Pulmonary hypertension associated with neurofibromatosis type 1: data from the French Pulmonary Hypertension Registry

Introduction: Pulmonary hypertension associated with neurofibromatosis type 1 (PH-NF1) is a rare but severe complication of NF1. The largest study about PH-NF1 described 8 patients and there are few data about outcomes on PH treatment. Methods: We report clinical, functional, radiologic, and hemodynamic characteristics and outcomes of patients with pre-capillary PH-NF1 identified within the French PH Registry. Computed tomography (CT) at PH diagnosis were analysed by a pneumologist and a radiologist. Results: We identified 39 NF1-PH cases, characterized by a female predominance (77%) and a median age at PH diagnosis of 63 [min-max 35-82] y-o. At diagnosis, 90% were in NYHA functional class III or IV. Median 6-min walk distance was 209 [50-460] m. Pulmonary function tests showed normal or mild abnormalities except low DLCO (29 [20-58] %). PH was severe with a mean pulmonary artery pressure of 45 [29-71] mmHg, a cardiac index of 2.3 [1.2-3.6] L/min/m2 and pulmonary vascular resistance of 9.8 [4.6-20.1] WU. CT showed pulmonary cysts (72%), ground glass opacities (67%) and emphysema (49%). 38 patients received PAH-specific therapy. Transplant-free survival rates at 1, 3 and 5 years were 92%, 64% and 44%, respectively. Four patients underwent lung transplantation. Conclusions: PH-NF1 was characterized by female predominance, advanced age, severe hemodynamic impairment and poor prognosis.