The Influence of Stent Design on Neointimal Hyperplasia of an Aortic Stent Covering the Visceral Arterial Ostia: An Experimental Study in Dogs Using a Self-expandable Nitinol Stent

ABSTRACT

PURPOSE: To assess the influence of stent design [interlacing (type A) vs. crossing method (type B)] on neointimal hyperplasia using a self-expandable nitinol stent, which crosses the side branches of the abdominal aorta. MATERIALS AND METHODS: In seven mongrel dogs, nitinol stents with type A and B intersections were placed in the abdominal aorta across the main branches 4 Niti-Ms and 3 Niti-Ds. Two months after the stent placement, a DSA was performed for a stent patency evaluation, followed by the extraction of the aortas. The degree of neointimal formation along the wire was evaluated by calculating the area ratio of intimal hyperplasia (type A vs. B). A Student's t-test was employed to investigate the differences in the neointimal hyperplasia between blood types A and B. RESULTS: The total number of wire intersections overlain at the ostia branch ostia was 23 for type A and 36 for type B. The area ratio of the neointimal hyperplasia, for a given area, was 29.09+/-10.82% (type A) and 13.80+/-6.94% (type B) (p < 0.0001)]. Furthermore, the area ratios of the neointimal hyperplasia per area of stent-wire in the given area were 138.38+/-10.84% (type A), 87.58+/-7.36% (type B) (p = 0.0002). CONCLUSION: In conclusion the interlacing pattern vs. the crossing pattern showed a higher level of neointimal formation than the crossing pattern.