Hemodynamic phenotypes in systemic sclerosis patients screened for pulmonary hypertension – impact of the new PH-definition

Background: Patients with systemic sclerosis (SSc) are at high risk of developing pulmonary hypertension (PH) which crucially affects patients’ symptoms, quality of life and prognosis. The aim of this study was to analyse the impact of the new hemodynamic definition of precapillary PH as proposed at the 2018 World Symposium on PH in SSc-patients. Methods: SSc-patients were screened for PH using clinical assessments as WHO-functional class, 6 minute walking distance (6MWD) and right heart catheterisation. Patients were divided into hemodynamic subgroups according to their mean pulmonary arterial pressure (mPAP) values with mPAP ≤20mmHg, 21-24mmHg and ≥25mmHg and their pulmonary vascular resistance (PVR) with PVR <3WU or ≥3WU. Results: The analysis included 158 patients (81% female, age 57±13years, 6MWD 438±101meters, 76% WHO-FC II or III) who were prospectively screened for PH. Among them, 40 had a manifest PH with an mPAP ≥25mmHg. Half of them presented with PVR ≥3WU. Thirteen presented with PH due to left heart disease. Out of 30 patients with mPAP 21-24mmHg, 4 (13%) met the new definition criteria of PH. Out of 88 patients with mPAP <21mmHg, 3 presented with PVR ≥3WU. Conclusions: The new definition of precapillary PH may allow detecting an additional ~10% of PH patients with mPAP 21-24mmHg. On the other hand, 11/27 patients (40.7%), would be classified as “normal” due to PVR <3WU. In this study suggest the cut-off value of mPAP >20mmHg presented as useful, while the criterium of PVR ≥3WU seemed too strict. Further studies will be needed to characterise thee hemodynamic subgroups and to define the extent of pulmonary vascular disease and treatability.