Vascular implant

Abstract

A medical implant ( 20 ) includes first and second ring members ( 22, 24 ), each including a resilient framework ( 26 ) having a generally cylindrical form. A tubular sleeve ( 28 ) is fixed to the first and second ring members so as to hold the ring members in mutual longitudinal alignment, thereby defining a lumen ( 32 ) passing through the ring members. A constricting element ( 30 ) is fit around the sleeve at a location intermediate the first and second ring members so as to reduce a diameter of the lumen at the location.

What is claimed is: 
     
         1 . A stent for implantation in a lumen, comprising:
 a plurality of struts, with intervening openings therebetween; and   narrow connecting pieces, bridging at least some of the openings so as to interconnect the struts,   wherein exertion of a first outward radial force on the struts causes the stent to open to a first diameter by opening the intervening openings between the struts, and   wherein the narrow connecting pieces are adapted to break under exertion on the struts of a second outward radial force, greater than the first outward radial force, so that the stent opens to a second diameter, greater than the first diameter