Operative mortality in adult cardiac surgery: is the currently utilized definition justified?

This study evaluated operative mortalities following adult cardiac surgical operations to determine if this metric remains appropriate for the modern era.

This was a retrospective review of Society of Thoracic Surgeons (STS) indexed adult cardiac operations that included coronary artery bypass grafting (CABG), aortic valve replacement (AVR), CABG + AVR, mitral valve repair (MVr), CABG + MVr, mitral valve replacement (MVR) and CABG + MVR, performed at a single institution between 2011 and 2017. The primary outcome was the timing and relatedness of operation mortality, as defined by the STS as mortality within 30-day or during the index hospitalization, compared to the index operation. The secondary outcomes evaluated cause of death and the rates of postoperative complications.

A total of 11,190 index cardiac operations were performed during the study period and operative mortality occurred in 246 (2.2%) of patients. The distribution of operative mortalities included 83.7% (n=206) who expired within 30-day while an inpatient, 6.9% (n=17) died within 30-day as an outpatient, 11.2% (n=23) expired after 30-day. The most common causes of operative mortality were cardiac (38.7%, n=92), renal failure (15.6%, n=37), and strokes (13.9%, n=33). Furthermore, 98.4% (n=242) of deaths were attributable to the index operation. Postoperative complications occurred frequently in those with operative mortality, with blood transfusions (80.1%), reoperations (65.0%) and prolonged ventilation (62.2%) being most common.

Most of the operative mortalities seemed to be attributable to the index cardiac operation. We believe that the current definition of mortality remains appropriate in the modern era.