Retrieval Catheter with Expandable Tip

Abstract

Catheters of the present disclosure include a catheter shaft and an expandable tip, which can retrieve materials slightly larger than an inner diameter of the catheter shaft. The tip may be expandable such that it can easily transform from a first size and shape to a second size and shape to aid in the retrieval of the materials (i.e., the thrombus, embolus, or foreign body). Catheter tips may be expanded by inflation, removal of a constraining member, or an input such as heat, light, or electrical energy.

1 . A retrieval catheter, comprising:
 an elongate shaft having a shaft lumen extending from a proximal end portion to a distal end portion of the elongate shaft, the elongate shaft having a distal end comprising a self-expanding member that expands from a collapsed state to an expanded state when unrestrained, the member extending distally of the distal end and forming a tip lumen distally of the distal end;   a cover over an outer surface of the self-expanding member that retains the member in the collapsed state, the cover being at least partially dissolvable when activated, wherein the self-expanding member is configured to expand to the expanded state when the cover is at least partially dissolved.   
     
     
         2 . The retrieval catheter of  claim 1 , wherein the self-expanding member comprises a plurality of woven strands. 
     
     
         3 . The retrieval catheter of  claim 1 , wherein the self-expanding member comprises a spiral coil. 
     
     
         4 . The retrieval catheter of  claim 1 , wherein the self-expanding member is substantially cylindrical in the first state. 
     
     
         5 . The retrieval catheter of  claim 1 , wherein the self-expanding member is substantially frusticonical in the second state. 
     
     
         6 . The retrieval catheter of  claim 1 , wherein the self-expanding member comprises a plurality of longitudinal slits.