WO2019053685A1 - Active crossing device with bendable tip - Google Patents

Active crossing device with bendable tip Download PDF

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Publication number
WO2019053685A1
WO2019053685A1 PCT/IB2018/057128 IB2018057128W WO2019053685A1 WO 2019053685 A1 WO2019053685 A1 WO 2019053685A1 IB 2018057128 W IB2018057128 W IB 2018057128W WO 2019053685 A1 WO2019053685 A1 WO 2019053685A1
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WO
WIPO (PCT)
Prior art keywords
tip
impactor tip
distal
impactor
spring
Prior art date
Application number
PCT/IB2018/057128
Other languages
French (fr)
Inventor
Dan Rottenberg
Yossi PESIS
Original Assignee
Upstream Peripheral Technologies Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Upstream Peripheral Technologies Ltd. filed Critical Upstream Peripheral Technologies Ltd.
Publication of WO2019053685A1 publication Critical patent/WO2019053685A1/en

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods
    • A61B17/22—Implements for squeezing-off ulcers or the like on inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones; for invasive removal or destruction of calculus using mechanical vibrations; for removing obstructions in blood vessels, not otherwise provided for
    • A61B17/22004—Implements for squeezing-off ulcers or the like on inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones; for invasive removal or destruction of calculus using mechanical vibrations; for removing obstructions in blood vessels, not otherwise provided for using mechanical vibrations, e.g. ultrasonic shock waves
    • A61B17/22012—Implements for squeezing-off ulcers or the like on inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones; for invasive removal or destruction of calculus using mechanical vibrations; for removing obstructions in blood vessels, not otherwise provided for using mechanical vibrations, e.g. ultrasonic shock waves in direct contact with, or very close to, the obstruction or concrement
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods
    • A61B17/32—Surgical cutting instruments
    • A61B17/3205—Excision instruments
    • A61B17/3207—Atherectomy devices working by cutting or abrading; Similar devices specially adapted for non-vascular obstructions
    • A61B17/320758—Atherectomy devices working by cutting or abrading; Similar devices specially adapted for non-vascular obstructions with a rotating cutting instrument, e.g. motor driven
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods
    • A61B17/00234—Surgical instruments, devices or methods for minimally invasive surgery
    • A61B2017/00292—Surgical instruments, devices or methods for minimally invasive surgery mounted on or guided by flexible, e.g. catheter-like, means
    • A61B2017/003—Steerable
    • A61B2017/00305—Constructional details of the flexible means
    • A61B2017/00309—Cut-outs or slits
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods
    • A61B17/22—Implements for squeezing-off ulcers or the like on inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones; for invasive removal or destruction of calculus using mechanical vibrations; for removing obstructions in blood vessels, not otherwise provided for
    • A61B2017/22094—Implements for squeezing-off ulcers or the like on inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones; for invasive removal or destruction of calculus using mechanical vibrations; for removing obstructions in blood vessels, not otherwise provided for for crossing total occlusions, i.e. piercing

Definitions

  • the invention is generally related to devices and methods for penetrating hard plaque that partially or completely occludes blood vessels and disturbs blood flow through the blood vessel.
  • Atherosclerosis is a complex, progressive and degenerative condition resulting in the build-up of cholesterol and other obstructive materials, known as plaque, on the wails of the arteries.
  • plaque obstructive materials
  • the accumulation of plaque narrows the interior or lumen of arteries, thereby reducing blood flow.
  • Plaque occurs in the arteries in several different forms and may be located in many different anatomies throughout the arterial system. Plaque varies in composition, with portions that are hard and brittle, referred to as calcified plaque, and other portions that are fatty or fibrous. Over time atheromatous deposits can become large enough to reduce or totally occlude blood flow through the vessels, leading to symptoms of low blood flow, such as pain in the legs (on walking or at rest), skin ulcer, angina, and other symptoms.
  • CTO's Chronic Total Occlusions
  • the atheroma deposits can be displaced by diametrically expanding the vessel by inflating balloons, expanding stents, and other methods.
  • the plaque can be pulverized using lasers and other methods; however, pulverization alone of atheromatous material may allow micro-emboli to flow downstream and lodge in distal vascular beds, further compromising blood flow to the tissue affected by the disease.
  • Atherectomy catheter devices including catheters with rotating burrs, lasers to photo-dissolve tissue, catheters with ultrasonic vibration mechanisms, and catheters which use balloons or other positioning features to position the cutter adjacent material to be removed.
  • Some crossing or atherectomy devices do not ride over a guidewire, but they must have some sort of imaging system and/or controlled maneuverability and bending capabilities, to keep inside the blood vessel lumen, preventing vessel perforation.
  • the CTO proximal cap is usually the hardest part of the occlusion, and if the guidewire or crossing device can penetrate the CTO proximal cap, they usually can cross the whole length of the CTO.
  • the CTO proximal cap is too hard and impossible to penetrate for any guidewire and/or crossing device.
  • the only options for the physician in such cases is to cross the CTO sub-intimally, probably using expensive lumen reentry devices, or use the relative complex retrograde technique and cross the occlusion from the distal cap, which is usually softer then the proximal cap.
  • the present invention is directed to device and method for penetrating hard plaque that partially or completely occludes blood vessels and disturbs blood flow through the blood vessel.
  • the device includes a distal pre-loaded spring.
  • the distal spring stores energy and releases it as a single impact at the device distal tip to penetrate or break through hard plaque that has been blocking the blood path in blood vessels.
  • the device of the invention is design for percutaneous insertion into the blood vessels over a standard guidewire.
  • the device is preferably used in cases where the plaque is too hard for a guidewire to penetrate, and there is a need for a crossing device to penetrate the occlusion proximal hard cap and /or the whole occlusion length.
  • the device of the invention can be used to break the hard proximal cap of the CTO, and then the rest of the occlusion is penetrated with CTO guidewires. In such cases standard balloon angioplasty and possibly stents are used to open the occlusion.
  • the crossing device of the invention and the guidewire can both be further advanced through the occlusion, while provide additional impacts on the plaque, in order to further penetrate it.
  • a distal tip bending mechanism may be added to the crossing device of the invention, positioned just proximally to the device distal tip.
  • the bending mechanism can be used to aim the device tip to the center of the occlusion before applying the impact.
  • Fig. 1 is a schematic illustration of an embodiment of the crossing device of the invention.
  • Fig. 2 is a schematic illustration of an embodiment of the distal section of the crossing device of the invention.
  • Fig. 3A is a partial schematic cross-section illustration of an embodiment of the distal section of the crossing device of the invention.
  • Fig. 3B is an enlarged view of the distal section of Fig. 3 A.
  • Figs. 4A and 4B are schematic illustrations of an embodiment of the distal section of the crossing device of the invention inside a blood vessel with total occlusion.
  • Fig. 5 is a cross-sectional schematic illustration of an embodiment of the handle of the device of the invention.
  • Fig. 6 is a schematic illustration of an embodiment of the distal section of the crossing device of the invention with rough knurled distal impactor tip surface.
  • Fig. 7 is a schematic illustration of an embodiment of the distal section of the crossing device of the invention, with rotating impactor tip.
  • FIG. 1 illustrates a crossing device 10, constructed and operative in accordance with a non-limiting embodiment of the present invention.
  • Device 10 includes a shaft 12 with a proximal section 14 that extends from a handle 16 that has an operative trigger 18.
  • a distal section 20 of shaft 12 is described more in detail with reference to Figs. 3 A and 3B.
  • the distal section 20 may extend distally from a bendable portion 22 of shaft 12; in some embodiments, there is no bendable portion 22.
  • Handle 16 is described more in detail below with reference to Fig. 5.
  • Handle 16 may have a proximal connector 24, such as but not limited to, a Luer connector 24.
  • the connector 24 and shaft 12 may be hollow so a guidewire 26 (Fig. 2) can pass through the assembly.
  • An impactor tip 28 protrudes distally from the distal section 20.
  • the bendable portion 22 can be deflected or bent in order to aim the impactor tip 28 in the required direction to impact an occlusion.
  • bendable portion 22 can be made of a small section of flexible tube, that is more resilient or flexible than the rest of the shaft 12, or may be made from a short metal hypo-tube with cuts 30 made by laser or mechanical means, allowing easy bending of the metal hypo-tube.
  • the bendable portion 22 may be bent with one or more pulling cords (wires) 21 coupled to the trigger 18 or other activation device on the handle. Deflection of bendable portion 22 can move the impactor tip 28 in any direction to properly aim impactor tip 28 at the occlusion.
  • Impactor tip 28 is preferably made from a hard metal (e.g., stainless steel) and shaped as a cone at its distal end. Impactor tip 28 is coupled (e.g., welded, bonded or made as one piece) to an inner sliding tube 32, which slides in an outer tube 34.
  • a stopper 36 is coupled (e.g., welded, bonded or made as one piece) to inner sliding tube 32. Stopper 36 limits the distal (forward) movement of impactor tip 28. Stopper 36 achieves this by abutting against an abutment 37 in outer tuber 34.
  • Outer tube 34 is preferably made from a stiff material (e.g., stainless steel).
  • a distal spring 38 is located between a proximal end of impactor tip 28 and a portion of outer tube 34, such as but not necessarily, the distal face of abutment 37.
  • Distal spring 38 is pre-loaded (pre-compressed) by impactor tip 28.
  • the pre-loading of spring 38 is an important feature of the invention, as is described below.
  • a pulling wire (or cord or other slender element) 40 is coupled to inner sliding tube 32 for pulling inner sliding tube 32 together with impactor tip 28 proximally against distal spring 38 (the proximal end of spring 38 being held stationary by the abutment), thereby increasing compression of spring 38 and storing more potential energy in spring 38. Release of pulling wire 40 causes rapid distal (forward) movement of impactor tip 28 together with sliding tube 32 towards plaque of an occlusion.
  • Outer tube 34 may be coupled (e.g., welded, bonded or made as one piece) to bendable portion 22 of shaft 12.
  • Pulling wire 40 may be made from a flexible polymer like polytetrafluoroethylene or silk or from a superelastic material (e.g., nitinol).
  • the crossing device 10 is designed for percutaneous insertion into a blood vessel 3 over guidewire 26.
  • Device 10 is preferably used in cases where the plaque of occlusion 4 is too hard for a guidewire to penetrate, and there is a need for a crossing-device or atherectomy device to penetrate through the plaque, starting with the occlusion proximal hard cap 5 (Fig. 4A), and/or the whole length of the occlusion (Fig. 4B).
  • device 10 may be used only to break the hard proximal cap 5 of a chronic total occlusion (CTO) and the rest of the occlusion 4 may be penetrated with the guidewire 26.
  • CTO chronic total occlusion
  • standard balloon angioplasty and possibly stents may be used to open the occlusion, following penetration by the guidewire.
  • guidewire 26 cannot cross the rest of the occlusion 4 by itself.
  • the guidewire 26 may be pulled back inside device 10, and the crossing device 10 can be further advanced through the occlusion 4, while providing additional multiple impacts on the plaque to further penetrate through it.
  • the guidewire 26 can be pushed forwards from time to time to check if the hard plaque section is crossed.
  • Protrusion of crossing device 10 led by impactor tip 28 into and through the plaque may be done in small multiple steps, one step at the time, limited in length, by the small and limited protrusion of impactor tip 28 from distal section 20 and outer tube 34.
  • steps are preferably in the range of 0.5-3.0 mm, and more preferably about 1.0- 1.5mm.
  • Such small steps provide better control of device advancement, reducing the risk of blood vessel dissection or perforation.
  • Multiple steps forward require many distal spring activations in order to penetrate long occlusions.
  • the diameter of the shaft 12 and distal section 20 must be relative small; usually in the range of 1.5-2.5 mm. Larger diameters require larger incisions to insert the device. Using such small diameters requires using a very small diameter distal spring. However, this causes a problem: this small spring needs to be squeezed over a long displacement in order to store enough energy to provide significant tip impact when released. Long displacement requires long springs and a long stiff distal section, which makes it difficult if not impossible for the device or shaft to pass through bends and curved blood vessels.
  • the rigid distal section length should be minimal, preferably not more than 20 mm, and more preferably 10-15 mm. (If the spring is not placed distally, but instead at some proximal position, then it is very difficult to transfer the spring force to the impactor tip without losses in the spring force so as to have sufficient impact on the occlusion.)
  • the crossing device 10 includes preloaded distal spring 38.
  • the pre-loaded spring 38 stores potential energy even when pulling wire 40 is not pulled at all. When pulling wire 40 is pulled back, the added energy is high enough to allow significant impact on the plaque.
  • the impact energy increases when impactor tip 28 moves distally until stopped by the stopper 36.
  • Pulling wire 40 may be tied to a rotating member 23 that can rotate around a pin 25.
  • a torsion spring 27 applies a force that resists swivel of rotating member 23 and resists pulling of pulling wire 40. This is the initial, at- rest orientation of the components of the handle.
  • Pulling trigger 18 overcomes the force of torsion spring 27 and rotates rotating member 23 and pulls the pulling wire 40. Release of the pulling force on trigger 18 returns trigger 18 to its initial position due to the returning force of a trigger return spring 29.
  • Other suitable handle mechanisms can be used.
  • Impactor tip 28 may have a smooth conical tip surface. Alternatively, as seen in Fig. 6, the impactor tip may have a rough or knurled surface 50 to help grind the occlusion. Alternatively, as seen in Fig. 7, the impactor tip 28 may include grooves 52, to provide some grinding effect on the plaque material, resulting in better plaque penetration by the device, especially when the device is rotated during and between impacts by the user.
  • the impactor tip 28 may be rotated by means of a pin 54 coupled to the inner sliding tube that slides in a curved slot 56 formed in the outer tube. As the impactor tip 28 is propelled forward by the spring, the movement of pin 54 in slot 56 causes the inner tube and the impactor tip to rotate. Other mechanisms for rotation of the impactor tip may be used.
  • the rough textures or grooves plus the rotation may increase the grinding effect on the plaque material, thereby helping removal of plaque and achieving better penetration into the occlusion.
  • One method of using the crossing device to treat hard chronic total blood vessel occlusion is by applying limited displacement impacts on the plaque, thereby breaking, cracking and/or grinding the plaque and allowing the guidewire to pass through the plaque.
  • Another method of using the crossing device to cross hard total occlusion is using maneuverable or bendable impactor tip to select each impact direction. The crossing device protrusion or penetration through the occlusion is led by impactor tip, and is done in small multiple steps, each step is redirected into the center of the occlusion, one step at the time, in steps limited in length, by the small and limited displacement of the impactor tip.
  • Another method of using the crossing device is to use the impactor tip to crack or brake the plaque proximal side, and then to use the guidewire to continue the penetration through the occlusion; if not successful, the guidewire may be pulled backwards inside the crossing device, and then the impactor tip may further apply repeated impacts on the plaque to further crack or break it, to allow pushing the guidewire through the occlusion.

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Abstract

A device (10) includes a shaft (12) and an impactor tip (28) that protrudes distally from a distal section (20) of the shaft (12). The impactor tip (28) is coupled to an inner sliding tube (32) which slides in an outer tube (34). A distal spring (38) is located between a proximal end of the impactor tip (28) and a portion of the outer tube (34). The distal spring (38) is pre-loaded by the impactor tip (28). A pulling wire (40) is coupled to the inner sliding tube (32) for pulling the inner sliding tube (32) together with the impactor tip (28) proximally against the distal spring (38).

Description

ACTIVE CROSSING DEVICE WITH BEND ABLE TIP
FIELD OF THE INVENTION
The invention is generally related to devices and methods for penetrating hard plaque that partially or completely occludes blood vessels and disturbs blood flow through the blood vessel.
BACKGROUND OF THE INVENTION
Atherosclerosis is a complex, progressive and degenerative condition resulting in the build-up of cholesterol and other obstructive materials, known as plaque, on the wails of the arteries. The accumulation of plaque narrows the interior or lumen of arteries, thereby reducing blood flow. Plaque occurs in the arteries in several different forms and may be located in many different anatomies throughout the arterial system. Plaque varies in composition, with portions that are hard and brittle, referred to as calcified plaque, and other portions that are fatty or fibrous. Over time atheromatous deposits can become large enough to reduce or totally occlude blood flow through the vessels, leading to symptoms of low blood flow, such as pain in the legs (on walking or at rest), skin ulcer, angina, and other symptoms.
Chronic Total Occlusions (CTO's) are usually hard calcified plaque blocking the blood path through the vessel. To treat this disease and improve or resolve these symptoms it is desirable to restore or improve blood flow through the vessel.
Various means are used to restore or improve blood flow through atheromatous vessels. The atheroma deposits can be displaced by diametrically expanding the vessel by inflating balloons, expanding stents, and other methods.
The plaque can be pulverized using lasers and other methods; however, pulverization alone of atheromatous material may allow micro-emboli to flow downstream and lodge in distal vascular beds, further compromising blood flow to the tissue affected by the disease.
Many types of atherectomy catheter devices have been proposed, including catheters with rotating burrs, lasers to photo-dissolve tissue, catheters with ultrasonic vibration mechanisms, and catheters which use balloons or other positioning features to position the cutter adjacent material to be removed.
Most f current CTO crossing devices or atherectomy devices are led over standard guidewires, preventing them from exiting the vessel walls while moving forward to remove the plaque. This means that a thin guidewire, usually between 0.014" to 0.035" in diameter, must first cross the total occlusion. Special crossing guidewires are available today, designed especially to cross plaque material, including calcified and hard plaque material.
Some crossing or atherectomy devices do not ride over a guidewire, but they must have some sort of imaging system and/or controlled maneuverability and bending capabilities, to keep inside the blood vessel lumen, preventing vessel perforation.
The CTO proximal cap is usually the hardest part of the occlusion, and if the guidewire or crossing device can penetrate the CTO proximal cap, they usually can cross the whole length of the CTO.
Still in about 10-20% of the peripheral CTO patients, the CTO proximal cap is too hard and impossible to penetrate for any guidewire and/or crossing device. The only options for the physician in such cases is to cross the CTO sub-intimally, probably using expensive lumen reentry devices, or use the relative complex retrograde technique and cross the occlusion from the distal cap, which is usually softer then the proximal cap.
SUMMARY OF THE INVENTION
The present invention is directed to device and method for penetrating hard plaque that partially or completely occludes blood vessels and disturbs blood flow through the blood vessel. The device includes a distal pre-loaded spring. The distal spring stores energy and releases it as a single impact at the device distal tip to penetrate or break through hard plaque that has been blocking the blood path in blood vessels.
The device of the invention is design for percutaneous insertion into the blood vessels over a standard guidewire. The device is preferably used in cases where the plaque is too hard for a guidewire to penetrate, and there is a need for a crossing device to penetrate the occlusion proximal hard cap and /or the whole occlusion length.
The device of the invention can be used to break the hard proximal cap of the CTO, and then the rest of the occlusion is penetrated with CTO guidewires. In such cases standard balloon angioplasty and possibly stents are used to open the occlusion.
In cases where the guidewire cannot cross the rest of the occlusion by itself, the crossing device of the invention and the guidewire can both be further advanced through the occlusion, while provide additional impacts on the plaque, in order to further penetrate it.
A distal tip bending mechanism may be added to the crossing device of the invention, positioned just proximally to the device distal tip. The bending mechanism can be used to aim the device tip to the center of the occlusion before applying the impact.
BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:
Fig. 1 is a schematic illustration of an embodiment of the crossing device of the invention.
Fig. 2 is a schematic illustration of an embodiment of the distal section of the crossing device of the invention.
Fig. 3A is a partial schematic cross-section illustration of an embodiment of the distal section of the crossing device of the invention. Fig. 3B is an enlarged view of the distal section of Fig. 3 A.
Figs. 4A and 4B are schematic illustrations of an embodiment of the distal section of the crossing device of the invention inside a blood vessel with total occlusion.
Fig. 5 is a cross-sectional schematic illustration of an embodiment of the handle of the device of the invention.
Fig. 6 is a schematic illustration of an embodiment of the distal section of the crossing device of the invention with rough knurled distal impactor tip surface.
Fig. 7 is a schematic illustration of an embodiment of the distal section of the crossing device of the invention, with rotating impactor tip.
DETAILED DESCRIPTION OF EMBODIMENTS
Reference is now made to Fig. 1, which illustrates a crossing device 10, constructed and operative in accordance with a non-limiting embodiment of the present invention.
Device 10 includes a shaft 12 with a proximal section 14 that extends from a handle 16 that has an operative trigger 18. A distal section 20 of shaft 12 is described more in detail with reference to Figs. 3 A and 3B. The distal section 20 may extend distally from a bendable portion 22 of shaft 12; in some embodiments, there is no bendable portion 22.
Handle 16 is described more in detail below with reference to Fig. 5. Handle 16 may have a proximal connector 24, such as but not limited to, a Luer connector 24. The connector 24 and shaft 12 may be hollow so a guidewire 26 (Fig. 2) can pass through the assembly.
Reference is now made to Fig. 2. An impactor tip 28 protrudes distally from the distal section 20. The bendable portion 22 can be deflected or bent in order to aim the impactor tip 28 in the required direction to impact an occlusion. For example, bendable portion 22 can be made of a small section of flexible tube, that is more resilient or flexible than the rest of the shaft 12, or may be made from a short metal hypo-tube with cuts 30 made by laser or mechanical means, allowing easy bending of the metal hypo-tube. The bendable portion 22 may be bent with one or more pulling cords (wires) 21 coupled to the trigger 18 or other activation device on the handle. Deflection of bendable portion 22 can move the impactor tip 28 in any direction to properly aim impactor tip 28 at the occlusion.
Reference is now made to Figs. 3 A and 3B. Impactor tip 28 is preferably made from a hard metal (e.g., stainless steel) and shaped as a cone at its distal end. Impactor tip 28 is coupled (e.g., welded, bonded or made as one piece) to an inner sliding tube 32, which slides in an outer tube 34. A stopper 36 is coupled (e.g., welded, bonded or made as one piece) to inner sliding tube 32. Stopper 36 limits the distal (forward) movement of impactor tip 28. Stopper 36 achieves this by abutting against an abutment 37 in outer tuber 34. Outer tube 34 is preferably made from a stiff material (e.g., stainless steel).
A distal spring 38 is located between a proximal end of impactor tip 28 and a portion of outer tube 34, such as but not necessarily, the distal face of abutment 37. Distal spring 38 is pre-loaded (pre-compressed) by impactor tip 28. The pre-loading of spring 38 is an important feature of the invention, as is described below. A pulling wire (or cord or other slender element) 40 is coupled to inner sliding tube 32 for pulling inner sliding tube 32 together with impactor tip 28 proximally against distal spring 38 (the proximal end of spring 38 being held stationary by the abutment), thereby increasing compression of spring 38 and storing more potential energy in spring 38. Release of pulling wire 40 causes rapid distal (forward) movement of impactor tip 28 together with sliding tube 32 towards plaque of an occlusion.
Outer tube 34 may be coupled (e.g., welded, bonded or made as one piece) to bendable portion 22 of shaft 12. Pulling wire 40 may be made from a flexible polymer like polytetrafluoroethylene or silk or from a superelastic material (e.g., nitinol).
Reference is now made to Figs. 4A and 4B. The crossing device 10 is designed for percutaneous insertion into a blood vessel 3 over guidewire 26. Device 10 is preferably used in cases where the plaque of occlusion 4 is too hard for a guidewire to penetrate, and there is a need for a crossing-device or atherectomy device to penetrate through the plaque, starting with the occlusion proximal hard cap 5 (Fig. 4A), and/or the whole length of the occlusion (Fig. 4B). In Fig. 4A, device 10 may be used only to break the hard proximal cap 5 of a chronic total occlusion (CTO) and the rest of the occlusion 4 may be penetrated with the guidewire 26. In such cases, standard balloon angioplasty and possibly stents may be used to open the occlusion, following penetration by the guidewire.
In Fig. 4B, guidewire 26 cannot cross the rest of the occlusion 4 by itself. In such a case, the guidewire 26 may be pulled back inside device 10, and the crossing device 10 can be further advanced through the occlusion 4, while providing additional multiple impacts on the plaque to further penetrate through it. The guidewire 26 can be pushed forwards from time to time to check if the hard plaque section is crossed.
Protrusion of crossing device 10 led by impactor tip 28 into and through the plaque may be done in small multiple steps, one step at the time, limited in length, by the small and limited protrusion of impactor tip 28 from distal section 20 and outer tube 34. Such steps are preferably in the range of 0.5-3.0 mm, and more preferably about 1.0- 1.5mm. Such small steps provide better control of device advancement, reducing the risk of blood vessel dissection or perforation. Multiple steps forward require many distal spring activations in order to penetrate long occlusions.
The importance of pre-tensioning the spring is now explained. For percutaneous insertion, the diameter of the shaft 12 and distal section 20 must be relative small; usually in the range of 1.5-2.5 mm. Larger diameters require larger incisions to insert the device. Using such small diameters requires using a very small diameter distal spring. However, this causes a problem: this small spring needs to be squeezed over a long displacement in order to store enough energy to provide significant tip impact when released. Long displacement requires long springs and a long stiff distal section, which makes it difficult if not impossible for the device or shaft to pass through bends and curved blood vessels. This is particularly a problem when using a cross-over approach (passing the iliac arc, getting to one leg from the other leg, done in majority of limb salvage cases). Therefore, the rigid distal section length should be minimal, preferably not more than 20 mm, and more preferably 10-15 mm. (If the spring is not placed distally, but instead at some proximal position, then it is very difficult to transfer the spring force to the impactor tip without losses in the spring force so as to have sufficient impact on the occlusion.)
To overcome this spring size limitation, the crossing device 10 includes preloaded distal spring 38. The pre-loaded spring 38 stores potential energy even when pulling wire 40 is not pulled at all. When pulling wire 40 is pulled back, the added energy is high enough to allow significant impact on the plaque. For example, the force applied by spring is F=kX, where F is force, X is displacement, and k is the spring constant that related to its size and material.
Potential energy stored in spring E=kX2/2. If there is limited pulling length, and one can only squeeze the spring for X=l cm from rest, the impact energy will be E = 0.5k. However, if the spring is pre-loaded (squeezed) to a pre-displacement of 5 cm, then the same squeezing displacement of 1 cm (i.e., from 5 cm to 6 cm) will result in significantly more energy to be released for the impact E=½ (62k) - ½(52k), meaning E = 5.5k (11 times higher compared to the spring which was not pre-loaded).
Thus, by using pre-loaded spring 38, the impact energy increases when impactor tip 28 moves distally until stopped by the stopper 36.
Reference is now made to Fig. 5. Pulling wire 40 may be tied to a rotating member 23 that can rotate around a pin 25. A torsion spring 27 applies a force that resists swivel of rotating member 23 and resists pulling of pulling wire 40. This is the initial, at- rest orientation of the components of the handle. Pulling trigger 18 overcomes the force of torsion spring 27 and rotates rotating member 23 and pulls the pulling wire 40. Release of the pulling force on trigger 18 returns trigger 18 to its initial position due to the returning force of a trigger return spring 29. Other suitable handle mechanisms can be used.
Impactor tip 28 may have a smooth conical tip surface. Alternatively, as seen in Fig. 6, the impactor tip may have a rough or knurled surface 50 to help grind the occlusion. Alternatively, as seen in Fig. 7, the impactor tip 28 may include grooves 52, to provide some grinding effect on the plaque material, resulting in better plaque penetration by the device, especially when the device is rotated during and between impacts by the user. The impactor tip 28 may be rotated by means of a pin 54 coupled to the inner sliding tube that slides in a curved slot 56 formed in the outer tube. As the impactor tip 28 is propelled forward by the spring, the movement of pin 54 in slot 56 causes the inner tube and the impactor tip to rotate. Other mechanisms for rotation of the impactor tip may be used.
The rough textures or grooves plus the rotation may increase the grinding effect on the plaque material, thereby helping removal of plaque and achieving better penetration into the occlusion.
One method of using the crossing device to treat hard chronic total blood vessel occlusion is by applying limited displacement impacts on the plaque, thereby breaking, cracking and/or grinding the plaque and allowing the guidewire to pass through the plaque. Another method of using the crossing device to cross hard total occlusion is using maneuverable or bendable impactor tip to select each impact direction. The crossing device protrusion or penetration through the occlusion is led by impactor tip, and is done in small multiple steps, each step is redirected into the center of the occlusion, one step at the time, in steps limited in length, by the small and limited displacement of the impactor tip.
Another method of using the crossing device is to use the impactor tip to crack or brake the plaque proximal side, and then to use the guidewire to continue the penetration through the occlusion; if not successful, the guidewire may be pulled backwards inside the crossing device, and then the impactor tip may further apply repeated impacts on the plaque to further crack or break it, to allow pushing the guidewire through the occlusion.

Claims

CLAIMS What is claimed is:
1. A device (10) comprising:
a shaft (12) with a proximal section (14) that extends from a handle (16) that has a trigger (18);
an impactor tip (28) that protrudes distally from a distal section (20) of said shaft (12), said impactor tip (28) being coupled to an inner sliding tube (32) which slides in an outer tube (34);
a distal spring (38) located between a proximal end of said impactor tip (28) and a portion of said outer tube (34), wherein said distal spring (38) is pre-loaded by said impactor tip (28); and
a pulling wire (40) coupled to said inner sliding tube (32) for pulling said inner sliding tube (32) together with said impactor tip (28) proximally against said distal spring (38).
2. The device (10) according to claim 1, wherein a stopper (36) is coupled to said inner sliding tube (32) and arranged to limit distal movement of said impactor tip (28) by abutting against an abutment (37) in said outer tuber (34).
3. The device (10) according to claim 1, wherein said distal section (20) extends distally from a bendable portion (22) of said shaft (12).
4. The device (10) according to claim 3, wherein said bendable portion (22) comprises a tube that is more resilient or flexible than a remainder of said shaft (12).
5. The device (10) according to claim 3, wherein said bendable portion (22) comprises a hypo-tube formed with cuts (30) and said bendable portion (22) is coupled to one or more pulling cords (21).
6. The device (10) according to claim 1, wherein said impactor tip (28) has a smooth conical tip surface.
7. The device (10) according to claim 1, wherein said impactor tip (28) has a rough surface (50).
8. The device (10) according to claim 1, wherein said impactor tip (28) includes grooves (52).
PCT/IB2018/057128 2017-09-18 2018-09-18 Active crossing device with bendable tip WO2019053685A1 (en)

Applications Claiming Priority (2)

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US201762559646P 2017-09-18 2017-09-18
US62/559,646 2017-09-18

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4936845A (en) * 1987-03-17 1990-06-26 Cordis Corporation Catheter system having distal tip for opening obstructions
WO2015105930A1 (en) * 2014-01-12 2015-07-16 Upstream Peripheral Technologies Ltd. Active obstruction crossing device
US20160183963A1 (en) * 2010-02-09 2016-06-30 Medinol Ltd. Device for Traversing Vessel Occlusions and Method of Use
US20160279386A1 (en) * 2013-11-12 2016-09-29 St. Jude Medical, Cardiology Division, Inc. Introducer with Steerable Distal Tip Section

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4936845A (en) * 1987-03-17 1990-06-26 Cordis Corporation Catheter system having distal tip for opening obstructions
US20160183963A1 (en) * 2010-02-09 2016-06-30 Medinol Ltd. Device for Traversing Vessel Occlusions and Method of Use
US20160279386A1 (en) * 2013-11-12 2016-09-29 St. Jude Medical, Cardiology Division, Inc. Introducer with Steerable Distal Tip Section
WO2015105930A1 (en) * 2014-01-12 2015-07-16 Upstream Peripheral Technologies Ltd. Active obstruction crossing device

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