Inhaled nitric oxide for pulmonary hypertension after heart transplantation

Background. Recipient pulmonary hypertension due to chronic congestive hear t failure is a major cause of right ventricular (RV) dysfunction after hear t transplantation. We hypothesized that inhaled nitric oxide (NO), in the p ostoperative period, would a) selectively reduce pulmonary vascular resista nce and improve RV hemodynamics and b) reduce the incidence of RV dysfuncti on compared with a matched historical group. Methods. Sixteen consecutive adult heart transplant recipients with lowest mean pulmonary artery (PA) pressures > 25 mmHg were prospectively enrolled. Inhaled NO at 20 parts per million (ppm) was initiated before termination of cardiopulmonary bypass (CPB). At 6 and 12 hours after CPB, NO was stoppe d for 15 minutes and systemic and pulmonary hemodynamics were measured. RV dysfunction was defined as central venous pressure > 15 mmHg and consistent echocardiographic findings. The incidence of RV dysfunction and 30-day sur vival in this group was compared with a historical cohort of 16 patients ma tched for pulmonary hypertension. Results. Discontinuation of NO for 15 minutes at 6 hours after transplantat ion resulted in a significant rise in mean PA pressure, pulmonary vascular resistance (PVR), and RV stroke work index. Systemic hemodynamics were not affected by NO therapy. One patient in the NO-treated group, compared with 6 patients in the historical cohort group, developed RV dysfunction (P < .0 5). The 30-day survival in the NO-treated group and the historical cohort g roup were 100% and 81%, respectively (P > .05). Conclusion. In heart transplant recipients with pulmonary hypertension, inh aled NO in the postoperative period selectively reduces PVR and enhances RV stroke work. Furthermore, NO reduces the incidence of RV dysfunction in th is group of patients when compared with a historical cohort matched for pul monary hypertension. Inhaled NO is a useful adjunct to the postoperative tr eatment protocol of heart transplant patients with pulmonary hypertension.