Delivery systems have been known for many years and have been used with the Seldinger technique and related percutaneous entry techniques for delivery of implantable medical devices into the vasculature of human or veterinary patients. Such systems typically utilize a wire guide inserted into the vasculature to extend to the site of implantation of a medical device such as a stent, stent graft, filter, occluder, valve or the like. An introducer sheath is placed over a portion of the guide wire, and a catheter inserted over the guide wire within the introducer sheath and beyond its distal tip. The medical device is contained within a distal portion of the catheter until delivery to the site of implantation. The medical device is then released from the catheter distal tip and deployed. The insertion and delivery procedure are monitored closely through fluoroscopy, angiograms or CT scanning or the like. Radiopaque markers are commonly used as landmarks on the wire guide, catheter and medical device to assure eventual accurate positioning of the device at the site of implantation and its full deployment.
One delivery system is known from U.S. Pat. No. 4,494,531 for delivery of a vena cava filter into the vena cava of the vasculature. The system includes a wire guide with a handle and a catheter that contains the filter at its distal end in a reduced diameter confinement. Once access is gained to the vasculature by an introducer sheath and a dilator, and the dilator is removed from the sheath, the catheter is inserted through the sheath until its distal end reaches the deployment site. The collapsed filter is then deployed by gradually retracting the catheter's distal end, while the filter is held axially fixed by a positioning wire guide extending to the proximal end of the filter. This process initially exposes the distal end of the filter, which includes outwardly curving struts with barbs. The exposed filter then expands so that its distal barbs engage and seat in the vessel wall in cooperation with sharp, forward jabs or manipulation of the catheter. The remainder of the filter then forms a “bird's nest” and its proximal barbs engage and seat in the vessel wall to anchor the filter in position as the catheter continues to be retracted. The particular filter disclosed in the patent is sold by Cook Incorporated, Bloomington, Ind. as the Gianturco-Roehm BIRD'S NEST Vena Cava Filter. Other delivery systems for filters are disclosed in U.S. Pat. Nos. 5,329,942 and 5,324,304.
U.S. Patent Publication No. 2003/0144670A1, published Jul. 31, 2001, discloses a delivery system, for medical devices such as vascular valves, that provides for assuredly centering the distal ends of the device during deployment from the delivery catheter and allows precise visualization of radiopaque markers on the device being implanted. This delivery system also enables hydration of any lyophilized tissue contained within the medical device at the time of delivery into the patient.