Pulmonary vasodilation after heart transplantation. A comparison among prostacyclin, sodium nitroprusside, and...

The aim of this study was to compare the effects of prostacyclin on central hemodynamics and right ventricular function to the more widely used vasodilators, sodium nitroprusside and nitroglycerin, and to investigate whether prostacyclin is more selective to the pulmonary vascular bed compared to sodium nitroprusside and nitroglycerin in patients after heart transplantation. Hemodynamic measurements were made after the operation in the intensive care unit with a pulmonary artery fast-response ejection fraction/volumetric thermodilution catheter. The aim was to maintain mean arterial pressure around 70 mm Hg with each drug. After a 10-minute infusion of each drug at a stable infusion rate, central hemodynamic variables and right ventricular end-diastolic volume, end-systolic volume, and ejection fraction were measured or derived in triplicate. The average infusion rates of sodium nitroprusside, nitroglycerin, and prostacyclin were 3.3 +/- 1.7 micrograms/kg/min, 6.6 +/- 1.8 micrograms/kg/min, and 12.4 +/- 1.7 ng/kg/min, respectively. Cardiac output, stroke volume, right ventricular end-diastolic volume, and central filling pressures were highest for prostacyclin compared to both nitroglycerin and sodium nitroprusside. Pulmonary vascular resistance was lower for prostacyclin compared to nitroglycerin but was comparable to that of sodium nitroprusside. Systemic vascular resistance was lowest for prostacyclin compared to both sodium nitroprusside and nitroglycerin. The pulmonary vascular resistance/systemic vascular resistance ratio used as an index of pulmonary selectivity did not differ between the vasodilators. The right ventricular ejection fraction did not differ among the three drugs.(ABSTRACT TRUNCATED AT 250 WORDS)