PREDICTION OF MORTALITY RISK BY DIFFERENT METHODS OF INDEXATION FOR LEFT-VENTRICULAR MASS

Objectives. We sought to compare the predictive value of echocardiogra phically determined left ventricular hypertrophy on death from all cau ses and cardiac mortality using various methods of indexation for left ventricular mass. Background. Considerable controversy exists regardi ng the optimal method for indexing left ventricular mass to body size in the clinical setting. Methods. The study included 988 consecutive p atients who had both coronary angiograms and echocardiographic examina tions in an inner-city public hospital in Chicago, Illinois. Patients were followed up for a mean of 7 years (range 2 to 11). Results. Vario us left ventricular mass indexes (e.g., mass indexed for height, heigh t(2), height(2.13), height(2.7), body surface area and body surface ar ea(1.5) were highly correlated (r = 0.90 to 0.99). Used as a continuou s measure, an increase in any left ventricular mass index was associat ed with similar risk of death from all causes and cardiac diseases. Al though left ventricular hypertrophy assessed by mass indexed for body surface area using the published conventional partition values provide d somewhat better prediction, the adjusted relative risk was in genera l not significantly different from hypertrophy based on other indexes. Patients with left ventricular hypertrophy defined concordantly by in dexes based on both body surface area and height (or height(2.7)) had, by definition, the highest average mass indexes among all groups and experienced as much as a threefold greater risk of death than those wi thout hypertrophy. A small proportion of patients (12%) who were class ified into the hypertrophy group by height-based indexes alone, but no t by body surface area, had a moderate increase in mass and showed no increase in risk, even though being overweight was extremely prevalent in this group. Conclusions. Because of the high correlation among var ious body size indexes, left ventricular hypertrophy, defined by diffe rent indexes for left ventricular mass, similarly confers increased ri sk of mortality in patients with or without codronary artery disease. (C) 1997 by the American College of Cardiology.