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.