By Prof Dario Vizza, Lucilla Piccari, MD, and Oksana Shlobin, MD, on behalf of the Pulmonary Vascular Research Institute.
Pulmonary hypertension (PH) is a frequent finding in advanced COPD. Usually pulmonary pressure is only mildly elevated, but a subgroup of patients develops severe PH, arbitrarily defined as mean pulmonary pressure (mPAP) ≥35 mmHg). Several studies suggest that pulmonary pressure has an independent prognostic role in COPD. In patients with mild-to-moderate PH, dyspnea is driven by airflow impairment, but in patients with severe COPD, exercise capacity is limited by circulatory insufficiency due to reduced cardiovascular reserve and/or an increase in pulmonary vascular resistance (PVR).
An important gap in this area is the lack of robust data on the treatment of PH in COPD as in literature we have only small randomized controlled studies with heterogeneous results. This is probably due to the lack of power and poor selection of the population studied (i.e. patients with COPD and normal or mild elevation of pulmonary pressure). Recent analysis of the COMPERA registry demonstrated that patients with PH-COPD had a poorer prognosis in comparison to patients with IPAH. The risk of death in the PH-COPD group was predicted by male sex, low exercise capacity evaluated by six-minute walking distance, and a high PVR.. Patients were COPD-PH were mainly treated with PDE5-inhibitors, and in treated patients with severe COPD-PH, increase in 6MWD by ≥30 m or improvements in WHO functional class were associated with a better survival.
These data suggest that patients with severe PH-COPD may benefit from PH treatment and emphasize the need for randomized, controlled studies to further explore this hypothesis.