188宝金博页面版

EP 1 292 244 B12510152025303540455055Description?[0001] This invention relates to a filter element for a transcatheter embolic protection device.Introduction?[0002] The invention is particularly concerned with filter elements for transcatheter embolic protection devices of thetype described in our WO-?A-?9923976. One type of such embolic filter comprises a filter body mounted on an associatedcollapsible support frame which can be collapsed against the guide wire by means of a catheter for deployment of thefilter through a patient’s vascular system. Upon retraction of the catheter the support frame and filter body expandoutwardly from the guidewire across a blood vessel within which the filter is positioned to filter blood flowing through theblood vessel.?[0003] A practical problem that arises with filter elements of such embolic protection devices is that they should beable to accommodate blood vessels of different diameter as it would be impractical to manufacture a large range offilters each of different size to accommodate all possible diameters of blood vessel. To provide flexibility and accommodatea range of vessel sizes with a given size of filter a relatively soft and elastic filter body material can be used. It is, however,important that the filter when deployed maintains its shape during use and to prevent distortion or collapsing of the filterbody in use. Because of this and also the need for adequate strength in the body material, the walls of the filter bodytend to be relatively thick. This presents a problem in that the filter then has a relatively large crossing profile when inthe collapsed delivery position, which is undesirable.?[0004] The present invention is directed towards overcoming these and other problems.Statements of Invention?[0005] According to the invention there is provided a collapsible filter element for a transcatheter embolic protectiondevice, the filter element comprising:?a collapsible filter body which is movable between a collapsed stored position for movement through a vascularsystem and an expanded position for extension across a blood vessel such that blood passing through the bloodvessel is delivered through the filter element;a proximal inlet portion of the filter body having one or more inlet openings sized to allow blood and embolic materialenter the filter body;a distal outlet portion of the filter body having a plurality of outlet openings to allow through-?passage of blood, butto retain embolic material within the filter body;the filter body being of an oriented polymeric material.?[0006] In one embodiment of the invention the filter element comprises a collapsible support frame, the support framebeing movable between a collapsed position for movement through the vascular system and an extended outwardlyprojecting position to support the filter body in the expanded position. Preferably the filter body is independent of thesupport frame. Ideally the filter body comprises a membrane.?[0007] In one case the filter body has a stored axial orientation in excess of 15%. Preferably the filter body has astored axial orientation in excess of 20%. Most preferably the filter body has a stored axial orientation in excess of 30%.Ideally the filter body has a stored axial orientation in excess of 40%.?[0008] In a preferred embodiment the material is biaxially oriented.?[0009] The filter body may have a stored biaxial orientation in excess of 30%. Preferably the filter body has a storedbiaxial orientation in excess of 60%. Most preferably the filter body has a stored biaxial orientation in excess of 80%.Ideally the filter body has a stored biaxial orientation in excess of 100%.?[0010] In another embodiment of the invention the ultimate tensile strength of the oriented polymeric material of thefilter body is at least 15, 000 psi (103.425 MPa). Preferably the ultimate tensile strength is at least 25, 000 psi (172.375MPa). Most preferably the ultimate tensile strength is at least 35, 000 psi (241.325 MPa). Ideally the ultimate tensilestrength is at least 40, 000 psi (275.8 MPa).?[0011] The material of the filter body may be of polyester or polyamide. The material of the filter body is preferably ofpolyester.?[0012] In one embodiment the material of the filter body is selected from polyethyleneterephthalate (PET), polybuty-leneterephthalate (PBT) and polynapthylterephthalate (PNT). The material of the filter body is preferably of PET.