Predictors of operative mortality following primary coronary artery bypass surgery.

BACKGROUND: Although quality assessment of coronary artery patients can be done by 30 days risk-adjusted operative mortality, it is still insufficient to study the outcome after primary coronary artery bypass graft surgery (CABG). In our study, we attempted to determine the factors, which can help predict operative mortality before and after CABG. METHODS: The study population consisted of 1000 prospective patients who underwent primary isolated CABG. Assessment was done by dividing the patients into two groups, i.e. non-survivors ( n= 12) and survivors ( n= 988). Data were analyzed using both univariate and multivariate models. RESULTS: On univariate analysis, recent acute myocardial infarction, intra-aortic balloon counterpulsation (IABC), left ventricular ejection fraction (LVEF) <25%, ventilator-associated pneumonia (VAP), tracheostomy, re-exploration, ventricular arrhythmias, low cardiac output (CO), multiple blood transfusions, post-operative renal dysfunction and longer intensive care unit and hospital stay were found as risk factors for mortality. Multivariate analysis showed that LVEF <25%,VAP, ventricular arrhythmias and low CO independently predicted mortality. Prior knowledge of these risk factors can help not only in predicting the outcome and the risks but also helps to plan the surgical and post-operative course of the patients to improve the morbidity and mortality. CONCLUSION: Our data suggest that operative mortality can be predicted prior to and after surgery considering factors such as LVEF, use of IABC, onset of ventricular arrhythmias and low CO.