ACUTE ENOXIMONE EFFECT ON SYSTEMIC AND RENAL HEMODYNAMICS IN PATIENTSWITH HEART-FAILURE

Patients with heart failure generally show improvement in their clinic al condition after enoximone infusion over the period of treatment; th is effect cannot be ascribed only to the known hemodynamic action of t his drug. Thirty-six patients (age range 44-82 years) with heart failu re (NYHA class II-IV) underwent 48-hour enoximone infusion to study wh ether this prolonged improvement might depend on changes in systemic o r renal hemodynamics or in neurohormonal balance. All patients underwe nt Swan-Ganz hemodynamic monitoring; renal plasma how, glomerular filt ration rate, plasma atrial natriuretic factor (ANF), and plasma renin activity (PRA) were all measured at baseline, at the peak of the enoxi mone action, and 48 hours after drug discontinuation. The main hemodyn amic parameters were significantly improved during enoximone infusion and after drug discontinuation. The cardiac index basal value of 2.2 /- 0.1 l/min/m(2) increased to 3.1 +/- 0.1 l/min/m(2) after 24-hour th erapy (p < 0.01); similarly, pulmonary wedge pressure, mean pulmonary arterial pressure, and right atrial pressure decreased markedly (p < 0 .01). Beneficial effects were also observed in renal hemodynamics; ind eed, renal plasma flow (basal value 485 +/- 39 ml/min) increased signi ficantly after 24-hour enoximone infusion (575 +/- 35 ml/min; p < 0.01 ), and this tendency was also observed 48 hours after drug discontinua tion. No significant modifications were observed in plasma hormone dat a; however, the PRA plasma level had a tendency to decrease. We conclu de that in patients with heart failure, enoximone infusion has a less marked effect on renal hemodynamics, but this is more lasting than sys temic hemodynamic effects. The tendency of PRA to decrease (although n ot statistically significant), still detectable 2 days after treatment in the presence of steady high plasma ANF concentrations, may also co ntribute to the paradoxical longlasting benefit despite the short-live d improvement in systemic hemodynamics after brief cycles of enoximone infusion.