Competitive Flow of Terminal Anastomosis to Right Coronary Territory in "Y" Coronary Artery Bypass

Abstract

BACKGROUND We evaluated the prevalence and outcomes of competitive flow in the terminal right coronary artery (RCA) graft after coronary artery bypass grafting (CABG) with left internal thoracic artery-based Y-composite grafting at 1 year after CABG. METHODS We enrolled 642 patients who underwent Y-composite graft-based off-pump CABG with in situ left internal thoracic artery between 2014 and 2022. All patients underwent early postoperative angiography, and 1-year postoperative angiography was performed in 81.2% (522/642) of patients. RESULTS The early occlusion rate of distal anastomoses with Y-composite graft was 2.1%. Competitive flow was observed in 69 of 642 anastomoses (10.7%). Multivariate analysis showed that the maximal degree of target vessel stenosis (odds ratio [OR], 0.909; 95% CI, 0.886-0.931; P < .001), maximal degree of non-terminal target vessel in Y-arm grafts (OR, 1.103; 95% CI, 1.047-1.172; P < .001), and diabetes mellitus (OR, 0.535; 95% CI, 0.303-0.934; P = .029) were factors associated with competitive flow to the RCA territory. The optimal cutoff value for the degree of terminal target vessel stenosis predicting competitive flow to the RCA territory was 92.5%. The 1-year graft failure rate of anastomoses with competitive flow of the terminal anastomosis was 30.9% (17/55). The presence of competitive flow on early angiography was the only factor associated with graft occlusion of the terminal anastomosis at 1 year (OR, 2.339; 95% CI, 1.165-4.481; P = .013). CONCLUSIONS For terminal anastomosis to the RCA territory in Y-composite graft-based CABG, the presence of competitive flow on early angiography was associated with graft occlusion of the terminal anastomosis at 1 year. Notably, 30.9% of these grafts demonstrated failure on 1-year follow-up angiography.