Abstract
IMPORTANCE: Multiarterial coronary bypass procedures offer improved clinical outcomes compared with single arterial grafting with supplementary saphenous vein grafts. However, the survival advantage of multiarterial grafting across varying levels of left ventricular impairment remains uncertain. OBJECTIVE: To compare long-term survival outcomes of patients undergoing multiple vs single arterial grafting, stratified by preoperative ejection fraction. DESIGN, SETTING, AND PARTICIPANTS: A complete-case retrospective cohort study was conducted using data from a multicenter population-based cardiac registry established by the Australian & New Zealand Society of Cardiac & Thoracic Surgeons with linkage to the National Death Index. Participants were individuals who underwent primary isolated coronary bypass surgery between June 1, 2001, and January 31, 2020. Exclusion criteria were nonadults, reoperations, concomitant or previous cardiac surgical procedures, single-graft procedure, and cases without any arterial grafts. Statistical analyses were conducted in September 2024. EXPOSURES: Patients underwent either multiple or single arterial grafting, stratified by their preoperative left ventricular ejection fraction. MAIN OUTCOMES AND MEASURES: Long-term all-cause mortality. RESULTS: The study included 59 641 patients (mean [SD] age at the time of surgery, 65.8 [10.2] years; 48 321 men [81.0%]). The median follow-up duration was 5.0 years (IQR, 2.3-8.6 years). Multiarterial grafting was associated with a 19.0% relative reduction in all-cause mortality compared with single arterial grafting among patients with a normal left ventricular ejection fraction (hazard ratio [HR], 0.81; 95% CI, 0.75-0.87; P < .001). Similar survival benefits were observed among patients with mild (HR, 0.83; 95% CI, 0.77-0.90; P < .001), moderate (HR, 0.82; 95% CI, 0.74-0.90; P < .001), and severe left ventricular impairment (HR, 0.82; 95% CI, 0.71-0.96; P = .01). A multivariable Cox proportional hazards regression interaction-term analysis indicated no significant differences in the multiarterial survival benefit by ejection fraction stratification (P = .75). Multiarterial grafting with exclusively arterial conduits was associated with enhanced survival benefits compared with other multiarterial procedures with saphenous vein grafts, except when the left ventricular ejection fraction was below 30% (HR, 0.87; 95% CI, 0.67-1.13; P = .30). CONCLUSIONS AND RELEVANCE: In this retrospective cohort study using data from a binational database, multiarterial procedures were associated with reduced long-term mortality risk compared with single arterial grafting across the spectrum of preoperative left ventricular ejection fractions. Total arterial revascularization was associated with incrementally improved survival, particularly among patients with preserved ejection fraction. Because most coronary surgery practice continues to use single arterial grafting, consideration to alter grafting strategy to multiarterial procedures may be indicated.