A flexible self-expandable stent comprises a plurality of radially cylindrical elastic units spaced at fixed intervals, a cylindrical cover fixing member which sheaths the cylindrical elastic units, and a reverse flow preventing valve. The reverse flow preventing valve is attached to the inner wall of...http://www.google.de/patents/US6027525?utm_source=gb-gplus-sharePatent US6027525 - Flexible self-expandable stent and method for making the same
