Patent ID: 7766973

Claim:
A device for implanting within an animal body comprising: a proximal anchor adapted for attachment within a natural body lumen; a thin-walled sleeve open at both ends and defining a lumen therebetween, a proximal end of the sleeve being coupled to the anchor, a substantial length of the sleeve being a floppy zone having material characteristics that result in the sleeve being prone to eversion; an eversion-resistant feature of the sleeve disposed only at the proximal end of the sleeve that inhibits eversion of the sleeve by collapsing radially in the presence of retrograde pressures, the floppy zone of the sleeve extending the substantial length of the sleeve beyond the eversion resistant feature, the eversion-resistant feature comprising: a proximal crumple zone of the sleeve that collapses radially in the presence of retrograde pressures; and a distal reinforced region of the sleeve between the crumple zone and the floppy zone of the sleeve, the reinforced region collapsing radially, but to a lesser extent than the crumple zone, in the presence of retrograde pressures.