ABSTRACT
The efficacy of amrinone was assessed in the treatment of low cardiac output states occurring within 24 h after mitral valve replacement in an open prospective trial. It included 7 women and 5 men, aged 58 +/- 10 years. Four patients had also had simultaneous aortic valve replacement. Patients entered in the study if their cardiac index (CI) remained less than 2.2 l.min-1.m-2 after pulmonary wedged pressure (Ppw) had been increased to at least 15 mmHg, the patient having a temperature greater than 36 degrees C. Amrinone was given so as to increase Cl by at least 30% and to decrease Ppw by at least 30%. Patients were given a mean of 1.5 mg.kg-1 amrinone during the first hour, followed by a constant rate infusion of 9 +/- 3 micrograms.kg-1.min-1 over at least 24 h. The usual haemodynamic parameters were measured and calculated before giving amrinone, and after 1, 3, 6, 24, and 48 h. After 1 h of treatment, systolic arterial pressure, cardiac index, systolic index and left ventricular stroke work increased by 22, 42, 23, and 47% respectively, whilst Ppw decreased by 27% (p less than 0.01). Heart rate rose and systemic vascular resistance decreased but not significantly. Right atrial pressure, right ventricular stroke work, pulmonary artery pressure and pulmonary vascular resistance did not change. These effects were all maintained throughout the 48 h infusion. Amrinone had to be replaced by another agent (a beta-agonist) in 3 cases because of arrhythmia, lack of efficacy or thrombocytopaenia. In this setting, amrinone increased left ventricular performance with little effect on the right ventricle.
