| 主权项 |
1. A vascular prosthesis for implantation in a body vessel having a vessel wall, the vascular prosthesis comprising:
an alternating helical section placeable in a contracted state, suitable for transluminal insertion into the body vessel, and in an expanded state, the alternating helical section having a flat ribbon-like helical structure with a width and thickness, the width being substantially greater than the thickness, the alternating helical section comprising first, second and third helical portions, the helical portions arranged in series with each helical portion having proximal and distal ends, wherein the first and the third helical portions have a direction of rotation about a longitudinal axis of the prosthesis opposite to that of the second helical portion, the distal end of the first helical portion connected directly to the proximal end of the second helical portion at a first apex, the distal end of the second helical portion connected directly to the proximal end of the third helical portion at a second apex, the first helical portion being connected to the second helical portion only at the first apex, the distal ends of the first and second helical portions and the proximal ends of the second and third helical portions having converging sides, each of the first and second apices also comprising converging sides terminating at a narrowed tip, and the entire first and second helical portions have different lengths to place the first and second apices at substantially different circumferential positions when in the expanded state, whereby a mechanical characteristic of the vascular prosthesis can be affected by said different positions. |
