African Americans with LVH demonstrate depressed sensitivity of the coronary microcirculation to stimulated relaxation.

Excess coronary heart disease morbidity and mortality among African Americans remains an important yet unexplained public health problem. We hypothesized that adverse outcome is in part due to intrinsic or acquired abnormalities in coronary endothelial function and vasoreactivity. We compared dose-response curves relating changes in coronary blood flow and epicardial diameter to graded infusions of acetylcholine in 50 African American and 65 white subjects with hypertensive left ventricular hypertrophy (LVH) and normal coronary arteries.

The presence of African American race predicts improvement in coronary endothelial function after supplementary L-arginine.

Objectives: The purpose of our study was to determine if the presence of African American ethnicity modulates improvement in coronary vascular endothelial function after supplementary L-arginine.

Background: Endothelial dysfunction is an early stage in the development of coronary atherosclerosis and has been implicated in the pathogenesis of hypertension and cardiomyopathy. Amelioration of endothelial dysfunction has been demonstrated in patients with established coronary atherosclerosis or with risk factors in response to infusion of L-arginine, the precursor of nitric oxide.