Clinical Study of Abdominal Aortic Aneurysm Exclusion Using the TALENT Enhanced LPS Endoluminal Stent-Graft System

An aneurysm is a localized dilatation of a blood vessel at least 1 1/2 to 2 times the normal vessel diameter. Abdominal aortic aneurysms are relatively common, and have been detected in 1.3% to 2.7% of patients 65 to 80 years of age (Blum, et al, 1996; Collins, Araujo, and Lindsell, 1988; Scott, Ashton, and Kay, 1991). A large proportion (up to 50%) of patients with untreated AAAs experience rupture and exsanguination (Johansen, 1995). Ruptured AAAs are the 13th leading cause of death in the US, accounting for more than 15,000 deaths per year (Cronenwett and Sampson, 1995).

Conventional treatment of abdominal aortic aneurysms is by a surgical procedure involving midline laparotomy, aortic clamping, aortic bypass, and blood loss with associated transfusion. Improvements in surgical techniques and patient care have allowed the mortality rate associated with this procedure to be reduced to approximately 5%, when elective repair is done prior to rupture of the aneurysm. Risks of surgery increase when the patient is considered to be a poor candidate for surgery.

Due to progress made in interventional radiology and endovascular surgery, it is now possible to treat aneurysms without an abdominal surgical procedure, thus potentially further reducing the risks associated with elective repair. This new therapeutic approach consists of transfemoral introduction of a metallic stent coupled with a vascular graft. When the stent device is deployed and expanded within the aneurysmal blood vessel, it creates a new aortic lumen for blood flow, effectively excluding the aneurysm sac from the flow while maintaining perfusion to the lower limbs. This less invasive technique is designed to prevent the need for laparotomy, to reduce the need for blood transfusions, to decrease the use of anesthetics and other drugs, and to speed recovery time.

The objective of this study is to evaluate the safety and effectiveness of the TALENT endoluminal stent-graft system in patients who may be categorized as standard risk, high risk or other indications. Standard risk patients are patients with indications for treatment that are consistent with those for a manufacturer IDE, when there is no active enrollment in the IDE. High risk patients are patients who do not meet the entrance criteria for the manufacturer sponsored IDE as they are at high risk of morbidity and mortality with standard surgical repair. Other indications would be considered patients with indications for treatment outside of those or the manufacturer sponsored IDE.

This study will be performed in both high risk and low risk patients who are considered good candidates for endoluminal repair of abdominal aortic aneurysms. Patients should be heparinized during the implant procedure such that an activated clotting time of 300 seconds is achieved. During implantation of the TALENT endoluminal stent-graft, the pre-implant CT scan and available angiograms are used together with (on-the-table) digital subtraction angiography (DSA), roadmapping, and angiography for proper implant positioning. The TALENT endoluminal stent-graft endoprosthesis is inserted by delivery catheter and introducer sheath via a surgical cutdown (e.g., external iliac artery, femoral artery) approach. The introducer sheath and delivery catheter containing the stent-graft is inserted over a guidewire and advanced into the aorta and above the aneurysm. With the delivery catheter in the correct position, the push rod is held stationary while the outer sheath is slowly withdrawn. The introducer sheath is then withdrawn further until the stent-graft is completely deployed. The balloon may be inflated along the full length of the implanted device to model the springs against the vessel wall and to unravel possible wrinkles in the graft fabric. After deployment of the stent-graft, angiography is performed to verify implant position and to check for the presence of endoleaks.