Abstract
Background
Patients with systemic sclerosis (SSc) are at high risk of developing concomitant pulmonary hypertension (PH) which has a crucial impact on the patients' symptoms, quality of life and prognosis.
Purpose
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 Nice in patients with SSc. Although recent data suggest that PVR >2 WU could be considered as abnormal in the new definition a conservative cut-off value of PVR ≥3 WU has been used.
Methods
SSc-patients were screened for PH using clinical assessments as WHO-functional class, 6 minute walking distance and right heart catheterisation. Patients were divided into hemodynamic subgroups according to their mean pulmonary arterial pressure (mPAP) values with mPAP ≤20 mmHg, 21–24 mmHg and ≥25 mmHg. These subgroups were further divided according to their pulmonary vascular resistance (PVR) with PVR <3 WU or ≥3 WU.
Results
One-hundred-twenty-two patients (79% female, age 57.6±12.7 years, 6MWD 439.5±98.1 meters, 70% diffuse cutaneous SSc, 30% limited cutaneous SSc, 53% WHO-FC II, 25% WHO-FC III) who were prospectively screened for PH were included in the analysis (Figure 1). Among them 26 had a symptomatic manifest PH using the cut-off value of mPAP ≥25 mmHg. Only half of this group presented with PVR ≥3 WU, the others had PVR <3 WU. Eight of these 26 PH-patients presented with PH due to left heart disease. Out of 21 patients with mildly elevated mPAP 21–24 mmHg, two (10%) met the new definition criteria of PH (pulmonary arterial wedge pressure <15 mmHg, mPAP 23 and 24 mmHg, PVR 3.0 and 3.2 WU, CI 2.2 L/min/m2 both, WHO-FC II both, respectively). Out of 75 patients with mPAP <21 mmHg, three presented with PVR ≥3 WU.
Overview of systemic sclerosis patients
Conclusions
The new definition of precapillary pulmonary hypertension may on the one hand allow detecting an additional 10% of PH patients with mild elevated mPAP. On the other hand, eight of 13 patients (62%), who met the former definition of pulmonary arterial hypertension, would be classified as “normal” due to a lack of increase in PVR according to the new definition. The data of this study suggest that for SSc-patients the cut-off value of mPAP >20 mmHg is useful, but the criteria of PVR ≥3 WU may be too strict.
Further studies with larger sample sizes will be needed to better characterise these hemodynamic subgroups and to define the extent of pulmonary vascular disease and treatability.
Pulmonary Hypertension Phenotypes in Systemic Sclerosis: The Right Diagnosis for the Right Treatment
