The Effects of Daytime Variation on Short-term Outcomes of Patients Undergoing Off-Pump Coronary Artery Bypass Grafting

OBJECTIVE:To evaluate the effects of time of surgery on the short-term outcomes of patients undergoing off-pump coronary artery bypass grafting (OPCABG). DESIGN:A retrospective cohort study. SETTING:A single large-volume cardiovascular center. PATIENTS:Patients undergoing elective OPCABG between September 2019 and July 2022. INTERVENTIONS:Patients were divided into the following 2 groups according to the start time of surgery: morning (AM group, before 11 AM) and afternoon (PM group, after 11 AM). Propensity-score matching (PSM) with a 1:1 matching ratio was used to create comparable cohorts. MEASUREMENTS AND MAIN RESULTS:The primary endpoint was the composite incidence of mortality and morbidities during hospitalization. Secondary endpoints included postoperative bleeding and transfusion, mechanical ventilation duration (MVD), and lengths of stay (LOS) in the intensive care unit (ICU) and hospital. From a consecutive series of 1,039 patients, PSM yielded 317 well-matched pairs. There was no difference in the composite incidence of in-hospital mortality and morbidities between the AM and PM groups (16.4% v 17.4%, p = 0.832). However, patients in the PM group were associated with less postoperative blood loss over the first 24 hours (470 v 540 mL, p = 0.002), decreased MVD (14 v 16 hours, p < 0.001), and shorter LOS in ICU (46 v 68 hours, p = 0.002) compared to patients in AM group. CONCLUSIONS:The current study suggested a lack of relevance regarding the time of surgery with in-hospital mortality and morbidities in patients undergoing OPCABG.