Priorities in coronary artery bypass grafting: Is midterm survival more dependent on completeness of revascularization or multiple arterial grafts?

OBJECTIVE: Both completeness of revascularization and multiple arterial grafts (multiple arterial coronary artery bypass grafting) have been associated with increased midterm survival after coronary artery bypass grafting. The purpose of this study was to evaluate the relative impact of completeness of revascularization and multiple arterial coronary artery bypass grafting on midterm survival after coronary artery bypass grafting.
METHODS: A retrospective review of 17,411 isolated, primary coronary artery bypass grafting operations from January 2002 to June 2016 at a US academic institution was performed. Patients were divided into groups based on complete or incomplete revascularization and number of arterial grafts. Inverse probability of treatment weighting based on the generalized propensity score was performed to minimize imbalance in preoperative characteristics. Between-group differences in outcomes were assessed using multivariable logistic and Cox regression analyses, incorporating the propensity score weights.
RESULTS: Patients undergoing multiple arterial coronary artery bypass grafting in this study were younger, had fewer comorbid conditions, and had lower incidence of left main stenosis compared with patients undergoing single-arterial coronary artery bypass grafting. Short-term perioperative outcomes were similar between groups once propensity score weighting was used to minimize between-group differences in preoperative variables. Median follow-up in the entire population was 630 days, but was 1366 days in the cohort with data available from the Social Security Death Index. Multiple arterial coronary artery bypass grafting was protective for midterm survival compared with single arterial coronary artery bypass grafting, regardless of complete or incomplete revascularization or strategy (multiple arterial complete revascularization vs single-arterial complete revascularization: hazard ratio, 0.82; 95% confidence interval, 0.69-0.97; P = .02; multiple arterial incomplete revascularization vs single-arterial incomplete revascularization: hazard ratio, 0.70; 95% confidence interval, 0.53-0.90; P = .007).
CONCLUSIONS: After controlling for preoperative comorbidities, multiple arterial coronary artery bypass grafting provides a modest midterm survival benefit over single-arterial coronary artery bypass grafting irrespective of completeness of revascularization, suggesting that when forced to choose, surgeons may elect to pursue multiple arterial conduits.