Severe pulmonary hypertension associated with chronic obstructive pulmonary disease: A prospective French multicenter cohort

Background: A small proportion of patients with chronic obstructive pulmonary disease (COPD) patients present severe pulmonary hypertension (PH), defined by mean pulmonary artery pressure (mPAP) ≥35 mm Hg measured by right heart catheterization. Little is known about the characteristics of severe PH-COPD. The aim of the study based on a national registry was to describe this phenotype.

Methods: We prospectively included and followed patients with incident PH-COPD. Clinical, functional, hemodynamic data at inclusion and follow-up were retrieved. Survival assessed by Kaplan-Meier analysis was the primary end-point.

Results: From 2012 to 2016, 99 patients from 13 French centers were included in the study (82 males; median age 66.0 years [interquartile range 62.0-72.0]). At inclusion, most patients had marked dyspnea (55.6% and 22.2% New York Heart Association class III and IV, respectively). During 12 months before inclusion, 42.9% had an exacerbation requiring a hospitalization. Pulmonary function tests showed a moderate obstructive pattern with median (interquartile range) FEV₁ 50.0 [35.0-63.0] % predicted and low diffusing capacity for carbon monoxide, median 20.0 [16.5-30.6] % predicted. The median values for PaO₂ and PaCO₂ on room air were 50.0 [44.8-62.0] and 36.0 [31.1-43.0] mm Hg. Median values of mPAP, pulmonary artery occlusion pressure, cardiac index and pulmonary vascular resistance were 42.0 [37.0-48.0] mm Hg, 11.0 [9.0-14.0] mm Hg, 3.0 [2.4-3.6] L/min/m², and 6.3 [4.2-7.9] WU, respectively. Mean restricted survival was 15.0 [13.9-16.0] months.

Conclusions: Severe PH-COPD is characterized by moderate airway obstruction but marked dyspnea and marked hypoxemia, low DLCO and high mPAP. This phenotype is associated with poor prognosis.