Cardiac surgery results in complications for some patients that lead to a longer hospital stay and higher costs. This study identified the presurgery characteristics of patients that were associated with the cost of their hospital stay and estimated how much of that cost could be attributed to a bleeding event, defined as requiring 3 units or more of packed red blood cells or returning to the operating room for bleeding. We also identified the presurgery characteristics that were associated with the bleeding event.

This prospective cohort of patients (n = 1459) underwent cardiac surgery at 3 tertiary referral hospitals in Australia during 2014 and 2015. Clinical data included the variables held by the Australian and New Zealand Society of Cardiac and Thoracic Surgeons registry. Cost data were collected as part of a state-level hospital data collection.

Many of the baseline patient characteristics were associated with the total cost of cardiac surgery. After adjusting for these characteristics, the cost of cardiac surgery was 1.76 (confidence interval, 1.64-1.90) times higher for patients who had a bleeding event ( P < .001), thus resulting in a median increase in costs (in Australian dollars) of $33,338 (confidence interval, $21,943-$38,415). Several baseline characteristics were strongly associated with a bleeding event.

The impact of a bleeding event on the cost of cardiac surgery is substantial. This study identified a set of risk factors for bleeding that could be used to identify patients for discussion at the heart team level, where measures to minimize the risk of transfusion may be initiated.