Amrinone versus conventional therapy in pulmonary hypertensive patients awaiting cardiac transplantation

Pulmonary hypertension is associated with an increased perioperative mortality for orthotopic heart transplantation. A transpulmonary gradient greater than 15 mm Hg or a pulmonary vascular resistance greater than 5 Woods units increases mortality secondary to right heart failure. This study compares amrinone with conventional therapy in 38 transplant candidates with pulmonary hypertension. All patients had elevated transpulmonary gradient, pulmonary vascular resistance, or both. Group 1 (n = 21) received prolonged continuous intravenous amrinone therapy, whereas group 2 (n = 16) received high-dose oral diuretics, digitalis, and captopril. Both groups 1 and 2 had decreased pulmonary hypertension, transpulmonary gradient, and pulmonary vascular resistance. However, amrinone was more effective, with a 86% response rate versus 63% response for conventional therapy. Survival awaiting transplantation was significantly higher in group 1 (20 of 22, 91%) than in group 2 (10 of 16, 63%). Although both groups 1 and 2 had significantly decreased pulmonary vascular resistance, only group 2 had significantly decreased systemic vascular resistance. Comparison of pulmonary vascular resistance after therapy showed that the response in group 1 (amrinone) was significantly lower than the response in group 2 (conventional therapy), suggesting that amrinone may function as a direct vasodilator of the pulmonary vasculature. There were no operative deaths or episodes of perioperative right heart failure in either group. Amrinone appears to be more effective and safe than conventional therapy in the treatment of prospective heart transplant candidates with pulmonary hypertension.