6-MONTH CLINICAL AND ANGIOGRAPHIC OUTCOME OF THE NEW, LESS SHORTENINGWALLSTENT IN NATIVE CORONARY-ARTERIES

Background The new, less shortening, self-expanding Wallstent is chara cterized by longitudinal flexibility, a protective membrane, a low pro file, and a customized range of diameters (3.5 to 6.0 mm). The recent modification of the braiding angle of the Wallstent has resulted in a new device with less shortening on expansion and a concomitant reducti on in radial force. We hypothesized that the enforced mechanical remod eling produced by the selection of an oversized Wallstent might result in improved accommodation of subsequent reactive intimal hyperplasia and prevention of chronic recoil of the vessel. Methods and Results To prove this hypothesis, we recently implanted 44 new, less shortening Wallstents in 35 native coronary arteries in 35 patients with acute or threatened closure after balloon angioplasty, according to a strategy of oversizing of Wallstent diameter and complete coverage of the lesi on length. The initial and B-month follow-up angiograms were analyzed with a computer-based quantitative coronary angiography (QCA) system. Acute gain (minimal luminal diameter [MLD] post minus MLD pre) and lat e loss (MLD post minus MLD at follow-up) were examined. Stent deployme nt was successful in 44 of 44 attempts (100%). Nominal stent diameter used was 1.40 mm larger than the maximal vessel diameter. One patient (3%) with a dilated but unstented lesion proximal to the stented segme nt sustained a subacute occlusion on day 1 associated with myocardial infarction. Event-free survival at 30 days after stent implantation wa s 97% (34 of 35 patients). Of the 34 patients eligible for 6-month ang iographic follow-up, 3 who were asymptomatic declined repeat angiograp hy. MLD (and percent diameter stenosis [% DS]) changed from 0.83+/-0.5 0 mm (72%) pre through 3.06+/-0.48 mm (15%) post to 2.27+/-0.74 mm (28 %) at follow-up. Acute gain was 2.23+/-0.63 mm, and late loss was 0.78 +/-0.61 mm. Angiographic restenosis (>50% DS) was observed in 5 of 31 patients (16%) at 6 months, all of whom underwent repeat angioplasty. Thus, the overall event-free survival at 6-month follow-up was 83% (29 of 35 patients). Conclusions The oversized Wallstent implantation wit h complete coverage of the lesion length conveyed a favorable B-month clinical and angiographic outcome. The large acute gain obtained by th e Wallstent afforded greater accommodation of the subsequent late loss . The enforced mechanical remodeling by oversized new Wallstents may r esult in prevention of acute and chronic recoil of the vessel wall and subsequently a lower restenosis rate at follow-up.