The Effects of Daytime Variation on Short-Term Outcomes of Cardiac Surgical Patients: A PRISMA-Compliant Systemic Review and Meta-Analysis.

OBJECTIVE

Circadian rhythms influence cardiovascular physiology and surgical stress responses, raising the possibility that the timing of cardiac surgery may affect outcomes. Previous studies have reported conflicting results regarding whether morning (AM) versus afternoon (AF) surgery influences perioperative morbidity and mortality. The present study aimed to systematically evaluate whether the timing of cardiac surgery, specifically AM versus AF procedures, influences short-term outcomes.

DESIGN

A meta-analysis of observational cohort studies.

SETTINGS: Cardiovascular centers.

PARTICIPANTS

Patients who underwent elective cardiac surgery.

INTERVENTIONS: The AM or the AF group.

MEASUREMENTS: The primary outcome was hospitalized mortality. Secondary outcomes included major morbidities (new-onset atrial fibrillation, myocardial infarction, stroke, renal and infectious complications, reexploration, mechanical circulatory support) and postoperative recovery profiles (mechanical ventilation duration, length of stay [LOS] in the intensive care unit and hospital).

MAIN

RESULTS

Fourteen observational studies involving 135,672 patients (81,391 in the AM group and 54,281 in the AF group) were included. Pooled analysis showed no significant difference in hospitalized mortality between the two groups (1.25% [998/79,550] v 1.17% [615/52,442], OR = 1.09, 95% CI = 0.99 to 1.21; p = 0.08]. The incidences of myocardial infarction, stroke, renal and infectious complications, reexploration, and mechanical circulatory support use were also comparable. However, AM surgery was associated with a modestly higher incidence of new-onset atrial fibrillation (26.05% [2,319/8,907] v 25.50% [1,000/3,921], OR = 1.11, 95% CI = 1.01 to 1.21; p = 0.03). No significant differences were observed in mechanical ventilation duration [MD = -0.20 hours, 95% CI = -0.40 to 0.00; p = 0.05], intensive care unit LOS [MD = -0.35 hours, 95% CI = -6.14 to 5.43; p = 0.90], or hospital LOS [MD = -0.10 days, 95% CI = -0.39 to 0.19; p = 0.49].

CONCLUSIONS

These findings suggest that circadian influences on elective cardiac surgical outcomes are limited. Future multicenter prospective studies are warranted to further define the role of surgery timing in high-risk populations.