The objective of this prospective study was to evaluate right ventricular function and pulmonary arterial compliance (PAC=stroke volume/pulse pressure) at rest and during exercise in patients with systemic sclerosis (SSc) with normal mean pulmonary artery pressures (mPAP) at rest, mildly elevated mPAP (mPAP 21-24mmHg) and manifest pulmonary hypertension (mPAP≥25mmHg).
Patients with SSc (n=112) underwent clinical assessment and right heart catheterization at rest and during exercise and were divided into three groups according to their resting mPAP values: normal mPAP (≤20mmHg), mildly elevated mPAP (21-24mmHg) and pulmonary hypertension (PH, mPAP ≥25mmHg). Results were compared between groups by ANOVA followed by post-hoc student's t-test.
Compared to patients with normal mPAP, patients with mildly elevated mPAP showed lower 6-minute-walking distance (6MWD; p<0.008), lower cardiac index (CI) (p=0.027) and higher PVR (p=0.0002) during exercise and lower PAC at rest (p=0.016) and different stages of exercise (25 Watts p=0.033, 75 Watts p=0.024).
The results of this study suggest that impaired 6MWD in SSc-patients with mildly elevated mPAP might be caused by reduced PAC during exercise and reduced RV output reserve, presumably due to impaired coupling between the right ventricle and the pulmonary vasculature. These findings give further evidence for the clinical relevance of mildly elevated mPAP in patients with SSc. This article is protected by copyright. All rights reserved.