ABSTRACT
BACKGROUND: Dobutamine and amrinone, phosphodiesterase-III inhibitor, are known to have both inotropic and vasodilatory properties. We evaluated the effects of both drugs on systemic and pulmonary hemodynamics in patients with pulmonary hypertension (PH). METHODS: With Institutional Review Board approval, 45 patients whose mean pulmonary arterial pressure was greater than 30 mmHg were studied. After sternotomy under the steady state of anesthesia and controlled ventilation (30 mmHg < PaCO2 < 40 mmHg), patients recieved one of following drugs for 30minutes (min); dobutamine 5.0ug/kg/min (Group I), low dose amrinone (loading dose 1.0 mg/kg, followed by infusion 7.5 g/kg/min, Group II) or high dose amrinone (loading dose 2.0 mg/kg, followed by infusion 10 g/kg/min, Group III). Hemodynamic variables were measured at 10 min and 30 min after start of infusion. RESULTS: Dobutamine didn't decrease pulmonary arterial pressure (PAP) and cause no hemodynamic change while low and high dose amrinone reduced PAP and especcially decrease of PAP in low dose amrinone group was statistically significnat. High dose amrinone increased cardiac index (CI) and decreased both systemic vascular resistance index (SVRI) and central venous pressure (CVP) more significantly than control value. CONCLUSIONS: In patients with chronic right ventricular failure associated with PH, amrinone may decrease the PAP and improve cardiac performance more effectively than dobutamin does. Increment of dosage of amrinone may not result in significant reduction of PAP.