Objectives. This study was designed to examine whether oversized implantation of the new, less shortening Wallstent provides a more favorable long-term clinical and angiographic outcome in chronic total occlusions than does conventional coronary balloon angioplasty. Background. Restenosis and reocclusion remain major limitations of balloon angioplasty for chronic total occlusions. Enforced mechanical remodeling by implantation of the oversized Wallstent may prevent elastic recoil and improve accommodation of intimal hyperplasia. Methods. Lumen dimension was measured by a computer- based quantitative coronary angiography system (CAAS II). These measurements (before and after intervention and at 6-month follow-up) were compared between the groups with Wallstent implantation (20 lesions, 20 patients) and conventional balloon angioplasty (266 lesions, 249 patients) for treatment of chronic total occlusion. Acute gain (minimal lumen diameter after intervention minus that before intervention), late loss (minimal lumen diameter after intervention minus that at follow-up) and net gain (acute gain minus late loss) were examined. Results. Wallstent deployment was successful in all patients. High pressure intra-Wallstent balloon inflation (mean ± SD 14 ± 3 atm) was performed in all lesions. Although vessel size did not differ between the Wallstent and balloon angioplasty groups, acute gain was significantly greater in the Wallstent group (2.96 ± 0.55 vs. 1.61 ± 0.34 mm, p < 0.0001). Although late loss was also significantly larger in the Wallstent group (0.81 ± 0.95 vs. 0.43 ± 0.68 mm, p < 0.05), net gain was still significantly greater in this group (2.27 ± 1.00 vs. 1.18 ± 0.69 mm, p < 0.0001). Angiographic restenosis (≤50% diameter stenosis) occurred at 6 months in 29% of lesions in the Wallstent group and in 45% of those in the balloon angioplasty group (p = 0.5150). Conclusions. Implantation of the oversized Wallstent, with full coverage of the lesion length, ensures resetting of the vessel size to its original caliber before disease and allows greater accommodation of intimal hyperplasia and chronic vessel recoil. Wallstent implantation provides a more favorable short- and long- term clinical and angiographic outcome than does conventional balloon angioplasty for chronic total occlusions.
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