Impact of coronary collateral circulation on angiographic in-stent restenosis in patients with stable coronary artery disease and chronic total occlusion.

Objective: This study aimed to evaluate the relationship between coronary collateralization and in-stent restenosis (ISR) in stable coronary artery disease patients with chronic total occlusion (CTO) after percutaneous coronary intervention (PCI) with drug-eluting stent (DES) implantation.

Methods: The degree of coronary collaterals supplying the distal aspect of a total occlusion from the contra-lateral vessel was graded according to Rentrop classification in 216 patients with stable angina undergoing successful DES based PCI for CTO. Univariable and multivariable logistic regression analyses were performed to assess the potential factors related to angiographic ISR during follow-up.

Results: Despite similar number of diseased coronary arteries, good collateralization (Rentrop score 2 or 3) was more frequently associated with right coronary artery occlusion (60%), whereas poor collaterals (Rentrop score 0 or 1) occurred more often in left anterior descending artery occlusion (40%). Despite similar number of CTO intervened, stent length was longer in patients with good collateralization (59±27mm vs 47±23mm, p=0.001). At mean 18months, the rate of ISR did not significantly differ between patients with good collateralization and those with poor collateralization (12.7% vs 20.2%, p=0.148). At multivariable analysis, age (OR 1.058, 95%CI 1.015-1.104, p=0.008), history of diabetes mellitus (OR 2.382, 95%CI 1.109-5.116, p=0.026) and reference CTO vessel diameter (OR 0.219, 95% CI 0.051-0.951, p=0.043) were independent risk factors for ISR while Rentrop collateral grade (OR 0.795, 95% CI 0.365-1.732, p=0.414) was not associated with ISR.

Conclusions: The occurrence of ISR after successful DES based PCI for CTO may be not influenced by coronary collateralization.