Hijazi RM, Sessler DI, Liang C, et al. - Among adults who underwent aortic and/or mitral valve repair/replacement and/or coronary artery bypass grafting from 2011 to 2018, this study was conducted to determine if mortality and cardiac complications, particularly low cardiac output syndrome, vary for morning and afternoon cardiac surgeries. A comparison was performed between patients who had aortic cross-clamping between 8 and 11 am (morning surgery) vs between 2 and 5 pm (afternoon surgery). In 2.8% (195 of 6,859) of morning patients and 3.4% (97 of 2,875) of afternoon patients, occurrence of composite of in-hospital mortality and low cardiac output syndrome was evident: morning vs afternoon confounder-adjusted odds ratio was estimated to be 0.96. Overall, findings revealed that outcomes did not differ significantly between morning and afternoon cardiac surgeries among patients receiving aortic valve surgery, mitral valve surgery, and/or coronary artery bypass grafting with aortic cross-clamping. Experts found no evidence to indicate that postoperative risk is altered by morning or afternoon surgical timing.