Do chronic total occlusive lesions affect patency of coronary bypass grafts to the right coronary artery?

Objectives: To evaluate the impact of chronic total occlusion (CTO) lesions on the patency of bypass grafts to the right coronary artery territory. Methods: Two hundred patients undergoing primary isolated coronary artery bypass grafting with revascularization to the right coronary artery territory between April 2015 and July 2022 were retrospectively analyzed. Study patients were divided into two groups according to their right coronary artery lesion: patients with CTO lesions (n = 76) and those without CTO lesions (n = 124). Graft flow of the right coronary artery territory was evaluated by intraoperative transit time flow measurement and patency of the bypass graft was evaluated by multidetector row computed tomography. Results: A total of 200 patients (76 patients with CTO and 124 patients without CTO) were included in this study. Intraoperative transit time flow measurement demonstrated that there was no significant difference in the median mean graft flow (30 ml/min vs. 25 ml/min; p = 0.114), pulsatility index (2.1 vs. 2.4; p = 0.079), and diastolic filling rate (65% vs. 64%; p = 0.844) between patients with CTO and those without CTO. Postoperative multidetector row computed tomography demonstrated that the patency of bypass grafts to the right coronary artery territory was similar between the groups (94.7% in patients with CTO vs. 96.0% in those without CTO; p = 0.733). In patients with CTO, the patency of bypass graft tended to be worse in subgroup with rich collateral blood flow (Rentrop grade 3). Conclusions: Chronic total occlusion lesions do not affect the patency of bypass grafts to the right coronary artery territory.