Abstract 3121: Endothelial Dysfunction is Associated with Left Ventricular Mass and Left Ventricular Ejection Fraction (assessed using MRI) Independent of Blood Pressure and Antihypertensive Medication Use (MESA)
Nitric oxide has been shown to modulate the cardiac inotropic state, sarcolemmal calcium homeostasis and inhibits direct and beta- adrenergic growth-promoting effects of catecholamines on cardiac myocytes through its autocrine and paracrine effects. Brachial Flow-mediated dilation (FMD), a measure of nitric oxide release by the brachial endothelium due to shear stress, is a measure of vascular health. Endothelial nitric oxide also controls vascular tone and is likely to modify the ventricular muscle coupling mechanism. The association between left ventricular mass, left ventricular ejection fraction (LVEF) and FMD is not well understood. We assessed the association between left ventricular mass index (LVMI), LVEF and FMD in participants of the Multi-Ethnic Study of Atherosclerosis (MESA). MESA is a population based study of 6814 adults free of clinical cardiovascular disease at baseline who were recruited from six US clinics. LVMI (left ventricular mass per height2), LVEF (assessed with MRI) and FMD were measured in 3027 subjects. Linear regression analysis was used to evaluate the association. The subjects had mean age 61.2 ± 9.9 years, 50.2% females with 34.3% Caucasians, 19.7% Chinese, 20.8% African Americans and 25.2% Hispanics. The mean BMI was 27.4 ± 5.0 Kg/m2, 9.4% diabetics and 11% current smokers. The mean LVMI was 51.6 ± 11.2 mg/m2, mean LVEF was 69.4 ± 7.2 % and mean FMD was 4.4% ± 2.8%. Less than 1% of the subjects had LVH by MRI criteria. In univariate analysis, FMD (log transformed) was inversely correlated with LVMI (r = −0.20, p<0.0001) and was positively correlated with LVEF (r=0.06, p=0.003) In the multivariable analysis, FMD was associated with LVMI [β coefficient (se) = −0.003 (0.001), p=0.022: translate to 0.3% reduction in FMD per unit LVMI] after adjusting for age, gender, race, systolic blood pressure, diabetes mellitus, smoking, weight, antihypertensive medication use, HDL and LDL. FMD was also associated with LVEF in the multivariable analysis [β coefficient (se) = 0.005 (0.001), p=0.026: translate to 0.5% increase in FMD per unit LVEF]. FMD is inversely related to LVMI and positively related to LVEF independent of blood pressure and antihypertensive medication use in adults.