Abstract Body (Do not enter title and authors here): Background: Although ambient air pollution exposure has been linked with increased mortality in many cardiovascular or pulmonary diseases, its relationship with pulmonary arterial hypertension (PAH) is still unknown. The present study aims to investigate the association of ambient particulate matter (PM) exposure with pulmonary hemodynamics and long-term survival in patients with PAH in China.
Methods: This retrospective multi-center cohort study included 1511 participants who underwent invasive right heart catheterization and were eventually diagnosed with PAH from January 2014 to December 2020. The primary outcome was transplant-free survival from the time of diagnosis. The association of PM_2.5 and PM₁₀ with all-cause death or lung transplantation was assessed by fitting Cox proportional risk models. Generalized linear models were used to examine the relationship between PM exposure and pulmonary hemodynamic severity at baseline. Restricted cubic splines were used to describe exposure-response curves. Mediation analysis with bootstrap method was used to explore whether potential variables mediated the associations.
Results: During a median follow-up of 36.7 months, all-cause death or lung transplantation occurred in 149 patients. Per 10 µg/m³ increase of PM_2.5 and PM₁₀ were associated with 14.5% and 7.9% increased risk of primary outcomes adjusting for potential confounding variables, respectively. PM_2.5 and PM₁₀ were associated with European Society of Cardiology risk stratification and with pulmonary hemodynamics at baseline, in particular pulmonary vascular resistance (PVR), mean pulmonary artery pressure (mPAP), cardiac index, and mixed venous oxygen saturation (S_VO₂). Effect of PM may be mediated in part by impaired glucolipid metabolism and inflammation-associated lymphocyte.
Conclusions: Particulate matter exposure was associated with disease severity and pulmonary hemodynamics at baseline in patients with PAH, and higher chronic exposure to PM_2.5 and PM₁₀ independently predicted shorter transplant-free survival.