Continuous Relation in Risk Between Left Ventricular Mass and Cardiovascular Disease Incidence in African-Americans
Objective: To determine the magnitude and the shape of the relation between left ventricular mass (LVM) and cardiovascular event (CVD) rates in African-Americans (AA). Background: Left ventricular hypertrophy on echocardiography is a powerful and independent CVD risk factor. Previous studies indicate a monotonic relation of increasing LVM index with increasing CVD rates in the general population (mostly whites). However, the relation between LVM index and incident CVD in AA has not been addressed. Methods: The Atherosclerosis Risk in Communities (ARIC) is an ongoing cohort study of CVD in 4 US communities. During the third visit, LVM was measured by echocardiography in AA from Jackson, MS (1,975 participants free of prevalent CVD, age range: 49-75, mean 58.9±1.5). Measurements were taken according to the ASE recommendations. LVM was calculated as (0.8[1.04((IVS+LVID+PWT) 3 -LVID 3 )]+ 0.6 g) and normalized by height 2.7 . Results: At a mean follow up of 2.95 years, range (0.03-4.4) there were 63 cardiovascular events (non-fatal MI= 19, fatal CHD= 8, non-fatal/fatal stroke= 30/8 and cardiac procedure= 4; 8 participants had more than one type of event) corresponding to an event rate of 1.08/100 patient-years. In the four quartiles of LVM index distribution (partition values: 38, 47, 57, and 162 g/m 2.7 ), CVD rates were 0.33, 0.80, 0.83, and 2.51 per 100 patient-years respectively (p-value for trend= 0.002). After adjustment for traditional risk factors (age, gender, smoking, diabetes, hypertension, obesity and education level), the relative risk of developing CVD increased progressively along a continuum of LVM index values (RR 1.24/per each 10 g/m 2.7 , 95%CI 1.10-1.39). Conclusion: Our findings showed a linear, powerful, and independent relation between LVM index and cardiovascular risk in AA who were free from overt cardiovascular disease at the time of the exam. Echocardiographic estimation of LVM index may be a useful tool for assessment of total CVD risk in AA.