Alteration of Right Ventricular to Pulmonary Artery Coupling in Systemic Sclerosis

Abstract

Purpose Pulmonary arterial hypertension (PAH) associated with systemic sclerosis (SSc) has a worse prognosis than idiopathic PAH. This may be explained, at least in part, by an uncoupling of the right ventricle (RV) to the pulmonary artery (PA). It has been shown by Guazzi that the RV/PA coupling may be assessed non-invasively by echocardiograpy, using the TAPSE/PAPs ratio². We therefore sought to determine whether this ratio was impaired in SSc and whether this may be associated with other variables assessing the RV function. Methods In our retrospective, single center analysis, 3 groups of subjects were compared: 1) healthy subjects; 2) SSc patients without cardiac or pulmonary impairment; 3) SSc-related PAH patients. We collected anthropometrics, clinical, functional, biological and echocardiographic (focusing the right ventricle function) data. We also analyzed some hemodynamic data of patients who had a right-heart catheterization (RHC), according to international guidelines. Results The TAPSE/PAPs ratio, obtained among 10 patients with SSc-related PAH (Mean ± S.D: 0.26 ±0.13), 66 SSc-patients without PAH (0.91±0.30) and 34 healthy subjects (1.13±0.24) was significantly different between the 3 groups, even after correction for age and sex (figure). The decrease of the RV coupling was related, in the SSc group PAH-free, with a decreased s’ wave and an increased blood level of NT-proBNP. In the PAH group, there is a relation between the decrease of the RV-arterial coupling and a decreased s'wave, an increased PVR and a decreased right ventricular ejection volume. Conclusion The right ventriculo-arterial coupling, assessed by the TAPSE/PAPs ratio, is impaired in systemic sclerosis, regardless of the presence of PAH. A decrease in TAPSE/PAPs is correlated with the level of NT-proBNP and the s’ wave. This suggest a myocardial impairment in SSc which is non-related to the vascular complications.