[Hemodynamic effects of amrinone, phosphodiesterase inhibitor, early after coronary artery bypass grafting].

This study was conducted to evaluate the hemodynamic effects of amrinone early after open-heart surgery. Eighteen patients who underwent coronary artery bypass grafting were randomly divided into two groups: ten patients (group A) were administered 5 micrograms/kg/min of amrinone, and eight patients (group B) were administered 10 micrograms/kg/min. No bolus of amrinone was administered before continuous infusion. The mean and systolic arterial pressure and systemic vascular resistance index were significantly decreased (p < 0.05) after infusion of amrinone in both groups. Cardiac index was not increased in group A, but was significantly increased in group B without increase in the double product. There were no significant changes in heart rate, mean pulmonary arterial pressure or pulmonary capillary wedge pressure in either group. Pulmonary vascular resistance index tended to decrease in either group. Transient hypotension after infusion of amrinone was a serious clinical problem. Of the eight patients with systemic vascular resistance index less than 2000 dyneseccm-5*m2 before infusion, blood pressure decreased below 100 mmHg in five patients. Administration of amrinone was discontinued in two patients in group B and one patient in group A because of transient hypotension. In this study, continuous infusion of amrinone (10 micrograms/kg/min) had both positive inotropic and vasodilating properties; however, transient hypotension must be monitored carefully.