EFFECTS OF NITRIC-OXIDE AFTER CARDIAC TRANSPLANTATION IN THE SETTING OF RECIPIENT PULMONARY-HYPERTENSION

Background. Recipient pulmonary hypertension secondary to chronic cong estive heart failure is a significant risk factor for right ventricula r failure after cardiac transplantation. In this study, the hemodynami c and inotropic effects of nitric oxide (NO) were examined after bicav al cardiac transplantation in the setting of monocrotaline pyrrole-ind uced recipient chronic pulmonary hypertension. Methods. Twenty dogs un derwent 10 successfully completed transplantation experiments. Recipie nts underwent pulmonary artery injection of 3 mg/kg monocrotaline pyrr ole 4 months before transplantation. Measurements were taken 1 hour af ter cessation of cardiopulmonary bypass and after NO inhalation. Pulmo nary vascular impedance was calculated using Fourier analysis, and car diac function was assessed with load-insensitive means (preload recrui table stroke work). Results. At the time of transplantation, the preca rdiopulmonary bypass levels of pulmonary vascular resistance in recipi ent animals were significantly greater when compared with donor levels , and were further significantly increased after cardiopulmonary bypas s. Three recipients died after transplantation secondary to acute righ t ventricular failure. In the surviving animals, NO led to significant improvements in pulmonary vascular resistance and vascular impedance, which occurred in association with significant increases in transpulm onary efficiency. No significant changes were observed in right and le ft ventricular preload recruitable stroke work after NO inhalation. Co nclusions. These data suggest that NO may be an effective means to imp rove vascular impedance and pulmonary vascular efficiency after cardia c transplantation in the setting of recipient chronic pulmonary hypert ension. (C) 1997 by The Society of Thoracic Surgeons.