Weighted ventriculographic wall motion score for improved survival prediction in patients with coronary artery disease

Global ventricular function parameters such as the ejection fraction and the sum of wall motion scores for segments of the left ventricle are excellent predictors of long-term survival in patients with coronary heart disease. These are usually determined from a monoplane right anterior oblique view. It was hypothesized that a biplane weighted wall motion score that included the left anterior oblique projection might better predict survival. A new score (BISCORE) was derived for 1,433 Mayo Clinic ventriculograms coded by the methods of the Coronary Artery Surgery Study (CASS). Weighting coefficients for each left ventricular segment were derived by the proportional hazards technique, and this resulted in the equation BISCORE = 120 - (8.6 x anterobasal + 3.4 x basal septum + 2.9 x apical + 2.7 x posterolateral + 2.4 diaphragmatic), which yielded a score from 0 (all segments aneurysmal) to 100 (all segments normal). This score stratified the original 1,433 patients into distinct groups by survival. As a single variable it was better than previous wall motion scores and ejection fraction at predicting survival. When prospectively applied to 5,172 Coronary Artery Surgery Study patients, this new score again proved to be a better predictor of survival than previous unweighted scores. Since the new score contains terms from the left anterior oblique ventriculographic projection, it is concluded that this projection adds information to that of the right anterior oblique projection regarding survival. Furthermore, this weighted score appears more highly associated with survival than unweighted scores.