Clinical characteristics and survival of systemic sclerosis patients with pulmonary hypertension and elevated wedge pressure: Observations from the PHAROS cohort

Background and objective: Systemic sclerosis (SSc) is a complex autoimmune disease commonly associated with pulmonary hypertension (PH). When associated with elevated pulmonary artery wedge pressure (PAWP), pulmonary artery pressure (PAP) is either in-proportion (post-capillary PH) or higher than expected (combined PH) relative to the increased PAWP.

Methods: Patients from the PHAROS registry (a prospective observational cohort of SSc-PH patients) who had mean PAP ≥ 25 and PAWP > 15 on right heart catheterization were stratified based on diastolic pressure gradient (DPG). Kaplan-Meier analysis was performed to compare survival and PH-related hospitalization. Baseline factors were compared between patients dying and those who survived using Cox regression analysis.

Results: A total of 59 patients were included, of whom 21 (36%) patients were classified as combined PH and 38 (64%) had post-capillary PH. No baseline characteristics were significantly different between the two groups. There were no differences in survival or PH-related hospitalization between the groups. The only baseline factor independently associated with death was lower 6-min walk distance (6MWD) (hazard ratio (HR): 1.33 per 25 m decrease, 95% CI: 1.11-1.59, P = 0.002). PH-specific medications were started during follow-up in significantly more patients in the combined PH group compared with the post-capillary group (86% vs 50%, P = 0.01).

Conclusion: Outcomes were similar between SSc patients with post-capillary PH and combined pre- and post-capillary PH. 6MWD at baseline can predict risk for death in SSc patients with PH and an elevated PAWP. More patients with combined PH were started on PH-specific medications, and the clinical benefit of treating this subgroup specifically in SSc patients needs further exploration.