Outcomes of non-elective coronary artery bypass grafting performed on weekends

OBJECTIVES: A weekend effect with increased mortality has previously been reported in surgical patients and those with acute myocardial infarction (MI). We hypothesized that a similar phenomenon may exist in coronary artery bypass grafting (CABG). METHODS: Patients undergoing non-elective isolated CABG (2011-2017) were included from a multicentre regional Society of Thoracic Surgeons database. Patients were stratified by weekend versus weekday operations and further analysed by specific day of the week. RESULTS: A total of 14 374 patients underwent urgent or emergency isolated CABG with 410 (2.9%) operated on over the weekend. Weekend operations were more often emergency (36.1% vs 5.0%, P < 0.001) and more likely to be in the setting of MI (70.0% vs 51.2%, P < 0.001). Cardiopulmonary bypass times were similar [91 min (71-114) vs 94 min (74-117), P = 0.0749] and the frequency of complete revascularization equivalent (83.4% vs 85.3%, P = 0.284) between weekend and weekday operations. In risk-adjusted analyses, there was no increased odds for mortality in patients operated on over the weekend [odds ratio (OR) 1.07, P = 0.811]; however, there was an increased odds of major morbidity (OR 1.37, P = 0.034). Furthermore, compared with Monday, morbidity increased as the operative day approached the weekend (Tuesday 0.98, P = 0.828; Wednesday 1.07, P = 0.469; Thursday 1.12, P = 0.229; Friday 1.19, P = 0.041; weekend 1.47, P = 0.014). CONCLUSIONS: While patients requiring surgery on the weekend are higher risk, there is no independent effect of weekend surgery on mortality. However, these patients are at increased risk for major morbidity, the causes of which require further investigation.