Risk stratifying systemic sclerosis-related pulmonary hypertension by left atrial strain.

Abstract

The objective of the study was to explore left atrial (LA) strain, a quantitative index of left ventricular (LV) diastolic function, in risk stratifying patients with SSc-related pulmonary hypertension (SSc-PH). This was an exploratory, retrospective single-centre study of 124 patients with SSc-PH confirmed on right heart catheterization. We quantified and clustered the three components of LA global longitudinal strain (GLS): (i) reservoir (systole); (ii) conduit (early diastole); and (iii) contractile (late diastole), using echocardiograms closest to timing of right heart catheterization. We applied both the Kaplan-Meier method and a Cox proportional hazards model to determine associations with our primary outcome of all-cause mortality. Using k-means clustering, we divided our cohort into three clusters: Cluster 1 (N = 40), Cluster 2 (N = 34) and Cluster 3 (N = 50). Compared with Cluster 1, Cluster 2 had the lowest median LA conduit strain, and Cluster 3 exhibited the lowest median LA contractile strain. There was a statistically significant difference in survival between clusters (log-rank P = 0.005). Median survival was 122.4 months, 67.9 months and 48.4 months for Cluster 1, Cluster 2 and Cluster 3, respectively. Compared with those in Cluster 1, patients in Cluster 2 and Cluster 3 had adjusted hazard ratios of 1.46 (95% CI: 0.71, 2.97) and 2.57 (95% CI: 1.32, 5.02) for all-cause mortality, respectively. Of the three LA GLS clusters, Cluster 3 had the shortest median survival. LA GLS may provide further risk stratification of patients with SSc-PH.