INHALED PROSTACYCLIN FOR TREATMENT OF PULMONARY-HYPERTENSION AFTER CARDIAC-SURGERY OR HEART-TRANSPLANTATION - A PHARMACODYNAMIC STUDY

Objective: To study the effects of incremental concentrations of inhal ed aerosolized prostacyclin (PGI(2)) on pulmonary and systemic hemodyn amics after cardiac surgery or heart transplantation. Design: Pharmaco dynamic dose-response study. Setting: Cardiothoracic intensive care un it (ICU) at a university hospital. Participants: Nine patients with pu lmonary hypertension after cardiac surgery or heart transplantation an d an elevated pulmonary vascular resistance (PVR) (>200 dynes . sec . cm(-5)) treated in the ICU with inotropic support were studied. Interv entions: Inhaled prostacyclin was administered at concentrations of 2. 5, 5.0, and 10.0 mu g/mL using conventional systems for nebulization. Measurements and Main Results: Pulmonary and systemic hemodynamics as well as right ventricular (RV) function variables (n = 3) were measure d before, during, and 10 and 20 minutes after inhalation of PGI(2). In haled PGI(2) induced a dose-dependent decrease in PVR and the transpul monary gradient (which decreased by -29% and -26%, respectively) at an inhaled concentration of 10 mu g/mL. Inhaled PGI(2) caused no changes in systemic vascular resistance. Central venous pressure decreased du ring PGI(2) inhalation with no change in stroke volume, indicating an improvement in RV performance, which was particularly obvious in one p atient with RV failure after heart transplantation. Twenty minutes aft er discontinuation of inhaled PGI(2), hemodynamic variables returned t o baseline. Conclusions: Inhaled PGI(2) induces a dose-dependent selec tive pulmonary vasodilation and may improve RV performance after cardi ac surgery complicated by pulmonary hypertension and RV failure. Copyr ight (C) 1996 by W.B. Saunders Company