smooth 45 u00b0 transition zone which more evenly transfers the force to the slip seal 30 referring now to fig1 an alternate embodiment of the invention is shown in which the self expanding stent is any self expanding stent made of a resilient metal or plastic material which would include shape memory metal stents such as nitinol stents which are well known in the art the self expanding stent is retained in its reduced delivery radius using a collagen sleeve liner or both applicants have a copending application entitled u201c improved tissue supporting devices u201d filed may 19 1994 as ser no 08 246 320 which discloses a preferred stent the entire contents of ser no 08 246 320 are hereby incorporated by reference the stents described in this application are generally cylindrical or tubular in overall shape and of such a configuration as to allow radial expansion for enlargement furthermore the stents are comprised of at least one component which exhibits a resiliency or spring like tendency to self expand the device and at least one other component which is deformable so as to allow an external force such as a balloon positioned within the body of the device to further expand it to a final desired size preferably the stents are made of metal and most preferably of shape memory alloys in its broader concept the device such as a stent of ser no 08 246 320 is made of a first component which is a resilient spring like metal for self expansion and the second component is.