Cutting balloon catheter

Abstract

A system for removing matter from a partially or totally occluded stent includes a cutter that is urged radially outward toward the inner surface of the stent. Preferably, the cutter has a hardness that is less than or equal to the hardness of the material used to make the stent. Aspiration may be provided to remove portions of the occluding material from the vessel.

Description

(shown in phantom lines). The balloon 98 can be inflated with the saline or other material that is delivered through the catheter 94 (shown by arrows). Preferably, the catheter 94 is sealed along its length to prevent loss of the material used to inflate the balloon. Inflating the balloon 98 urges the helical cutter 90 radially outward toward the inner surface of a stent.

FIGS. 5A-5C show three of many possible embodiments of the helical cutter 90. The helical cutter 90 can comprise a generally round wire 100 that is selectively coated with an abrasive material such as diamond grit 102 as shown in FIG. 5A. The diamond grit is plated to a wire selectively such that the grit is not exposed on the surfaces that contact the stent itself, if the plated wire momentarily engages the stent, but only cuts deformable restenosis tissue that deforms in the abrasive.

Alternatively, as shown in FIG. 5B, the helical cutter 90 can comprise a relatively flat spring 104 having an outer edge 106 that is sharpened to provide a cutting surface. The material used to make the flat spring 104 preferably has a hardness that is less than or equal to the hardness of the material used to make the stent to be cleared.

Alternatively, as shown in FIG. 5C, the helical cutter 90 can comprise a cutaway tube, such as a hypotube, having a sharpened outer edge 110. The tube is wound into a helical coil around the guide wire. The material used to make the tube should have a hardness less or equal to the hardness of the material used to make the stent.

FIG. 6 shows how a helical cutter 90 of a type shown in FIG. 5 is used within a vessel. The helical cutter 90 is positioned within a partially or totally occluded stent 120 that is within a vessel 122. A catheter 130 is advanced into the vessel 122 and a sealing mechanism such as one or more balloons 134 at the distal end of the catheter is used to seal the vessel. A catheter 94 that contains the helical cutter 90 is then advanced through the catheter 94. The helical cutter 90 is expanded radially outward once it is within the stent 120 by inflating the balloon 98. The catheter 94 is then rotated by a prime mover such as gas turbine or an electric motor (not shown) at the proximal end of the catheters 94 and 130. Rotation of the helical cutter 90 removes the occluding material 124 from the stent 120. In addition, aspiration can be provided to the catheter 130 and/or 94 to remove portions of the ablated, occluding material 124. The aspirated material can be removed from the vessel using a pump 140 and a filter 144 before the aspirated liquid is returned to the patient.

While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention. It is therefore intended that the scope of the invention be determined from the following claims and equivalents thereto.

Claims

1. A system for removing deposits from a partially or totally occluded stent balloon catheter, comprising:

a catheter shaft configured to be routed over a guidewire;

an expandable cutter disposed over a guide wire coupled to the catheter shaft, the cutter including a coiled member having a proximal end directly affixed to a distal end of the catheter shaft and a distal end directly affixed to a distal bearing through which the guidewire is routed; and

a balloon disposed within the coiled member that expands to urge the cutter radially outward, the balloon being a separate component from the expandable cutter, a proximal end of the balloon directly affixed to the distal end of the catheter shaft proximate the proximal end of the coiled member and a distal end of the balloon directly affixed to the distal bearing proximate the distal end of the coiled member, wherein the balloon is inflated when the cutter is within the occluded stent to urge the cutter toward an inner wall of the occluded stent, the expandable cutter being rotatable in the occluded stent to remove occluding matter with a fluid delivered through the catheter shaft.

2. The system balloon catheter of claim 1, wherein the coiled member is a diamond coated helical wire.

3. The system balloon catheter of claim 1, wherein the coiled member is a flat spring having a sharpened outer edge.

4. The system balloon catheter of claim 1, wherein the coiled member is a semi-cylindrical wire having a sharpened edge.

5. A method for removing restenotic tissue from within a stent, comprising:

advancing a cutter into the stent, the cutter being secured to a drive shaft and including an expandable coil having a cutting surface, wherein the cutting surface is positioned on the coil such that the cutting surface does not contact the stent when removing restenotic tissue from within the stent;

rotating the cutter; and

aspirating ablated particles of the restenotic tissue.

6. The balloon catheter of claim 1, wherein the cutter is rotatable to remove occluding matter during use.

7. A medical device, comprising:

a catheter shaft having a proximal and a distal end, the catheter shaft being configured to be routed over a guidewire;

an inflatable balloon having a proximal end directly affixed to the distal end of the catheter shaft and a distal end directly affixed to a distal member through which the guidewire is routed; and

a helical cutter disposed over a portion of the inflatable balloon such that the balloon is disposed within the helical cutter, the helical cutter being a separate component from the inflatable balloon, a proximal end of the helical cutter being directly affixed to the distal end of the catheter shaft proximate the proximal end of the inflatable balloon and a distal end of the helical cutter being directly affixed to the distal member proximate the distal end of the inflatable balloon;

wherein the inflatable balloon is inflated with a fluid delivered through the catheter shaft to move the helical cutter radially outward.

8. The medical device of claim 7, wherein the helical cutter includes an abrasive.

9. The medical device of claim 8, wherein the abrasive is a diamond coating.

10. The medical device of claim 7, wherein the helical cutter is a flat spring.

11. The medical device of claim 7, wherein the helical cutter is a wire.

12. The medical device of claim 7, wherein the helical cutter is rotatable to remove occluding matter during use.

13. The medical device of claim 7, wherein the distal member is a distal bearing.