Prognostic value of right atrial stiffness in systemic sclerosis

We hypothesised that right atrial (RA) size and mechanics may have prognostic role in systemic sclerosis (SSc) patients without manifest pulmonary arterial hypertension (PAH), thus we aimed to investigate the prognostic power of RA volume, strain and stiffness parameters alone and when added to the echocardiographic marker of RV longitudinal systolic function.

Seventy SSc patients (57±12 years) were enrolled into our follow-up study. They underwent standard echocardiographic and tissue Doppler measurements at baseline. In addition to maximal RA volume index, RA reservoir, conduit and contractile strain were measured with 2D speckle tracking technique. RA stiffness was calculated as ratio of TriE/e' to reservoir strain. Survival was assessed after 5 years. All-cause mortality was chosen as outcome. Sequential χ2 analysis was used to evaluate the incremental prognostic benefit of adding RA volume, strain or stiffness to tricuspid S (TriS).

During the follow-up period of 4.7±0.9 years, 6 patients (8.6%) died. When added to TriS in sequential Cox model, RA stiffness significantly improved the diagnostic performance of the model (Δχ2= 3.950; p=0.047) and remained independent predictor of the outcome (HR 2.460 (1.005-6.021); p=0.049). Vmax index and strain parameters did not show incremental prognostic value over TriS. Using ROC analysis, RA stiffness ≥0.156 was the best predictor of mortality (sensitivity=83.3%, specificity =89.1%, AUC=0.859).

RA stiffness is associated with all-cause mortality in SSc patients without PAH independent of and incremental to the RV longitudinal systolic function. It may be proposed as non-invasive marker for identifying patients with high mortality risk.