Oral combination therapy does not appear to help achieve or maintain low risk status in most treatment-naive patients with pulmonary arterial hypertension (PAH), according to the results of a recent study published in the American Journal of Respiratory and Critical Care Medicine.

Treatment-naive patients with PAH received combination oral therapy consisting of endothelin receptor antagonist (ERA) and phosphodiesterase-5 inhibitor (PDE-5i) medications. After 6 months, clinical evaluation and risk assessments were performed using European guidelines (European Respiratory Society and European Society of Cardiology) and REVEAL scores.

Of the 181 treatment-naive patients, there were 120 women, and the mean age was 53 years. A total of 146 of the patients were defined as having idiopathic PAH, while 28 had connective tissue disease-associated PAH. Initial functional class and 6-minute walk distance scores improved after beginning the combination therapy regimen. Additionally, pulmonary vascular resistance decreased by an average of 35%. However, at the 6-month follow-up, a low risk status was achieved or maintained in only 34.8% and 43.1% of the patients according to REVEAL and European scoring systems, respectively.

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“The present study shows that a low-risk status, as suggested by the current guideline, is achieved or maintained in a minority of patients with the initial ERA and PDE-5i combination therapy,” the study authors wrote. “This unsatisfactory treatment response appears related to a moderate treatment-induced decrease in [pulmonary vascular resistance].”


Badagliacca R, D’Alto M, Ghio S, et al. Risk reduction and hemodynamics with initial combination therapy in pulmonary arterial hypertension. Am J Respir Crit Care Med. Published online August 28, 2020. doi:10.1164/rccm.202004-1006OC