Treatment of severe pulmonary hypertension secondary to chronic lung disease: A multicentre study

Introduction: The aim of the study was to assess the effect on clinical, hemodynamic and gas exchange of pulmonary vasodilator therapy in patients with severe PH secondary to chronic lung disease (CLD-PH). Methods: Observational, prospective, multicentre study of 33 patients with severe CLD-PH (mPAP≥35 mmHg and/or mPAP≥25 mmHg with low CI<2 L/min/m2) referred to expert Pulmonary Hypertension and Lung Disease Centres between 2012 to 2019 who received PH therapy. Patients with hypercapnia were excluded. Results: Of 33 patients with severe CLD-PH, 67% were men, with mean age of 65±12 years. Most common etiology was chronic obstructive pulmonary disease (42%) with an average FEV1 of 46±22% and DLCO of 34±17% of predictive value. Most patients (81%) received phosphodiesterase type 5 inhibitors (PDE-5) monotherapy and 19% combination therapy with PDE-5 and endothelin receptor antagonist or inhaled iloprost. In follow-up we observed an improvement of functional class (III-IV WHO 79 vs 61%, p=0.017) with significant decrease in NT-proBNP (1595 vs 794 pg/ml, p=0.05) and hemodynamic response (mPAP 49 vs 39 mmHg, p=0.034 and PVR 9 vs 5.5 WU, p=0.25), without gas exchange deterioration (p02 of 52 vs 53 mmHg, p=0.906 and pCO2 of 41 vs 39 mmHg, p=0.433). No improvement in 6-minute walking distance (213 vs 235 meters, p=0.165) was observed. During follow up, 11 patients died (4 due to right heart failure and the others due to secondary causes). Lung transplantation was performed in two patients. Conclusions: In our series PH targeted therapy in patients with severe CLD-PH showed significantly improvement in functional class, NT-proBNP and hemodynamic parameters, without respiratory deterioration.