Pulmonary hypertension in patients with chronic obstructive pulmonary disease: Impact of lung hyperinflation on the response to pulmonary hypertension treatment.

Background: Pulmonary hypertension (PH) is common during chronic obstructive pulmonary disease (COPD), particularly in patients with severe COPD. These patients can be classified into different PH groups due to frequent comorbidities. Emphysema is often associated with COPD and is responsible for lung hyperinflation, which may contribute to the development of PH. The treatment of PH in COPD is not well defined, and the response to treatment is variable depending on the phenotype of the patients. The aim of this study was to determine whether pulmonary hyperinflation in COPD patients predicts response to treatment.

Methods: This observational, retrospective, single-center study included COPD patients diagnosed with PH, treated with PH treatments. Patient were divided into two groups according to lung hyperinflation, judged on the ratio of residual volume to total lung capacity. Response to treatment was defined by an improvement of at least 30 m in the 6-minute walk test or a one-point improvement in World Health Organization functional class at the first reassessment performed at least three months after treatment initiation.

Results: Of the 47 patients included, 30 (63.8 %) were responders to PH treatments, with no significant difference between patients in the "lung hyperinflation" (HI) group and those in the "no lung hyperinflation" (NoHI) group (64.3 % vs. 63.2 %, p = 0.937). However, response to treatment was significantly lower in the most distended patients when compared to non-distended patients (p = 0.033). Mean overall survival was 59.1 months (95 % CI [47.4-70.7]) and was significantly better in responders, with a mean survival of 71.5 months (95 % CI [58.6-84.5]) vs. 35.4 months (95 % CI [17.3-53.4], p = 0.001). Mean survival did not differ according to lung hyperinflation, with a mean survival of 50.3 months (95 % CI [35.2-65.3]) for patients with HI, and 70.4 months (95 % CI [54.3-86.5], p = 0.105) for NoHI patients.

Conclusions: In COPD and PH patients eligible for PH treatments, the presence of lung hyperinflation did not predict response to treatment. However, patients with high degree of lung hyperinflation had a significantly poorer response to PAH treatment than patients without lung hyperinflation. Further studies are needed to confirm these results and to investigate other determinants of response in this population.

Clinical Trial Registration: The study design has been registered on ClinicalTrials (NCT06613321).