ObjectiveTo discern the impact of depressed left ventricular ejection fraction (LVEF) on the outcomes of open descending thoracic aneurysm (DTA) and thoracoabdominal aneurysms (TAAA) repair. MethodsRestricted cubic spline analysis was used to identify a threshold of LVEF, which corresponded to an increase in operative mortality and major adverse events (MAE: operative death, myocardial infarction, stroke, spinal cord injury, need for tracheostomy or dialysis). Logistic and Cox regression were performed to identify independent predictors of MAE, operative mortality, and survival. ResultsDTA/TAAA repair was performed in 833 patients between 1997 and 2018. Restricted cubic spline analysis showed that patients with LVEF <40% (n = 66) had an increased risk of MAE (odds ratio [OR], 2.17; 95% confidence interval [CI], 1.22-3.87; P < .01) and operative mortality (OR, 2.72; 95% CI, 1.21-6.12; P = .02) compared with the group with LVEF ≥40% (n = 767). The group with LVEF <40% had a worse preoperative profile (eg, coronary revascularization, 48.5% vs 17.3% [P < .01]; valvular disease, 82.8% vs 49.39% [P < .01]; renal insufficiency, 45.5% vs 26.1% [P < .01]; respiratory insufficiency, 36.4% vs 21.2% [P = .01]) and worse long-term survival (35.5% vs 44.7% at 10 years; P = .01). Nonetheless, on multivariate regression, depressed LVEF was not an independent predictor of operative mortality, MAE, or survival. ConclusionsLVEF is not an independent predictor of adverse events in surgery for DTA.