Renal Vasculature in Essential Hypertension: Racial Differences

In an attempt to explain the greater morbidity from essential hypertension in the black as compared with the white race, we evaluated the intrarenal vasculature of 27 patients with hypertension (19 white and 8 black). All patients had mild-to-moderate hypertension (mean arterial pressure, 110 to 125 mm Hg), normal renal function, and minimal target-organ damage. All patients had selective renal angiograms, which were evaluated for arterial nephrosclerosis. Additionally, renal blood flow was estimated by the clearance of para-aminohippurate. Patient age, blood pressure, and plasma renin activity did not differ between the two races. Black hypertensives had significantly (P less 0.01) more severe nephrosclerosis than the white patients. Renal blood flow was lower (P less than 0.05) in black patients (390 +/- 35 ml/min - m2 body surface area) than white patients (473 +/- 19 ml/min - m2 body surface area). These findings may help to explain racial differences in morbidity and mortality from essential hypertension.