Clinical Phenotype and Outcomes of Pulmonary Hypertension Associated with Myeloproliferative Neoplasms: A Population-based Study.

RATIONALE: Precapillary pulmonary hypertension (PH) is a rare and largely unrecognized complication of myeloproliferative neoplasms (MPNs), including polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (MF).

OBJECTIVES: To describe characteristics and outcomes of MPN-associated PH.

METHODS: We report clinical, functional, and hemodynamic characteristics, classification and outcomes of patients with PV, ET or primary MF in the French PH registry.

MEASUREMENTS AND MAIN RESULTS: Ninety MPN patients (42 PV, 35 ET; 13 primary MF) presented with precapillary PH with severe hemodynamic impairment, with a median mPAP and PVR of 42 mmHg and 6.7 WU, respectively, and impaired clinical conditions, with 71% in NYHA functional classes III/IV and having a median 6-minute walk distance of 310 m. Half of patients were diagnosed with CTEPH; the other half were considered to have group 5 PH. MF was preferentially associated with group 5 PH, whereas PV and ET in the absence of MF were generally related to CTEPH. Proximal lesions were diagnosed in half of CTEPH patients. Thromboendarterectomy was performed in 18 selected patients with high risk of complications (5 early deaths). Overall survival at 1, 3, and 5 years was 67%, 50% and 34% in group 5 PH and 81%, 66% and 42% in CTEPH, respectively.

CONCLUSION: Precapillary PH is a life-threatening condition potentially occurring in MPN, with causes equally distributed between CTEPH and group 5 PH. Physicians should be aware that PH affects the burden of MPN patients, especially in group 5 PH, with unknown pathophysiological mechanisms.