Inhaled Nitric Oxide Through a Noninvasive Ventilation Device to Assess Reversibility of Pulmonary Hypertension in Selecting Recipients For Heart Transplant

Abstract

Introduction Pulmonary hypertension (PHT) is an independent risk factor for right ventricular failure and death after heart transplant. Nitric oxide (NO) is a powerful and selective vasodilator, indicated in this scenario, but its response is unpredictable. Thus, it should be assessed prior to the intervention. However, preoperative assessment has not been widespread due to its difficulties and risks. Objective We describe herein a pulmonary vasodilatory test with NO administered through a noninvasive ventilation (NIMV) device. We also assessed the effect of NO in patients with severe PHT owing to cardiac disease. Assessment of the utility of the test to select patients for heart transplant. Methods We enrolled 19 patients with severe PHT for a preoperative assessment for heart transplant. Thresholds used were as follows: systolic pulmonary arterial pressure (SPAP) ≥65 mm Hg, transpulmonary gradient (TPG) ≥15 mm Hg, and pulmonary vascular resistance (PVR) ≥4.5 Wood units (WU). NO was administered through a modified noninvasive ventilation device. Cardiac output and pulmonary pressures were measured simultaneously by right heart catheterization. Results All patients agreed to be enrolled in the test. No difficulties, interruptions, or severe complications happened in any case. Basal and NO average measured values were SPAP (74.16 and 57.95 mm Hg), PVR (7.5 and 3.7 WU), and TPG (23.25 and 12.58 mm Hg). The differences were significant ( P < .05) for all three tests. We consider acceptable for heart transplant a response that reduces PHT to a moderate grade. Using these criteria 14 patients were accepted and 11 underwent heart transplant. Two deaths in the postoperative period were both secondary to mediastinal bleeding and not related to right ventricular failure. Conclusions A pulmonary vasodilatory test with NO administered through a NIMV device was feasible and useful to select suitable heart transplant recipients with severe pulmonary hypertension.