Salt and water retention and calcium blockade in uremia.

Blood pressure, echocardiography, and aortic and peripheral arterial pulse-wave velocity were studied in 40 hypertensive patients on long-term hemodialysis during a 24-week administration of nitrendipine (1,4-dihydro-2,6-dimethyl-4-m-nitrophenyl-3,5-pyridine-dicarboxylic acid ethyl methylester) monotherapy. In a double-blind placebo-randomized study, nitredipine effectively lowered the blood pressure (p less than 0.001) before hemodialysis without causing postdialysis hypotension. The antihypertensive effect of nitrendipine was greater in patients with significant salt and water retention, as indicated by interdialytic body weight gain (delta BW), that is, a significant correlation was observed between delta BW and the decrease in blood pressure (r = 0.72; p less than 0.001). The antihypertensive effect was not related to age, pretreatment plasma renin activity, or serum-ionized calcium concentration. After nitrendipine, a time-related decrease in aortic (p less than 0.005) and femoral (p less than 0.05) pulse-wave velocity was observed with a significant time-treatment interaction (p less than 0.01). Nitrendipine treatment did not influence left ventricular mass (which was positively correlated with delta BW; p less than 0.01) but was associated with an increase in the left ventricular ejection fraction. The increase in ejection fraction was correlated with changes in aortic pulse-wave velocity (r = 0.548; p less than 0.02) but not with changes in blood pressure (r = 0.352; p = 0.19) or delta BW.(ABSTRACT TRUNCATED AT 250 WORDS)