HEMODYNAMIC, RENAL AND HORMONAL RESPONSES TO ENALKIREN IN 4 PATIENTS WITH POSTSURGICAL OLIGURIA

1. The haemodynamic and hormonal responses of four patients with acute post-surgical oliguria (urine output <0.5 mL/kg per h) were measured in response to the renin inhibitor enalkiren. Enalkiren was infused at 0.01 up to 0.1 mg/kg per h for up to 4 h. 2. Enalkiren infusion was a ssociated with a progressive fall in blood pressure, clinically signif icant in three of the four patients. Systemic vascular resistance fell in proportion to blood pressure fall. Cardiac output and pulse rate r emained unchanged. Effective renal plasma flow rose in all four cases (236+/-19 to 327+/-38). There was no change in urine flow rate, or uri nary sodium excretion. 3. Plasma renin activity (ng angiotensin I/mL p er h) fell from 1.9+/-0.5 to 0.02+/-0.01 (P<0.04), plasma angiotensin II (pg/mL) fell from 104+/-93 to 7.7+/-1.5, and plasma aldosterone (ng /dL) fell from 32+/-8 to 21+/-9 (P = 0.03) at the highest infusion dos e. 4. Enalkiren inhibited plasma renin activity with reduced plasma an giotensin II and aldosterone concentrations. This was associated with vasodilation, reduced blood pressure and maintained cardiac output. Th ere was no beneficial effect on renal function in these patients with post-surgical oliguria.