Mechanical pump for removal of fragmented matter and methods of manufacture and use
Material transport catheters and methods for their use rely on rotation of an impeller within a catheter body and a clearing element for preventing buildup of materials at the opening of the catheter body. The impeller preferably comprises an inner tube or shaft having a helical rotor formed over an outer surface thereof. The clearing element may comprise a free end of a structure near the distal end of the catheter body for disrupting clot, wherein the free end of the structure extends into the distal opening of the catheter body to break up materials as the impeller is rotated. Alternatively, the clearing element may comprise a cutting member disposed at the distal opening of the catheter body.
1. A circulation catheter comprising:
a catheter body having a proximal end, a distal end, and a lumen therebetween, the lumen forming a distal opening at the distal end of the catheter body;
a macerator at the distal end of the catheter body, wherein the macerator is self-expandable;
an expansible cage surrounding the macerator;
an impeller rotatably disposed in the lumen of the catheter body to aspirate materials generated by the macerator from the distal end to the proximal end of the catheter body; and
a clearing element disposed at the distal opening of the catheter body between the macerator and the impeller to prevent the materials from accumulating at the distal opening.
2. A circulation catheter as in claim 1 wherein the macerator is configured to engage at least a portion of the expansible cage.
3. A circulation catheter as in claim 1 , the impeller comprising a helical rotor having a distal end and a proximal end extending at least partially over an outer surface of a shaft, wherein a distal portion of the shaft extends beyond the distal opening of the catheter body.
4. A circulation catheter as in claim 3 , wherein the macerator comprises a distal end and a proximal end, and wherein the distal end of the macerator is fixed to the distal end of the shaft, and wherein the proximal end of the macerator extends into the distal opening of the catheter body to form the clearing element.
5. A circulation catheter as in claim 3 , wherein the rotor comprises a helical coil, and wherein the distal end of the helical coil is unattached to the shaft to form the clearing element.
6. A circulation catheter as in claim 3 , wherein the clearing element comprises a cutting member coupled to the impeller at or near the distal opening.
7. A circulation catheter as in claim 6 , wherein the cutting member is attached to the macerator.
8. A circulation catheter as in claim 6 , wherein the cutting member is attached to the shaft.
9. A circulation catheter as in claim 6 , wherein the cutting member is attached to the helical rotor.
10. A circulation catheter as in any of claims 4 - 6 , wherein the shaft is rotated to induce aspiration through the catheter body lumen, and wherein the clearing element spins relative to the catheter body to clear the distal opening of the catheter body as the shaft is rotated.
11. A circulation catheter as in claim 1 , wherein the macerator expands and collapses in response to expansion of the cage.