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

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.

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.

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).

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.