Changes in hemodynamic classification over time are common in systemic sclerosis-associated pulmonary hypertension: insights from the PHAROS cohort

Group classification of pulmonary hypertension (PH) is based on pulmonary artery wedge pressure (PAWP) on right heart catheterization (RHC). How hemodynamics, particularly PAWP, change over time in systemic sclerosis (SSc)-PH patients is unknown. SSc-PH patients enrolled in the prospective observational PHAROS registry who had > 1 RHC (n = 120) were included in this analysis. Patients were considered to have a "PAWP class change" if they had a PAWP ≤ 15 mmHg on RHC-1 and then a PAWP > 15 on RHC-2 or had a PAWP > 15 on RHC-1 and then PAWP ≤ 15 on RHC-2. There was a median time of 1.4 years between RHC-1 and RHC-2 and 75% of patients had a PH medication added after their initial RHC. PAWP increased significantly (11 ± 5 versus 13 ± 6 mmHg, P = 0.01) between RHC-1 and RHC-2, particularly for patients who were started on PH medications. Overall, 30% of patients who had a repeat RHC experienced a PAWP class change between their initial and follow-up RHC, independent of whether a PH medication was added. Patients initially classified as World Health Organization group 2 PH were most likely to change PAWP class over time. In conclusion, PAWP values commonly change to a significant degree in SSc-PH, which highlights the challenges in using a single time-point PAWP to define clinical classification groups.