COMPARISON OF INHALED NITRIC-OXIDE AND INHALED AEROSOLIZED PROSTACYCLIN IN THE EVALUATION OF HEART-TRANSPLANT CANDIDATES WITH ELEVATED PULMONARY VASCULAR-RESISTANCE

Study objective: Elevated pulmonary vascular resistance is a risk fact or in heart transplantation and reversibility of high pulmonary vascul ar resistance is evaluated preoperatively in potential recipients usin g IV vasodilators or inhaled nitric oxide. Prostacyclin is a potent va sodilator, which when inhaled, has selective pulmonary vasodilatory pr operties. The aim of this study was to compare the central hemodynamic effects of inhaled prostacyclin with those of inhaled nitric oxide in heart transplant candidates, Design: A pharmacodynamic comparative st udy. Setting: Cardiothoracic ICU or laboratory for diagnostic heart ca theterization at a university hospital. Patients: Ten heart transplant candidates with elevated pulmonary vascular resistance (>200 dynes . s . cm(-5) anti/or a transpulmonary pressure gradient >10 mm Hg) were included in the study. Interventions: Nitric oxide (40 ppm) and aeroso lized prostacyclin (10 mu g/mL) were administered by inhalation in two subsequent 10-min periods. Hemodynamic measurements preceeded and fol lowed inhalation of each agent. Measurements and results: Both inhaled nitric oxide and inhaled prostacyclin reduced mean pulmonary artery p ressure (-7% vs -7%), pulmonary vascular resistance (-43% vs -49%), an d the transpulmonary gradient (-44% vs -38%). With inhaled prostacycli n, an 11% increase in cardiac output was observed. Other hemodynamic v ariables, including the systemic BP, remained unaffected by each of th e agents. Conclusions: Inhaled prostacyclin induces a selective pulmon ary vasodilation that is comparable to the effect of inhaled nitric ox ide, Major advantages with inhaled prostacyclin are its lack of toxic reactions and easy administration as compared with the potentially tox ic nitric oxide requiring more complicated delivery systems.