Prognostic Value of Echocardiographic Coupling Metrics in Systemic Sclerosis-Associated Pulmonary Vascular Disease

Abstract

Ineffective right ventricular (RV) adaptation to increasing pulmonary arterial (PA) afterload in pulmonary vascular disease (PVD) significantly contributes to morbidity and mortality. PVD in systemic sclerosis (SSc) arises through various mechanisms, yet detecting abnormal contractile response remains challenging. Here, we examine whether echocardiographic RV-PA coupling metrics correlate with invasive pressure-volume (PV) loops, enhancing the prediction of adverse clinical outcomes in SSc-PVD patients. Prospectively enrolled patients with SSc-PVD with paired echocardiogram and PV loops were included. Linear regression and receiver-operating curve (ROC) analysis were used to assess the relationship between tricuspid annular plane systolic excursion (TAPSE)/PA systolic pressure (PASP), fractional area change (FAC)/PASP, tissue Doppler velocity (TDI S')/PASP, RV free wall strain (RVFWS)/PASP and coupling thresholds defined by end-systolic to end-arterial elastance (Ees/Ea), obtained by the multi-beat method. The contribution of right atrial strain (RAS) to RV-PA coupling parameters was also investigated. Kaplan-Meier analysis was used to identify the relationship between coupling ratios and composite outcomes including clinical worsening, lung transplant, and death. 42 patients with SSc were studied with mean age 59 ± 12 years, 91% female and varying degrees of PVD: mPAP 29.5 ± 12.8 mmHg, PVR 4.7 ± 4.2 WU, PCWP 10.3 ± 4.1 mmHg. Echocardiographic coupling metrics including TAPSE/PASP, FAC/PASP, TDI S'/PASP, RVFWSglobal and RVFWSbasal/PASP, and RASreservoir/PASP were linearly associated with Ees/Ea. At cut-points obtained through ROC analysis, all ratios were predictive of RV-PA uncoupling, defined by Ees/Ea, and composite outcomes. Additionally, RASreservoir/RVFWS correlated with Ees/Ea even after adjustment for PASP, suggesting that diminished RAS further impacts RV performance and coupling. Echocardiographic RV-PA coupling ratios strongly correlate with invasive Ees/Ea and predict adverse clinical outcomes in SSc patients across the spectrum of PVD. Further, we demonstrate how RAS impacts RV performance. These findings may refine risk stratification and prognostication in this at-risk cohort.