Impact of Left Internal Mammary Artery–to–Left Anterior Descending Artery Anastomotic Location on Graft Patency: A Secondary Analysis of the PATENCY Trial Data Set

Background The impact of the left internal mammary artery (LIMA)–to–left anterior descending artery (LAD) anastomotic location on graft patency remains uncertain. Methods This study included 1597 patients with isolated proximal LAD lesions from the PATENCY (Graft Patency Between no‐touch Vein Harvesting Technique and Conventional Approach in Coronary Artery Bypass Graft Surgery) trial who underwent coronary artery bypass grafting. The relative anastomotic site (RAS) of the LIMA–LAD anastomosis was quantified using postoperative coronary computed tomography angiography and defined as the ratio of anastomotic height/heart height. The primary end point was LIMA occlusion at 3 years, and the secondary end point was major adverse cardiac events. Multivariable logistic regression was used to evaluate the association between RAS and 3‐year LIMA occlusion, and Cox proportional hazards regression was used to evaluate associations with time‐to‐event clinical outcomes. Results The exploratory RAS threshold was 46%. Distal anastomosis (RAS >46%) was associated with a significantly lower 3‐year LIMA occlusion rate compared with proximal anastomosis (RAS ≤46%) (2.3% versus 6.3%; adjusted odds ratio, 0.37 [95% CI, 0.20–0.68]; P =0.002). At 3 years, major adverse cardiac event rates were similar between groups (3.4% versus 4.4%; adjusted hazard ratio, 0.68 [95% CI, 0.40–1.15]; P =0.16). Conclusions In patients with isolated proximal LAD disease, a more distal LIMA–LAD anastomotic location may be associated with a lower risk of graft occlusion at 3 years. Further prospective validation is warranted.