Filter element for embolic protection device

Abstract

A collapsible filter element ( 105 ) for a transcatheter embolic protection device ( 100 ) comprises a collapsible filter body ( 30 ) which is movable between a collapsed stored position for movement through a vascular system and an expanded position for extension across a blood vessel such that blood passing through the blood vessel is delivered through the filter element ( 105 ). A proximal inlet portion of the filter body ( 30 ) has one or more inlet openings ( 117 ) sized to allow blood and embolic material enter the filter body ( 30 ) and a distal outlet portion of the filter body ( 30 ) has a plurality of outlet openings ( 119 ) sized to allow through-passage of blood, but to retain embolic material within the filter body ( 30 ). The filter body ( 30 ) is at least partially of laminate construction comprising a membrane ( 31 ) coated with a coating ( 32, 33 ) which is biocompatible, the thickness of the coating ( 32, 33 ) being from 4% to 40% of the thickness of the membrane ( 31 ). The coating ( 32, 33 ) may be of hydrophilic material. To facilitate retrieval of captured embolic material the distal portion and/or an intermediate portion of the filter membrane ( 31 ) may be stretchable. The filter body ( 30 ) may have regions of varying hardness or stiffness.

1 . A method for reducing thrombus formation during a medical procedure, comprising:
 tracking an embolic protection device through a body lumen;   moving the embolic protection device from a first position to a second position, the second position configured to at least partially filter fluid passing through the embolic protection device, wherein a portion of the embolic protection device includes a coating disposed thereon, the coating adapted to reduce thrombus formation.   
   
   
       2 . The method according to  claim 1 , wherein the coating is selected from the group consisting of hydrophilic and hydrophobic coatings. 
   
   
       3 . The method according to  claim 2 , wherein the coating further includes a physiologically acceptable additive. 
   
   
       4 . The method according to  claim 3 , wherein the additive is heparin. 
   
   
       5 . The method according to  claim 2 , wherein the coating has a thickness between about 5% and 40% of a thickness of the embolic protection device. 
   
   
       6 . The method according to  claim 2 , wherein the coating is chosen from the group comprising, Poly(2-hydroxy ethyl methacrylate)—(PHEMA), Poly(vinyl alcohol)—(PVA), Poly (ethylene oxide)—(PEO), Poly (carboxylic acids), Poly (acrylic acid)—(PAA), Poly (methacrylic acid)—(PMAA), Poly (N-vinyl-2-pyrollidone)—(PNVP), Poly (sulfonic acids), poly (acrylonitrile), poly (acrylamides), Cellulose ethers, Collagen, Carrageenan, Aquamer (Sky Polymers Inc.), Phosphorylcholine (PC) (Biocompatibiles Ltd), Surmodics (Surmodics Inc. BSI), Hydak (Biocoat Inc), Hydomer (Hydormer Inc). 
   
   
       7 . The method according to  claim 1 , wherein the coating is configured to provide a low friction surface interaction between the filter body and a wall of a body lumen. 
   
   
       8 . The method according to  claim 1 , wherein the coating is at least partially composed of a non thrombogenic material and a fluropolymer material. 
   
   
       9 . A method for reducing thrombus formation during a medical procedure, comprising:
 tracking an expandable filter within a body lumen, the filter having a frame and a filtering element associated with the frame;   deploying the filter from a first position to a second position, wherein in the second position the filtering element opposes at least a portion of the body lumen:   passively filtering fluid through the filtering element, wherein the filtering element is further provided with a coating, the coating configured to mimic an inner surface of the body lumen.   
   
   
       10 . The method according to  claim 9 , wherein the coating comprises between about 5 percent to about 40 percent of the thickness of the filtering element. 
   
   
       11 . The method according to  claim 10 , wherein the filtering element comprises a flexible membrane having a plurality of apertures formed therein. 
   
   
       12 . The method according to  claim 9 , wherein the coating comprises a first component and a second component. 
   
   
       13 . The method according to  claim 12 , wherein the first component is chosen from the group consisting of hydrogels and hydrophilics; the second component is heprin. 
   
   
       14 . The method according to  claim 9 , wherein the coating is chosen from the group comprising, Poly(2-hydroxy ethyl methacrylate)—(PHEMA), Poly(vinyl alcohol)—(PVA), Poly (ethylene oxide)—(PEO), Poly (carboxylic acids), Poly (acrylic acid)—(PAA), Poly (methacrylic acid)—(PMAA), Poly (N-vinyl-2-pyrollidone)—(PNVP), Poly (sulfonic acids), poly (acrylonitrile), poly (acrylamides), Cellulose ethers, Collagen, Carrageenan, Aquamer (Sky Polymers Inc.), Phosphorylcholine (PC) (Biocompatibiles Ltd), Surmodics (Surmodics Inc. BSI), Hydak (Biocoat Inc), Hydomer (Hydormer Inc). 
   
   
       15 . The method according to  claim 9 , wherein the coating is configured to provide a low friction surface interaction between the filter body and a wall of a body lumen. 
   
   
       16 . The method according to  claim 9 , further including the step of moving the filter from the second position back to the first position, thereby entrapping any debris within the filtering element. 
   
   
       17 . The method according to  claim 9 , further including the step of performing a medical procedure after moving the filter from the first position to the second position. 
   
   
       18 . A method for reducing thrombus formation during a medical procedure, comprising:
 providing a collapsible filter element, the filter element having a filter body, the filter body being movable between a collapsed stored position and an expanded position for extension across a body lumen, a proximal inlet portion of the filter body having one or more openings sized to allow fluid and embolic material enter the filter body, at least one distal outlet opening sized to allow passage of fluid through the filter body, but to retain the embolic material within the filter body, the filter body comprising a membrane coating with a biocompatible coating, wherein the biocompatible coating is configured to reduce the formation of thrombus from fluid contact with the membrane;   expanding the filter body from the collapsed stored position to the expanded position; and   performing at least one medical procedure proximal to the filter body.   
   
   
       19 . The method according to  claim 18 , wherein the coating is chosen from the group comprising, Poly(2-hydroxy ethyl methacrylate)—(PHEMA), Poly(vinyl alcohol)—(PVA), poly (ethylene oxide)—(PEO), Poly (carboxylic acids), Poly (acrylic acid)—(PAA), Poly (methacrylic acid)—(PMAA), Poly (N-vinyl-2-pyrollidone)—(PNVP), Poly (sulfonic acids), poly (acrylonitrile), poly (acrylamides), Cellulose ethers, Collagen, Carrageenan, Aquamer (Sky Polymers Inc.), Phosphorylcholine (PC) (Biocompatibiles Ltd), Surmodics (Surmodics Inc. BSI), Hydak (Biocoat Inc), Hydomer (Hydormer Inc). 
   
   
       20 . The method according to  claim 18 , wherein the coating is configured to provide a low friction surface interaction between the filter body and a wall of a body lumen.