Vascular filter device

Abstract

A vascular filter device comprises a support; and a filter comprising one or more filter elements configured to capture thrombus passing through a blood vessel. A holder holds the filter in a closed filtering state and releases to convert the filter to an open state after a period of time. The filter is adapted to retain thrombus after said conversion. In one case the filter elements are arranged to remain in a closed state after released by the holder, because they are blocked by a retained clot from opening fully, and the filter elements are biased to the open state with a bias level which is counter balanced by force exerted by a retained clot under action of blood flow.

1 . A vascular filter device comprising:
 a support;   a filter comprising one or more filter elements, and being configured to capture thrombus passing through a blood vessel,   a holder for holding the filter in a closed filtering state and for releasing to convert the filter to an open state after a period of time; and   wherein the filter is adapted to retain captured thrombus after said conversion.   
     
     
         2 . A filter device as claimed in  claim 1  wherein at least some of the filter elements are arranged to remain in a closed state after release by the holder, because they are blocked by a retained clot from opening fully. 
     
     
         3 . A filter device as claimed in  claim 2 , wherein said filter elements are biased to the open state with a bias level which is counter balanced by force exerted by a retained clot under action of blood flow. 
     
     
         4 . A filter device as claimed in  claim 2 , wherein the filter elements are adapted to converge at an apex between the ends of the filter elements and in the closed state the holder retains the filter elements interconnected at the apex with proximal ends of the filter elements forming a proximal cone to capture thrombus, and the filter elements are adapted to retain a clot-retaining proximal cone shape after conversion if a clot is present at conversion. 
     
     
         5 . A filter device as claimed in  claim 4  wherein said filter elements are biased towards the open state and so are pressed against a retained clot as they attempt to move to the open state, thereby aiding clot break down. 
     
     
         6 . A filter device as claimed in  claim 5 , wherein at least one filter element is configured to be directed radially inwardly at a proximal end when in the closed state for improved clot retention. 
     
     
         7 . A filter device as claimed in  claim 1 , wherein at least some of the filter elements are looped and inter-engage through each other. 
     
     
         8 . A filter device as claimed in  claim 7 , wherein at least one filter element includes a filter arm within the loop. 
     
     
         9 . A filter device as claimed in  claim 1 , wherein at least one filter element is splayed out at a proximal end to promote endothelial coverage when in the open state. 
     
     
         10 . A filter device as claimed in  claim 1 , wherein at least one filter element is connected in a cantilevered manner to the support to be biased to the open state. 
     
     
         11 . A filter device as claimed in  claim 10 , wherein said element is connected to a proximal end of the support by a support hoop extending distally, and is within the support hoop. 
     
     
         12 . A filter device as claimed in  claim 1 , wherein at least one filter element is in the configuration of an arm. 
     
     
         13 . A filter device as claimed in  claim 12  wherein the arm is curved. 
     
     
         14 . A filter device as claimed in  claim 10 , wherein at least two arms are in a twisted configuration with the holder in place, and are configured to unwind upon conversion to aid clot break down. 
     
     
         15 . A filter device as claimed in  claim 1 , wherein at least one filter element is configured with a Y-shaped part at its proximal end. 
     
     
         16 . A filter device as claimed in  claim 1 , wherein at least one filter element is fork-shaped at its proximal end. 
     
     
         17 . A filter device as claimed in  claim 1 , wherein the filter comprises a proximal region and a distal region, and the holder is adapted to release the proximal region upon conversion leaving the distal region to retain a clot after conversion. 
     
     
         18 . A filter device as claimed in  claim 17 , wherein the distal region is cone-shaped and has an apex facing the proximal direction. 
     
     
         19 . A filter device as claimed in  claim 18 , wherein the holder is adapted to release the distal region after a time and the filter elements are biased radially outwardly to press a clot against a vessel wall upon release. 
     
     
         20 . A filter device as claimed in  claim 17 , wherein the proximal region is coarser than the distal region. 
     
     
         21 - 47 . (canceled)