# US 8,784,477 B2 · Stent graft with two layer ePTFE layer system with high plasticity and high rigidity > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,784,477 B2 - Document ID: US8784477B2 - Status: Granted - Kind: B2 - Application number: 12/985,151 - Filed: 2011-01-05 - Published: 2012-07-05 - Granted: 2014-07-22 - Earliest claimed: 2011-01-05 - Assignees: Abbott Cardiovascular Systems Inc. - Applicants: Rainer Bregulla; Gunther Stockert - Inventors: Rainer Bregulla; Gunther Stockert - Web page: https://patentgrep.com/patent/US8784477B2 ## CPC - A61L 27/3683: {subjected to a specific treatment prior to implantation, e.g. decellularising, demineralising, grinding, cellular disruption/non-collagenous protein removal, anti-calcification, crosslinking, supercritical fluid extraction, enzyme treatment} - A61F 2/07: Stent-grafts - A61F 2/915: with bands having a meander structure, adjacent bands being connected to each other - A61L 27/507: {for artificial blood vessels (apparatus for applying cells on a blood vessel prosthesis A61F2/062)} - A61L 31/048: {obtained by reactions only involving carbon-to-carbon unsaturated bonds (A61L31/041 takes precedence)} - A61L 31/14: Materials characterised by their function or physical properties {, e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials} - C08L 27/18: Homopolymers or copolymers or tetrafluoroethene - A61F 2002/072: {Encapsulated stents, e.g. wire or whole stent embedded in lining} - A61F 2002/91575: {connected peak to trough} - A61F 2210/0076: multilayered, e.g. laminated structures - A61F 2220/005: using adhesives - A61F 2220/0058: soldered or brazed or welded - A61F 2230/0013: Horseshoe-shaped, e.g. crescent-shaped, C-shaped, U-shaped - A61L 2400/16: Materials with shape-memory or superelastic properties - Y10T 29/49826: Assembling or joining - A61L: METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES (preservation of bodies or disinfecting characterised by the agents employed A01N; preserving, e.g. sterilising, food or foodstuffs A23; preparations for medical, dental or toiletry purposes A61K) - A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C) - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A vascular prosthesis and method are disclosed comprising a first flexible stent having a lattice structure with a compacted configuration and an expanded configuration, a second flexible stent inside the first flexible stent to form a tubular structure, a first film layer of graft material such as expanded polytetrafluoroethylene sandwiched between the first and second flexible stents, and a second film layer of expanded polytetrafluoroethylene sandwiched between the first and second flexible stents, the second layer having a higher rigidity and a lower plasticity than the first layer. ## Claims ### Claim 1 A vascular prosthesis comprising: a first flexible stent having a lattice structure with a compacted configuration and an expanded configuration; a second flexible stent inside the first flexible stent to form a tubular structure, the second flexible stent having a lattice structure with a compacted configuration and an expanded configuration; a first film layer of expanded polytetrafluoroethylene sandwiched between the first and second flexible stents; and a second film layer of expanded polytetrafluoroethylene sandwiched between the first and second flexible stents, the second layer having a higher rigidity and a lower plasticity than the first layer, wherein the first film layer and second film layer are circumferentially positioned from each other in a first circumferential position when the first and second flexible stents are in the compacted configuration and are circumferentially positioned from each other in a second circumferential position which is different from the first circumferential position when the first and second flexible stents are in the expanded configuration. ### Claim 2 (depends on 1) The vascular prosthesis of claim 1, wherein the first film layer is sintered at a lower level than the second film layer. ### Claim 3 (depends on 1) The vascular prosthesis of claim 1, wherein the first film layer expands to a different circumferential position than a circumferential position of the second film layer when the first and second flexible stents are expanded to their expanded configuration. ### Claim 4 A method for making a vascular prosthesis comprising: providing a first expandable, tubular stent; forming a multi-layer graft member by applying a first tubular member of ePTFE on a mandrel, and then applying a second tubular member of ePTFE onto the first tubular member, the first tubular member being movable circumferentially relative to the second tubular member, wherein the second tubular member of ePTFE has a different rigidity and plasticity than the first tubular member; placing the multi-layer graft member on the first expandable, tubular stent; placing a second expandable tubular stent over the multi-layer graft member to sandwich the multi-layer tubular graft member between the first and second stents; and affixing the first expandable tubular stent to the second expandable tubular stent. ### Claim 5 (depends on 4) The method of making a vascular prosthesis of claim 4, further comprising a step of forming the first tubular member of ePTFE with a different sintering level than the second tubular member of ePTFE. ### Claim 6 (depends on 4) The method of making a vascular prosthesis of claim 4, further comprising the step of forming the first and second tubular stents out of a shape memory material. ### Claim 7 (depends on 4) The method of claim 4, wherein the vascular prosthesis is adapted to be crimped onto a catheter balloon.