Weekend Operation and Outcomes of Patients Admitted for Nonelective Coronary Artery Bypass Surgery

Abstract

The "weekend effect" is a purported phenomenon whereby patients admitted for time-sensitive medical and surgical conditions on a weekend suffer worse outcomes than those admitted on a weekday. There are limited data on the weekend effect for nonelective coronary artery bypass grafting (CABG). We studied outcomes for weekend vs weekday operations for all adult patients in the 2013 to 2014 National Inpatient Sample (NIS) undergoing nonelective CABG. Of 101,510 patients undergoing nonelective CABG, 12,795 patients (12.6%) underwent CABG on the day of admission (n= 1230 for weekend and 11,565 for weekday admission, respectively). Patients undergoing surgical procedures on a weekend were more likely to have a diagnosis of ST-elevation acute coronary syndrome (47.2% vs 20.2%, P < .001), require intraaortic balloon pump support (46.3% vs 23.1%, P < .001), and undergo same-day coronary angiography (66.7% vs 41.8%; P < .001) or same-day percutaneous coronary intervention (11.8% vs 7.1%; P= .01). Weekend admission was associated with increased mortality in unadjusted analysis (6.1% vs 3.2%; odds ratio, 1.99; 95% confidence interval, 1.13-3.52; P= .02), but this effect was attenuated in the adjusted model (adjusted odds ratio, 1.22; 95% confidence interval, 0.63-2.33; P= .47). Patients undergoing CABG on a weekend had higher crude mortality but similar risk-adjusted mortality compared with their weekday counterparts. Some of the excess mortality observed for weekend operations is likely attributable to a sicker cohort of patients undergoing CABG on the weekend.