Prognostic implications of right ventricular to pulmonary artery uncoupling in cardiac amyloidosis

Background Right ventricular–pulmonary arterial (RV–PA) uncoupling in cardiac amyloidosis (CA) has been underexplored, with focus mainly on tricuspid annular plane systolic excursion (TAPSE)/pulmonary artery systolic pressure (PASP). This study aims to evaluate the association of various echocardiographic surrogates of RV–PA coupling with outcomes in cardiac transthyretin (ATTR-CA) and light-chain (AL-CA) amyloidosis. Methods We analyzed RV–PA coupling in patients diagnosed with ATTR-CA and AL-CA at our center between 2014 and 2023. RV–PA coupling was assessed using TAPSE/PASP, fractional area change (FAC)/PASP, and RV free wall strain (RVFWS)/PASP. The primary endpoint was all-cause mortality. Results A total of 120 patients (86% ATTR-CA, 14% AL-CA) were included in the study (median age 77 years, 88% male). During a median follow-up period of 23 (IQR: 15–34) months, the primary endpoint occurred in 25 patients (21%). The study population was stratified based on the ROC-derived TAPSE/PASP cutoff of <0.30 mm/mmHg, demonstrating RV–PA uncoupling. Lower RV–PA coupling surrogates were independently associated with higher mortality (HR per +0.1 unit: TAPSE/PASP, 0.74, 95% CI: 0.59–0.93, p = 0.011; FAC/PASP, 0.87, 0.77–0.98, p = 0.018; RVFWS/PASP, 0.78, 0.63–0.97, p = 0.024). TAPSE/PASP demonstrated the strongest prognostic discrimination (AUC: 0.79, bootstrapped 95% CI: 0.66–0.91), compared with FAC/PASP (AUC: 0.75, 0.58–0.91) and RVFWS/PASP (AUC: 0.72, 0.52–0.87). Conclusions RV–PA uncoupling may be linked to a higher risk of all-cause mortality in CA. TAPSE/PASP outperformed numerically FAC/PASP and RVFWS/PASP in predicting long-term survival, although it did not clearly outperform established RV function parameters.