A system for delivering a prosthesis (100, 120) to a targeted site comprising; a catheter device sized and configured for introduction to a targeted site in a hollow body organ or blood vessel, the catheter device including: a shaft (210, 216) sized and configured to carry the prosthesis during introduction of the catheter device; a first release mechanism coupled to the prosthesis to secure at least one region of the prosthesis to the catheter shaft, and a first actuator to operate the first release mechanism, said first release mechanism comprising a first proximal release hub; and a second release mechanism coupled to the prosthesis in cooperation with the first release mechanism to prevent full release of the at least one region of the prosthesis from the catheter shaft after actuation of the first actuator, whereby actuation of the first actuator partially releases the at least one region of the prosthesis from the catheter shaft at the targeted site without fully releasing the at least one region from the catheter shaft, a second actuator to operate the second release mechanism to fully release the at least one region of the prosthesis from the catheter shaft; wherein the second release mechanism comprises one or more resilient stabilizing arms, a second proximal release hub and a release wire, wherein the distal ends of the one or more stabilizing arms are coupled to the second proximal release hub and wherein the proximal ends of the one or more stabilizing arms are releasably coupled to a proximal end of the prosthesis by the release wire; and wherein before the second release mechanism fully releases the at least one region of the prosthesis, the release wire extends through respective apertures at the proximal ends of each of the one or more stabilizing arms and through the prosthesis, and the proximal ends of the one or more stabilizing arms are arched back generally toward the first proximal release hub; and a fastening device sized and configured for introduction to the targeted site in the hollow body organ or blood vessel occupied by the catheter device, the fastening device including an actuator to deploy a fastener in the at least one region of the prosthesis after actuation of the first release mechanism and before actuation of the second release mechanism. a shaft (210, 216) sized and configured to carry the prosthesis during introduction of the catheter device; a first release mechanism coupled to the prosthesis to secure at least one region of the prosthesis to the catheter shaft, and a first actuator to operate the first release mechanism, said first release mechanism comprising a first proximal release hub; and a second release mechanism coupled to the prosthesis in cooperation with the first release mechanism to prevent full release of the at least one region of the prosthesis from the catheter shaft after actuation of the first actuator, whereby actuation of the first actuator partially releases the at least one region of the prosthesis from the catheter shaft at the targeted site without fully releasing the at least one region from the catheter shaft, a second actuator to operate the second release mechanism to fully release the at least one region of the prosthesis from the catheter shaft; wherein the second release mechanism comprises one or more resilient stabilizing arms, a second proximal release hub and a release wire, wherein the distal ends of the one or more stabilizing arms are coupled to the second proximal release hub and wherein the proximal ends of the one or more stabilizing arms are releasably coupled to a proximal end of the prosthesis by the release wire; and wherein before the second release mechanism fully releases the at least one region of the prosthesis, the release wire extends through respective apertures at the proximal ends of each of the one or more stabilizing arms and through the prosthesis, and the proximal ends of the one or more stabilizing arms are arched back generally toward the first proximal release hub; and a fastening device sized and configured for introduction to the targeted site in the hollow body organ or blood vessel occupied by the catheter device, the fastening device including an actuator to deploy a fastener in the at least one region of the prosthesis after actuation of the first release mechanism and before actuation of the second release mechanism.