Pharmacologic reduction of pretransplantation pulmonary vascular resistance predicts outcome after pediatric heart transplantation

Pulmonary hypertension leading to donor right ventricular dysfunction remains a major risk factor associated with poor outcome after heart transplantation. This study evaluated a pretransplantation protocol to assess pulmonary vascular resistance index and its response to pharmacologic modulation. Cardiac catheterization was performed in 25 patients (mean age, 8.6 years [range, 1 to 17 years]; mean weight, 27.3 kg [range, 8.1 to 54 kg]) with end-stage heart failure. Mean pulmonary artery and capillary wedge pressures and cardiac index were measured in the baseline state and during administration of 100% oxygen, dobutamine at 10 μg/kg/min, and nitroprusside at 1 to 4 μg/kg/min. Transpulmonary pressure gradient and pulmonary vascular resistance index were calculated. In 22 survivors, hemodynamics were reassessed 1 and 4 weeks after transplantation. The mean cardiac index significantly increased (2.2 to 3.2 L/min/m²); transpulmonary pressure gradient (12.7 to 9.6 mm Hg) and pulmonary vascular resistance index (6.2 to 3.0 units/m²) decreased during the drug study. In 12 patients with a baseline pulmonary vascular resistance index of more than 6 units/m², 10 survived heart transplantation. This study shows that pharmacologic reduction of the pulmonary vascular resistance index in the pretransplantation protocol predicts reduced pulmonary vascular resistance index and a favorable outcome after heart transplantation.