Association between the weekday on which coronary artery bypass graft surgery is performed and the 30-day mortality: A nationwide cohort study in South Korea.

Abstract

Postoperative mortality associated with elective coronary artery bypass graft (CABG) surgery may reportedly increase as the weekday of surgery approaches the weekend. We aimed to investigate the potential effect of the weekday of CABG surgery on the 30-day mortality. This population-based cohort study analyzed data obtained from the South Korea national health insurance service database. The cohort included all adult patients diagnosed with ischemic heart disease (International Classification of Diseases-10 codes I20*-I25*) who underwent isolated and elective CABG surgery from January 2012 to December 2017. Of the 13,556 patients included in the analysis, 595 (4.4%) died within 30 days after CABG surgery. In a multivariable Cox model, the 30-day mortality of patients who underwent CABG surgery later in the week (Wednesday-Friday) was not significantly associated with the weekday of surgery as similar to those who underwent surgery early in the week (Monday-Tuesday)(hazard ratio [HR]: 1.14, 95% confidence interval [CI]: 0.97-1.34; p = .109). Multivariable sensitivity analysis revealed that CABG surgery on Friday was associated with a 1.40-fold higher hazard of 30-day mortality (HR: 1.40; 95% CI: 1.09-1.80; p = .008) than CABG surgery on Monday. This South Korean population-based cohort study revealed that relative to surgery early in the week (Monday-Tuesday), CABG surgery later in the week (Wednesday-Friday) was not associated with higher 30-day mortality. However, using surgery on Monday as a reference, CABG surgery on Friday was associated with higher 30-day mortality. Future studies must confirm these findings.