A prosthetic tri-leaflet valve formed by involuting a portion of a tubular structure inside itself. The valve can be made by a method comprising providing a tubular segment in which three equidistant longitudinal incisions are made in one end of the tube creating three flaps which are involuted, i.e.,...http://www.google.co.uk/patents/US7331993?utm_source=gb-gplus-sharePatent US7331993 - Involuted endovascular valve and method of construction
