Amrinone in the management of low cardiac output after open heart surgery

Abstract

Hemodynamic effects of amrinone were studied in 2 groups of patients after open heart surgery. Group I consisted of 10 patients with moderate heart failure. In the absence of inotropic agents, their mean cardiac index (CI) was 2.02 ± 0.41 liters/min/m2 and mean pulmonary capillary wedge pressure (PCWP) 19 ± 3 mm Hg. Amrinone was administered 24 hours postoperatively by bolus injection (2 mg/kg) and by 12-hour infusions (20 μg/kg/min). Hemodynamic data and plasma concentrations were obtained 10 and 20 minutes after the bolus injection and at 1, 4, 8 and 12 hours during infusion. Significant beneficial changes were noted in CI, PCWP, right atriai pressure, systemic vascular resistance and pulmonary vascular resistance. Group II consisted of 5 patients in severe cardiogenic shock (mean CI 1.97 ± 0.3 liters/min/m2, mean PCWP 28 ± 8 mm Hg) despite adrenergic agonists in all patients and intraaortic counterpulsation in 2. After these measures, amrinone was given intravenously for 36 to 72 hours as additional inotropic support. Significant improvement was observed in CI, PCWP, right atrial pressure, systemic vascular resistance and pulmonary vascular resistance. Four patients in this group were discharged; 1 patient died after 5 days in acute renal failure and coma grade IV. No serious adverse effects of amrinone were observed in any group 11 patient. Amrinone administered soon after open heart surgery had a beneficial effect on patients with moderate heart failure. Amrinone also markedly improved the hemodynamic status of patients in cardiogenic shock already treated with adrenergic agonists or intraaortic counterpulsation. Except in 1 patient from group 1, no major adverse effects were observed.