We evaluated the predictors of in-stent restenosis (ISR) and the angiographic patterns for ostial lesions of the right coronary artery (RCA) to better identify this population at risk.

Although the prevalence of ISR of the RCA is diminishing, the mechanisms of restenosis are still unknown.

Between January 2003 and December 2017, we recruited 550 consecutives patients undergoing a coronarography for ostial lesion of RCA. 149 angioplasties are realized for acute coronary syndrome (ACS) or stable angina. Restenosis, defined as a stenosis within 5mm distance, proximal or distal to the previously placed stent, with ≥ 50% diameter stenosis, appeared for 46 patients. These patients were included in the IRS+ group. We defined also an IRS- group composed by 44 patients without restenosis in the initial population. We used Chi square test and Mann Whitney test for univariable analysis of ISR predictors. Multiple logistic regression analysis was used to determine the independent factors of ISR, and the adjusted odds ratios (aOR) and 95% confidence intervals (95% CI) were calculated.

We diagnosed 46 of 149 patients with RCA-ISR, which were classifiable between 19,8% of restenosis in case of implantation of a drug-eluting stent (DES) and 53,6% of restenosis in case of bare metallic stent (BMS). By univariable analysis we found 7 statistically significant predictors of ISR in our population: mono-troncular lesions, ad-hoc angioplasty, BMS stenting, guiding-catheter diameter, early generation DES, post-dilatation, anti-platelet drugs. After multivariable analysis, ad-hoc angioplasty and the BMS stenting were the only independent predictors of ISR (aOR, 0.23; 95% CI, 0.39–0.58; P=0.009 and respectively aOR, 0.21; 95% CI, 0.39–0.55; P=0.002) (Fig. 1).

We found a high prevalence of RCA-ISR in our study population. The risk of ISR is higher in patients with ad-hoc angioplasty or in case of BMS implantation.