National trends in emergency coronary artery bypass grafting

Emergency coronary artery bypass grafting (CABG) is often omitted from current research, and volumes as well as outcomes are unknown. The purpose of this research is to examine national trends in emergency CABG.

The Society of Thoracic Surgeons national adult cardiac surgical database was queried from 2005 to 2017 for patients who underwent emergency and emergency salvage isolated CABG procedures, and 92 607 patients were included for analysis. Generalized linear mixed models were used to assess time trends, taking into account the clustering effect of region.

Over the study period, volumes of emergency and emergency salvage CABG declined from 7991 to 6916 cases/year. Emergency and emergency salvage cases accounted for ∼4.9% of all CABG procedures performed nationwide in 2005 and 4.1% in 2017. The predicted risk of mortality (PROM) declined in the entire patient cohort over time from 12% to 8% (P < 0.0001). Rates of important postoperative morbidities also declined including prolonged intubation, re-exploration for haemorrhage and postoperative pneumonia (P < 0.001). Observed-to-expected mortality rates rose over the study period from 0.81 to 1.06 as the overall PROM declined from 9.3% to 7.6%. Emergency salvage CABG rates also declined over the course of the study from 358 to 323 cases/year. The observed-to-expected ratios for mortality increased for emergency salvage CABG during the study from 1.16 to 1.66, and emergency salvage mortality rates averaged 46.5%.

The volume of patients undergoing emergency and emergency salvage CABG in the USA has declined. Increases in mortality are largely driven by emergency salvage cases, and the PROM algorithm may not accurately reflect the risk involved for these patients.