Implantable vascular device

A valve prosthesis for implantation within a vascular vessel, comprising:

• at least two leaflets;
• and
• a support frame having a lengthwise axis and comprising a leaflet support portion and a circumferential centering support element disposed adjacent the leaflet support portion on the lengthwise axis, the leaflet support portion comprising a self-expanding support frame having a plurality of struts interconnected by bends and configured for expansion to conform to a wall of the vascular vessel, the self-expanding support frame having a first end with only two bends and a second, opposite end with only two bends, the bends of the first end disposed on a first transverse axis and the bends of the second end disposed on a second transverse axis, the first transverse axis oriented approximately orthogonally with the second transverse axis;
• the circumferential centering support element comprising a ring-shaped frame having a plurality of struts interconnected by bends to define a zig-zag pattern with a third end and a fourth opposite end, at least two of the bends at the fourth end of the circumferential centering support element including a closed circumference;
• the self-expanding support frame and the ring-shaped frame being discrete;
• a first radial constraint disposed at the fourth end of the circumferential centering support element and configured to constrain the radial expansion thereof, the first radial constraint attaching two of the bends of the fourth end of the circumferential centering support element to the bends of the first end of the leaflet support portion;
• the at least two leaflets attached along the struts of the leaflet support portion and forming a valve opening that extends between the two bends at the first end of the leaflet support portion and the attached two bends at the fourth end of the circumferential centering support element.