SHORT-TERM AND LONG-TERM CLINICAL AND QUANTITATIVE ANGIOGRAPHIC RESULTS WITH THE NEW, LESS SHORTENING WALLSTENT FOR VESSEL RECONSTRUCTION IN CHRONIC TOTAL OCCLUSION - A QUANTITATIVE ANGIOGRAPHIC STUDY

Objectives. This study was designed to examine whether oversized impla ntation of the new, less shortening Wallstent provides a more favorabl e long-term clinical and angiographic outcome in chronic total occlusi ons than does conventional coronary balloon angioplasty. Background. R estenosis and reocclusion remain major limitations of balloon angiopla sty for chronic total occlusions. Enforced mechanical remodeling by im plantation of the oversized Wallstent may prevent elastic recoil and i mprove accommodation of intimal hyperplasia. Methods. Lumen dimension mas measured by a computer-based quantitative coronary angiography sys tem (CAAS II). These measurements (before and after intervention and a t 6-month follow-up) were compared between the groups with Wallstent i mplantation (20 lesions, 20 patients) and conventional balloon angiopl asty (266 lesions, 249 patients) for treatment of chronic total occlus ion. Acute gain (minimal lumen diameter after intervention minus that before intervention), late loss (minimal lumen diameter after interven tion minus that at follow-up) and net gain (acute gain minus late loss ) were examined. Results. Wallstent deployment was successful in all p atients. High pressure intra-Wallstent balloon inflation (mean +/- SD 14 +/- 3 atm) was performed in all lesions. Although vessel size did n ot differ beta een 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 signifi cantly 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 resteno sis (greater than or equal to 50% diameter stenosis) occurred at 6 mon ths in 29% of lesions in the Wallstent group and in 45% of those in th e balloon angioplasty group (p = 0.5150). Conclusions. Implantation of the oversized Wallstent, with full coverage of the lesion length, ens ures resetting of the vessel size to its original caliber before disea se 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 convention al balloon angioplasty for chronic total occlusions.