Pulmonary hypertension and lung transplantation waitlist outcomes for hypersensitivity pneumonitis.

Background: Hypersensitivity pneumonitis is an interstitial lung disease that can progress to pulmonary hypertension which increases mortality. The European Society of Cardiology recently reduced the diagnostic criteria for precapillary pulmonary hypertension from mean pulmonary artery pressure ≥25mmHg to ≥20mmHg and pulmonary vascular resistance from ≥3Wu to ≥2Wu. Methods: We conducted a retrospective cohort study of the Scientific Registry of Transplant Recipients.1175 hypersensitivity pneumonitis patients listed for lung transplantation were divided into three groups based on the presence of precapillary pulmonary hypertension; those with pre-capillary pulmonary hypertension based on old criteria, new criteria, and those without precapillary pulmonary hypertension based on either criterion. The individual components of precapillary pulmonary hypertension were also assessed with three mean pulmonary artery pressure groups (≤20mmHg, >20mmHg to <25mmHg, ≥25 mmHg) and three pulmonary vascular resistance groups (≤2Wu, >2Wu to <3Wu, ≥3Wu). Survival analysis was performed. Results: Kaplan-Meier analysis showed a difference in waitlist survival probability among the mean pulmonary artery pressure groups and among the pulmonary vascular resistance groups driven by the most severe groups. Multivariate Cox regression showed no difference between the various pre-capillary pulmonary hypertension groups. Pulmonary vascular resistance ≥3Wu was associated with increased waitlist mortality. Conclusions: The new thresholds of mean pulmonary artery pressure and pulmonary vascular resistance do not appear to prognosticate waitlist outcomes when combined. PVR ≥3Wu is associated with worse waitlist outcomes and may be useful in prognostication.