Catheter-based apparatuses and methods

Abstract

Blood flow into vascular tissue is filtered in a manner that can also be useful for trapping particulates while allowing the flow of blood. Consistent with one or more embodiments, a filter apparatus includes a filter, an outer delivery sheath such as a catheter, and one or more shafts that are operable to manipulate the shape of the filter for positioning within vascular tissue. The filter conforms to various types of vascular tissue, and filters blood flow passing through openings in the vascular tissue. In some implementations, the filter is used to trap particulates that have been collected on the filter, and collapses to trap and draw the particulates into the outer delivery sheath.

What is claimed is: 
     
         1 . An apparatus comprising:
 a catheter extending from a proximal end to a distal end and configured and arranged for insertion into vascular tissue;   a shaft structure configured and arranged to move within the catheter and to at least partially retract within the distal end of the catheter;   a mesh sheet having opposing surfaces and configured and arranged to pass human red blood cells and to filter particles having a dimension larger than the human red blood cells; and   a frame having opposing members that form respective lobes of a perimeter of the frame, with each of the members extending between first and second ends of the frame, the members being connected to the mesh sheet and the shaft structure, the frame being configured and arranged with the shaft structure and mesh sheet to:
 in response to movement of the shaft structure, expand the mesh sheet to an expanded state by spreading the respective members relative to the first and second ends, with the first end being adjacent the distal end of the catheter, and with the members extending away from the distal end of the catheter to the second end; and 
 in the expanded state, conform a perimeter of the mesh sheet to a sidewall of the vascular tissue and around an opening in the sidewall by applying pressure with the respective members of the frame to the perimeter of the mesh sheet and to the sidewall, therein sealing the mesh sheet around the opening for filtering blood passing via the opening. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the frame is configured and arranged with the shaft structure and the mesh sheet to, in response to movement of the shaft structure, collapse the mesh sheet and trap particles on the filter therein, and retract the collapsed filter material within the catheter for removal of the trapped particles from within the vascular tissue. 
     
     
         3 . The apparatus of  claim 1 , wherein the members extend, in the expanded state, in opposing arcs between the first and second ends of the frame and are cantilevered out from the first end in a direction away from the distal end of the catheter. 
     
     
         4 . The apparatus of  claim 1 , wherein the frame is configured and arranged with the shaft structure, mesh sheet and catheter to, in the expanded state, seal the mesh sheet around the opening in a sidewall of a blood vessel of the vascular tissue, with the catheter extending from the proximal end to the distal end within the blood vessel, and with the frame extending out from the catheter and further into the blood vessel along a direction therein extending from the proximal end to the distal end. 
     
     
         5 . The apparatus of  claim 1 , wherein the frame is configured and arranged with the shaft structure, mesh sheet and catheter to, in the expanded state, seal the mesh sheet around the opening in the sidewall of the vascular tissue with the catheter extending along the sidewall within the vascular tissue. 
     
     
         6 . The apparatus of  claim 1 , wherein
 the shaft structure and catheter are configured and arranged with stiffness characteristics to apply a force to the first end of the frame and away from the distal end of the catheter; and   the frame is configured and arranged to translate the force applied to the first end of the frame to the mesh sheet via the members, to apply the pressure to the perimeter of the mesh sheet that seals the mesh sheet around the opening.   
     
     
         7 . The apparatus of  claim 1 , wherein the frame is configured and arranged with the shaft structure and the mesh sheet to conform the perimeter of the mesh sheet around the opening in the vascular tissue utilizing stiffness characteristics of the shaft structure and the catheter to apply force to the mesh sheet and the sidewall. 
     
     
         8 . The apparatus of  claim 1 , wherein the shaft structure includes:
 a first shaft extending through the catheter from the proximal end to the distal end and being configured and arranged to move within the catheter, the first shaft having an end portion configured and arranged to retract within the proximal end; and   a second shaft extending through the first shaft and the catheter, the second shaft being configured and arranged to move within the first shaft and having an end portion that extends beyond the end portion of the first shaft, at least a portion of the second shaft being configured and arranged to retract into the first shaft.   
     
     
         9 . The apparatus of  claim 8 , wherein the first and second ends are respectively connected to the end portions of the first and second shafts; and
 the second shaft extends between the first and second end portions along a central portion of a surface of the mesh sheet, and is configured and arranged to
 expand the mesh sheet by causing the members to spread apart from one another, with the mesh sheet and frame forming a concave surface bound by the frame and being configured and arranged to prevent particulates from passing from one of the opposing surfaces, through the mesh sheet and to the other one of the opposing surfaces, while the mesh sheet sealed around the opening in the sidewall, and 
 collapse the filter by causing the respective members to curl and overlap. 
   
     
     
         10 . The apparatus of  claim 8 , wherein the first shaft, second shaft and frame are configured and arranged to, with the second shaft extending from the distal end of the catheter into the vascular tissue along the sidewall, and with the catheter extending from its proximal end to its distal end within the vascular tissue and along the same sidewall,
 expand the mesh sheet to the expanded state and conform the perimeter of the mesh sheet around the opening in the sidewall in response to a portion of the second shaft passing into the first shaft, and   collapse the mesh sheet to the collapsed state in response to the portion of the second shaft passing out of the first shaft.   
     
     
         11 . The apparatus of  claim 1 , wherein the frame includes a center wire or wire/catheter with lumen that extends across a center region of the mesh sheet and is configured and arranged to facilitate conformity of the mesh sheet to curved regions of the sidewall. 
     
     
         12 . The apparatus of  claim 1 , wherein the frame is configured and arranged with the catheter and shaft structure maintain the mesh sheet sealed around the opening under conditions in which pressure in blood flowing in the vascular tissue fluctuates due to pumping of a heart. 
     
     
         13 . The apparatus of  claim 1 , wherein the frame is configured and arranged with the mesh sheet, shaft structure and catheter to, in the expanded state, position a first portion of one of the opposing surfaces of the mesh sheet over the opening and conform substantially all of the other portions of the one of the opposing surfaces of the mesh sheet to the sidewall around the opening. 
     
     
         14 . The apparatus of  claim 1 , wherein the members are configured and arranged to, in the expanded state, conform to deviations in the sidewall and therein facilitate sealing of the mesh sheet to portions of the sidewall including the deviations. 
     
     
         15 . A method comprising:
 deploying a catheter in vascular tissue, with the catheter extending from a proximal end to a distal end, the catheter including:
 a shaft structure configured and arranged to move within the catheter and to at least partially retract within the distal end of the catheter; 
 a mesh sheet having opposing surfaces and configured and arranged to pass human red blood cells and to filter particles having a dimension larger than the human red blood cells; and 
 a frame having members that form respective lobes of a perimeter of the frame, with each of the members extending between first and second ends of the frame, the respective members being connected to the mesh sheet and the shaft structure; and 
   utilizing frame, the shaft structure and the mesh sheet to:
 via movement of the shaft structure, expand the mesh sheet to an expanded state by spreading the respective members relative to the first and second ends, with the first end being adjacent the distal end of the catheter, and with the members extending away from the distal end of the catheter to the second end; and 
 in the expanded state, conform a perimeter of the mesh sheet to a sidewall of the vascular tissue and around an opening in the sidewall by applying pressure with the members of the frame to the perimeter of the mesh sheet and to the sidewall, therein sealing the mesh sheet around the opening for filtering blood passing via the opening. 
   
     
     
         16 . The method of  claim 15 , further including:
 via further movement of the shaft structure, collapsing the mesh sheet and trapping particles on the filter therein; and   retracting the collapsed filter material within the catheter and removing the trapped particles from within the vascular tissue.   
     
     
         17 . The method of  claim 15 , wherein spreading the members includes spreading the members in opposing arcs between the first and second ends of the frame and cantilevering the members out from the first end in a direction away from the distal end of the catheter. 
     
     
         18 . The method of  claim 15 , wherein sealing the mesh sheet around the opening includes sealing the mesh sheet around an opening in a blood vessel with the catheter extending from the proximal end to the distal end within the blood vessel, and with the frame extending out from the catheter and further into the blood vessel along a direction therein extending from the proximal end to the distal end. 
     
     
         19 . The method of  claim 15 , wherein sealing the mesh sheet around the opening in the sidewall includes:
 utilizing stiffness characteristics of the shaft structure and the catheter, applying a force to the first end of the frame and away from the distal end of the catheter; and   translating the force applied to the first end of the frame to the mesh sheet via the members, and therein applying the pressure to the perimeter of the mesh sheet that seals the mesh sheet around the opening.   
     
     
         20 . The method of  claim 15 , wherein
 the shaft structure includes a first shaft extending through the catheter from the proximal end to the distal end and being configured and arranged to move within the catheter, and an end of the first shaft being connected to the first end of the frame;   the shaft structure includes a second shaft extending through the first shaft and being configured and arranged to move within the first shaft and having an end portion that extends beyond the end portion of the first shaft and is connected to the second end of the frame, at least a portion of the second shaft being configured and arranged to retract into the first shaft; and   expanding the mesh sheet to the expanded state includes causing the members to spread apart by moving the first shaft relative to the second shaft.