Differential value of left ventricular mass index and wall thickness in predicting cardiovascular prognosis : data from the PAMELA population

BACKGROUND Data on the prognostic value of echocardiographic left ventricular (LV) hypertrophy (LVH) as defined by LV wall thickness rather than LV mass estimate are scarce and not univocal. Thus, we investigated the value of LV mass index, wall thickness, and relative wall thickness (RWT) in predicting cardiovascular events in the PAMELA population. METHODS At entry 1,716 subjects underwent diagnostic tests, including laboratory investigations, 24-hour ambulatory blood pressure (BP) monitoring, and echocardiography. For the purpose of this analysis, all subjects were divided into quintiles of LV mass, LV mass/body surface area (BSA), LV mass/height(2.7), interventricular septum (IVS), posterior wall (PW) thickness, IVS+PW thickness, and RWT. RESULTS Over a follow-up of 148 months, 139 nonfatal or fatal cardiovascular events were documented. After adjustment for age, sex, BP, fasting blood glucose, total cholesterol, and use of antihypertensive drugs, only the subjects stratified in the highest quintiles of LV mass indexed to body surface area (BSA) or height2.7 exhibited a greater likelihood of incident cardiovascular disease (relative risk (RR) = 2.72, 95% confidence interval (CI) = 1.05-7.00, P = 0.03; RR = 4.83, 95% CI = 1.45-16.13, P = 0.01, respectively) as compared with the first quintile (reference group). The same was not true for the highest quintiles of IVS, PW thickness, IVS+PW thickness, and RWT. Similar findings were found when echocardiographic parameters were expressed as continuous variables. CONCLUSIONS This study indicates that LV wall thickness, different from LV mass index, does not provide a reliable estimate of cardiovascular risk associated with LVH in a general population. From these data it is recommended that echocardiographic laboratories should provide a systematic estimate of LV mass index, which is a strong, independent predictor of incident cardiovascular disease.