Clot retrieval system

Abstract

Catheter-delivered endovascular medical devices are described. The devices may include a pull wire attached to a distal body. The distal body may be formed of a basket or other lattice that has a plurality of cells and an impermeable or permeable film that prevents a clot captured by the basket from escaping distally out of the basket. Methods of using and making the devices are also described.

What is claimed is: 
     
         1 . A system for removing a blood clot from a human blood vessel, the system comprising:
 a pull wire having a proximal end and a distal end;   a distal body attached to the pull wire, the distal body comprising an interior, a distal body proximal end, a distal body distal end, a distal body length extending from the distal body proximal end to the distal body distal end, the distal body having a relaxed state wherein the distal body has a first height and a first width, and a collapsed state wherein the distal body has a second height and a second width, the second height less than the first height, the second width less than the first width,   wherein, in the relaxed state, the distal body comprises a proximal zone comprising a plurality of proximal cells, a middle zone distal to the proximal zone and comprising a plurality of middle zone cells, and a distal zone distal to the middle zone,   wherein at least some of the proximal cells are configured to expand to contact a wall of a human blood vessel,   wherein at least some of the middle zone cells are configured to allow a blood clot to enter laterally into the distal body interior and   wherein the distal body comprises a film at least partially located in the distal zone, the film configured to prevent a blood clot located in the distal body interior from escaping distally out of the distal body interior.   
     
     
         2 . The system of  claim 1  wherein at least one of the middle zone and the distal zone comprises a plurality of memory metal strips and further wherein the film is attached to one or more of the memory metal strips. 
     
     
         3 . The system of  claim 2  wherein the film has no free edges. 
     
     
         4 . The system of  claim 1  wherein the film comprises a plurality of pores and further wherein in the relaxed state, the median size of the plurality of pores is less than the median size of the proximal cells and the median size of the middle zone cells. 
     
     
         5 . The system of  claim 4  wherein the median size of the pores is no more than about 250 microns. 
     
     
         6 . The system of  claim 1  wherein the film is impermeable to the passage of human red blood cells. 
     
     
         7 . The system of  claim 6  wherein, in the relaxed state, the distal body comprises a gap located adjacent to and not covered by the film, the gap configured to allow blood located in the distal body interior to flow distally therethrough and out of the distal body 
     
     
         8 . The system of  claim 1  wherein the film is hydrophilic. 
     
     
         9 . The system of  claim 1  wherein the film is configured to reduce blood flow when the distal body is placed in a human blood vessel. 
     
     
         10 . The system of  claim 1  wherein the proximal zone, middle zone and distal zone form a basket having a substantially closed distal end. 
     
     
         11 . The system of  claim 1  wherein the system further comprises a catheter having an interior, a proximal end leading to the interior and a distal end leading to the interior, the catheter comprised of a biocompatible material and configured to envelope the distal body when the distal body is in the collapsed state. 
     
     
         12 . The system of  claim 1  wherein the distal body has a non-uniform outward radial force along the distal body length. 
     
     
         13 . The system of  claim 1  wherein the proximal zone and the middle zone comprise a plurality of memory metal strips. 
     
     
         14 . The system of  claim 13  wherein, in the relaxed state, each proximal cell has a proximal crown pointing generally in the proximal direction and attached to a memory metal strip and a distal crown pointing generally in the distal direction and attached to a memory metal strip, and wherein at least some of the middle zone cells comprise a proximal crown pointing generally in the proximal direction and attached to a memory metal strip and a free distal crown pointing generally in the distal direction. 
     
     
         15 . The system of  claim 14 , wherein, in the relaxed state, the middle zone comprises at least two free distal crowns located on opposite sides of the distal body. 
     
     
         16 . The system of  claim 14  wherein, in the relaxed state, the distal body has no free proximal crowns pointing generally in the proximal direction. 
     
     
         17 . The system of  claim 14  wherein the memory metal strips of the proximal zone and the middle zone are comprised of the same memory metal and are integrally attached to each other and further wherein the proximal zone and the middle zone are prepared by cutting memory metal from a single memory metal tube and shape setting the cut memory metal tube. 
     
     
         18 . The system of  claim 14  wherein the film is located entirely distal to the free distal crowns. 
     
     
         19 . The system of  claim 14  wherein the distal body comprises a perimeter, and further wherein the film and the proximal cells and the middle zone cells are spaced about the distal body perimeter. 
     
     
         20 . A method of removing a blood clot from a blood vessel of an animal the method comprising the steps of:
 a) providing the system of  claim 1 ;   b) positioning the system in the blood vessel having a blood vessel wall;   c) allowing the height and width of the distal body to increase so that at least some of the proximal cells contact the blood vessel wall;   d) moving the blood clot into the distal body interior; and   e) moving the distal body proximally out of the blood vessel.   
     
     
         21 . The method of  claim 20  wherein step d) comprises moving the distal body proximally to move the blood clot into the distal body interior. 
     
     
         22 . The method of  claim 20  wherein the film traps the blood clot in the distal body interior. 
     
     
         23 . The method of  claim 20  further comprising the step of deploying the distal body from a catheter into the blood vessel during step c) and further wherein the middle zone is distal to the blood clot when the distal body is deployed. 
     
     
         24 . The method of  claim 20  wherein, in the relaxed state, each proximal cell has a proximal crown pointing generally in the proximal direction and attached to a memory metal strip and a distal crown pointing generally in the distal direction and attached to a memory metal strip, and wherein at least some of the middle zone cells comprise a proximal crown pointing generally in the proximal direction and attached to a memory metal strip and a free distal crown pointing generally in the distal direction. 
     
     
         25 . The method of  claim 24 , wherein, in the relaxed state, the middle zone comprises at least two free distal crowns located on opposite sides of the distal body and further wherein, in the relaxed state, the distal body has no free proximal crowns pointing generally in the proximal direction. 
     
     
         26 . A system for removing objects from an interior lumen of an animal, the system comprising:
 a pull wire having a proximal end and a distal end;   a distal body attached to the pull wire, the distal body comprising an interior, a distal body proximal end, a distal body distal end, a distal body length extending from the distal body proximal end to the distal body distal end, a proximal junction forming the proximal end of the distal body, a plurality of proximal strips, a basket comprised of a plurality of open and closed cells formed by a plurality of basket strips, and a distal junction forming a distal end of the basket, the basket comprising a basket interior, each proximal strip having a distal end attached to a cell and a proximal end, the proximal ends of the proximal strips converging at the proximal junction, the distal body having a relaxed state wherein the distal body has a first height and a first width, and a collapsed state wherein the distal body has a second height and a second width, the second height less than the first height, the second width less than the first width,   wherein, in the relaxed state, the basket comprises a plurality of proximal closed cells having a proximal crown attached to a proximal strip and pointing generally in the proximal direction and a distal crown attached to another cell of the basket and pointing generally in the distal direction,   wherein, in the relaxed state, the basket comprises a first drop zone segment distal to the plurality of proximal closed cells, the first drop zone segment comprising at least two closed cells located on opposite sides of the basket having a proximal crown attached to another cell of the basket and pointing generally in the proximal direction and a distal crown attached to another cell of the basket and pointing generally in the distal direction, and at least two cells having a proximal crown attached to another cell of the basket and pointing generally in the proximal direction and a free distal crown pointing generally in the distal direction,   wherein, in the relaxed state, each free distal crown of the first drop zone segment forms part of an enlarged open cell configured to allow a thrombus to pass therethrough and into the basket interior,   wherein, in the relaxed state, the basket comprises a plurality of distal closed cells distal to the first drop zone segment and having a proximal crown attached to another cell of the basket and pointing generally in the proximal direction and a distal crown pointing generally in the distal direction and attached to the distal junction,   wherein, in the relaxed state, the basket does not have any free crowns that point generally in the proximal direction,   wherein the distal body, in the relaxed state, comprises a distal tapered region in which the distal body height and width decrease as the basket approaches the distal junction,   wherein the distal body, in the relaxed state comprises a proximal tapered region in which the distal body height and width decrease as the proximal strips approach the proximal junction and   further wherein the distal body further comprises a film attached to the basket, the film at least partially located distal to the first drop zone segment.   
     
     
         27 . The system of  claim 26  wherein the film is impermeable to the passage of human red blood cells. 
     
     
         28 . The system of  claim 26  wherein, in the relaxed state, the basket further comprises a second drop zone segment distal to the first drop zone segment, the second drop zone segment comprising at least two closed cells located on opposite sides of the basket having a proximal crown attached to another cell of the basket and pointing generally in the proximal direction and a distal crown attached to another cell of the basket and pointing generally in the distal direction and at least two cells having a proximal crown attached to another cell of the basket and pointing generally in the proximal direction and a free distal crown pointing generally in the distal direction, wherein, in the relaxed state, each free distal crown of the second drop segment forms part of an enlarged open cell configured to allow a thrombus to pass therethrough and into the basket interior, and further wherein the film is located at least partially distal to the second drop zone segment. 
     
     
         29 . A system for removing objects from an interior lumen of an animal, the system comprising:
 a pull wire having a proximal end and a distal end;   a distal body attached to the pull wire, the distal body comprising an interior, a distal body proximal end, a distal body distal end, a distal body length extending from the distal body proximal end to the distal body distal end, a proximal junction forming the proximal end of the distal body, a plurality of proximal strips, a basket comprised of a plurality of open and closed cells formed by a plurality of basket strips, and a distal junction forming a distal end of the basket, the basket comprising a basket interior, each proximal strip having a distal end attached to a cell and a proximal end, the proximal ends of the proximal strips converging at the proximal junction, the distal body having a relaxed state wherein the distal body has a first height and a first width, and a collapsed state wherein the distal body has a second height and a second width, the second height less than the first height, the second width less than the first width,   wherein, in the relaxed state, the basket comprises a plurality of proximal closed cells having a proximal crown attached to a proximal strip and pointing generally in the proximal direction and a distal crown attached to another cell of the basket and pointing generally in the distal direction,   wherein, in the relaxed state, the basket comprises a first drop zone segment distal to the plurality of proximal closed cells, the first drop zone segment comprising at least two closed cells having a proximal crown attached to another cell of the basket and pointing generally in the proximal direction and a distal crown attached to another cell of the basket and pointing generally in the distal direction, and at least two closed cells having a proximal crown attached to another cell of the basket and pointing generally in the proximal direction and a free distal crown pointing generally in the distal direction,   wherein, in the relaxed state, each free distal crown of the first drop segment forms part of an enlarged open cell configured to allow a thrombus to pass therethrough and into the basket interior,   wherein, in the relaxed state, the basket comprises a plurality of distal closed cells distal to the first drop zone segment and having a proximal crown attached to another cell of the basket and pointing generally in the proximal direction and a distal crown pointing generally in the distal direction and attached to the distal junction by a distal strip having a proximal end attached to the distal crown and a distal end attached to the distal junction,   wherein, in the relaxed state, the basket does not have any free crowns that point generally in the proximal direction,   wherein each of the distal ends of the distal strips converge at the distal junction,   wherein the distal body, in the relaxed state, comprises a distal tapered region in which the distal body height and width decrease as the distal strips approach the distal junction,   wherein the distal body, in the relaxed state comprises a proximal tapered region in which the distal body height and width decrease as the proximal strips approach the proximal junction; and   further wherein the distal body further comprises a film attached to the basket, the film at least partially located distal to the first drop zone segment.   
     
     
         30 . The system of  claim 29  wherein, in the relaxed state, the basket further comprises a second drop zone segment distal to the first drop zone segment, the second drop zone segment comprising at least two closed cells having a proximal crown attached to another cell of the basket and pointing generally in the proximal direction and a distal crown attached to another cell of the basket and pointing generally in the distal direction and at least two closed cells having a proximal crown attached to another cell of the basket and pointing generally in the proximal direction and a free distal crown pointing generally in the distal direction, wherein, in the relaxed state, each free distal crown of the second drop segment forms part of an enlarged open cell configured to allow a thrombus to pass therethrough and into the basket interior, and further wherein the film is located at least partially distal to the second drop zone segment.