Systemic systolic hypertension in the elderly: Correlation of hemodynamics, plasma volume, renin, aldosterone, urinary metanephrines and response to thiazide therapy

Twenty-four men, mean age 63 ± 1.7 years, with systemic systolic hypertension were studied before and after 1 month of therapy with oral hydrochlorothiazide, 50 mg/day. The control mean plasma volume was 2,664 ± 96 ml, cardiac index 3.9 ± 0.2 liters/min/m 2, stroke volume index 52 ± 2 ml/beat/m 2, systemic vascular resistance 1,351 ± 80 dynes s cm −5, plasma aldosterone 8.6 ± 1.0 ng/dl and 24-hour urinary excretion of metanephrines 0.371 ± 0.044 mg. On renin-sodium profiling in 23 patients, 12 were classified into a normal group and 11 into a low-renin group; none had high renin values. Based on multiple regression analysis, the 24-hour urinary excretion of total metanephrines appeared to be the single most important factor explaining 28% of the variability in systolic blood pressure (BP). After therapy with oral hydrochlorothiazide, the elevated systolic BP decreased (p