Fatigue and In Vivo Validation of a Peritoneum-Lined Self-Expanding Nitinol Stent-Graft

Abstract

.P urpose: To assess the fatigue and in vivo performance of a new stent-graft incorporating bovine peritoneum lining that is designed for application in peripheral vascular occlusive disease. Methods: Bovine peritoneum-lined stent-grafts were subjected to accelerated in vitro pulsatile fatigue and axial/torsional fatigue testing designed to simulate 10 years of physiological strain on the devices. At specified times the devices were evaluated for stent fracture, suture failure, or tissue tearing. Seven dogs underwent bilateral common iliac artery (CIA) balloon angioplasty injury with unilateral placement of the peritoneum-lined stent-graft. Angiography and intravascular ultrasound were performed prior to treatment, after treatment, and prior to sacrifice at 30 days. Vessels were perfusion fixed and histologically evaluated at 5 regions: above stent, proximal stent, mid stent, distal stent, and below stent. Results: No evidence of stent, suture, or tissue failure was present during or after pulsatile and axial/torsional fatigue testing. At 3060.3 days after implantation, all vessels were patent. The average lumen area at explantation across stented vessels was 25.45 mm ). The mean neointimal area in peritoneum-lined stents was 2.0261.52 mm 2 , with a neointima:media ratio of 1.0360.50. These values were significantly lower in the above and below stent areas than in the stented regions, but there was no difference in either measure within the proximal, mid, or distal stent. Conclusion: The custom-designed peritoneum-lined stent-graft is promising for clinical peripheral applications due to its ability to resist relevant long-term physiological stresses and outstanding short-term patency rates in canine implantations.

Comparison of Mechanical Stability of Elastic Titanium, Nickel-Titanium, and Stainless Steel Nails Used in the Fixation of Diaphyseal Long Bone Fractures

“…Nitinol (Nickel Titanium Naval Ordnance Laboratory) is a type of SMA and has been widely used in many implant types, such as vascular stents and memory staples [13,14], as well as in medical instruments, such as the Nitinol rod used for treating scoliosis, tissue ablation devices, and endoscopes [15,16,17]. Nitinol is the most widely used SMA in medical applications because of its excellent biocompatibility, mechanical properties, and anticorrosion ability [18,19,20].…”