Effects of vasodilators on renal function in severe heart failure

Changes in renal function associated with heart failure (HF) and the response to vasodilator therapy were investigated in 21 patients (pts) with ischemic heart disease. Serial measurements of systemic arterial pressure (AP), pulmonary arterial end diastolic pressure, cardiac index (CI) and effective renal plasma flow (ERPF) were obtained before and after isosorbide dinitrate (ISD) or prazosin (PZ). Baseline ERPF values measured by 131-I-orthoiodohippurate clearance correlated well with CI (r = 83). Pts with low ERPF (< 300 ml/min) had an increase of 20 to 80% in response to vasodilatation. This improvement in ERPF was not dependent on an increase in the Cl. Pts on nonic ISD/PZ with systolic AP < 90 mmHg developed edema and ascites that responded to spironolactone. These data indicate that vasodilators can significantly improve ERPF in pts with low Cl and suggests a specific beneficial effect on the renal vascular bed.

In pts with low cardiac output HF : 1) the ERPF is reduced in proportion to the Cl; 2) vasodilation will improve ERPF independently of the cardiac response although; 3) persistent hypotension and vasodilation may result in a clinical picture of secondary hyperaldosteronism.