Prediction of the left ventricular ejection fraction response to doxorubicin using a multiple linear regression model.
The aim of this study was to develop a model for predicting clinically significant deterioration in the left ventricular ejection fraction due to chronic doxorubicin administration. Twenty-six patients were monitored during their courses of doxorubicin chemotherapy with serial gated equilibrium radionuclide angiography. Multiple linear regression analysis was used to derived the best combination of clinical and radionuclide angiographic predictors of resting left ventricular ejection fraction at any point during the course of chemotherapy. The final model consisted of five variables: left ventricular ejection fraction at the previous monitoring point; cumulative dose of doxorubicin achieved at the previous monitoring point; increment in dose from the previous monitoring point; age of the patient; and time to peak left ventricular emptying at the previous monitoring point. The cumulative dose, the ejection fraction at the previous monitoring point and the final model, respectively, explained 11%, 33% and 53% of the variability in ejection fraction determinations during the 26 patient courses. The final model also forecast a potentially very low resting left ventricular ejection fraction (less than 35%) at the cumulative doses of doxorubicin which provoked serious clinical cardiotoxicity in two patients. A multivariate model is a useful aid in timing discontinuation of doxorubicin prior to the development of a clinically significant deterioration in left ventricular ejection fraction.