Vasoreactivity and inhaled treprostinil response in interstitial lung disease pulmonary hypertension

Abstract

IntroductionDespite shared features with pulmonary arterial hypertension, acute vasoreactivity in pulmonary hypertension with interstitial lung disease (PH-ILD) is not well characterized, including its potential ability to predict therapeutic outcomes. We sought to determine if acute vasoreactivity in PH-ILD to oxygen (O2) and inhaled nitric oxide (iNO) predicts inhaled treprostinil (iTre) outcomes.Materials and MethodsIn this retrospective cohort analysis, we identified treatment-naïve PH-ILD patients with vasoreactivity testing using O2 and O2+iNO. Six-month iTre outcome was assessed. “iTre improvement” required fulfillment of criteria on objective assessment without clinical worsening. “iTre failure” was defined by lack of objective improvement or a clinical worsening event.ResultsAmong 75 PH-ILD patients, mPAP decreased by −3 mmHg (−12.6%) and PVR by −1.3WU (−23.7%) with O2+iNO. With O2+iNO, mPAP decreased ≥10 mmHg to <40 mmHg in 4 patients (5.3%), and 23 (30.7%) had ≥20% reduction in mPAP and PVR. Among 33 iTre-treated patients, there were 13 improvements and 20 failures. The microvascular response, measured by distensibility, to O2 aloneversusO2+iNO correlated with 6-month iTre outcome. Patients with 6-month iTre improvement had large relative distensibility increases with O2+ iNO (versusfailure, 76.0%versus15.3%, p=0.004). Conversely, iTre failure was associated with increased distensibility with O2 alone (versusimprovement, 26.8%versus−3.9%, p=0.045).ConclusionsIn PH-ILD, the microvascular response to O2versusO2+iNO testing was associated with six-month iTre outcome, likely reflecting the differential contributions of hypoxic vasoconstriction and remodeling. Acute vasoreactivity may inform therapeutic decision-making in PH-ILD.