Patent ID: 7766960

Claim:
A vascular prosthesis assembly comprising: a delivery device comprising: an elongate member; and a sheath over at least a portion of the elongate member; a vascular prosthesis comprising a self expanding helical portion, the helical portion placeable in a contracted, delivery state and an expanded, deployed state, the vascular prosthesis defining a central axis; the vascular prosthesis mounted on the elongate member in the contracted, delivery state with at least the helical portion located between the sheath and the elongate member; the helical portion comprising a continuous helical element extending along a helical path along the central axis in an axial direction and extending along the helical path completely around the central axis in a rotary direction in both the contracted, delivery state and the expanded, deployed state; the helical portion having a first wrap angle around said central axis and a first axial length along said central axis when in the contracted, delivery state; the helical portion having a second wrap angle around said central axis and a second axial length along said central axis when in the expanded, deployed state; and the first axial length being equal to the second axial length and the first wrap angle being equal to the second wrap angle.