A delivery device system for delivering a low profile prosthesis and a method for releasably retaining a prosthesis on the device are described. The delivery device comprises a prosthesis disposed about the proximal end of the inner cannula. In a first configuration the prosthesis is releasably secured to the inner cannula in a radially inwardly contracted low profile delivery configuration and in a second configuration the prosthesis is at least partially radially outwardly deployed. First and second trigger wires extend longitudinally and circumferentially about the prosthesis in helical configurations. The first trigger wire is helically wound in a clockwise direction and the second trigger wire is helically wound in a counter-clockwise direction. When the first and second helical trigger wires are in a tensioned condition, the prosthesis is releasably secured to the inner cannula in a radially inwardly contracted low profile delivery configuration.