Percutaneous stent and method for retrieval thereof

Claim 1

Saifme: The claims defining the Invention are as follows: 1. A stent assembly comprising: a first wire formed into a closed zig-zag configuration including; an endless series of straight sections having opposite ends, said straight sections being joined by bends at said opposite ends to form a stent; a set of eyes formed at several of said bends at one of said opposite ends; and a thread passing through successive ones of said set of eyes, said thread including a pair of free ends trailing from said stent; wherein said stent is resiliently contractable into a smaller first shape for conveyance through a body passageway; and wherein said stent is resiliently expandable into a second shape in which the straight sections press against Sthe walls of the body passageway. 2. The stent assembly of claim 1, wherein: said second shape of said stent includes a circumference at said one of said opposite ends, said set of eyes being situated at said circumference; and said thread passes through successive eyes at least 3600 around said circumference. 3. The stent assembly of claim 2, wherein said thread passes through successive eyes approximately 540° around said circumference. 4. The stent assembly of claim 1, wherein said free ends are sufficiently long to extend outside the body passageway when said stent is situated within the passageway. 4. I~ -12- The stent assembly of claim 1, further comprising: a second wire formed into a closed zig-zag configuration including; a second endless series of straight sections having opposite ends, said straight sections being joined by bends at said opposite ends to form a second stent; a second set of eyes formed at several of said bends at one of said opposite ends; wherein said second stent is resiliently contractable into a smaller first shape for conveyance through a body passageway; wherein said second stent is resiliently expandable into a second shape in which the straight sections press against the walls of the body passageway; and wherein said second set of eyes of said second wire are engaged about said first wire at one of said opposite ends. 0 o 6. The stent assembly of claim 5, wherein: a 00I 20 said first wire includes a third set of eyes formed oa qa at several bends at the other of said opposite ends of said first wire; and 00 said second set of eyes of said second wire are 00 interengaged with said third set of eyes. 0000 7. A method for combining a first and second self-expanding stent to form a stent assembly for insertion into a body passageway comprising the steps of: *a d.J forming a first stent from a continuous first length of wire formed into a closed zig-zag configuration having an endless series of straight sections joined at 0 0 their ends by a plurality of bends; forming a second stent from a continuous second length of wire formed into a closed zig-zag configuration Sa 35 having an endless series of straight sections joined at their ends by a plurality of bends, the bends at one end defining eyes open at the straight sections of the second stent; engaging the eyes at the one end of the second stent about bends at one end of the first stent; and closing the eyes at the one end of the second stent. 8. The method of claim 7 wherein: the step of forming the first stent includes forming eyes at the one end of the first stent, the eyes open at the straight sections of the first stent; and the step of engaging the eyes at one end of the second stent includes interlocking the eyes of the second stent with the eyes of the first stent and closing the eyes at the one end of the first stent. 9. A method for retrieving a stent disposed within a body passageway, the stent including a resilient wire formed in a closed zig-zag configuration having a set of eyes i formed at one end of the stent, with a thread passing i 20 through successive eyes of the stent and having two free S ends trailing from the stent outside the body passageway, the stent having a first compressed shape and a second expanded shape in which the resilient wire contacts the wall of the body passageway, comprising the steps of: I 25 pulling the free ends of the thread through the tube to reduce the diameter of the one end of the stent while maintaining the position of the stent within the body ,f passageway; 4 reducing the diameter of the remainder of the stent sufficient to permit travel of the stent through the body 4 t passageway; retracting the compressed stent through the passageway. I 44 4 The method for retrieving a stent of claim 9, wherein said step of pulling the free ends further includes the steps of: threading a tube over the trailing free ends of the thread, the tube having an inner diameter smaller than the diameter of the first compressed shape of the stent; introducing the tube into the body passageway and conveying the tube to a position adjacent the stent; pulling the free ends of the thread through the tube to reduce the diameter of the one end of the stent. 11. The method for retrieving a stent of claim wherein said step of reducing the diameter of the remainder of the stent further .ncludes the steps of: introducing a sheath concentrically disposed over the tube into the body passageway; conveying the sheath over the tube through the body passageway and over the reduced diameter end of the stent; .o further conveying the sheath over the remainder of 20 the stent to compress the remainder of the sheath and o° withdraw the stent from contact with the wall of the body 0* passageway. (o0 12. The method for retrieving a stent of claim 9, wherein said step of reducing the diameter of the remainder of the stent further includes the steps of: threading a sheath over the trailing free ends of the thread, the sheath having an inner diameter larger than the diameter of the first compressed shape of the stent but smaller than the diameter of the second expanded shape of the stent; introducing the sheath into the body passageway and conveying the sheath through the body passageway and over the reduced diameter end of the stent; further conveying the sheath over the remainder of the stent to compress the remainder of the sheath and withdraw the stent from contact with the wall of the body passageway. DATED this TENTH day of JANUARY 1990 Cook Incorporated Patent Attorneys for the Applicant SPRUSON FERGUSON 4 4* 44 4 441 4 t '4 44 I 4 4' 4, 4 4v~ 4441 4 '44 1 4 C4 4 '14414 4 1 44 4 444 I PRIOR ART 9 9 C. 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