The clinical impact of acute vasoreactivity testing in patients with severe pulmonary hypertension associated with lung disease: A retrospective exploratory analysis.

BACKGROUND

The clinical impact of acute vasoreactivity testing with inhaled nitric oxide (NO testing) in severe pulmonary hypertension associated with lung disease (LD-PH) remains unknown.

METHODS

We retrospectively reviewed 48 consecutive patients with severe LD-PH (73 ± 9 years; male: 81%) who underwent NO testing between 2014 and 2022. We conducted an exploratory analysis of the association between the response to NO testing and both the efficacy of pulmonary vasodilators and prognosis.

RESULTS

NO testing demonstrated a significant improvement in hemodynamics, with an average reduction of 1.8 wood units in pulmonary vascular resistance (PVR) without a decrease of oxygen saturation. Patients were divided into the vasoreactive and non-vasoreactive groups based on the median PVR response (-15%) to NO testing. The vasoreactive group had a higher proportion of patients who initiated pulmonary vasodilators and had better long-term prognosis than that of the non-vasoreactive group (P = 0.03). Among the 36 patients (75%) who initiated pulmonary vasodilators after NO testing, the vasoreactive group demonstrated a significant improvement in the symptom, brain natriuretic peptide level, and hemodynamics at the first follow-up (median 4 months), whereas the non-vasoreactive group did not. Moreover, a correlation was observed between the change in PVR at NO testing and the change in PVR after initiation of pulmonary vasodilators (r = 0.42, P = 0.02).

CONCLUSIONS

The PVR response to NO testing associated with short-term efficacy of pulmonary vasodilators in patients with severe LD-PH. Prospective studies of PVR response to NO testing on the clinical efficacy in large-scale LD-PH cohorts are warranted.