In-stent restenosis in small coronary arteries: impact of strut thickness

OBJECTIVES; We sought to evaluate whether strut thickness may impact the restenosis rate after stent implantation in small coronary arteries.

Small vessel size (<3.0 mm) is an independent risk factor for the occurrence of in-stent restenosis. It has been reported that vessel damage induced during stent deployment is an important factor in restenosis.

From our database, we selected all patients who had successful stenting in small native vessels, with angiographic follow-up available, between March 1996 and April 2001. The strut was defined as thin when <0.10 mm and thick when > or = 0.10 mm. According to these criteria, we identified two subgroups: a thin group and a thick group.

A total of 821 (57%) of the 1,447 patients had angiographic follow-up available and were included in the analysis. The thin group included 400 patients with 505 lesions. The thick group included 421 patients with 436 lesions. The restenosis rate was 28.5% in the thin group and 36.6% in the thick group (p = 0.009; odds ratio [OR] 1.44, 95% confidence interval [CI] 1.09 to 1.90). The study group was classified into three subgroups according to the reference vessel diameter: < or = 2.50 mm, 2.51 to 2.75 mm and 2.76 to 2.99 mm. Strut thickness influenced the restenosis rate only in the subgroup with a reference vessel diameter between 2.76 and 2.99 mm, with rates of 23.5% in the thin group and 37% in the thick group (p = 0.006). By logistic regression analysis, predictors of restenosis were stent length (OR 1.03, 95% CI 1.01 to 1.04; p = 0.001), strut thickness (OR 1.68, 95% CI 1.23 to 2.29; p = 0.001) and diabetes mellitus (OR 2.10, 95% CI 1.21 to 3.68; p = 0.007).

This study supports that strut thickness is an independent predictor of restenosis in coronary arteries with a reference diameter of 2.75 to 2.99 mm.