Impact of Stent-to-Vessel Diameter Ratio on Restenosis in the Superficial Femoral Artery After Endovascular Therapy

Background: Although stent-to-vessel (S/V) diameter ratio has been described as a restenotic factor after superficial femoral artery (SFA) stenting, the reference vessel diameter is commonly measured distally at a healthy site. It remains unclear whether S/V ratio assessed at the lesion site would be more predictive than that assessed distally at a healthy site. Methods and Results: A total of 117 patients (mean age, 73 +/- 7 years; 74% male) who underwent successful nitinol stent implantation in SFA lesions (mean lesion length, 172 +/- 104 mm) on intravascular ultrasound (IVUS) were retrospectively analyzed. S/V ratio at the proximal and distal healthy site, and at the smallest lesion site, was evaluated on IVUS. One-year restenosis predictors were evaluated on multivariate analysis. Mean S/V diameter ratio on IVUS at proximal and distal healthy sites, and at the lesion site, was 0.98 +/- 0.11, 1.02 +/- 0.11 and 1.15 +/- 0.16, respectively. One-year primary patency was 77%. On multivariate analysis, lesion length (OR, 1.06 per 10-mm increment; P=0.046) and S/V ratio measured at the lesion site (OR, 1.34 per 0.1 increment; P=0.032), but not that at the distal healthy site (OR, 1.05 per 0.1 increment; P=0.705), were significantly associated with 1-year restenosis. Conclusions: S/V ratio assessed on IVUS at the lesion site, but not at the distal healthy site, was independently associated with 1-year restenosis after SFA stenting.