How did the updated hemodynamic definitions affect the frequency of pulmonary hypertension in patients with systemic sclerosis?

Pulmonary hypertension (PH) is a one of the major causes of death in patients with systemic sclerosis (SSc). In this study, we investigated the impact of updated hemodynamic definition proposed by the 6th PH World Symposium (6th WSPH) on the frequency of PH and its subtypes in patients with SSc. Patients with SSc admitted between 2015 and 2019 and who underwent right heart catheterization (RHC) were included. The frequency of PH and its subgroups based on the hemodynamic definitions of both 2015 European Society of Cardiology/European respiratory Society (ESC/ERS) PH guidelines and 6th WSPH was compared. Of the 65 patients with SSc, 23 (35.4%) had normal mean pulmonary arterial pressure (mPAP), 20 (30.8%) had mildly elevated mPAP (21-24 mm Hg), and 22 (33.8%) had PH [pulmonary arterial hypertension (PAH) (n=16, 24.6%), group 2 PH (n=5, 7.7%), group 3 PH (n=1, 1.5%)] according to the 2015 ESC/ERS PH definition. Based on the updated criteria, 7 (10.8% of total cohort) additional patients were reclassified as having PH [PAH (n=3), group 2 PH (n=3), group 3 PH (n=1)]. The impact of the updated definition on the frequency of PH and PAH in our cohort was greater than previously reported, which may be caused by the difference in screening strategies for PAH.