Aims: Right atrial (RA) dilatation may be important for patients' outcome in pulmonary arterial hypertension (PAH). The aim of this study was to examine the longitudinal RA and right ventricular (RV) remodelling in PAH patients using real-time three-dimensional echocardiography (3DE) and their relation to clinical outcome.
Methods and results: Sixty-two consecutive PAH patients were studied and compared with a control group of 30 healthy volunteers. RA and RV sphericity indices were measured with 3DE. RV ejection fraction (RVEF), RA volume (RAvol), and the quantification of jet area of tricuspid regurgitation (TR) were measured. Two observers were used for reproducibility assessment. The geometrical change of RA and RV was assessed in relation to clinical outcome, as defined by the increase of functional class or admission to the hospital due to right heart failure. Over 1 year of follow-up, there was significant increase of RA sphericity index (0.85±0.16 vs. 1.2±0.24, P<0.01), RV dilatation (RV sphericity index 0.71±0.07 vs. 0.98±0.04, P<0.01), as well as deterioration of RV systolic function (RVEF 33±8.2 vs. 28±7.6%, P<0.01). Twenty-three patients (37%) had a clinical deterioration within 1 year. An increase of RA sphericity index>0.24 predicted clinical deterioration with a sensitivity of 96% and a specificity of 90% [area under the curve (AUC) 0.97]. RV sphericity index was less sensitive (70%) and specific (62%) in predicting clinical deterioration (AUC 0.649). The deterioration in RVEF had a sensitivity of 91.1% and a specificity of 35.3% (AUC 0.479) in predicting clinical deterioration. The dilatation of RA>14 mL over 1 year had high sensitivity at 82.6% but low specificity at 30.8% in predicting clinical deterioration.
Conclusion: PAH leads to RA and RV dilatation and functional deterioration which are linked to an adverse clinical outcome. 3DE measurement of RA sphericity index may be a suitable index in predicting clinical deterioration of PAH patients.