The effect of completeness of revascularization during CABG with single versus multiple arterial grafts

INTRODUCTION: Incomplete coronary revascularization is associated with suboptimal outcomes. We investigated the long-term effects of Incomplete, Complete, and Supra-complete revascularization and whether these effects differed in the setting of single-arterial and multi-arterial coronary artery bypass graft (CABG). METHODS: We analyzed 15-year mortality in 7157 CABG patients (64.1 ± 10.5 years; 30% women). All patients received a left internal thoracic artery to left anterior descending coronary artery graft with additional venous grafts only (single-arterial) or with at least one additional arterial graft (multi-arterial) and were grouped based on a completeness of revascularization index (CRI = number of grafts minus the number of diseased principal coronary arteries): Incomplete (CRI ≤ -1 [N = 320;4.5%]); Complete (CRI = 0 [N = 2882;40.3%]; reference group); and two Supra-complete categories (CRI = +1[N = 3050; 42.6%]; CRI ≥ + 2 [N = 905; 12.6%]). Risk-adjusted mortality hazard ratios (AHR) were calculated using comprehensive propensity score adjustment by Cox regression. RESULTS: Incomplete revascularization was rare (4.5%) but associated with increased mortality in all patients (AHR [95% confidence interval] = 1.53 [1.29-1.80]), those undergoing single-arterial CABG (AHR = 1.27 [1.04-1.54]) and multi-arterial CABG (AHR = 2.18 [1.60-2.99]), as well as in patients with 3-Vessel (AHR = 1.37 [1.16-1.62]) and, to a lesser degree, with 2-Vessel (AHR = 1.67 [0.53-5.23]) coronary disease. Supra-complete revascularization was generally associated with incrementally decreased mortality in all patients (AHR [CRI = +1] = 0.94 [0.87-1.03]); AHR [CRI ≥ +2] = 0.74 [0.64-0.85]), and was driven by a significantly decreased mortality risk in single-arterial CABG (AHR [CRI = +1] = 0.90 [0.81-0.99]; AHR [CRI ≥ +2] = 0.64 [0.53-0.78]); and 3-Vessel disease patients (AHR [CRI = +1] = 0.94 [0.86-1.04]; and AHR [CRI ≥ +2] = 0.75 [0.63-0.88]) with no impact in multi-arterial CABG (AHR [CRI = +1] = 1.07 [0.91-1.26]; AHR [CRI ≥ +2] = 0.93 [0.73-1.17]). CONCLUSIONS: Incomplete revascularization is associated with decreased late survival, irrespective of grafting strategy. Alternatively, supra-complete revascularization is associated with improved survival in patients with 3-Vessel CAD, and in single-arterial but not multi-arterial CABG.