The value of ejection fraction as a predictor of early and late survival following aortocoronary bypass surgery in patients with moderate to severe depression of the left ventricular function.

Predictability analysis of early and late survival of coronary bypass patients with reduced left ventricular function was performed using stepwise logistic regression based on preoperative and operative data. The total perioperative mortality was 3.4% and the total actuarial survival of the whole group at 42 months was 87.7%. Thirty preoperative and operative parameters of 149 patients were entered into a first mathematical model. Four parameters were selected as a consequence: ejection fraction, anginal class, obesity, septal infarct. A prediction model based on these parameters, gave a correct prediction of the operative outcome in 99.3% of the patients. However due to the only five perioperative deaths, this model should be interpreted with caution. The accuracy of ejection fraction alone was 97.3%, the sensitivity was 100% but the specificity was only 20%. The same parameters of 97 patients were entered into a second mathematical model. Four parameters were selected in this case: ejection fraction, NYHA functional classification, septal infarct, anterior infarct. A second prediction model, based on these parameters, gave a correct prediction of the late outcome at 24 months in 93.8% of the patients. The accuracy of the discrimination on the basis of ejection fraction alone was 89.7%, its sensitivity was 96.5% but its specificity was only 41.7%. Ejection fraction was the best predictor out of the studied variables but due to its low specificity not good enough as a sole parameter.