Objective: Pulmonary hypertension is commonly found in patients undergoing valvular surgery and can be worsened by cardiopulmonary bypass. Inhaled epoprostenol (prostacyclin) has been used for the treatment of pulmonary hypertension, but its effects compared with those of placebo on hemodynamics, oxygenation, echocardiographic examination, and platelet function have not been studied during cardiac surgery.
Methods: Twenty patients with pulmonary hypertension undergoing cardiac surgery were randomized in a double-blind study to receive inhaled epoprostenol (60 microg) or placebo. The inhalation occurred after induction of anesthesia and before surgical incision. The effects on left and right systolic and diastolic cardiac functions evaluated by means of pulmonary artery catheterization and transesophageal echocardiography, as well as oxygenation and platelet aggregation, were studied.
Results: Inhalation of epoprostenol significantly reduced indexed right ventricular stroke work from 10.7 +/- 4.57 g. m. m(-2) to 7.8 +/- 3.94 g. m. m(-2) (P =.003) and systolic pulmonary artery pressure from 48.4 +/- 18 mm Hg to 38.9 +/- 11.9 mm Hg (P =.002). The effect was correlated with the severity of pulmonary hypertension (r = 0.76, P =.01) and was no longer apparent after 25 minutes. There was no significant effect on systemic arterial pressures, left ventricular function, arterial oxygenation, platelet aggregation, and surgical blood loss.
Conclusion: Inhaled epoprostenol reduces pulmonary pressure and improves right ventricular stroke work in patients with pulmonary hypertension undergoing cardiac surgery. A dose of 60 microg is hemodynamically safe, and its effect is completely reversed after 25 minutes. We did not observe any evidence of platelet dysfunction or an increase in surgical bleeding after administration of inhaled epoprostenol.