Angiographic and histological results following implantation of a novel stent-on-a-wire in the animal model

Aims: The Svelte Stent-On-A-Wire (SOAW) is a thin strut novel device consisting of a balloon-expandable cobalt-chromium stent premounted onto a single lumen fixed-wire delivery catheter platform. We evaluated the performance of the novel Svelte SOAW in comparison with the MultiLink Vision (ML Vision) balloon-expandable stent, in porcine coronary arteries. Methods and results: Eight Yorkshire swine (30-day follow-up cohort) and eight Yucatan mini-swine (90-day follow-up cohort) were implanted with either Svelte or control ML Vision. Acute performance characteristics were graded by interventionalists during implantation. Angiographic assessments were performed at the index procedure and at 30 or at 90 days post implantation. Scanning electron microscopy (SEM), histological and histomorphometric analysis of stented segments were performed after angiographic follow-up. Acute implantation performance was similar between the two stents; however, deflation time was significantly lower in the Svelte stent group (Svelte 4.70 +/- 0.93 s vs. ML Vision 9.56 +/- 0.96 s, p <0.05). Angiographic late loss was similar for both stents at 30 (Svelte 0.83 +/- 0.59 mm vs. ML Vision 0.88 +/- 0.71 mm, p=0.969) and at 90 days (Svelte 0.76 +/- 0.35 mm vs. ML Vision 0.83 +/- 0.35 mm, p=0.679). SEM analysis showed complete endothelialisation at 30 days in both stent types. Histopathological assessment demonstrated minimal injury and inflammation at 30 and 90 days with Svelte and ML Vision stents as well as similar endothelialisation, neointimal maturation, adventitial fibrosis and neointimal fibrin. No evidence of in-stent thrombus was reported in either stent group. Histomorphometric analysis showed no differences between the two groups in lumen, stent, media or neointimal areas at either 30 or 90 days post implantation. Conclusions: At 30 and 90 days after implantation in porcine coronary arteries, the Svelte Stent-On-A-Wire showed vascular healing and tissue response equivalent to that observed with ML Vision stent.