Results of the quantitative coronary angiographic analysis in the angiographic subgroup of the Multi-Link 2.5 Portuguese Registry.

INTRODUCTION: The restenosis rate of stents implanted into small coronary arteries is considered higher than that of stents in arteries > or = 3 mm, but could be influenced by clinical parameters and by the type and length of the stents. OBJECTIVE: To assess the incidence of angiographic restenosis at 6 months after implantation of 2.5 mm ACS RX Multi-Link (ML) stents, 15 and 25 mm length, in de novo coronary stenosis. DESIGN: Angiographic substudy of the Portuguese Multi-Link 2.5 Registry, which included Interventional Cardiology centers with facilities for coronary angiographic recordings allowing quantitative analysis. POPULATION: Between April 7 and November 20 1998 and in the 5 hospitals that agreed to participate, 61 patients were enrolled and 40 selected as having procedural and 6-month angiographies of sufficient quality for quantitative analysis. The only significant differences in the demographic, clinical and angiographic characteristics of the patients relative to those of the Registry were the lower prevalence of unstable angina and smoking in the angiographic substudy. There were 43 lesions and 46 ML stents were implanted. In 37% the lesions were located in the LAD, in 37% in the LCx and 26% in the RCA. 29 stents of 15 mm length and 17 stents of 25 mm were used. METHODS: The morphologic characteristics of the lesions were analyzed subjectively using the AHA/ACC classification. Quantitative coronary analysis (QCA) was performed, in an independent laboratory using the CAAS 2 system, for reference vessel diameter, lesion length, percentage of stenosis, minimum lumen diameter (MLD) and related parameters. Restenosis was defined as > or = 50% lumen obstruction at 6-month angiography. RESULTS: In the subjective analysis, 2 lesions were type B1, 27 type B2 and 14 type C. The overall restenosis rate was 32.6%. Restenosis was 27.7% for 15 mm stents and 36% for 25 mm stents (p = 0.4). For the QCA parameters analyzed, only MLD at the end of stent implantation was a predictor of 6-month restenosis (2.19 +/- 0.30 without vs. 2.03 +/- 0.18 with restenosis, p = 0.048). CONCLUSIONS: The restenosis rate of the Multi-Link 2.5 mm stents, of 15 and 25 mm length, was similar to that described with other types of stents in small coronary arteries. Minimum lumen diameter after stenting was found to be the best predictor of 6-month restenosis.