Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/82—Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/86—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure
  • A61F2/90—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/12—Surgical instruments, devices or methods for ligaturing or otherwise compressing tubular parts of the body, e.g. blood vessels or umbilical cord
  • A61B17/12022—Occluding by internal devices, e.g. balloons or releasable wires
  • A61B17/12099—Occluding by internal devices, e.g. balloons or releasable wires characterised by the location of the occluder
  • A61B17/12109—Occluding by internal devices, e.g. balloons or releasable wires characterised by the location of the occluder in a blood vessel
  • A61B17/12113—Occluding by internal devices, e.g. balloons or releasable wires characterised by the location of the occluder in a blood vessel within an aneurysm
  • A61B17/12118—Occluding by internal devices, e.g. balloons or releasable wires characterised by the location of the occluder in a blood vessel within an aneurysm for positioning in conjunction with a stent
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/12—Surgical instruments, devices or methods for ligaturing or otherwise compressing tubular parts of the body, e.g. blood vessels or umbilical cord
  • A61B17/12022—Occluding by internal devices, e.g. balloons or releasable wires
  • A61B17/12131—Occluding by internal devices, e.g. balloons or releasable wires characterised by the type of occluding device
  • A61B17/1214—Coils or wires
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/12—Surgical instruments, devices or methods for ligaturing or otherwise compressing tubular parts of the body, e.g. blood vessels or umbilical cord
  • A61B17/12022—Occluding by internal devices, e.g. balloons or releasable wires
  • A61B2017/1205—Introduction devices
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/82—Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2002/823—Stents, different from stent-grafts, adapted to cover an aneurysm
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2250/00—Special features of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof
  • A61F2250/0014—Special features of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof having different values of a given property or geometrical feature, e.g. mechanical property or material property, at different locations within the same prosthesis
  • A61F2250/0023—Special features of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof having different values of a given property or geometrical feature, e.g. mechanical property or material property, at different locations within the same prosthesis differing in porosity

Definitions

• Intracranial aneurysms are among the most serious of medical conditions. Their typical size and location make them especially difficult to detect and treat; but even small ones, if ruptured, can cause debilitating physical and cognitive impairment, coma, and death.
• Initial treatment methods involved clip ligation of the neck of the aneurysm in open surgical procedures. More recently, minimally invasive endovascular techniques have been developed. Given the clinical significance of the condition and the difficulties encountered in addressing it, treatment for intracranial aneurysms remains an especially active area of device and surgical procedure development.
• a device for temporarily protecting a neck of an aneurysm of an intracranial blood vessel during an aneurysm treatment comprises one or more wires forming a frame, wherein the frame has a collapsed configuration and an expanded configuration, wherein the frame is configured to transition in use from the collapsed configuration to a deployed configuration that substantially conforms to a shape of an inside surface of the intracranial blood vessel in the vicinity of the aneurysm being treated, and wherein the frame is configured to transition back to the collapsed configuration and removed from the intracranial blood vessel after the aneurysm is treated.
• the device further comprises a cover disposed on at least a portion of the frame, the cover comprising at least a first portion configured to be disposed against a neck of the aneurysm while the aneurysm is being treated, the first portion of the cover having pores formed therein defining a first porosity thereof.
• the device comprises one or more wires forming a frame, wherein the frame has a collapsed configuration and an expanded configuration, wherein the frame is configured to transition in use from the collapsed configuration to a deployed configuration that substantially conforms to a shape of an inside surface of the intracranial blood vessel in the vicinity of the aneurysm being treated, and wherein the frame is configured to transition back to the collapsed configuration and removed from the intracranial blood vessel after the aneurysm is treated.
• the device further comprises an electrospun cover disposed on at least a portion of the frame, the cover comprising at least a first portion configured to be disposed against a neck of the aneurysm while the aneurysm is being treated, the first portion of the cover having pores formed therein defining a first porosity thereof, wherein the first porosity is 20% or less, and wherein a pore size associated with the first porosity is less than approximately 10 microns.
• a method of treating an intracranial aneurysm is provided.
• the method comprises threading a first microcatheter through an intracranial blood vessel and at least partly into the intracranial aneurysm, threading a guide wire through the intracranial blood vessel to a position outside a neck of the aneurysm while the first microcatheter is disposed within the intracranial blood vessel, threading a second microcatheter over the guide wire and through the intracranial blood vessel to the position outside the neck of the aneurysm, threading a device for temporarily protecting the neck of the aneurysm through the second microcatheter in a collapsed state and out of a distal end of the second microcatheter, wherein the device for temporarily protecting the neck of the aneurysm comprises one or more wires forming a collapsible frame with a cover on at least a portion thereof having pores defining a first porosity, expanding the device to a deployed configuration that substantially conforms to a shape of an inside surface of the intracranial blood vessel in the vicinity of the aneurys
• an intravascular flow diverter for treating an aneurysm of an intracranial blood vessel comprises one or more wires forming a frame, wherein the frame has a collapsed configuration and an expanded configuration, wherein the frame is configured to transition in use from the collapsed configuration to a deployed configuration that substantially conforms to a shape of an inside surface of the intracranial blood vessel in the vicinity of the aneurysm.
• the flow diverter further comprises an electrospun cover disposed on at least a portion of the frame.
• the cover comprises a first portion configured to be disposed against a neck of the aneurysm, the first portion of the cover having pores formed therein defining a first porosity thereof and a second portion having a second porosity to blood flow greater than the first porosity, wherein the second portion is configured to be disposed adjacent to and not directly over the aneurysm.
• an intravascular flow diverter for treating an aneurysm of an intracranial blood vessel comprises one or more wires forming a frame, wherein the frame has a collapsed configuration and an expanded configuration, wherein the frame is configured to transition in use from the collapsed configuration to a deployed configuration that substantially conforms to a shape of an inside surface of the intracranial blood vessel in the vicinity of the aneurysm.
• the flow diverter further comprises an electrospun cover disposed on at least a portion of the frame.
• the cover comprises a first portion configured to be disposed against a neck of the aneurysm, the first portion of the cover having pores formed therein defining a first porosity thereof, a second portion distal to the first portion having a second porosity to blood flow greater than the first porosity, wherein the second portion is configured to be disposed adjacent to and not directly over the aneurysm, and a third portion proximal to the first portion having a third porosity to blood flow greater than the first porosity, wherein the third portion is configured to be disposed adjacent to and not directly over the aneurysm.
• each of the one or more wires has a diameter of less than .002 inches, wherein the frame porosity over substantially the whole length of the frame is at least 93% in an expanded frame configuration, wherein the first porosity is less than 0.05 and the second porosity and the third porosities are each greater than 0.05.
• a method of using an intravascular flow diverter to treat an aneurysm of an intracranial blood vessel comprises disposing the intravascular flow diverter within a microcatheter, threading the microcatheter through the intracranial blood vessel to a location of the aneurysm and removing the intravascular flow diverter from a distal end of the microcatheter such that a stent of the intravascular flow diverter, comprising a plurality of wires coiled to form an expandable structure, expands sufficiently within the intracranial blood vessel such that a first portion of an electrospun cover disposed on an entire outer surface of the stent is disposed directly against a neck of the aneurysm, the first portion having a first porosity to blood flow and at least one second portion of the membrane is disposed adjacent to and not directly over the aneurysm, the at least one second portion having a second porosity to blood flow greater than the first porosity.
• an intrasacular flow diverter for treating an aneurysm of an intracranial blood vessel comprises one or more wires forming a frame, wherein the frame has a collapsed configuration and an expanded configuration, wherein the frame is configured to transition in use from the collapsed configuration to a deployed configuration that substantially conforms to a shape of an inside surface of a sac of the aneurysm.
• the intrasaccular flow diverter further comprises an electrospun cover disposed on at least a portion of the frame.
• the cover comprises a first portion configured to be disposed against a neck of the aneurysm, the first portion of the cover having pores formed therein defining a first porosity thereof, and a second portion having a second porosity to blood flow greater than the first porosity, the second portion configured to be disposed within the sac of aneurysm distal to the neck of the aneurysm.
• a method of utilizing an intrasacular flow diverter to treat an aneurysm of a blood vessel comprises disposing the intrasacular flow diverter within a microcatheter in a collapsed state, threading the microcatheter through the blood vessel to a location within the aneurysm, and removing the intrasacular flow diverter from a distal end of the microcatheter such that a plurality of coiled wires forming a collapsed substantially spherical frame of the intrasacular flow diverter expand sufficiently within the aneurysm.
• a first portion of a membrane disposed on at least a portion of the outer surface of the substantially spherical frame is disposed directly against a neck of the aneurysm, the first portion having a first porosity to blood flow, and a second portion of the membrane is disposed within the aneurysm and distal to the neck of the aneurysm, the second portion having a second porosity to blood flow greater than the first porosity.
• FIG. 1A illustrates blood flow in the vicinity of an aneurysm
• FIG. 1B illustrates a coil filled aneurysm
• FIG. 2A illustrates balloon assisted aneurysm coiling
• FIG. 2B illustrates stent assisted aneurysm coiling
• FIG. 2C illustrates a commercially available stent for stent assisted aneurysm coiling
• FIG.3A illustrates a portion of a blood vessel having an aneurysm, in accordance with some embodiments
• FIG.3B illustrates a first microcatheter disposed within the blood vessel and into the aneurysm, in accordance with some embodiments
• FIG.3C illustrates a guidewire inserted into the blood vessel as illustrated in FIG.
• FIG. 3D illustrates a second microcatheter guided by the guide wire of FIG. 3C to be disposed within the blood vessel, in accordance with some embodiments;
• FIG. 3E illustrates the second microcatheter as illustrated in FIG. 3D, having the guide wire removed, in accordance with some embodiments;
• FIG.3F illustrates a temporary aneurysm neck protection device disposed within the blood vessel and against a neck of the aneurysm, in accordance with some embodiments;
• FIG. 4A illustrates a the temporary aneurysm neck protection device of FIG. 3F; [0026] FIG.
• FIG. 4B illustrates a modified construction for the temporary aneurysm neck protection device of FIG. 3F with frame struts being connected at the frame distal end as well as the proximal end;
• FIG. 4C illustrates a top view of an alternative embodiment of a temporary aneurysm neck protection device;
• FIG. 4D illustrates a side view of the embodiment of FIG. C;
• FIG. 5A illustrates blood flow during stent assisted coiling in some example embodiments;
• FIG. 5B is a histogram of cover pore sizes in one embodiment of a temporary aneurysm neck protection device; [0031] FIG.
• FIG. 6 illustrates side and cross-sectional views of a temporary aneurysm neck protection device in expanded and collapsed states, in accordance with some example embodiments;
• FIG. 7 illustrates side and cross-sectional views of another temporary aneurysm neck protection device in expanded and collapsed states, in accordance with some example embodiments;
• FIG. 8 illustrates side and cross-sectional views of another temporary aneurysm neck protection device in expanded and collapsed states, in accordance with some example embodiments;
• FIG. 9 illustrates example wire stent framework designs. [0035] FIG.
• FIG. 10 illustrates yet another temporary aneurysm neck protection device disposed within the blood vessel and against a neck of the aneurysm, in accordance with some embodiments;
• FIG. 11 illustrates a side view of at least a portion of the temporary aneurysm neck protection device of FIG. 10, in accordance with some example embodiments;
• FIG.12 illustrates a flowchart related to a method of using a temporary aneurysm neck protection device, in accordance with some example embodiments;
• FIG. 13 illustrates a flowchart related to a method of manufacturing a temporary aneurysm neck protection device, in accordance with some example embodiments. [0039] FIG.
• FIG. 14A illustrates a portion of a blood vessel having an aneurysm, in accordance with some embodiments; [0040] FIG. 14B illustrates an intravascular flow diverter located across the neck of an aneurysm. [0041] FIG. 15 illustrates a microcatheter disposed within the blood vessel and near the aneurysm, in accordance with some embodiments; [0042] FIG. 16 illustrates an intravascular flow diverter disposed within the blood vessel and immediately against the aneurysm, in accordance with some embodiments; [0043] FIG. 17 illustrates a magnified view of a portion of the intravascular flow diverter of FIG.
• FIG.18A illustrates a cross-section of a first embodiment of the intravascular flow diverter of FIG.16, in accordance with some example embodiments;
• FIG. 18B illustrates a cross-section of a second embodiment of the intravascular flow diverter of FIG. 16, in accordance with some example embodiments;
• FIG. 18C illustrates a cross-section of a third embodiment of the intravascular flow diverter of FIG. 16, in accordance with some example embodiments;
• FIG. 19 illustrates a flowchart related to a method of using an intravascular flow diverter, in accordance with some example embodiments; and [0048] FIG.
• FIG. 20 illustrates a flowchart related to a method of manufacturing intravascular flow diverters, in accordance with some example embodiments.
• FIG. 21A illustrates a portion of a blood vessel having an aneurysm, in accordance with some embodiments;
• FIG. 21B illustrates an intrasaccular flow diverter located inside of an aneurysm.
• FIG. 21C illustrates an embodiment of an intrasaccular flow diverter.
• FIG. 22 illustrates a microcatheter disposed within the blood vessel and into the aneurysm, in accordance with some embodiments; [0053] FIG.
• FIG. 23 illustrates an intrasacular flow diverter disposed within the aneurysm within the blood vessel, in accordance with some embodiments;
• FIG.24A illustrates an embodiment of the intrasacular flow diverter of FIG.23, in accordance with some example embodiments;
• FIG. 24B illustrates the intrasacular flow diverter of FIG. 24A but viewed from a different angle from that of FIG.24A, in accordance with some example embodiments;
• FIG. 24C illustrates yet another embodiment of the intrasacular flow diverter of FIG. 23, in accordance with some example embodiments;
• FIG. 24D illustrates yet another embodiment of the intrasacular flow diverter of FIG. 23, in accordance with some example embodiments; [0058] FIG.
• FIG. 25A illustrates a cross-section of a collapsed embodiment of the intrasaccular flow diverter of FIG. 23, in accordance with some example embodiments;
• FIG. 25B illustrates a cross-section of another collapsed embodiment of the intrasaccular flow diverter of FIG. 23, in accordance with some example embodiments;
• FIG. 25C illustrates a cross-section of yet another collapsed embodiment of the intrasaccular flow diverter of FIG. 23, in accordance with some example embodiments;
• FIG. 25D illustrates a cross-section of yet another collapsed embodiment of the intrasaccular flow diverter of FIG. 23, in accordance with some example embodiments; [0062] FIG.
• FIG. 26 illustrates a flowchart related to a method of using an intrasacular flow diverter, in accordance with some example embodiments; and [0063]
• FIG. 27 illustrates a flowchart related to a method of manufacturing an intrasacular flow diverter, in accordance with some example embodiments.
• DETAILED DESCRIPTION [0064] The following description and examples illustrate some exemplary implementations, embodiments, and arrangements of the disclosed invention in detail. Those of skill in the art will recognize that there are numerous variations and modifications of this invention that are encompassed by its scope. Accordingly, the description of a certain example embodiment should not be deemed to limit the scope of the present invention.
• Collapsed Configuration – A device is in a collapsed configuration when it is sheathed proximate to and inside a distal end of a catheter ready for use in an endovascular surgical procedure.
• Expanded Configuration – A device is in an expanded configuration when unsheathed outside the vasculature such that outward expansion of the sidewall is unconstrained by any surrounding walls. For flow diverters that are manually expanded by the surgeon, the expanded configuration is obtained when the flow diverter is manually expanded to its maximum intended diameter for normal use.
• Deployed Configuration – A device is in the deployed configuration when unsheathed and with its side wall in contact with the inner wall of a vessel.
• a deployed configuration may have a smaller diameter for the sidewall than an expanded configuration depending on the size of the vessel in which the device is deployed.
• a device in the deployed configuration is typically close to but not fully in the expanded configuration.
• An arrangement of metal wires is a common implementation of struts for a frame.
• Frame Porosity The fractional open area of a selected portion of the sidewall defined by the struts of the device when the device is in a deployed configuration. The frame porosity may vary in different portions of a sidewall.
• the frame porosity is the total area of a selected portion of a sidewall minus the area of the struts defining the selected portion of the sidewall, divided by the total area of the selected portion of the sidewall when the device is in an expanded configuration.
• Cover – A film or membrane connecting two or more struts of a frame and extending over some or all of the open area of the sidewall defined by the struts of the frame.
• Cover Porosity The fractional open pore area of a selected portion of a cover membrane when the device is in an expanded configuration. Cover porosity may vary in different portions of a sidewall that is covered by the membrane.
• Pore Size – The size of a given pore is defined to be the diameter of an inscribed circle with three points of contact with the actual boundary of the given pore.
• Cover Porosity Distribution The cover porosity in a selected region of a cover may be distributed among groups of pores having particular pore characteristics, usually size characteristics. For example, a cover with 30% porosity may have a certain fraction of that porosity contributed by pores with a defined size range.
• the cover porosity distribution refers to a characterization of the amount of total porosity contributed by pores with a defined set of one or more properties.
• Cover Permeability – Cover permeability is a qualitative or quantitative measure of the ability of different substances to pass through the cover when the device is in normal use in a vessel. Cover permeability is affected by several different aspects of a cover, including cover porosity and porosity distribution with respect to different size components of blood and/or particles in blood as well as the chemical properties of the cover material with respect to the chemical properties of different components of blood and/or particles in blood. Cover permeability to various blood components can also be affected by local flow and pressure conditions at the site of implantation in a vessel.
• FIG. 1A illustrates blood flow through a vessel 110 in the region around an aneurysm 120.
• FIG. 1 When the aneurysm is filled with coils in this way, blood flow 150 is no longer significantly diverted into the aneurysm sac, relieving internal pressure and also assisting aneurism embolization by trapping red blood cells inside the aneurysm.
• Interventional neuroradiologists have developed several important adjuncts to assist in their treatment of intracranial aneurysms, such as balloon- and stent- assisted coiling of wide-necked aneurysms. These techniques have made it possible to treat many aneurysms that would have previously required more invasive open neurosurgical clipping. [0079] FIG.
• FIG. 2A illustrates a portion of a blood vessel having an aneurysm 120, shown as a bulging of a vessel wall in a portion of a blood vessel 110.
• the aneurysm 120 in FIG. 2A is being treated with balloon assisted coiling.
• the balloon 250 is used to confine the coil 230 as the coil 230 is deployed into the aneurysm sac.
• a potential problem with balloon assisted coiling techniques is that introduction of an occlusion balloon can increase the rate of thrombus formation and thromboembolic events.
• presence of such a balloon in the parent vessel could theoretically promote stasis and lead to thrombus formation or platelet aggregation.
• FIG. 2B is an illustration of stent assisted coiling.
• intravascular stents or flow diverters 270 that have been previously used as permanent implants have been modified and re-purposed for temporary coiling support. But these devices are relatively poor at protecting the neck of the aneurysm from outflow due to the high frame porosity of such conventional intravascular stents once expanded across the aneurysm neck.
• the Comaneci aneurysm neck protection device from Rapid Medical (290, shown in FIG. 2C) is an expandable braid which opens to protect the neck and allows for coiling to proceed while “jailing” the coils within the aneurysm during the procedure. While helpful for retaining the coils, the open structure of the Comaneci device does not prevent displacement of embolic debris out of the aneurysm through the braid and, potentially, into the parent artery.
• exposed metal on such devices is a known thrombogenic surface that allows clots to form on the exposed wire or wire interstices associated with the braid.
• a device for temporarily protecting a neck of an aneurysm of a blood vessel may comprise one or more struts forming a frame configured to expand and substantially conform to a shape of an inside surface of the blood vessel while the aneurysm is being treated.
• the frame may define a frame porosity.
• the device may include a retention wire disposed at a proximal end of the frame of the plurality of wires for unsheathing and resheathing the device before and after an aneurysm coil insertion treatment is performed.
• the device may include a cover adhered to or deposited over some or all of the frame.
• the cover may include at least a first portion configured to be disposed directly against a neck of the aneurysm while the aneurysm is being treated.
• the first portion may define a cover porosity, porosity distribution, and permeability while the aneurysm is being treated.
• Common locations for intracranial aneurysms include the communicating arteries, the internal carotid arteries, and the middle cerebral artery.
• the devices described herein can, for example, be used in these arteries.
• the method may include threading a first catheter through the blood vessel and at least partly into the aneurysm.
• the method may include threading a guide wire through the blood vessel to a position outside a neck of the aneurysm while the first catheter is disposed within the blood vessel and threading a second microcatheter over the guide wire and through the blood vessel to the position outside the neck of the aneurysm.
• the method may further include threading a device for temporarily protecting the neck of the aneurysm constructed in accordance with the principles and embodiments described herein through the second microcatheter in a collapsed state and out of a distal end of the second microcatheter such that a plurality of struts forming a collapsible frame expand and substantially conform to a shape of an inside surface of the blood vessel.
• a retention wire, disposed at a proximal end of the frame of the plurality of wires, may extend through the second catheter. At least a first portion of a cover over all or part of the frame may be disposed directly against a neck of the aneurysm.
• the first portion may define a cover porosity, porosity distribution, and permeability while the aneurysm is being treated.
• a method of manufacturing a device for temporarily protecting a neck of an aneurysm of a blood vessel may include forming a collapsible frame configured to expand and substantially conform to a shape of an inside surface of the blood vessel.
• the method may include disposing a retention wire to a proximal end of the frame of the plurality of wires.
• the method may include disposing a cover over some or all of a predetermined length of the frame.
• the cover may be configured to be disposed directly against a neck of the aneurysm during an aneurysm treatment procedure such as coiling.
• a temporary aneurysm neck protection device which may be visible on angiography for precise placement, may be suitable for use in neurovascular aneurysm embolization cases, soft dilation (e.g., opening other neurovascular devices against the vessel wall), potentially vasospasm cases, and potentially vessel stenosis cases, among other suitable applications.
• Some embodiments as described herein may have similar benefits to balloon assisted aneurysm coiling but without the risk of parent artery occlusion or blockage of blood flow to distal neurovasculature during expansion and/or dilation of the temporary aneurysm neck protection device.
• FIGs. 3A through 3F illustrate a one embodiment of performing a stent assisted aneurysm coiling procedure.
• a first catheter 200 may be threaded through blood vessel 110 and at least partly into aneurysm 120.
• First catheter 200 will be utilized to deploy coils into aneurysm 120 at a later step.
• a guide wire 300 may be threaded through blood vessel 110 to a position outside a neck of aneurysm 120.
• a second catheter 400 may be threaded through blood vessel 100, guided over guide wire 300, to a position outside a neck of aneurysm 120.
• guide wire 300 may be pulled back or removed through second catheter 400.
• use of guide wire 300 may be optional.
• temporary aneurysm neck protection device 600 may be deployed out of a distal end of second catheter 400 over the neck of the aneurysm and a portion of the first catheter. The device 600 may self- expand under bias from the frame 610 or expand manually under surgeon control.
• the stent 600 of FIG. 3F differs from conventional stents used for stent assisted coiling in that the frame of the stent comprises a cover 610, which may comprise a polymer material extending between some or all of the struts of the frame.
• This stent embodiment is illustrated further in FIG. 4A.
• FIG. 4A a first embodiment of temporary aneurysm neck protection device 600 is illustrated in an expanded state.
• Device 600 comprises a frame defined by struts 640.
• FIG. 4B is a modified version of device 600 wherein the struts 640 of the frame are also connected together at the distal end of the stent in addition to the proximal end.
• a retention wire 630 is coupled to the frame at a proximal end of the frame.
• the frame may define a total stent length L1 between its proximal and distal ends in the substantially expanded state.
• a cover 610 is disposed on some or all of the frame, in this embodiment around the circumference of the frame sidewall along a predetermined length L2 (e.g., portion) of the frame of wires 640.
• L2 e.g., portion
• at least the portion of the frame of wires 640, over which membrane 610 is disposed may have a substantially cylindrical sidewall.
• distal end 850 of the frame of wires 640 may be unobstructed by any of the struts 640.
• FIGs. 4C and 4D illustrate another embodiment of a temporary aneurysm neck protection device, wherein 4C is a top view and FIG. 4D is a side view.
• the distal end 674 is unobstructed by any struts, similar to the embodiment of FIG. 4A.
• the proximal end 672 has only one location where a retention wire 630 attaches to the proximal end, leaving the opening in the proximal end 672 with little to no obstruction as well.
• the circumferential opening of the proximal end 672 may be angled or beveled toward the distal end from the location where the retention wire 630 attaches to the struts of the protection device. This can both increase blood flow through the device and assist re-sheathing of the device inside the introducing catheter for removal after the coiling procedure.
• the distal end may be heat set and bias the wire(s) towards the vessel wall.
• Cover 610 is provided over the struts 640 forming the frame of the stent.
• the cover 610 has porosity, porosity distribution, and permeability characteristics that substantially block the circulating aneurysm inflow 155 and outflow 165 that is illustrated in FIG. 1A. It has been found that this inflow 155 and outflow blocking function can be provided with membranes of surprisingly high porosities and large pore sizes. Generally, to generate a membrane that has low permeability to inflow 155 and outflow 165 in the presence of vessel flow 150, porosity and pore size may be appropriately balanced. Higher total porosities require smaller pore sizes, while lower porosities can have large pore sizes while maintaining the desired inflow 155 and outflow 165 suppression.
• this product may be in the range of 0.1 to 50, with 5 to 20 having been found particularly suitable, if the pore size units are microns.
• a suitable membrane may have a total porosity of 0.05 to 0.5 and a median pore size between 10 and 100 microns.
• a membrane with a porosity of 0.3 to 0.6 and a median pore size between 20 and 30 microns is utilized.
• a membrane with a total porosity between 0.05 and 0.15 and a median pore size between 30 and 100 microns is utilized.
• a membrane with a total porosity between 0.15 and 0.25 and a median pore size between 20 and 80 microns is utilized.
• the pore size range may be from 5 to 400 microns, 5 to 200 microns, or 5 to 100 microns, wherein outliers outside of these ranges that do not significantly contribute the total porosity of the cover (e.g. less than 5% of the total porosity) are ignored.
• blood components such as plasma and red blood cells can still migrate out of the aneurysm sac essentially perpendicular to the cover membrane surface (as illustrated at 175 in FIG.5A) as the coils 230 are deployed and displace the original content of the aneurysm.
• lower pressure drops across more porous cover membranes from the blood vessel to the internal volume of the aneurysm allows blood pressure to keep the aneurism sac inflated while the coiling procedure is performed.
• membranes with higher porosities allow the use of wire stent frames of very high porosity by providing structural support to the stent, which allows the production of highly flexible stents that are more easily navigated through complex vasculature to an aneurysm.
• any embolic debris generated during the coiling procedure remain trapped inside the aneurysm sac while the main blood components of plasma and red blood cells are allowed to migrate out of the aneurysm sac in a manner similar to currently used uncovered stents for coiling assist.
• An electrospun stent cover membrane having porosity and permeability suitable for accomplishing this is described in paragraphs [0092] through [0103] of US Published Patent Application 2021/0052360.
• blood components displaced by the coils can migrate out as described above, but the embolic debris can be substantially retained in the sac.
• Cover membranes 610 having any of the above contemplated porosity and permeability characteristics may also help to redirect coils away from the neck to effectively fill aneurysm 120 as the coil structure is built and eliminate the risk of such coils protruding into and getting caught or tangled in the frame, as has been known to occur with use of the above- described open-braid Comaneci device.
• the cover membrane may be substantially impermeable to red blood cell migration out of the aneurysm sac, but substantially permeable to plasma migration out of the aneurysm sac. This will still allow the sac of the aneurysm to drain fluid as the embolization coils are installed but the cover membrane will trap free red blood cells inside with the coils in addition to any embolic debris, potentially enhancing the coil driven embolization process.
• Another advantage of the small pore size is that radiographic contrast agent may flow through the device without entering the sac of the aneurism during the procedure.
• FIG. 5B is a histogram of one embodiment of pore size distribution in a portion of a cover that has been found suitable in some device embodiments.
• the median pore size is between 5 and 6 microns.
• the total porosity was about 0.025.
• the covers which have been found especially suitable may be characterized by a median pore diameter times cover fractional porosity of 0.1 to 2.
• a surgical kit may be provided for support of aneurysm sac coiling treatments where the kit contains different stents having different porosity and permeability characteristics such that the surgeon can choose the cover membrane characteristics suitable for a given procedure based on surgeon preference, experience, and the physiological characteristics of the specific aneurysm being treated.
• the temporary aneurysm neck protection device 600 may comprise a frame comprising struts 640 formed from plurality of wires braided or coiled around one another.
• each of wires may be coiled into a collapsible and subsequently re-expandable, substantially helical shape or structure configured to ultimately provide the frame with its overall length L1 and a diameter D1 in an expanded configuration (e.g., approximately 0.12 inches or 3 mm for intracranial applications, although any other suitable maximum diameter is also contemplated).
• each wire is offset from adjacent wires by a predetermined spacing L4.
• each of wires may have a predetermined pitch L3 (i.e., each loop or winding of a particular one of wires extends predetermined length L3 along a length of extension of temporary aneurysm neck protection device 600).
• the spacing L4 may be determined as the result of dividing pitch L3 of wires by a number of those wires wound in the same direction.
• wires 640 comprise super-elastic nitinol.
• a cobalt chromium may be used.
• a nitinol shape memory alloy may be used.
• wires may comprise any suitably flexible, expandable and compressible material including polymers, which may themselves be electrospun polymer fibers.
• a laser cut nitinol tube can be constructed, then expanded, and then heat set. The resulting nitinol tube may also be super-elastic in nature, thereby allowing its subsequent collapse for introduction into the vasculature and re-expansion during subsequent deployment.
• each of wires may be coated with an elastomeric polymer 1210 configured to eliminate or substantially reduce exposed metallic surfaces of wires and, thereby, minimize thrombogenicity of the frame.
• the coated wires may then be covered by a membrane 610 having the desired porosity and permeability as described above.
• membrane 610 may provide support for the underlying expanded frame of struts 640 while also possessing a very thin construction.
• a cover membrane 610 providing such support allows a reduction in a number of wires 640 (e.g., 6 wires as illustrated FIGs 6-8 or fewer wires, even a single wire) needed for construction and effective operation, compared conventional devices not comprising such a membrane.
• the cover membrane allows an increase in frame porosity while providing all desired filtering functions with the membrane 610.
• the frame porosity over a majority of its overall length is greater than 90%, more preferably greater than 95%.
• This reduction in strut area also advantageously reduces device mass per unit length, delivery profile, longitudinal stiffness of, and radial force exerted by, device 600 during navigation to aneurysm 120 in the delivery system.
• the primary or even sole function of the cover membrane 610 is frame support rather than filtering.
• the frame porosity can be very high and the cover membrane porosity can also be very high and dominated by large pores that serve no substantial filtering function of any blood component, embolic debris, etc.
• the frame porosity is greater than 90% and the frame is covered over at least a region of its length intended for bridging an aneurism neck by an electrospun polymer membrane that is substantially permeable to blood plasma and red blood cell migration out of the aneurysm sac during coiling and substantially impermeable to blood flow past the neck of the aneurysm during normal circulation.
• the frame porosity is greater than 93% and the frame is covered over at least a region of its length intended for bridging an aneurism neck by an electrospun polymer membrane that is substantially permeable to blood plasma and red blood cell migration out of the aneurysm sac during coiling and substantially impermeable to blood flow past the neck of the aneurysm during normal circulation.
• the frame porosity is greater than 93%
• the expanded configuration has a sidewall maximum diameter of less than 10 mm
• the frame is covered with an electrospun membrane over at least a portion of its length having a distribution of pore sizes, wherein the distribution of pore sizes includes a first group of pores with a maximum dimension of no more than about 25 microns and a second group of pores with a maximum dimension of at least about 50 microns, and wherein the prevalence of pores in the first group is at least three times the prevalence of pores in the second group.
• the cover porosity may be at least about 30%.
• membrane 610 being applied to the frame of wires 640 is that the porosity, and therefore flow control, achieved by membrane 610 will advantageously allow fewer sizes of device 600 to be made available and/or used compared to existing devices, all of which have fairly narrow ranges of vessel diameters for which each size is effective at satisfactorily manipulating blood flow.
• traditional wire braids are generally provided in 0.25 mm increments while, at least in some embodiments, temporary aneurysm neck protection device(s) 600, 700 may be made available in sizes with much larger increments, e.g., 1.0 to 1.5 mm, thereby allowing 4 – 6 fewer sizes of device 600 to be included in a surgical kit for aneurysm treatment.
• FIGs 6-8 illustrate different example side and cross-sectional views of embodiments an example temporary aneurysm neck protection devices.
• the embodiments of FIGs 6-8 are substantially similar to one another, except each utilizes wire 640 having a different diameter D2, D5, D8 and, therefore, each illustrated embodiment also comprises respective minimum collapsed diameters for each of the two example configurations for the orientation of the wires when the frame is in the substantially collapsed state.
• the first example orientation of wires in each of FIGs.6-8, illustrated in respective cross sections 1250, 1350, 1450, comprises an innermost subset of 6 wires and an outermost subset of 6 wires.
• Each of the innermost threads is disposed in direct contact with each of two adjacent threads of the innermost subset and one thread of the outermost subset.
• a center of each of the outermost threads is radially in-line with both a center of the frame’s cross section and a center of the corresponding inner thread with which the outermost thread is in direct contact.
• the second example orientation of wires is shown in cross sections 1280, 1380, 1480 in each of FIGs. 6-8 and comprises the same innermost subset of 6 threads and an outermost subset of 6 threads. However, each of the innermost threads is disposed in direct contact with each of two adjacent threads of the innermost subset as well as each of two adjacent threads of the outermost subset.
• a center of each of the outermost threads is equally but oppositely offset from a center of each of the adjacent inner threads with which the outermost thread is in direct contact.
• This second example orientation is more tightly packed than the first (e.g., centers of each immediately adjacent pair of innermost threads and the center of the shared immediately adjacent outermost thread form vertices of equilateral triangles) and so provides a smallest possible minimum collapsed diameter between the two example orientations.
• the wires are illustrated as having an outside diameter of approximately 0.001 inches and, accordingly, may be configured to have the maximum expanded diameter D1 and a minimum contracted diameter D3 (e.g., 0.005 inches) in the first example orientation of cross section 1250, and the maximum expanded diameter D1 and a minimum contracted diameter D4 (e.g., 0.004 inches) in the second example orientation of cross section 1280.
• a minimum contracted diameter D3 e.g., 0.005 inches
• D4 e.g., 0.004 inches
• the wires are illustrated as having an outside diameter of approximately 0.002 inches and, accordingly, may be configured to have the maximum expanded diameter D1 and a minimum contracted diameter D6 (e.g., 0.010 inches) in the first example orientation of cross section 1350, and the maximum expanded diameter D1 and a minimum contracted diameter D7 (e.g., 0.009 inches) in the second example orientation of cross section 1280.
• a minimum contracted diameter D6 e.g., 0.010 inches
• D7 e.g., 0.009 inches
• the wires are illustrated as having an outside diameter of approximately 0.003 inches and, accordingly, may be configured to have the maximum expanded diameter D1 and a minimum contracted diameter D9 (e.g., 0.015 inches) in the first example orientation of cross section 1450, and the maximum expanded diameter D1 and a minimum contracted diameter D10 (e.g., 0.013 inches) in the second example orientation of cross section 1480.
• D9 e.g., 0.015 inches
• D10 e.g., 0.013 inches
• FIG. 9 shows example stent frame configurations of currently available commercial stents.
• the cover membrane 610 may be provided on only a portion of the deployed functional portion of the frame or may be configured to have one or more of variable porosity, variable porosity distribution, and/or variable permeability over different portions of the sidewall along its length. Embodiments having such features are illustrated in FIGs 10 and 11.
• the device 700 comprises a substantially cylindrical frame of wires allowing blood flow through substantially open proximal and distal ends and retention wire 630.
• Membrane 610 is disposed on at least a portion of the frame and may be substantially around an entire perimeter of a predetermined length L2 (e.g., portion) of frame of wires 640.
• cover 610 has a first portion 710 extending along a first portion of the length of the frame and comprising first porosity and permeability characteristics, and a second portion 720 extending along a second portion of the length of the frame and comprising second porosity and/or permeability characteristics, one or both of which may be different from the first.
• cover membrane portion 720 may have porosity and permeability characteristics as set forth above, and cover membrane portion 710 may be essentially fluid tight (e.g. less than 5% cover porosity). This can be accomplished by, for example, depositing a relatively thick multilayer mat of electrospun fibers onto the stent frame, essentially eliminating the ability of any pores to extend through the thickness of the cover.
• retention wire 630 may be pulled and temporary aneurysm neck protection device 700 ultimately moved, relative to blood vessel 100, until the more distal, first portion 710 of membrane 610 is now disposed over the neck of aneurysm 120 to, thereby, advantageously prevent unwanted passage of the embolism or clot into the parent blood vessel 100 and prevent blood flow into the ruptured aneurysm without having to remove temporary aneurysm neck protection device 700 or insert another device.
• Step 1502 includes threading a first microcatheter through the blood vessel and at least partly into the aneurysm.
• first microcatheter 200 may be threaded through blood vessel 100 and at least partly into aneurysm 120.
• Step 1504 includes threading a guide wire through the blood vessel to a position outside a neck of the aneurysm while the first microcatheter is disposed within the blood vessel.
• guide wire 300 may be threaded through blood vessel 100 to a position outside a neck of aneurysm 120 while first microcatheter 200 is disposed within blood vessel 100.
• Step 1506 includes threading a second microcatheter over the guide wire and through the blood vessel to the position outside the neck of the aneurysm.
• second microcatheter 400 may be threaded over guide wire 300 and through blood vessel 100 to the position outside the neck of aneurysm 120.
• guide wire 300 may be removed from second microcatheter 200 and from the blood vessel 100.
• step 1504 may be omitted and step 1506 may comprise threading second microcatheter 400 through blood vessel 100 to the position outside the neck of aneurysm 120 without guide wire guidance.
• Step 1508 includes threading the device for temporarily protecting the neck of the aneurysm through the second microcatheter in a collapsed state and out of a distal end of the second microcatheter, wherein the device comprises one or more wires forming a collapsible frame with a cover on at least a portion thereof having pores defining a first porosity.
• the device is expanded to a deployed configuration that substantially conforms to a shape of an inside surface of the blood vessel in the vicinity of the aneurysm with the cover disposed against a neck of the aneurysm.
• device(s) 600, 700 for temporarily protecting the neck of aneurysm 120 may be threaded through second microcatheter 400 in a collapsed state and out of a distal end of second microcatheter 400 such that wires 640, coiled to form a collapsible frame, expand and substantially conform to a shape of an inside surface of blood vessel 100, retention wire 630, disposed at a proximal end of the frame of wires 640, extends through an entire length of second catheter 400, and at least first portion, having a first porosity to blood flow, of membrane 610 that is disposed substantially around an entire perimeter of predetermined length L2 of the frame is disposed directly against a neck of aneurysm 120.
• a method related to this flowchart may include an optional step including utilizing membrane 610 to retain an intra-aneurysmal clot within aneurysm 120 and, thereby, prevent displacement of the clot into blood vessel 100 while aneurysm 120 is being treated.
• a method related to this flowchart may include a step 1512 including disposing at least one coil into aneurysm 120 through first microcatheter 200 while the frame of device 600, 700 is substantially conformed to the shape of the inside surface of blood vessel 110 and utilizing membrane 610 to redirect the at least one coil away from the neck of aneurysm 120 to, thereby, facilitate effective filling of aneurysm 120 with the coils.
• a method related to this flowchart may include an optional step including utilizing membrane 610 to prevent the at least one coil from protruding into and/or tangling in wires 640 of the frame.
• a method related to this flowchart may include an optional step including allowing blood to flow freely longitudinally through the frame and directly feed tissues distal of the aneurysm while the frame is expanded.
• wires 640 each converge to meet at distal end 650 of the frame.
• none of wires 640 meet at distal end 850 of the frame, thereby providing an unobstructed distal end 850 of the frame.
• each of wires 640 terminates, doubles back, or integrates into a substantially circular structure at distal end 850 of the frame.
• the frame is configured to elongate while collapsing to, thereby, minimize a collapsed diameter of device 600, 700.
• the frame has a substantially cylindrical shape at least along the predetermined length L2 on which membrane 610 is disposed.
• the collapsible frame comprises each of wires 640 wound in a substantially helical shape, each of wires 640 comprising a plurality of helical loops and each having a predetermined pitch L3. In some embodiments, each wire 640 is offset from at least one adjacent wire 640 by a predetermined spacing L4. In some embodiments, there are 6 wires 640. In some embodiments, the frame is configured to self- expand under a bias from wires 640. [0133] In some embodiments, device 600, 700 is configured to be disposed, in a collapsed state, within microcatheter 400 configured to be threaded through blood vessel 100 to a location immediately adjacent a neck of aneurysm 120.
• device 600, 700 is configured to be threaded therethrough while microcatheter 200 is disposed in blood vessel 100 and at least a distal tip is disposed in aneurysm 120.
• the first porosity is within the range of approximately 0- 0.1, a pore size associated with the first porosity is less than approximately 20 microns, and device 600, 700 is configured to support hemostasis within aneurysm 120 by substantially blocking blood flow into aneurysm 120 through first portion 610, 710 of membrane 610.
• the first porosity is within the range of approximately 0.1-0.4
• a pore size associated with the second porosity is greater than approximately 100 or 200 microns
• device 600, 700 is configured to allow substantially free flow of fluid through first portion of membrane 610 such that fluid freely flows out of aneurysm 120 through first portion 610 of membrane 610 as intrasacular volume is displaced by coils introduced into aneurysm 120, and systemic blood pressure keeps aneurysm 120 inflated while the coils are introduced into aneurysm 120.
• membrane 610 is configured to retain any intra- aneurysmal clot within aneurysm 120 and, thereby, prevent displacement of the clot into blood vessel 100 while aneurysm 120 is being treated. In some embodiments, membrane 610 is configured to redirect coils introduced into aneurysm 120 away from the neck of aneurysm 120 to, thereby, facilitate effective filling of aneurysm 120 with the coils. In some embodiments, membrane 610 is configured to prevent coils introduced into aneurysm 120 from protruding into and/or tangling in wires 640 of the frame.
• each end of the frame (e.g., proximal and distal) is substantially open such that the frame is configured to allow blood to flow freely longitudinally therethrough and directly feed tissues distal of the aneurysm while the frame is expanded.
• wires 640 form a first subset of innermost wires and a second subset of outermost wires when the frame is collapsed.
• each of the innermost wires is disposed in direct contact with each of two adjacent innermost wires and with one of the outermost wires, and a center of each of the outermost wires is disposed in-line with a center of a cross-section of the collapsed frame and with a center of the corresponding innermost wire with which the outermost wire is in direct contact.
• each of the innermost wires is disposed in direct contact with each of two adjacent innermost wires and with each of two adjacent outermost wires, and a center of each of the outermost wires is equally but oppositely offset from a center of each of the adjacent innermost wires with which the outermost wire is in direct contact.
• each of wires 640 has a diameter of one of approximately 0.001 inches, approximately 0.002 inches and 0.003 inches.
• device(s) 600, 700 is configured to have a minimum outside diameter of one of approximately 0.004 inches, approximately 0.005 inches, approximately 0.009 inches, approximately 0.010 inches, approximately 0.013 inches, and approximately 0.015 inches when the frame is fully collapsed.
• device 600, 700 is configured to have a maximum outside diameter D1 of approximately 0.12 inches or approximately 3 millimeters when the frame is fully expanded.
• membrane 610 further comprises second portion 720 having a second porosity to blood flow different than the first porosity of first portion 710 of membrane 610.
• a substantial majority of an aggregate porosity of device 600, 700 at first portion of membrane 610 is derived from the first porosity of membrane 610.
• each of wires 640 comprises at least one of a super- elastic nitinol, a cobalt chromium alloy, and a nitinol shape memory alloy.
• membrane 610 comprises a polymer.
• each of wires 640 is coated with polymer 1210 configured to substantially reduce exposure of wires 640 with the blood and, thereby, substantially reduce a thrombogenicity of the coated wires compared to uncoated wires.
• FIG. 13 illustrates a flowchart related to an example method of manufacturing a device for temporarily protecting a neck of an aneurysm of a blood vessel, as described anywhere in this disclosure.
• the method(s) disclosed herein comprise(s) one or more steps or actions for achieving the described method(s), such steps and/or actions may be interchanged with one another, and/or a subset of these steps and/or actions may be used, without departing from the scope of the claims.
• Step 1602 includes coiling (e.g. looping, braiding, joining, or otherwise arranging) a plurality of wires to form a collapsible frame configured to expand and substantially conform to a shape of an inside surface of the blood vessel.
• wires 640 may be coiled to form a collapsible frame configured to expand and substantially conform to a shape of an inside surface of blood vessel 100.
• Step 1604 includes disposing a retention wire at a proximal end of the frame of the plurality of wires.
• retention wire 630 may be disposed at a proximal end of the frame of wires 640.
• Step 1606 includes disposing a membrane substantially around an entire perimeter of a predetermined length of the frame, the membrane comprising at least a first portion having a first porosity to blood flow and being configured to be disposed directly against a neck of the aneurysm.
• membrane 610 may be disposed substantially around an entire perimeter of a predetermined length L2 of the frame.
• Membrane 610 comprises at least a first portion 610, 720 having a first porosity to blood flow and being configured to be disposed directly against a neck of aneurysm 120.
• a method related to this flowchart may include an optional step 1608 including coating each of the plurality of wires with a polymer configured to substantially reduce exposure of the plurality of wires with the blood and, thereby, substantially reduce a thrombogenicity of the coated wires compared to uncoated wires.
• each wire 640 may be coated with polymer 1210 configured to substantially reduce exposure of wires 640 with the blood and, thereby, substantially reduce a thrombogenicity of the coated wires compared to uncoated wires.
• a method related to this flowchart may include an optional step 1610 including forming a second portion of the membrane having a second porosity to blood flow different than the first porosity of the first portion of the membrane.
• second portion 720 of membrane 610 may be formed having a second porosity to blood flow different than the first porosity of first portion 710 of membrane 610.
• a method related to this flowchart may include any optional step corresponding to provision, formation or assembly of any feature of any of devices 600, 700 described herein.
• Intravascular Flow Diverter [0150] The present disclosure relates to intravascular flow diverters and related methods of using and/or manufacturing the same. Several example embodiments of such intravascular flow diverters, and related methods, will now be described in connection with one or more figures. [0151] Endovascular repair of fusiform aneurysms or bifurcation aneurysms is difficult due to complex flow geometries, side branching blood vessels at the bifurcation and the potential for perforating blood vessels that it is desirable to preserve. Accordingly, a need exists for improved intravascular flow diverters and related methods of using and/or manufacturing the same. [0152] FIG. 14A illustrates a portion of a blood vessel 110.
• Vessel 110 is illustrated as including one or more branching blood vessels 130 and an aneurysm 120, shown bulging beyond adjacent portions of blood vessel 110.
• FIG.14A illustrates blood flow through the vessel 110 in the region around the aneurysm 120.
• some of the vessel blood flow 150 past the aneurysm neck is diverted into the aneurysm as aneurysm inflow 155, where it may circulate backwards and then re-enter the vessel flow 150 as aneurysm outflow 165.
• This intrasaccular circulation pushes outward on the aneurysm wall, causing expansion and possibly rupture.
• Treatments for such types of aneurysms 120 can involve the use of flow diverters to bypass the diseased area.
• One contemporary treatment involves the use of a Medtronic's Pipeline flow diverter 205, having 64 x 0.001-inch diameter wires in a dense braid, configured to bridge over aneurysm 120. This is illustrated generally in FIG.14B. Resistance to blood flow through the sidewall of such a pipeline flow diverter 270 is provided by this very dense wire braiding.
• an intravascular flow diverter for treating an aneurysm of a blood vessel is provided.
• the diverter includes a stent including a plurality of wires coiled to form an expandable structure.
• the diverter includes a membrane disposed on an entire outer surface of the stent.
• the membrane includes a first portion configured to be disposed directly against a neck of the aneurysm.
• the membrane includes at least one second portion configured to be disposed adjacent to and not directly over the aneurysm.
• the first portion has a first porosity to blood flow
• the second portion has a second porosity to blood flow greater than the first porosity, at least one of the at least one second portions.
• Common locations for intracranial aneurysms include the communicating arteries, the internal carotid arteries, and the middle cerebral artery.
• a method for utilizing an intravascular flow diverter to treat an aneurysm of a blood vessel includes disposing the intravascular flow diverter within a microcatheter. The method includes threading the microcatheter through the blood vessel to a location of the aneurysm.
• the method includes removing the intravascular flow diverter from a distal end of the microcatheter such that a stent of the intravascular flow diverter, including a plurality of wires coiled to form an expandable structure, expands sufficiently within the blood vessel that a first portion of a membrane disposed on an entire outer surface of the stent is disposed directly against a neck of the aneurysm, and that at least one second portion of the membrane is disposed adjacent to and not directly over the aneurysm.
• the first portion has a first porosity to blood flow
• the at least one second portion has a second porosity to blood flow greater than the first porosity.
• a method of manufacturing an intravascular flow diverter configured for treating an aneurysm of a blood vessel includes coiling a plurality of wires to form an expandable stent.
• the method includes disposing a membrane on an entire outer surface of the stent such that the membrane includes a first portion configured to be disposed directly against a neck of the aneurysm, and at least one second portion having a second porosity to blood flow greater than the first porosity and being configured to be disposed adjacent to and not directly over the aneurysm.
• Improvements to intravascular flow diverters as described herein may include a stent comprising a self-expanding and/or balloon expandable braid of wires 420 (which may be constructed from known techniques including, but not limited to, braiding and/or laser cutting) and coated with a thin membrane 410 comprising one or more portions 310, 320a and 320b having one or more desired porosities. Particulars of such an intravascular flow diverter 300 will be described in more detail in connection with at least FIGs. 16-18C. [0158] As illustrated in FIG.
• such a flow diverter 300 comprising such a collapsible, collapsed stent and thin membrane, may be disposed within a microcatheter 200 and the microcatheter 207 threaded through blood vessel 100 until flow diverter 300 is disposed immediately adjacent aneurysm 120 with a goal of eliminating blood flow into aneurysm 120 and, thereby, reducing stress induced on a wall of aneurysm 120.
• the stent of flow diverter 300 may be allowed to self-expand under bias from the plurality of braided wires 420 (see, e.g., FIGs.
• intravascular flow diverter 300 may comprise a first portion 310 configured to be disposed directly over a neck of aneurysm 120.
• First portion 310 has a first porosity which prevents the circulating blood inflow 155 and outflow 165. This can be accomplished by, for example, depositing a relatively thick multilayer mat of electrospun fibers onto the stent frame in this region, essentially eliminating the ability of significant numbers of pores to span the thickness of the cover, producing, e.g., 0-0.05 (5%) porosity.
• this inflow 155 and outflow 165 blocking function can be provided with membranes of surprisingly high porosities and large pore sizes.
• porosity and pore size should be appropriately balanced. Higher total porosities require smaller pore sizes, while lower porosities can have large pore sizes while maintaining the desired inflow 155 and outflow 165 suppression. This may be evaluated in a more quantitative manner by considering the product of median pore size times total fractional porosity as a characterization of cover porosity distribution.
• this product may be in the range of 0.5 to 50, with 5 to 20 having been found particularly suitable.
• a suitable membrane may have a total porosity of 0.05 to 0.5 and a median pore size between 10 and 100 microns.
• a membrane with a porosity of 0.3 to 0.6 and a median pore size between 20 and 30 is utilized.
• a membrane with a total porosity between 0.05 and 0.15 and a median pore size between 30 and 100 microns is utilized.
• a membrane with a total porosity between 0.15 and 0.25 and a median pore size between 20 and 80 microns is utilized.
• intravascular flow diverter 305 may further comprise one or more second portions 320a, 320b adjacent to first portion 310 and configured to allow for increased blood flow through side branches 130 of blood vessel 100 as compared to the reduced or substantially eliminated blood flow through first portion 310 and into aneurysm 120.
• Second portion(s) 320 has a second porosity that is greater than the first porosity of first portion 310 (e.g., 0.05-0.4 porosity). In some embodiments, one of second portions 320 may have a different porosity from either first portion 310 or the other second portion 320. Accordingly, flow diverter 305 may be configured to address side-wall aneurysms, bifurcation aneurysms, and fusiform aneurysms. [0163] An electrospun stent cover membrane having porosity and permeability suitable for accomplishing one or more of these functions is described in paragraphs [0092] through [0103] of US Published Patent Application 2021/0052360, which paragraphs are incorporated herein by reference.
• flow diverter 305 comprises a plurality of wires 420 braided around one another.
• each of wires 420 may be coiled into a collapsible and expandable, substantially helical shape or structure configured to have a predetermined length L1 (e.g., approximately 0.79 inches or 20mm, although any other suitable length is also contemplated) and a predetermined maximum diameter D1 (e.g., approximately 0.18 inches or 4.5mm, although any other suitable diameter is also contemplated) when fully expanded.
• L1 e.g., approximately 0.79 inches or 20mm, although any other suitable length is also contemplated
• D1 e.g., approximately 0.18 inches or 4.5mm, although any other suitable diameter is also contemplated
• each wire 420 is offset from adjacent wires 420 by a predetermined spacing L3.
• each of wires 420 may have a predetermined pitch L2 (i.e., each loop or winding of a particular one of wires 420 extends predetermined length L2 (e.g., approximately 0.18 inches or 4.5mm, although any other suitable length is also contemplated) along a length of extension of flow diverter 305).
• the spacing L3 may be determined as the result of dividing pitch L2 of wires 420 by a number of those wires that are wound in a same direction.
• a subset (e.g., 8 of the plurality of wires 420) of the plurality of wires 420 are wound in a clockwise direction, while another subset of the plurality of wires 420 (e.g., another 8 of the plurality of wires 420) are wound in a counterclockwise direction. Accordingly, where subsets of wires 420 are wound in opposite directions from one another, one subset of wires 420 will overlap the other subset of wires 420 at multiple points along the predetermined length L1.
• the frame is configured to elongate while collapsing to, thereby, minimize a collapsed diameter of the frame.
• wires 420 advantageously provide for easy, unobstructed expansion of flow diverter 305 in vivo.
• wires 420 comprise super-elastic nitinol.
• a cobalt chromium may be used.
• a nitinol shape memory alloy may be used.
• wires 420 may comprise any suitably flexible, expandable and compressible material.
• each of wires 420 may be further coated with a polymer 510 which may be a dip coating configured to substantially reduce or minimize metal exposure to the blood.
• flow diverter 305 comprises a membrane 410 disposed on at least a portion of the outer surface, typically an entire outer surface, e.g., substantially around an entire perimeter, of flow diverter 305 and along the entire length of extension L1.
• membrane 410 has a substantially cylindrical form when the entirety of flow diverter 305 is disposed parallel to the length of extension L1, as shown in FIG. 4.
• Membrane 410 may provide support for the underlying expanded frame of wires 420 as well as a near or substantially impermeable layer that, advantageously, has a very thin construction, for example having a thickness T1, as a result of an electrospinning process utilized to form membrane 410.
• the above-mentioned dip coating can provide a good bond between the electrospun membrane and the frame.
• Membrane 410 providing such support, as well as this near impermeable layer work together to allow a reduction in a number of wires 420 (e.g., 6, 8, 12 or 16 of wires 420) needed for construction and effective operation, for example compared to the Medtronic pipeline flow diverter (e.g., having and requiring 64 wires).
• cover membrane 410 may provide support for the underlying expanded frame of struts 640 while also possessing a very thin construction. A cover membrane 410 providing such support allows a reduction in a number of wires 420 needed for construction and effective operation, compared conventional devices not comprising such a membrane. The cover membrane allows an increase in frame porosity.
• the frame porosity over a majority, substantially all, or all of its overall length is greater than 90%, preferably greater than 93%, more preferably greater than 95%.
• This reduction in strut area also advantageously reduces device mass per unit length, delivery profile, longitudinal stiffness of, and radial force exerted by, device 305 during navigation to aneurysm 120 in the delivery system. All of these improvements separately and collectively allow for easier tracking into the vasculature and improved delivery and deployment of device(s) 300.
• This reduction in wire number also advantageously reduces a delivery profile and longitudinal stiffness of, as well as a radial force exerted by, diverter 305 during navigation to aneurysm 120 in the delivery system. All of these improvements separately and collectively allow for easier tracking into the vasculature and improved delivery and deployment of diverter 305.
• the reduced number of wires 420 also provides more uniform porosity across the neck of a curve of diverter 300 at least because the smaller number of wires crowd to a comparatively lesser degree on the inside of such curves.
• the porosity and/or permeability of membrane 410 can be tailored to allow very low or substantially no blood flow through areas of membrane 410 immediately over or against the diseased blood vessel wall of aneurysm 120 (see, e.g., the portion of membrane 410 shown in FIG. 17 forming first portion 310 shown in FIG.
• a density and/or a porosity of membrane 410 may be tuned to have different or variable values at different locations and, thereby, provide for the relatively high porosity of second portion(s) 320 (for positioning adjacent side branches 130) and for the relatively low porosity first portion 310 (for positioning at aneurysm 120, where isolation from blood flow and clotting external to the stent should be promoted).
• areas of blood vessel 110 having perforating vessels or side branches 130 that require maintained blood flow advantageously remain viable by virtue of the increased blood flow through second portion(s) 320 of membrane 410.
• membrane 410 being applied to the stent formed from wires 420 is that the porosity, and therefore flow control, achieved by membrane 410 will advantageously allow fewer sizes of diverter 305 to be made available and/or used compared to existing flow diverters, all of which have fairly narrow ranges of vessel diameters for which each size is effective at segregating blood flow.
• flow diverter 305 may be made available in sizes with much larger increments, e.g., 1.0 to 1.5mm, thereby allowing 4 – 6 fewer sizes of diverters 300 than compared to traditional wire braid stents.
• flow diverter 305 may have an improved ability for use with coils, or intrasaccular flow diverters. For example, in the event of inadvertent rupture of an aneurysm while using flow diverter 305, in combination with such coils or intra-saccular flow diverters, flow diverter 305 provides additional hemostasis via membrane 410 compared to traditional dense wire braid stents.
• wires 420 may have one of a variety of different thicknesses, according to requirements of a desired application.
• FIGs. 18A-18C illustrates cross-sections of first through third example embodiments of intravascular flow diverter 305, for example, as viewed along a cutline A-A’ shown in FIG. 17.
• Each of the embodiments of FIGs. 18A-18C may be substantially similar to one another, except each utilizes wire 420 having a different diameter and, therefore, each illustrated embodiment of diverter 305 also comprises a respective minimum collapsed diameter.
• wires 420 may have an outside diameter of approximately 0.002 inches, and diverter 305 may, accordingly, be configured to have a minimum contracted diameter D2 (e.g., 0.011 inches) and the maximum expanded diameter D1.
• wires 420 may have an outside diameter of approximately 0.0015 inches and diverter 305 may, accordingly, be configured to have a minimum contracted diameter D3 (e.g., 0.008 inches) and the maximum expanded diameter D1.
• wires 420 may have an outside diameter of approximately 0.001 inches, and diverter 305 may, accordingly, be configured to have a minimum contracted diameter D4 (e.g., 0.006 inches) and the maximum expanded diameter D1.
• the example orientation of wires 420 in the collapsed state illustrated in each of FIGs. 18A-18C comprises an innermost subset of 8 threads and an outermost subset of 8 threads.
• Each of the innermost threads is disposed in direct contact with each of two adjacent threads of the innermost subset and one thread of the outermost subset.
• a center of each of the outermost threads is radially in-line with both a center of the frame’s cross section and a center of the corresponding inner thread with which the outermost thread is in direct contact.
• FIG. 19 illustrates a flowchart related to an example method for utilizing an intravascular flow diverter 305, as described anywhere in this disclosure.
• Step 602 includes disposing the intravascular flow diverter within a microcatheter.
• intravascular flow diverter 305 can be disposed within microcatheter 207.
• Step 604 includes threading the microcatheter through the blood vessel to a location of the aneurysm.
• microcatheter 207 can be threading through blood vessel 110 to a location of aneurysm 120.
• Step 606 includes removing the intravascular flow diverter from a distal end of the microcatheter such that a stent of the intravascular flow diverter, comprising a plurality of wires coiled to form an expandable structure, expands sufficiently within the blood vessel that a first portion of a membrane disposed on an entire outer surface of the stent is disposed directly against a neck of the aneurysm, the first portion having a first porosity to blood flow, and at least one second portion of the membrane is disposed adjacent to and not directly over the aneurysm, the at least one second portion having a second porosity to blood flow greater than the first porosity.
• a stent of the intravascular flow diverter comprising a plurality of wires coiled to form an expandable structure, expands sufficiently within the blood vessel that a first portion of a membrane disposed on an entire outer surface of the stent is disposed directly against a neck of the aneurysm, the first portion having a first porosity to blood
• intravascular flow diverter 305 can be removed from a distal end of microcatheter 207 (see, e.g., FIG. 15) such that a stent of intravascular flow diverter 305, comprising wires 420 coiled to form an expandable structure, expands sufficiently within blood vessel 110 that first portion 310 of membrane 410 is disposed directly against a neck of aneurysm 120, and at least one second portion 320 of membrane 410 is disposed adjacent to and not directly over aneurysm 120.
• First portion 310 has a first porosity to blood flow and second portion(s) 320a, 320b have a second porosity to blood flow greater than the first porosity.
• a method related to this flowchart may include an optional step 608 of expanding the plurality of wires by expanding a balloon from within the substantially helical shape.
• a balloon may be expanded from within the substantially helical shape of wires 420.
• the expandable structure comprises each of plurality of wires 420 wound in a substantially helical shape.
• each of wires 420 comprises a plurality of helical loops, each having a predetermined pitch L2. In some embodiments, a first subset of wires 420 are wound in a clockwise direction and a second subset of wires 420 are wound in a counterclockwise direction. In some embodiments, each of wires 420 is offset from at least one adjacent wire 420 by a predetermined spacing L3. In some embodiments, the plurality of wires is one of 6 wires, 8 wires, 12 wires and 16 wires. In some embodiments, wires 420 are configured to self-expand under a self-bias once intravascular flow diverter 305 is removed from microcatheter 207.
• threading microcatheter 207 through blood vessel 110 to a location of aneurysm 120 comprises disposing at least one of the at least one second portions 320 directly over a side branch 130 of blood vessel 110.
• the first porosity is sufficiently low that, when intravascular flow diverter 305 is properly disposed within blood vessel 110, first portion 310 of membrane 410 is configured to allow substantially no blood flow therethrough to, thereby, allowing a clot to form and ultimately scar over at aneurysm 120.
• the second porosity is sufficiently high that, when intravascular flow diverter 305 is properly disposed within blood vessel 110, at least one of the at least one second portions 320 of membrane 410 are configured to allow substantial blood flow therethrough and directly into side branch 130 of blood vessel 110.
• each of wires 420 has a diameter of one of approximately 0.002 inches, approximately 0.015 inches, and 0.001 inches (see, e.g., FIGs. 18A-18C).
• intravascular flow diverter 305 has a minimum outside diameter D2, D3, D4 of one of approximately 0.011 inches, approximately 0.008 inches, and approximately 0.006 inches when the expandable structure of the stent is fully collapsed (see, e.g., FIGs.
• intravascular flow diverter 300 has a maximum outside diameter D1 of approximately 0.18 inches when the expandable structure of the stent is fully expanded.
• a substantial majority of an aggregate porosity of intravascular flow diverter 305, at first and second portions 310, 320 of membrane 410, is derived from the first and second porosities of membrane 410 at the respective first and second portions 310, 320.
• Step 702 includes coiling (e.g. looping, braiding, joining, or otherwise arranging) a plurality of wires to form an expandable stent. For example, as previously described in connection with at least one of FIGs.
• Step 704 includes disposing a membrane on an entire outer surface of the stent such that the membrane comprises a first portion having a first porosity to blood flow and being configured to be disposed directly against a neck of the aneurysm, and at least one second portion having a second porosity to blood flow greater than the first porosity and being configured to be disposed adjacent to and not directly over the aneurysm.
• membrane 410 may be disposed on an entire outer surface of the stent such that membrane 410 comprises first portion 310 having a first porosity to blood flow and being configured to be disposed directly against a neck of aneurysm 120, and at least one second portion 320 having a second porosity to blood flow greater than the first porosity and being configured to be disposed adjacent to and not directly over aneurysm 120.
• coiling wires 420 comprises winding each of wires 420 into a substantially helical shape.
• each of wires 420 are wound into the substantially helical shape such that each of a plurality of helical loops has a predetermined pitch L2.
• a first subset of wires 420 are wound in a clockwise direction and a second subset of wires 420 are wound in a counterclockwise direction.
• each of wires 420 is offset from at least one adjacent wire 420 by a predetermined spacing L3.
• the plurality of wires 420 is one of 6 wires, 8 wires, 12 wires and 16 wires.
• wires 420 are configured to self-expand under a self-bias.
• wires 420 are configured to expand under influence of a balloon configured to be expanded from within the substantially helical shape.
• intravascular flow diverter 305 is configured to be disposed, in a collapsed form, within microcatheter 207 that is configured to be threaded through blood vessel 100 to a location of aneurysm 120 (see, e.g., FIG. 15).
• at least one of the at least one second portions 320 is configured to be disposed directly over side branch 130 of blood vessel 110.
• the first porosity is sufficiently low that, when intravascular flow diverter 305 is properly disposed within blood vessel 110, first portion 310 of membrane 410 is configured to allow substantially no blood flow therethrough to, thereby, allow a clot to form and ultimately scar over at aneurysm 120.
• the second porosity is sufficiently high that, when intravascular flow diverter 305 is properly disposed within blood vessel 110, at least one of the at least one second portions 320 of membrane 410 are configured to allow substantial blood flow therethrough and directly into side branch 130 of blood vessel 100.
• each of wires 420 is provided to have a diameter of one of approximately 0.002 inches, approximately 0.015 inches, and 0.001 inches (see, e.g., FIGs. 18A-18C).
• intravascular flow diverter 305 is configured to have a minimum outside diameter D2, D3, D4 of one of approximately 0.011 inches, approximately 0.008 inches, and approximately 0.006 inches when the expandable structure of the stent is fully collapsed (see, e.g., FIGs. 18A-18C).
• intravascular flow diverter 305 is configured to have a maximum outside diameter D1 of approximately 0.18 inches when the expandable structure of the stent is fully expanded (see, e.g., FIGs. 18A-18C).
• a substantial majority of an aggregate porosity of intravascular flow diverter 305, at the first and second portions 310, 320 of membrane 410, is derived from the first and second porosities of membrane 410 at the respective first and second portions 310, 320.
• each of wires 420 comprises at least one of a super-elastic nitinol, cobalt chromium, and a nitinol shape memory alloy.
• FIG. 21A illustrates a portion of a blood vessel 110.
• Vessel 110 is illustrated as including one or more branching blood vessels 130 and an aneurysm 120, shown bulging beyond adjacent portions of blood vessel 110.
• FIG.21A illustrates blood flow through the vessel 110 in the region around the aneurysm 120.
• Endovascular repair of sidewall or bifurcation aneurysms are not always amenable to standard treatments.
• One such class of aneurysms can include those having particularly wide neck anatomies.
• Typical treatments for some such types of aneurysms involve the use of a balloon to support and block flow in the parent blood vessel and associated aneurysm while coiling of the aneurysm is accomplished.
• coils have been used to fill the aneurysm sac due to their inherent softness. However, such coils lack sufficient retention force in large neck aneurysms.
• Another difficulty can be posed by nearby branching vessels 130, which may prevent the use of a conventional fluid impermeable stent in the vessel 110 across the neck of the aneurysm 120.
• One option is to deploy an intrasaccular occluder into the sac of the aneurysm. This is illustrated in FIG. 22A.
• Microvention’s WEB device 270 a dense braid of super-elastic nitinol wires that deploys into a 3D shape configured for insertion into the aneurysm sac is one example of such a device, shown in FIG. 22B.
• an intrasacular flow diverter for treating an aneurysm of a blood vessel.
• the intrasacular flow diverter includes a plurality of wires coiled to form a collapsible frame configured to expand within, and substantially conform to a shape of an inside surface of, the aneurysm.
• the intrasacular flow diverter includes a membrane disposed on all or some of the outer surface of the frame.
• the membrane includes a first portion configured to be disposed directly against a neck of the aneurysm.
• the membrane may include a second portion configured to be disposed within the aneurysm and distal to the neck of the aneurysm.
• the first portion has a first porosity to blood flow and the second portion has a second porosity to blood flow greater than the first porosity.
• Common locations for intracranial aneurysms include the communicating arteries, the internal carotid arteries, and the middle cerebral artery.
• the devices described herein can, for example, be used in these arteries.
• a method for utilizing an intrasacular flow diverter to treat an aneurysm of a blood vessel includes disposing the intrasacular flow diverter within a microcatheter in a collapsed state. The method includes threading the microcatheter through the blood vessel to a location within the aneurysm.
• the method includes removing the intrasacular flow diverter from a distal end of the microcatheter such that a plurality of coiled wires forming a collapsed substantially spherical frame of the intrasacular flow diverter expand sufficiently within the aneurysm that a first portion of a membrane disposed on an entire outer surface of the substantially spherical frame is disposed directly against a neck of the aneurysm, and a second portion of the membrane is disposed within the aneurysm and distal to the neck of the aneurysm.
• the first portion has a first porosity to blood flow and the second portion has a second porosity to blood flow greater than the first porosity.
• a method of manufacturing an intrasacular flow diverter configured for treating an aneurysm of a blood vessel includes coiling a plurality of wires to form a collapsible, substantially spherical frame configured to expand within, and substantially conform to a shape of an inside surface of, the aneurysm.
• the method includes disposing a membrane on all or part of an outer surface of the frame such that the membrane comprises a first portion configured to be disposed directly against a neck of the aneurysm, and a second portion configured to be disposed within the aneurysm and distal to the neck of the aneurysm.
• Improvements to intrasaccular flow diverters as described herein may include a self-expanding frame of wires 420 that is configured to fill an aneurysm sac and aid in reconstruction of the neck of aneurysm 120 to, thereby, prevent further growth of aneurysm 120 (see, e.g., any of FIGs. 24A-24D).
• each of wires 420 may be covered in a polymer 510 configured to minimize metal exposure to the blood (see, e.g., any of FIGs.
• Such intrasacular flow diverters 900 will be described in more detail in connection with at least FIGs. 23-25C.
• a flow diverter 900 may be disposed within a microcatheter 200 in a collapsed state and the microcatheter 200 threaded through blood vessel 100 until a distal end of microcatheter 200 is disposed within aneurysm 120.
• intrasacular flow diverter 900 may comprise a collapsed or collapsible, substantially spherical frame, formed by wires 420 (see, e.g., FIGs. 24A-24D), that is configured to expand and substantially conform to a shape of an inside surface of aneurysm 120.
• Diverter 900 comprises a first portion 910, having a first desired porosity, configured to be disposed within and/or directly against a neck of aneurysm 120 and, thereby, protect the neck of aneurysm 120.
• Diverter 900 may further comprise a second portion 920, adjacent to first portion 910, having a second desired porosity that is greater than the first porosity of first portion 910, and configured to be disposed within aneurysm 120 and distal to the neck of aneurysm 120.
• Second portion 920 is configured for increased perfusion of blood flow therethrough as compared to the reduced or substantially eliminated perfusion of blood flow through first portion 910. As will be described in more detail in connection with at least FIGs.
• these aggregate first and second porosities of first and second portions 910, 920 of diverter 900 may be largely and/or substantially entirely achieved through manipulation of the porosities of corresponding portions of membrane disposed on at least a portion of the outer surface of the frame, preferably an entire outer surface of the frame formed by wires 420, rather than through utilization of an ultra-dense collection of a much larger number of wires, as in conventional intrasaccular occluders and/or stents.
• flow diverter 900 may be configured to address, in some cases, side-wall and/or bifurcation aneurysms having sufficiently wide neck anatomies to contraindicate standard aneurysm treatments.
• the cover membrane 910 has porosity, porosity distribution, and permeability characteristics that substantially block the circulating aneurysm inflow 155 and outflow 165 that is illustrated in FIG. 21A. It has been found that this inflow 155 and outflow blocking function can be provided with membranes of surprisingly high porosities and large pore sizes. Generally, to generate a membrane that has low permeability to inflow 155 and outflow 165 in the presence of vessel flow 150, porosity and pore size should be appropriately balanced. Higher total porosities require smaller pore sizes, while lower porosities can have large pore sizes while maintaining the desired inflow 155 and outflow 165 suppression.
• this product may be evaluated in a more quantitative manner by considering the product of median pore size times total fractional porosity as a characterization of cover porosity distribution.
• this product may be in the range of 0.5 to 50, with 5 to 20 having been found particularly suitable.
• a suitable membrane may have a total porosity of 0.05 to 0.5 and a median pore size between 10 and 100 microns.
• a membrane with a porosity of 0.3 to 0.6 and a median pore size between 20 and 30 is utilized.
• a membrane with a total porosity between 0.05 and 0.15 and a median pore size between 30 and 100 microns is utilized.
• a membrane with a total porosity between 0.15 and 0.25 and a median pore size between 20 and 80 microns is utilized.
• the pore size range may be from 5 to 400 microns, 5 to 200 microns, or 5 to 100 microns, wherein outliers outside of these ranges that do not significantly contribute the total porosity of the cover (e.g. less than 5% of the total porosity) are ignored.
• Endothelial ingrowth is enhanced by having relatively small median pore sizes such as 10 to 50 microns and high porosity greater than 0.3, more preferably greater than 0.4.
• Relatively high porosity membranes that retain the ability to block significant aneurism inflow 155 and outflow 165 have many advantages.
• membranes with higher porosities allow the use of wire frames of very high porosity by providing structural support to the device, which allows the production of highly flexible devices that are more easily navigated through complex vasculature to an aneurysm.
• An electrospun stent cover membrane having porosity and permeability suitable for accomplishing one or more of these objectives is described in paragraphs [0092] through [0103] of US Published Patent Application 2021/0052360, which paragraphs are incorporated by reference herein. [0208] As illustrated in FIGs.
• flow diverter 900 comprises a plurality of wires 420 braided around one another to form a collapsed and/or collapsible (and so also expanded and/or expandible), frame.
• each of wires 420 may be coiled into a plurality of collapsible and expandable, substantially helical shape or structure comprising a plurality of loops having successively increasing and then decreasing diameters such that wires 420 form a frame having a predetermined maximum spherical diameter D1 (e.g., approximately 0.18 inches or 4.5mm) when fully expanded.
• each wire 420 is offset from adjacent wires 420 by a predetermined spacing L3.
• each of wires 420 may have a predetermined pitch (i.e., each loop or winding of a particular one of wires 420 extends predetermined length).
• this predetermined pitch may be the same distance as the diameter D1 of the frame, e.g., 0.18 inches or 4.5mm.
• the spacing L3 may be determined as the result of dividing the pitch of wires 420, or in appropriate above-mentioned embodiments, diameter D1, by a number of those wires that are wound in a same direction. For example, in some embodiments according to FIGs.
• a subset (e.g., 8, 12 or 16 of the plurality of wires 420 in FIGs. 24A-B, 24C and 24D, respectively) of the plurality of wires 420 are wound in a clockwise direction, while another subset of the plurality of wires 420 (e.g., another 8, 12 or 16 of the plurality of wires 420 in FIGs. 24A-B, 24C and 24D, respectively) are wound in a counter-clockwise direction. Accordingly, where subsets of wires 420 are wound in opposite directions from one another, one subset of wires 420 will overlap the other subset of wires 420 at multiple points along the predetermined maximum-expanded diameter D1.
• wires 420 advantageously provide for easy, unobstructed expansion of flow diverter 300 within aneurysm 120.
• wires 420 comprise super-elastic nitinol.
• a cobalt chromium may be used.
• a nitinol shape memory alloy may be used.
• wires 420 may comprise any suitably flexible, expandable and compressible material. As most easily seen in any of FIGs. 25A-25D, each of wires 420 may be further coated with a polymer 510 configured to substantially reduce or minimize metal exposure to the blood.
• flow diverter 900 comprises a membrane 410 disposed on an entire outer surface of flow diverter 900.
• membrane 410 has a substantially spherical form, as shown in any of FIGs. 24A-24D. At least some portions of membrane 410 may provide a near or substantially impermeable layer that, advantageously, has a very thin construction, as a result of an electrospinning process utilized to form membrane 410 from, for example a polymer.
• membrane 410 may comprise a high-elongation, solvent-dispersible material having good antithrombogenicity properties.
• Membrane 410 may also provide support for the underlying expanded frame of wires 420. This support function, along with that of providing the near impermeable layer in at least some portions of membrane 410, work together to allow a reduction in a number of wires 420 (e.g., 8, 12 or 16 wires 420) needed for construction and effective operation, for example compared to the Microvention Web.
• Microvention Web relies on the density and close proximity of the many (e.g., 144) individual wires to provide sufficient support to the wall of aneurysm 120 and to also provide sufficiently low porosity to prevent blood flow to aneurysm 120
• at least some of the requisite support to the inside surface of aneurysm 120 is provided by membrane 410 in embodiments described anywhere herein.
• Membrane 410 additionally provides a force that helps expand diverter 900.
• a majority of the requisite low permeability of flow diverter 900 is provided by membrane 410.
• the smaller number of wires 420 makes diverter 900 easier to navigate into aneurysm 120 than other conventional designs due to the reduced moment of inertia possessed by the smaller number and mass of wires. This is true when diverter 900 is utilized in isolation as well as when diverter 900 is utilized in conjunction with one or more of a stent-based diverters within blood vessel 100 and/or coils disposed within diverter 900 for additional wall contact, radial force, and/or filling of aneurysm 120.
• additional radial force may be delivered to aneurysm 120 by disposing coils within diverter 300 after diverter 900 is deployed within aneurysm 120.
• microcatheter 200 (see FIG. 2) may be repositioned adjacent to diverter 900 after diverter 900 has been deployed within aneurysm 120.
• a guidewire may be passed through microcatheter 200 and extended sufficiently beyond a distal tip of microcatheter 200 to puncture membrane 410 of diverter 900 and extend within aneurysm 120. Then, microcatheter 200 may be advanced over the guidewire into an interior of diverter 900.
• Another advantage of the use of fewer wires 420, as compared to other conventional designs, is a reduction in stiffness of diverter 900 during the early portions of deployment. This reduction in stiffness also carries over to advantages for diverter 900 in the deployed, extended state, for example, improved wall apposition in irregularly shaped aneurysms. All of these improvements separately and collectively allow for easier tracking into the vasculature and improved delivery and deployment of diverter 900.
• the porosity and/or permeability of membrane 410 can be tailored independently of a number or density of wires 420 to allow very low or substantially no blood flow through areas of membrane 410 configured to be disposed within and/or directly against a neck of aneurysm 120 (see, e.g., the portion of membrane 410 in any of FIGs. 24A-24D that would form or coincide with first portion 910 in FIG. 23) and, thereby, protect the neck of aneurysm 120.
• a density and/or a porosity of membrane may be tuned to have different or variable values at different locations and, thereby, provide for the relatively high porosity of second portion(s) 920 (e.g., a 5-40% porosity) and for the relatively low porosity first portion 910 (e.g., a 0-5% porosity).
• flow diverter 900 may have an improved applicability for use with coils, or intravascular flow diverters.
• flow diverter 900 provides additional hemostasis via membrane compared to traditional dense wire braids of intrasaccular occluders.
• One benefit of traditional coils is that their softness may be tailored or selected to provide minimal disruption or reshaping of irregular shaped aneurysms.
• Embodiments of diverter 900 described herein comprise far fewer wires 420 than traditional diverters and so are able to provide a similar benefit, at least in that lower force may be applied to the wall of aneurysm 120.
• wires 420 may have one of a variety of different thicknesses, according to requirements of a desired application.
• FIGs. 25A-25D illustrates cross-sections of first through fourth example embodiments of intrasacular flow diverter 900 in a collapsed state. Each of the embodiments of FIGs. 25A-25D may be substantially similar to one another, except each utilizes wire 420 having a different diameter and, so, providing a different minimal diameter of flow diverter 300 when in a fully collapsed state.
• FIG. 25A-25D illustrates cross-sections of first through fourth example embodiments of intrasacular flow diverter 900 in a collapsed state.
• Each of the embodiments of FIGs. 25A-25D may be substantially similar to one another, except each utilizes wire 420 having a different diameter and, so, providing a different minimal diameter of flow diverter 300 when in a fully collapsed state.
• wires 420 may have an outside diameter of approximately 0.0003 inches, and diverter 900 may, accordingly, be configured to have a minimum contracted diameter D2 (e.g., 0.002 inches) and the maximum expanded diameter D1.
• wires 420 may have an outside diameter of approximately 0.0005 inches and diverter 900 may, accordingly, be configured to have a minimum contracted diameter D3 (e.g., 0.003 inches) and the maximum expanded diameter D1.
• wires 420 may have an outside diameter of approximately 0.0007 inches, and diverter 900 may, accordingly, be configured to have a minimum contracted diameter D4 (e.g., 0.004 inches) and the maximum expanded diameter D1.
• wires 420 may have an outside diameter of approximately 0.001 inches, and diverter 900 may, accordingly, be configured to have a minimum contracted diameter D5 (e.g., 0.006 inches) and the maximum expanded diameter D1.
• the example orientation of wires 420 in the collapsed state illustrated in each of FIGs. 25A-25D comprises an innermost subset of 8 threads and an outermost subset of 8 threads. Each of the innermost threads is disposed in direct contact with each of two adjacent threads of the innermost subset and one thread of the outermost subset.
• FIG. 26 illustrates a flowchart related to an example method for utilizing an intrasacular flow diverter, as described anywhere in this disclosure.
• the method(s) disclosed herein comprise(s) one or more steps or actions for achieving the described method(s), such steps and/or actions may be interchanged with one another, and/or a subset of these steps and/or actions may be used, without departing from the scope of the claims.
• Step 612 includes disposing the intrasacular flow diverter within a microcatheter in a collapsed state.
• intrasacular flow diverter 900 may be disposed within microcatheter 200 in a collapsed state.
• Step 614 includes threading the microcatheter through the blood vessel to a location within the aneurysm. For example, as previously described in connection with at least FIG.
• Step 616 includes removing the intrasacular flow diverter from a distal end of the microcatheter such that a plurality of coiled wires forming a collapsed substantially spherical frame of the intrasacular flow diverter expand sufficiently within the aneurysm that a first portion of a membrane disposed on an entire outer surface of the substantially spherical frame is disposed directly against a neck of the aneurysm, the first portion having a first porosity to blood flow, and a second portion of the membrane is disposed within the aneurysm and distal to the neck of the aneurysm, the at least one second portion having a second porosity to blood flow greater than the first porosity.
• intrasacular flow diverter 900 may be removed from a distal end of microcatheter 200 such that wires 420, forming a collapsed substantially spherical frame of intrasacular flow diverter 900, expand sufficiently within aneurysm 120 that first portion 910 of membrane disposed on an entire outer surface of the substantially spherical frame is disposed directly against a neck of aneurysm 120, and second portion 920 of membrane is disposed within aneurysm 120 and distal to the neck of aneurysm 120.
• First portion 910 has a first porosity to blood flow and second portion 920 has a second porosity to blood flow greater than the first porosity.
• each of wires 420 are wound in a substantially helical shape.
• each of wires 420 includes a plurality of helical loops, each having predetermined pitch that is substantially equal to maximum expanded diameter D1 of the substantially spherical frame.
• the plurality of helical loops have successively increasing and then decreasing diameters to, thereby, form the substantially spherical structure.
• a first subset of wires 420 are wound in a clockwise direction and a second subset of wires 420 are wound in a counterclockwise direction.
• each wire 420 is offset from at least one adjacent wire 420 by a predetermined spacing L1.
• wires 420 are one of 8 wires, 12 wires and 16 wires.
• wires 420 are configured to self-expand under a self-bias.
• the first porosity of first portion 910 of intrasacular flow diverter 900 is within the range of approximately 0-5%.
• the second porosity of second portion 920 of intrasacular flow diverter 900 is within the range of approximately 5-40%.
• each of wires 420 has a diameter of one of approximately 0.0003 inches, approximately 0.0005 inches, 0.0007 inches and 0.001 inches.
• intrasacular flow diverter 900 is configured to have a minimum outside diameter D2, D3, D4, D5 of one of approximately 0.002 inches, approximately 0.003 inches, approximately 0.004 inches, and approximately 0.006 inches when the substantially spherical structure is fully collapsed.
• intrasacular flow diverter 900 is configured to have a maximum outside diameter D1 of approximately 0.18 inches when the substantially spherical structure is fully expanded.
• a substantial majority of an aggregate porosity of intrasacular flow diverter 900, at first and second portions 910, 920 of membrane 410, is derived from the first and second porosities of membrane at respective first and second portions 910, 920.
• each of wires 420 comprises a super-elastic nitinol.
• membrane comprises a polymer.
• membrane is electrospun from a polymeric material.
• each of wires 420 is coated with polymer 510 configured to substantially reduce exposure of wires 420 with the blood.
• wires 420 include a number of wires sufficiently low such that wires 420 expanding sufficiently within aneurysm 120 cause apposition of membrane 410 to an irregular shape of an inside surface of aneurysm 120.
• FIG. 27 illustrates a flowchart related to an example method of manufacturing an intrasacular flow diverter, as described anywhere in this disclosure.
• Step 712 includes coiling a plurality of wires to form a collapsible, substantially spherical frame configured to expand within, and substantially conform to a shape of an inside surface of, the aneurysm.
• wires 420 may be coiled to form a collapsible, substantially spherical frame configured to expand within, and substantially conform to a shape of an inside surface of, aneurysm 120.
• coiling the plurality of wires to form the collapsible, substantially spherical frame comprises winding each of wires 420 in a substantially helical shape.
• winding each of the plurality of wires wound in a substantially helical shape comprises winding each of wires 420 to form a plurality of helical loops, each having a predetermined pitch that is substantially equal to a maximum expanded diameter D1 of the substantially spherical frame.
• the plurality of helical loops are wound to have successively increasing and then decreasing diameters to, thereby, form the substantially spherical structure.
• a first subset of wires 420 are wound in a clockwise direction and a second subset of wires 420 are wound in a counterclockwise direction.
• each wire 420 is offset from at least one adjacent wire 420 by a predetermined spacing L1.
• wires 420 include one of 8 wires, 12 wires and 16 wires. In some embodiments, wires 420 are configured to self-expand under self-bias. In some embodiments, each of the plurality of wires has a diameter of one of approximately 0.0003 inches, approximately 0.0005 inches, 0.0007 inches and 0.001 inches. In some embodiments, each of the plurality of wires comprises a super-elastic nitinol. In some embodiments, wires 420 include a number of wires sufficiently low to allow for apposition of membrane to an irregular shape of an inside surface of aneurysm 120 when intrasacular flow diverter 900 is properly disposed within aneurysm 120.
• intrasacular flow diverter 900 is configured to have a minimum outside diameter D2, D3, D4, D5 of one of approximately 0.002 inches, approximately 0.003 inches, approximately 0.004 inches, and approximately 0.006 inches when the substantially spherical structure is fully collapsed. In some embodiments, intrasacular flow diverter 900 is configured to have a maximum outside diameter D1 of approximately 0.18 inches when the substantially spherical structure is fully expanded.
• Step 714 includes disposing a membrane on an entire outer surface of the frame such that the membrane comprises a first portion having a first porosity to blood flow, the first portion configured to be disposed directly against a neck of the aneurysm, and a second portion having a second porosity to blood flow greater than the first porosity, the second portions configured to be disposed within the aneurysm and distal to the neck of the aneurysm.
• membrane may be disposed on an entire outer surface of the frame such that membrane comprises first portion 910 having a first porosity to blood flow and configured to be disposed directly against a neck of aneurysm 120, and second portion 920 having a second porosity to blood flow greater than the first porosity and configured to be disposed within aneurysm 120 and distal to the neck of aneurysm 120.
• first porosity is within the range of approximately 0- 5%.
• the second porosity is within the range of approximately 5-40%.
• a substantial majority of an aggregate porosity of intrasacular flow diverter 900, at first and second portions 910, 920 of membrane is derived from the first and second porosities of membrane at respective first and second portions 910, 920.
• the cover membrane is electrospun from a polymeric material.
• a method related to flowchart 700 may include an optional step 716, including coating each of the plurality of wires with a polymer configured to substantially reduce exposure of the plurality of wires with the blood.
• each of wires 420 may be coated with a polymer configured to substantially reduce exposure of wires 420 with the blood.
• these terms refer to a range of the characteristic or property that is consistent with providing a desired function associated with that characteristic or property.
• a single numerical value is given for a characteristic or property, it is intended to be interpreted as at least covering deviations of that value within one significant digit of the numerical value given.
• a numerical value or range of numerical values is provided to define a characteristic or property of a thing or act described herein, whether or not the value or range is qualified with a term of degree, a specific method of measuring the characteristic or property may be defined herein as well.
• the measurement method should be interpreted as the method of measurement that would most likely be adopted by one of ordinary skill in the art given the description and context of the characteristic or property.
• the value or range of values should be interpreted as being met regardless of which method of measurement is chosen.
• the methods disclosed herein comprise one or more steps or actions for achieving the described method.
• the method steps and/or actions may be interchanged with one another without departing from the scope of the claims.
• the order and/or use of specific steps and/or actions may be modified without departing from the scope of the claims.

Landscapes

• Health & Medical Sciences (AREA)
• Engineering & Computer Science (AREA)
• Biomedical Technology (AREA)
• Cardiology (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Transplantation (AREA)
• Heart & Thoracic Surgery (AREA)
• Vascular Medicine (AREA)
• Life Sciences & Earth Sciences (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Surgical Instruments (AREA)

Applications Claiming Priority (4)

Publications (1)

Family

ID=86052144

Family Applications (1)

Country Status (5)

Family Cites Families (7)

• 2023
  • 2023-02-24 EP EP23717681.3A patent/EP4482437A1/de active Pending
  • 2023-02-24 JP JP2024550790A patent/JP2025506875A/ja active Pending
  • 2023-02-24 AU AU2023224101A patent/AU2023224101A1/en active Pending
  • 2023-02-24 CA CA3252913A patent/CA3252913A1/en active Pending
  • 2023-02-24 WO PCT/US2023/013858 patent/WO2023164158A1/en not_active Ceased

Also Published As

Similar Documents

Legal Events