Risk assessment in severe pulmonary hypertension due to interstitial lung disease

The updated hemodynamic definition of pulmonary hypertension (PH) due to interstitial lung disease (ILD) differentiates severe and non-severe phenotypes, but no further risk stratification strategy has been established or validated for severe PH due to ILD. We aimed to assess the prognostic value of a truncated version of the European Society of Cardiology/European Respiratory Society (ESC/ERS) PH risk stratification scheme in severe PH due to ILD.

We retrospectively analyzed 185 patients with severe PH (mean pulmonary artery pressure of ≥35 mm Hg or ≥25 mm Hg with cardiac index <2.0 liter/min/m²) due to ILD who were enrolled in the Giessen PH Registry after being referred for invasive diagnostic work-up of suspected PH during 1995‒2018. A truncated ESC/ERS risk stratification scheme (based on 8 parameters from the full scheme) was applied. Kaplan-Meier and univariate Cox regression analyses were used to evaluate transplant-free survival and hazard ratios, respectively.

During follow-up (median [interquartile range]: 19 [7-40] months), 146 events occurred. Using baseline data for risk stratification, 5-year transplant-free survival of low-, intermediate-, and high-risk groups was 43%, 15%, and 4%, respectively (log-rank p = 0.010; hazard ratio of high- vs low-risk group: 3.116 [95% CI: 1.428-6.800]). Using follow-up data (at 11 [6.0-32.5] months) for risk stratification, 5-year survival of low-, intermediate-, and high-risk groups was 22%, 3%, and 0%, respectively (log-rank p = 0.005).

The truncated ESC/ERS scheme was clinically useful and demonstrated prognostic relevance in severe PH due to ILD.