , thedevice 2 is shown in a closed configuration as theproximal arm 28 is placed in tension. Thefilament excess length 96 may unbend more than is shown in the figure, but it should be noted that the shape of thefilament 6 in the closed configuration is unique and different from the shape of thefilament 6 in the constrained position. - In some embodiments, the
filament perimeter 48 shape when thecontainer element 4 is in the constrainingcatheter 8 is different than the shape of thefilament perimeter 48 when thedistal opening 20 is closed. Thefilament perimeter 48 therefore goes through at least 3 unique shapes. First, when thecontainer element 4 is in the constrainingcatheter 8, thefilament perimeter 48 is in a shape that may look like the ‘bunny ears’ or any other shape where thefilament excess length 96 is accounted for. This includes the askew plane configuration described in greater detail below. Second, when thecontainer element 4 is in the open deployed configuration, thefilament perimeter 48 forms a circumference of thedistal opening 20 that is generally circular. Thefilament perimeter 48 may be at or close to itspredetermined shape 46 at this point. Third, when thefilament 6 is in tension and thedistal opening 20 is closed, thefilament perimeter 48 resembles an elongated loop or stretched rubber band where the distal end of thefilament perimeter 48 forms a small circumference of thedistal opening 20 which may or may not be circular. Thefilament perimeter 48 transitions between these three shapes during the normal use of thedevice 2. Specifically, the first and third shapes are unique meaning that the shape of thefilament perimeter 48 when thecontainer element 4 is in the constrainingcatheter 8 is not necessarily the same as when thedistal opening 20 is closed. - In
FIGS. 8A and 8B , another embodiment which accounts for the diameter change is shown. In some embodiments other designs which address the filament length issue may be utilized. Thefilament perimeter 48 generally forms a plane. The plane may be aperpendicular plane 66 which is perpendicular to the longitudinal axis LA of thecontainer element 4 as shown inFIGS. 4A-4P , or the plane may be askew to the longitudinal axis LA. InFIG. 8B , the plane is tilted by anaskew angle 64 of about 30 degrees from theperpendicular plan 66. Thefilament perimeter 48 forms an ellipse or similar shape and has a distal section at one apogee and a proximal section at the other apogee. An advantage to this design is that when thecontainer element 4 is constrained within the constrainingcatheter 8, as shown inFIG. 8A , it increases in length. Therefore, if thefilament perimeter 48 is askew, it will increase in length as it is constrained radially and the amount that it is askew will increase. So thefilament excess length 96 is transformed from a larger diameter when it is deployed to a longer length when it is constrained. This addresses the same problem identified above such that thefilaments 6 do not need to move distally so that thedistal end 16 of thecontainer element 4 can open once it is deployed. The excess filament length needed to change from a constrained shape to a deployed shape is already in place at the distal end and thearms clot engaging element 58 into thecontainer element 4. In some embodiments thedistal end 16 of thecontainer element 4 with its crown of looped ends is also askew to its longitudinal axis LA while in other embodiments thefilament perimeter 48 is simply threaded through the braid of thecontainer element 4 at an angle while the distal end is still perpendicular to the longitudinal axis LA. The amount that the snare is askew to theperpendicular plane 66 may be between 2-60 degrees or between 10-30 degrees. When the embodiment shown inFIGS. 8A and 8B is in the closed configuration by placing tension on one or both of thearms filament perimeter 48 in the closed configuration is not necessarily the same as the shape of thefilament perimeter 48 in the constrained configuration. - In some embodiments, the
filament perimeter 48 does not define a single plane and instead may be a more complex three-dimensional shape. For example, thefilament perimeter 48 may have portions that are askew to the longitudinal axis LA of thecontainer element 4 and other portions that are askew in a different angle or orientation. Thefilament perimeter 48 may have protrusions that extend proximally or distally. Thefilament perimeter 48 is not constrained by a single plane. - In
FIGS. 9A-9F , the closure of thedistal opening 20 of thecontainer element 4 is shown in greater detail. Thecontainer element 4 is within a 5 mm vessel. In these figures, theclot 78 andclot engagement elements 58 are not shown but would be within thecontainer element 4 during this step. InFIG. 9A , thedistal end 16 of thecontainer element 4 is generally open such that it could receive theclot engagement element 58 to be pulled into thecontainer element 4. Thefilament perimeter 48 is in an open shape and there may be little or no tension in thearms clot 78 andclot engagement elements 58 are within thecontainer element 4, tension can be placed on thearms FIG. 9B which moves thedistal end 16 of thecontainer element 4 proximally as the braid bunches up and expands radially. Thedistal opening 20 of thecontainer element 4 effectively closes as thefilament 6 is pulled proximally. As can be seen inFIG. 9C , the shape set profile of thecircular filament perimeter 48 is retracted further and stretched so that only a small amount of thefilament perimeter 48 remains at thedistal opening 20 as it is closed and thedistal opening perimeter 62 is significantly reduced. - In
FIG. 9D , thefilaments arms distal opening 20 of thecontainer element 4 moves proximally as well and even folds back within itself. InFIG. 9E , thedistal end 16 is folded back even further. This may be required in some embodiments while in other embodiments less tension is required on thearms clot 78 particles do not escape thecontainer element 4. - In
FIG. 9F , thecontainer element 4 is shown removed from avessel 80 with the distal end constricted. As can be seen there is generally no opening at the distal opening to allow further embolization of theclot 78. Thefilament 6 is effectively closing thedistal opening 20 as a purse string so that all the looped ends 106 of the braid are close together. - In other embodiments, a
filament catheter 82 is included in thedevice 2. Afilament catheter 82 can provide several advantages. First, it can provide axial support to thedevice 2 as thefilament 6 is being cinched. The support may hold thedistal end 16 of thedevice 2 in a fixed position during thedistal opening 20 closure. Second, it can facilitate in the deployment and retraction of thecontainer element 4 in the vessel. In the configurations where thecontainer element 4 is a braid, thefilament 6 catheter can be used to stretch the braid and thereby reduce its diameter by applying a distally acting tension on the braid. Third, it can keep thearms container element 4. -
FIG. 10A shows thefilament catheter 82 within theintermediate catheter 72 and thedistal opening 20 in the closed configuration. Thecontainer element 4 is completely within theintermediate catheter 72 in this configuration and theintermediate catheter 72 can be advanced to thetarget vessel 80 in this configuration. In this embodiment, thefilament catheter 82 is shown external to thecontainer element 4. Alternatively, thefilament catheter 82 could be within the lumen of thecontainer element 4. InFIG. 10B , theintermediate catheter 72 has been retracted while thefilament catheter 82 remained in the same location. Alternatively, thefilament catheter 82 can be advanced while theintermediate catheter 72 remains in the same location. Thefilament perimeter 48 is distal to the end of theintermediate catheter 72 and is still in the closed configuration with the proximal end of thecontainer element 4 still within theintermediate catheter 72. It should be noted that the amount of closure of thedistal opening 20 can be less or more than what is shown. For example, thedistal opening 20 can be closed more so that thecontainer element 4 at thefilament perimeter 48 touches itself and forms a full or partial seal at thedistal opening 20. InFIG. 10C , thefilament 6 has been advanced and thedistal opening 20 is in the open configuration. Thefilament perimeter 48 is opened to approximately the size of the vessel diameter and the container is therefore opened as well. - Turning now to
FIG. 11A-11K , the use of the inventeddevice 2 and method will be shown.FIGS. 11A-11F show a series of steps that is similar to what may be currently practiced in thrombectomy procedures. InFIG. 11A , aclot 78 is shown in avessel 80 such as a middle cerebral artery. Anintermediate catheter 72 has been advanced to thetarget vessel 80 as shown. InFIG. 11B , amicrocatheter 74 has been advanced and aguidewire 84 has been advanced so that it traverses theclot 78. InFIG. 11C , themicrocatheter 74 follows theguidewire 84 and traverses theclot 78. Contrast may be injected through themicrocatheter 74 at these steps to confirm its location with fluoroscopy. Theguidewire 84 is removed from themicrocatheter 74 inFIG. 11D . InFIG. 11E , aclot engagement element 58 such as a stent retriever is inserted into themicrocatheter 74 until its tip extends distally from the end of themicrocatheter 74. InFIG. 11F , themicrocatheter 74 is retracted and the stent retriever expands into theclot 78 and grabs it so that it can be pulled with the stent retriever. In a typical thrombectomy procedure the stent retriever is now pulled along with the microcatheter andintermediate catheter 72. They can be pulled through the vessel and into a silicon balloon catheter in the carotid. While this can remove the clot it can also create fragmentation and distal embolization of the clot as described above. -
FIGS. 11G-11K show the use of an embodiment of part of the inventeddevice 2 and method which can reduce the problems associated with just pulling theclot engagement element 58 and barenon-covered clot 78 out through thevessel 80. - In
FIG. 11G , theintermediate catheter 72 andmicrocatheter 74 are removed, leaving the stent retriever behind in thevessel 80 with theclot 78. Monorail type catheters (e.g. Rapid Exchange) may be used instead of over-the-wire catheters for any of the catheters described herein to make exchanges of the catheters and wires easier. Alternatively, theintermediate catheter 72 can be left in place proximal to theclot 78 and the stent retriever. In this embodiment thedevice 2 can be fed into the existingintermediate catheter 72 and the remaining steps of the described procedure can be followed. - In
FIG. 11H , a newintermediate catheter 72 or the pre-existingintermediate catheter 72 with thedevice 2 is inserted onto the stent retriever wire and advanced to the target vessel. As described a monorail style catheter may be used. In at least some embodiments, the stent retriever wire is inserted through a hole at the proximal end of the container element such that the wire extends through the lumen of thecontainer element 4. In other embodiments the hole may be significantly larger such that thecontainer element 4 does not come to a closed end like a wind sock. Thefilament 6 is within theintermediate catheter 72 and is in the closed configuration. - In
FIG. 11I , theintermediate catheter 72 is retracted and thecontainer element 4 is opened in thevessel 80. Thefilament perimeter 48 expands manually or automatically such that it approximates thevessel 80 inner diameter. In some embodiments, thecontainer element 4 orfilament 6 significantly reduces or occludes blood flow through the vessel to further prevent distal embolization of the clot. The full or partial occlusion of the vessel may additionally prevent the need for aspiration or a silicone balloon catheter in the carotid artery. In other embodiments, thecontainer element 4 may only slightly limit the blood flow. Thefilament perimeter 48 anddistal opening 20 may open more or less than is shown. For example, thefilament perimeter 48 can be opened to provide a positive radial force on thevessel 80 and further ensure flow arrest. - In
FIG. 11J , the stent retriever andclot 78 are pulled through thedistal opening 20 and into thecontainer element 4. Since thefilament perimeter 48 may approximate the diameter of thetarget vessel 80, it acts like a funnel that the stent retriever andclot 78 are pulled into. Theclot 78 is fully within thecontainer element 4. In some embodiments, thecontainer element 4 is connected to thefilament catheter 82 along some portion of its length. For example, the proximal end of thecontainer element 4 may be connected to thefilament catheter 82 so it is not free floating. Alternatively, the entire length of thecontainer element 4 may be connected or integrated into thefilament catheter 82. - In
FIG. 11K , thefilament perimeter 48 at the end of thedevice 2 is closed by pulling thearms distal opening 20 of thecontainer element 4 is therefore approximated andclot 78 is fully contained within thecontainer element 4. At this point thedevice 2 with theclot 78 can be pulled from thevessel 80 and there may be a reduced likelihood of distal embolization since the clot is contained. Thedevice 2 may then be withdrawn from the patient. - In
FIGS. 12A and 12B , alternative embodiments of thedevice 2 are shown. Thefilaments 6 are on the outside of thecontainer element 4 in these embodiments and additionally are routed within afilament catheter 82. Thefilament catheter 82 can hold thedistal end 16 of thecontainer element 4 in place as the tension is applied to thefilaments 6 and thedistal opening 20 is closed. Additionally, thefilament catheter 82 can provide tension on thedistal end 16 of thecontainer element 4 such that thecontainer element 4 can be stretched by pulling the proximal end of thecontainer element 4 while holding thefilament catheter 82 stationary or by pushing thedistal end 16 of thecontainer element 4 with thefilament catheter 82 while holding the proximal end stationary or some combination therein. Thefilament catheter 82 may be comprised of any suitable catheter or tube material, such as nitinol, stainless steel, Pebax, PEEK, braided polyimide composite, or any other suitable construction. In some embodiments thefilament catheter 82 can be a closed wound coil. In some embodiments there is afilament catheter 82 for eacharm filament catheter 82 is shown on the outside of thecontainer element 4 inFIGS. 12A and 12B , it can also be within the inner diameter of thecontainer element 4. -
FIGS. 10-11 andFIG. 12 show similar devices having features which are incorporated for each other. For example, both show the containingelement 4 being free of attachments to the constrainingcatheter 8 and that theintermediate catheter 72 has the secondary lumen with thefirst filament 6 extending through the secondary lumen. Further still, both devices show theintermediate catheter 72 positioned in thelumen 24 of the constrainingcatheter 8 with theintermediate catheter 72 being movable relative to the constrainingcatheter 8 so that relative motion can move the containingelement 4 to the released position (such as moving theintermediate catheter 72 distally relative to the constraining catheter 8). Thedevices 2 do differ in some respects in that thedevice 2 ofFIGS. 10 and 11 is free of attachments to theintermediate catheter 72 while inFIG. 12 the containingelement 4 is coupled to theintermediate catheter 72 for a length of at least 5 mm. -
FIGS. 10-12 show embodiments where thefilament 6 may include the features of any of the other embodiments described herein. For example, thefilament 6 may having the leading portion which will still emerge from the constrainingcatheter 8 in the manner describe above even though thecontainer element 4 is not attached to the constrainingcatheter 8. Of course, a feature such as the inverted portion is not implicitly included in the embodiment ofFIG. 10A-10C while the features of the closed position would be implicitly included in the embodiments ofFIGS. 10-12 . It is also understood that in the interest of brevity that some claims are omitted when considering method claims similar to device claims and vice versa. Thus, either method or device claims so missing still form part of the present invention even when not specifically claimed. - In
FIG. 13A-13B , an embodiment of thedevice 2 and method are shown. InFIG. 13A , acontainer element 4 is shown with adistal opening 20. Thecontainer element 4 may be braided construction, stent construction, framed cage construction, or any other suitable structure. Thecontainer element 4 is generally tubular and has a distal end with adistal opening 20 as well as at least oneflap 88. Theflap 88 is a piece which extends distally past thedistal opening 20 and has a flexingarea 86. Afilament 6 is attached to theflap 88 at thefilament 6 connection. Thefilament 6 may be a wire such as a stainless steel, nitinol, plastic, or suture. Thefilament 6 may be connected to theflap 88 by aconnection 90 as shown or by welding, heat bonding, mechanical swaging, or any other suitable process. InFIG. 13A , theflap 88 is in an unactuated state and there is minimal tension on thearm 28. Therefore, thedistal opening 20 is generally open and may receiveclots 78 or other material through thedistal opening 20. When the user is ready to contain the materials in thecontainer element 4, tension may be applied to thearm 28. The tension creates a force on theflap 88 that causes it to bend about the flexingarea 86. InFIG. 13B , theflap 88 is rotated about 30 degrees and is thereby partially closing thedistal opening 20. InFIG. 13C , additional tension is applied to thearm 28 and thedistal opening 20 is primarily covered by theflap 88 that has been rotated and flexed into position. In some embodiments, theflap 88 may be comprised of the same material as the container element 4 (integrally formed). Alternatively, theflap 88 may be a separate component that is connected to thecontainer element 4 at the flexingarea 86. The connection may be a hinged connection (such as a living hinge) such that theflap 88 is primarily free to rotate about the flexingarea 86. In some embodiments, a more rigid material may be applied to theflap 88 so that it does not crumple when thearm 28 is in tension. This may include adding fabric or plastic to theflap 88. InFIG. 13D , an alternative embodiment is shown with more than oneflap 88. Threeflaps 88 are shown each with theirown filament 6 but any number ofother flaps 88 may be contemplated such as between 1 to 10 flaps or 2 to 4 flaps. Thefilaments 6 may be tensioned at the same time or individually. Thus, any number of folding patterns may be contemplated. Theflaps 88 may act like anatomical valve flaps which meet at the longitudinal axis LA of thecontainer element 4. Theflaps 88 do not need to be symmetric necessarily and can each be unique shapes. The shape of theflap 88 may be designed so that when all theflaps 88 are closed, thedistal opening 20 of thecontainer element 4 is mostly covered and materials within thecontainer element 4 are trapped in place. - In any of the embodiments described herein aspiration may additionally be applied within the
device 2 to further assist in capturing theclot 78. The aspiration may be connected to theintermediate catheter 72, constrainingcatheter 8,container element 4, orfilament 6 catheter. In embodiments where aspiration is applied to thecontainer element 4, the pieces of theclot 78 may be sucked into thecontainer element 4. The aspiration reverses the blood flow so that it goes proximally. This may be useful especially in embodiments where thedevice 2 provides local flow arrest so that the suction only comes from the distal side of theclot 78 and ensures that even if theclot 78 breaks apart it will not distally embolize. The aspiration could be applied during certain steps in the procedure outlined above such as when theclot engagement element 58 is being deployed and then retracted into thecontainer element 4. Alternatively, the use of aspiration may obviate the need for theclot engagement element 58. Aspiration may be used to suck theclot 78 into thecontainer element 4 without using a separate retriever. In still other embodiments an agitator mechanism may be used to break up the clot and the aspiration then sucks the broken up pieces into thecontainer element 4. The agitator may be mechanical such as a spinning or axially sliding element that contacts the clot and breaks it into smaller pieces that can be sucked up. Alternatively, the agitator may be vibratory or ultrasonic such that the clot breaks apart. Aspiration may be achieved with the use of a syringe or a vacuum source connected to thedevice 2. In some embodiments, theaspiration catheter 76 has a connected morcellating tip that is capable of breaking upclots 78. Theaspiration catheter 76 can pull theclot 78 into thecontainer element 4 and then thedistal opening 20 can be closed. The morcellating tip can be used to emulsify or break down the clot into smaller pieces which can be sucked through theaspiration catheter 76. Once theclot 78 material is no longer within thecontainer element 4, thedistal opening 20 can be opened and theaspiration catheter 76 can be advanced to engage with stillmore clot 78. This process can be repeated any number of times. In some embodiments the same procedure is used for a stent retriever. - In still other embodiments, the
container element 4 may not have an active closing element such as thefilament 6 described herein but instead may be passively closed. Thecontainer element 4 may be shape set such that it is a long tube as shown in the figures but at thedistal end 16 thecontainer element 4 may funnel back to a constricted shape when it is deployed. A separate frame element may be used to actively hold thecontainer element 4 open when it is ready to accept theclot engagement element 58 being retracted within thecontainer element 4. Once it is within thecontainer element 4, the frame can be moved axially to allow thecontainer element 4 to constrict back to its shape set profile. This may allow the opening and closing of thedistal end 16 of thecontainer element 4 by sliding a frame element distally and proximally. - In some embodiments, the
device 2 may contain all or only a portion of the devices described herein. For example, thedevice 2 may include aclot engagement element 58 such as a stent retriever or aspiration catheter. Alternatively, thedevice 2 may only include thecontainer element 4 andfilament 6 and thedevice 2 may be used with an existing off-the-shelf available stent retriever. In such an embodiment, thecontainer element 4 andfilament 6 may be sized to accept such a retriever. Thedevice 2 may be inserted into the body after the stent retriever has been deployed and captured the clot. In this way it is a stand-alone system for capturing the clot that includes using other clot engagement elements. Any number of other configurations of the devices described herein are contemplated. - The
device 2 can have a variety of shapes and sizes serving as a platform for any type of thrombectomy, embolectomy, or foreign body, calculi or tissue removal in any part of the body or vessel. Thedevice 2 may provide proximal support for placement of distal devices such as rheolytic catheters, suction devices, graspers, balloons such as a Fogarty balloon, wire snares, stent retrievers, etc. for any size tube or vessel including arteries, veins, ureters, airways, bile ducts, and hollow viscous for retrieval of material. - The devices and methods described within may be used in any number of other surgical procedure. For example, peripheral blood clots may be likewise removed with such a system. Any number of other suitable applications may use such a
device 2 for contained removal of a tissue, foreign body, calculi or other objects within a tubular contained space or even within non-tubular or non-contained spaces. - The names and labels applied to the various components and parts should not be considered limiting to the scope of the invented device and method. For example, the term filament used herein may be interchangeably used with snare, wire, ribbon, coil, elongate member, or any other suitable term. The term catheter is used to describe an elongate member with a distal and proximal end with a lumen extending there through. The terms intermediate catheter, constraining catheter, filament catheter, guide catheter, and micro catheter may often be used interchangeably. The term container element may often be interchangeably used with bag, containing element, container element, pouch, or any other suitable term. When referring to the opening of the distal opening, the terms releasing, deploying, opening, and expanding may be used interchangeably. When referring to the closure of the distal opening the terms cinching, closing, constraining, collapsing, constricting, snaring, or any other suitable term may often be used interchangeably. When referring to the radial constraining of the container element by catheters, vessels, or filaments, the terms constraining, restricting, containing, or constricting may also often be used interchangeably. The term filament perimeter may be used interchangeably with concave portion.
- Although embodiments of various methods and devices are described herein in detail with reference to certain versions, it should be appreciated that other versions, embodiments, methods of use, and combinations thereof are also possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.
Claims (1)
1. A device for removing occlusive material from a blood vessel, the device comprising:
a constraining catheter;
a containing element configurable into each of a collapsed configuration and an expanded configuration, said containing element at least partially encompassed by said constraining catheter when in said collapsed configuration, said containing element further comprising an expandable interior chamber for containing said occlusive material and an outer wall portion adapted to restrict antegrade flow in said blood vessel when in use, wherein a distal portion of said containing element in said collapsed configuration comprises a filament extending distal of said outer wall portion,
wherein, as said containing element expands towards said expanded configuration when released from said constraining catheter, said filament biases towards an unbiased shape that causes said filament to retract proximally into said distal portion and opens said distal portion; and
an actuator operatively coupled to said distal portion for reducing an area of a distal opening of said distal portion after capturing said occlusive material within said chamber.
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2019
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- 2019-03-12 JP JP2021500017A patent/JP2021517850A/en active Pending
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US11589882B2 (en) | 2023-02-28 |
JP2021517850A (en) | 2021-07-29 |
CN112384152A (en) | 2021-02-19 |
US20200253624A1 (en) | 2020-08-13 |
EP3764922A4 (en) | 2022-01-12 |
IL277002A (en) | 2020-10-29 |
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