Right atrial function for the prediction of prognosis in connective tissue disease-associated pulmonary arterial hypertension: a study with two-dimensional speckle tracking

Pulmonary arterial hypertension (PAH) is a serious and often fatal complication of connective tissue disease (CTD). Right atrial (RA) function is essential to maintaining adequate total right heart function in PAH. However, little is known about prognostic utility of RA function in CTD-PAH. RA longitudinal strain (LS) and strain rate (LSR) were evaluated in 53 consecutive patients (51 female, mean age 42 +/- 15 years) with CTD-PAH, including systemic lupus erythematosus (SLE) (33.7%), mixed connective tissue disease (MCTD) (32.1%), primary Sjogren's syndrome (pSS) (26.4%), and systemic sclerosis (SSc) (3.8%). At a mean follow-up of 19.3 +/- 10.9 months, 20 patients (37.7%) were clinically worse. The group with clinical events had worse clinical conditions and poorer RA function at baseline compared with the group that had no clinical events. RA LS independently reflected World Health Organization functional class (WHO FC) after adjusting for RA area (RAA), tricuspid regurgitation (TR) grade, right ventricular (RV) global longitudinal strain (GLS), and pulmonary vascular resistance (PVR) (P = 0.006). Receiver operator characteristic (ROC) curve analysis indicated that RA LS < 22.9% was predictive of clinical worsening during follow-up (sensitivity = 80%; specificity = 87.9%; area under the curve (AUC) = 0.858), and the Kaplan-Meier curve confirmed that RA LS >= 22.9% was associated with more favorable long-term outcomes compared to RA LS < 22.9% (log-rank P < 0.01). On univariate Cox proportional hazards analysis, PVR, RVGLS, RAA, and RA LS were associated with long-term outcome, while RA LS was the only independent predictor in the multivariate analysis. Our findings suggest that RA LS measurements by speckle-tracking echocardiography (STE) can independently reflect the extent of right heart failure and predict clinical outcomes in patients with CTD-PAH. RA LS < 22.9% is associated with a higher risk of clinical worsening.