Reoperation for bleeding in patients undergoing coronary artery bypass surgery: incidence, risk factors, time trends, and outcomes

Reoperation for bleeding represents an important complication in patients undergoing coronary artery bypass surgery (CABG). Yet, few studies have characterized risk factors and patient outcomes of this event. We evaluated 528 686 CABG patients at >800 hospitals in the Society of Thoracic Surgeons National Cardiac Database (2004 to 2007). Clinical features and in-hospital outcomes were evaluated in patients with and without reoperation for bleeding after CABG. Logistic regression was used to identify predictors of risk of this event and to estimate weights for an additive risk score. A total of 12 652 CABG patients (2.4%) required reoperation for bleeding. These rates remained fairly stable over time (2.2%, 2.3%, 2.5%, and 2.4% from 2004 to 2007, respectively). Although overall operative mortality was 4.5-fold higher in patients requiring reoperation for bleeding versus those who did not (2.0% versus 9.1%), this mortality risk declined significantly over time (11.3%, 9.5%, 8.8%, and 8.2% from 2004 to 2007, respectively, P for trend=0.0006). Factors associated with higher risk for reoperation were identified by multivariable analysis (c statistic=0.60) and summarized into a simple bedside risk score. The risk-score performed well when tested in the validation set (Hosmer-Lemeshow P=0.16). Reoperation for bleeding remains an important morbid event after CABG. Nonetheless, death in patients with this complication has decreased over time. Our risk tool should allow estimation of patients risk for reoperation for bleeding and promote preventive measures when feasible in this at-risk group.