Milrinone in the treatment of chronic cardiac failure: a controlled trial

This study examines the acute hemodynamic response to intravenous and oral milrinone in 12 patients with moderate to moderately severe heart failure. The patients received milrinone or placebo at random in an 8-week double-blind trial. Dosing level and schedule were determined by the hemodynamic results. Acute and chronic plasma samples for milrinone concentration were drawn from patients throughout the study. Milrinone was administered intravenously in successive doses of 25, 50, and 75 micrograms/kg. This resulted in a 16.5%, 12.5%, and 28.4% peak increase in cardiac index, with a concomitant 24%, 29%, and 38% decrease in pulmonary capillary wedge pressure. There were no significant relationships between any of the mean maximal hemodynamic values and milrinone plasma concentration. Six patients received milrinone and six patients received placebo; only five patients completed the blinded phase. There was no significant difference between the groups in exercise capacity, but the conditions of five of the six patients who received placebo deteriorated. In two of the patients who received milrinone the aerobic capacity improved greater than 2 cc/min/kg over baseline, and an additional two patients reported a marked subjective improvement. The results of this study indicate that oral milrinone in the management of patients with chronic cardiac failure would justify larger controlled studies.