Renal hemodynamics in patients with sustained essential hypertension and in patients with unilateral stenosis of the renal artery.

Systemic and renal hemodynamics including split renal function tests were studied in 41 patients with renovascular hypertension (RVH) related to unilateral stenosis of main renal artery in comparison to 36 subjects with essential hypertension (EH). The two populations were matched for age, sex, body surface area, and systemic arterial pressure. Cardiac output and total peripheral resistances were similar in both groups, with total peripheral resistances increased in comparison to normal values (P less than .001). Patients with EH had a decreased blood volume (P less than .01) with a normal cardiopulmonary blood volume. Patients with RVH had a normal blood volume with an increase in cardiopulmonary blood volume (P less than .02). The para-amino hippurate clearance (CPAH) was decreased in EH. The decrease was similar in the right (160.3 +/- 56.9 mL/min/m2) and left kidneys (158.7 +/- 45 mL/min/m2). The inulin clearance (Cin) was similar in both kidneys (35.2 +/- 12.5 v 33.6 +/- 11.6 mL/min/m2). In addition, in EH, CPAH was negatively correlated with blood pressure (P less than .01). In patients with RVH, CPAH of the "stenotic" kidney was reduced (91.5 +/- 47.8 mL/min/m2) as well as Cin (22.9 +/- 9.3 mL/min/m2). In contrast a significant increase in CPAH (194.1 +/- 63.8 mL/min/m2) and Cin (47.6 +/- 12.6 mL/min/m2) was observed in the contralateral kidney. Kidney function (CPAH and Cin) was not correlated with blood pressure in the "stenotic" kidney. The CPAH and Cin of the nonstenotic kidney were positively and significantly correlated with systemic arterial pressure (P less than .001). The Cin was positively correlated with CPAH in all kidneys in RVH or in EH.(ABSTRACT TRUNCATED AT 250 WORDS)