Coronary Less Shortening Wallstent in the Long Lesion of Coronary Artery Disease: 6 Months Follow-up Results

Lee, Namho; Jang, Yangsoo; Hong, Bumkee; Choi, Donghoon; Ha, Jongwon; Rim, Sejoong; Kim, Taeyong; Shim, Wonheum; Cho, Seungyun

Abstract

BACKGROUND
Despite of the first coronary wallstent implantation ushered in the new era in interventional cardiology with the purpose of circumventing the two major limitation of coronary balloon angioplasty, early acute occlusion and late restenosis, however, previous investigators suggested the high rate of subacute occlusion after original wallstent implantation. Recently the low incidence of the subacute closure and restenosis rate with the newely modified less shortening coronary wallstent in native coronary artery and in aortocoronary vein grafts were reported. In this study we report the acute and 6 months follow up results with less shortening coronary wall stent in 32 patients.
METHODS
Thirty two patients were enrolled from March 1996 through February 1997 at the Yonsei cardiovascular center of Yonsei University. The specific angiographic criteria for enrollment included at least 70% stenosis and a lesion that was 20mm or more in length and a vessel diameter of at least 2.5mm. Enteric coated aspirin(100mg daily) and ticlopidine(500mg daily) at least 3 days before the procedure and received continuous infusion of 24,000U of heparin for 1day after the procedure. Angiography was performed in two orthogonal views at pre, post procedure and 6months later. Quantitative analysis was performed with the use of the electronic caliper comparing to the empty catheter. All continuous variables were expressed as mean SD and analyzed with the t-test. Differences between groups were analyzed with Chi-square analysis and Fishers Exact test where appropriate.
RESULTS
The newly modified Coronary Less Shortening Wallstents were successfully implanted in all the 35 diffuse coronary lesions(more than 20mm in length) of the 32 patients, including 15 pts of acute myocardial infarction, 14 pts of unstable angina, and 3 pts of stable angina. Average 6 months follow up angiography was performed in 26 patients. Immediate angiographic results with Less Shortening Wallstent comparing with 6 months follow up were 3.0+/-0.4mm and 1.7+/-0.9mm in minimal luminal diameter(MLD), 5.1+/-9.1% and 46.8+/-25.8% in diameter stenosis(DS). During the in-hospital phase, no major cardiac event occurred except 2 cases of transmural myocardial infarction, including one of stent thrombosis(3.1%) and one of side branch occlusion, despite of inclusion of 7 cases of threatened occlusion in the long lesion. The restenosis rate at follow up angiography was 30.7%(8/26 pts). The restenosis rate was higher in patients with stent insertion into right coronary artery or adjuvant high pressure oversize ballooning after stent insertion but not statistically significant.
CONCLUSIONS
The results of this study suggested that new Less Shortening Wallstent might reduce the requirement of multiple stent in the long lesion and a lower rate of subacute thrombotic occlusion in comparison to the reports with its prototype. Restenosis rate was not significantly different from other types of stents. Althouth the restenosis rate was high in patients with stent insertion, there was no statistical significance probably due to small sample size. But further large scale long term follow-up study is needed to evaluate the role of new Less Shortening Wallstent.