Outcomes for endocarditis surgery in North America: a simplified risk scoring system

Abstract

Objective: Operation for infective endocarditis is associated with the highest mortality of any valve disease, with overall rates of in-hospital mortality exceeding 20%. The Society of Thoracic Surgeons Adult Cardiac Surgery Database was examined to develop a simple risk scoring system and identify areas for quality improvement.

Methods: From 2002 through 2008, 19,543 operations were performed for infective endocarditis. Logistic regression analysis related baseline characteristics to both operative mortality and a composite of mortality and major morbidity within 30 days. Points were assigned to each risk factor, and estimated risk was obtained by averaging events for all patients having the same number of points.

Results: Overall unadjusted mortality was 8.2%, and complications occurred in 53%. Significant preoperative risk factors for mortality (associated points) were as follows: emergency, salvage status, or cardiogenic shock (17), preoperative hemodialysis, renal failure, or creatinine level less than 2.0 (12), preoperative inotropic or balloon pump support (10), active (vs treated) endocarditis (10), multiple valve involvement (9), insulin-dependent diabetes (8), arrhythmia (8), previous cardiac surgery (7), urgent status without cardiogenic shock (6), non-insulin-dependent diabetes (6), hypertension (5), and chronic lung disease (5), with a C statistic of 0.7578 (all P < .001). Risk-adjusted mortality and major morbidity were unchanged over the course of the study. In the entire data set, mortality was better if "any valve" was repaired (odds ratio = 0.76; P = .0023).

Conclusions: Operative mortality for surgically treated infective endocarditis is substantially lower than reported in-hospital mortality rates for infective endocarditis. The described risk scoring system will inform clinical decision-making in these complex patients.