Dogs With and Without Low Cardiac Output Differential Effects on Renal Function

Exogenous prostaglandin (PG) administration has been proposed as a vasodilator therapy for heart failure patients. The effects of this therapy on renal function have not been well studied in this dis-order. Therefore, we investigated the renal effects of the PGI 2 analog iloprost in comparison to PGE 2 in 12 conscious dogs before and after induction of a low cardiac output state by rapid right ventricular pacing (250 beats/min for 10 days). In healthy dogs, 5 to 150 ng/kg/min iloprost increased renal plasma flow without affecting glomerular filtration rate and decreased urine flow without affecting natriur-esis. PGE 2 at the same dosages increased renal plasma flow and urinary sodium excretion without changing the glomerular filtration rate or amount of diuresis. In dogs with low cardiac output and lower basal renal plasma flow, iloprost did not change renal plasma flow, but decreased glomeru-lar filtration rate and filtration fraction. In these animals, PGE 2 insignificantly increased renal plasma flow, but significantly augmented urine flow and sodium excretion. We therefore conclude that in an experimental low cardiac output state, PGI 2 may cause a deterioration of renal function. In contrast, PGE 2 induces natriuresis and diuresis de-spite an attenuated increase in renal plasma flow. Thus, PGE 2 promises to exert a more favorable pro-file of renal effects in heart failure therapy. Am