Pulmonary vascular reactivity in severe pulmonary hypertension associated with COPD

Severe pulmonary hypertension (PH) is a rare clinically significant complication of COPD. The prognostic relevance of acute pulmonary vasoreactivity is well defined in pulmonary arterial hypertension (PAH) but remains poorly understood in PH-COPD.

We reported in a retrospective cohort study the clinical, functional and haemodynamic 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 per cent decrease in pulmonary vascular resistance (PVR) during nitric oxide (NO) testing (ΔPVR post-NO).

42 patients (female/male ratio 0.2, aged 65 (59-71) years) with severe PH-COPD (PVR 7.4 (6.2-9.3) WU, forced expiratory volume in 1 s 61 (50-84)%, diffusing capacity of the lung for carbon monoxide (D _LCO) 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.

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.