Pulmonary vascular reactivity in severe pulmonary hypertension associated with COPD

Rationale Severe pulmonary hypertension (PH) is a rare clinically significant complication of chronic obstructive pulmonary disease (COPD). The prognostic relevance of acute pulmonary vasoreactivity is well defined in pulmonary arterial hypertension (PAH) but remains poorly understood in PH-COPD. Methods We reported in a retrospective cohort study the clinical, functional, and hemodynamic characteristics, the response to PAH-approved drugs, and the overall survival of patients with severe PH-COPD from the French PH National Referral Centre, according to acute pulmonary vasoreactivity testing. The acute vasodilator response was defined as the percent decrease in pulmonary vascular resistance (PVR) during nitric oxide (NO) testing (ΔPVR post-NO). Results Forty-two patients (female/male ratio 0.2, age of 65 [59–71] years) with severe PH-COPD (PVR 7.4 [6.2–9.3] WU, forced expiratory volume in one second (FEV1) 61 [50–84]%, diffusing capacity for carbon monoxide (DLco) 24 [18–38]%) underwent NO testing at diagnosis. During NO testing, PVR decreased significantly from 7.4 [5.1–9.3] to 6.1 [5.0–8.5] WU (p<0.0001). An acute NO response (ΔPVR post-NO ≥19%) was associated with improved survival at 1, 3, and 5 years (93%, 70% and 61%) compared with patients with ΔPVR post-NO <19% (44%, 38% and 19%; p=0.01). Amongst 28 patients receiving PAH-approved drugs, ΔPVR post-NO correlated with PVR change at first reassessment. Conclusion In severe PH-COPD, acute pulmonary vasoreactivity is associated with improved long-term survival and a better response to PAH-approved therapies. Further studies are warranted to confirm that acute NO testing may help identify a specific PH-COPD subgroup likely to benefit from PAH-approved treatment.