Thrombectomy System and Method

• US 20090054918A1
• Filed: 08/06/2008
• Published: 02/26/2009
• Est. Priority Date: 08/06/2007
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Reverse Medical Corporation (Medtronic Plc)
• Inventors: Henson, Michael R.
• Granted Patent: US 8,343,167 B2
• Time in Patent Office: Days
• US Class Current: 606/159
• CPC Class Codes: A61B 17/221 Gripping devices in the form of loops or baskets for gripping calculi or similar types of obstructions surgical snare instruments A61B17/32056
• CPC Class Codes: A61B 2017/00867 shape memory effect for prostheses A61F2210/0014
• CPC Class Codes: A61B 2017/22034 for gripping the obstruction or the tissue part from inside
• CPC Class Codes: A61B 2017/2217 single wire changing shape to a gripping configuration

Abstract

Disclosed is a clot and foreign body removal system, including a catheter with at least one lumen. Located within the catheter is a clot capture wire that is connected to a hub at the proximal end. In one embodiment, the clot capture wire includes a coil made out of an elastic or superelastic material, preferably nitinol. The elasticity or superelasticity of the coil allows it to be deformed within the catheter and to then reform its original coil configuration when the coil is moved outside of the catheter lumen. In another embodiment the coil is a biphasic, shape memory coil, which changes shape upon heating, energy application, or passing an electric current. Once the coil configuration has been established, the coil can be used to ensnare and corkscrew a clot or blockage in a vessel. A clot is extracted from the vessel by moving the clot capture coil and catheter proximally until the clot can be removed completely or released into a different vessel that does not perfuse a critical organ. Foreign bodies are similarly captured by deploying the coil distal to the foreign body and moving the clot capture coil proximally until the foreign body is trapped within the coil. By removing the device from the body, the foreign material is also removed.

Claims

1. A system for removing thrombus or other obstructive material from body lumen in a human or non-human animal subject, said system comprising:

a flexible catheter having a lumen and a distal opening in communication with said lumen;

an elongate member having a distal end, said elongate member being advanceable through the lumen of the catheter and out of the distal opening;

an obstructive material engaging structure located at or near the distal end of the elongate member, said obstructive material engaging structure being transitionable in response to energy delivered to the obstruction engaging structure from a collapsed configuration wherein the obstruction engaging structure is substantially linear and advanceable through the obstructive material to an expanded configuration wherein the obstructive material engaging structure will engage the obstructive material; and

a source of energy connected to the obstructive material engaging member, said source of energy being operative to deliver to the obstructive material engaging structure energy which will cause the obstructive material engaging structure to transition from its collapsed configuration to its expanded configuration.

2. A system according to claim 1 wherein the obstructive material engaging structure comprises a shape memory material that will assume the collapsed configuration at or below a first temperature and will assume the expanded configuration when at or above a second temperature and wherein the delivery of energy from the energy source causes the temperature of the shape memory material to change from a temperature that is at or below the first temperature to a temperature that is at or above the second temperature.

3. A system according to claim 2 wherein the shape memory material comprises a shape memory nickel-titanium alloy.

4. A system according to claim 3 wherein the nickel titanium alloy contains approximately 50% to approximately 55.6% nickel.

5. A system according to claim 2 wherein the shape memory material transitions from its collapsed configuration to its expanded configuration when heated to a temperature between about 37.5 degrees C. and about 42 degrees C.

6. A system according to claim 2 raise the shape memory material comprises a metal alloy that has a martensite start temperature and an austenite finish temperature and wherein the collapsed configuration is further maintained through hysteresis effects, thereby causing the martensite start temperature to be lower than the austenite finish temperature.

7. A system according to claim 2 wherein the obstructive material engaging structure is thermally insulated.

8. A system according to claim 1 wherein the obstructive material engaging structure comprises a discrete segment of the elongate member.

9. A system according to claim 1 wherein:

the elongate member is formed of a shape memory material;

the obstructive material engaging structure comprises a segment of the elongate member; and

the source of energy comprises at least one heating element positioned so as to selectively heat said segment of the elongate member, thereby causing only said segment of the elongate member to transition from the collapsed configuration to the expanded configuration.

10. A system according to claim 1 wherein the obstructive material engaging structure becomes coiled as it transitions from its collapsed configuration to its expanded configuration.

11. A system according to claim 3 wherein the obstructive material engaging structure forms a generally complex coil shape when in its expanded configuration.

12. A system according to claim 1 wherein at least the distal opening of the catheter is capable of diametric expansion.

13. A system according to claim 12 wherein a distal region of the catheter including the distal opening is capable of selective diametric expansion.

14. A system according to claim 12 wherein said distal region of the catheter undergoes diametric expansion in response to delivery of energy to said distal region and wherein the system further comprises:

a source of energy connected to the catheter for delivering energy to energy to said distal region to cause diametric expansion of said distal region.

15. A system according to claim 12 wherein a distal region of the catheter undergoes diametric expansion as its temperature changes from a pre-insertion temperature to the subject'"'"'s body temperature.

16. A system according to claim 1 wherein the source of energy is attached to a proximal end of the elongate member and wherein energy flows from the source of energy, through the elongate member, to the obstructive material engaging structure.

17. A system according to claim 1 wherein the obstructive material engaging member is further adapted to cauterize tissue.

18. A method for removing obstructive material from a body lumen in a human or non-human animal subject, said method comprising the steps of:

(A) providing an obstructive material removal system that comprises (i) a flexible catheter having a lumen and a distal end opening in communication with said lumen, (ii) an elongate member having a distal end, said elongate member being advanceable through the lumen of the catheter and out of the distal end opening, (iii) an obstructive material engaging structure located at or near the distal end of the elongate member, said obstructive material engaging structure being transitionable in response to energy delivered to the obstruction engaging structure from a collapsed configuration wherein the obstruction engaging structure is substantially linear and advanceable through the obstructive material to an expanded configuration wherein the obstructive material engaging structure will engage the obstructive material and (iv) a source of energy connected to the obstructive material engaging member.

(B) advancing the catheter to a position within the body lumen without causing the catheter to pass through the obstructive material;

(C) advancing the elongate member, with the obstructive material engaging member in its collapsed configuration, out of the distal end opening of the catheter and through the obstructive material to a position where the distal end opening of the catheter is on one side of the obstructive material and the obstructive material engaging member is on the other side of the obstructive material;

(D) delivering energy from the energy source to the obstructive material engaging member causing the obstructive material engaging member to transition to its expanded configuration;

(E) moving the obstructive material engaging member, while in its expanded configuration, toward the obstructive material until it engages the obstructive material; and

(F) removing the system and the obstructive material from the body lumen.

19. A method according to claim 18 wherein the elongate member is not inserted into the lumen of the catheter until after performance of Step B.

20. A method according to claim 18 wherein the elongate member resides within the lumen of the catheter during performance of Step B.

21. A method according to claim 18 wherein the obstructive material engaging structure transitions from its collapsed configuration to its expanded configuration in response to a change in temperature and wherein the delivery of energy in Step D causes a change in the temperature of the obstructive material engaging structure.

22. A method according to claim 21 wherein the obstructive material engaging structure comprises a shape memory alloy which undergoes a change in crystalline state during performance of Step D thus resulting in transition from the collapsed configuration to the expanded configuration.

23. A method according to claim 21 wherein Step D comprises warming the obstructive material engaging structure to a temperature above about 37.5 degrees C. in response to which the obstructive material engaging structure transitions from its collapsed configuration to its expanded configuration.

24. A method according to claim 18 wherein the elongate member is formed of a shape memory material, the obstructive material engaging structure comprises a segment of the elongate member and the source of energy comprises at least one heating element positioned so as to selectively heat said segment of the elongate member, thereby causing only said segment of the elongate member to transition from the collapsed configuration to the expanded configuration, and wherein:

Step D comprises causing said at least one heating element to selectively heat said segment of the elongate member to a temperature that causes it to transition from the collapsed configuration to the expanded configuration.

25. A method according to claim 18 wherein the performance of Step D causes the obstructive material engaging structure to becomes coiled.

26. A method according to claim 25 wherein the obstructive material engaging structure forms a generally complex coil shape as a result of the performance of Step D.

27. A method according to claim 18 wherein Step E further comprises moving the obstructive material engaging member along with a quantity of engaged obstructive material through the distal opening and into the catheter lumen.

28. A method according to claim 27 wherein at least the distal opening of the catheter is capable of diametric expansion and wherein the method further comprises the step of:

diametrically expanding at least the distal opening of the catheter before moving the obstructive material engaging member along with a quantity of engaged obstructive material through the distal opening and into the catheter lumen.

29. A system according to claim 28 wherein at least the distal opening of the catheter undergoes diametric expansion in response to a delivery of energy and wherein the step of diametrically expanding at least the distal opening of the catheter is carried out by delivering energy to the catheter.

30. A method according to claim 18 wherein the obstructive material engaging member is further adapted to cauterize tissue and wherein the method further comprises the step of:

causing the obstructive material engaging member to cauterize tissue.