Is right ventricular-pulmonary arterial coupling a red flag in amyloidosis?

Background Cardiac amyloidosis (CA) is a cardiomyopathy characterized by amyloid infiltration in the myocardium. The value of right ventricular-pulmonary arterial (RV-PA) coupling as an echocardiography red flag in patients with CA has not been rigorously studied. Purpose We compared RV-PA and other different echocardiography parameters to discriminate CA from hypertrophic cardiomyopathy (HCM). Methods We retrospectively included consecutive patients with left ventricular wall thickness >1.4cm between 2023 to 2025. RV-PA coupling was estimated by the ratio between tricuspid annular plane systolic excursion (TAPSE) and pulmonary artery systolic pressure (PASP) on echocardiogram. Technetium-99m pyrophosphate (99mTc-PYP) cardiac scintigraphy and serum free light chain assay were performed. Both negative studies were considered hypertrophic cardiomyopathy. CA was diagnosed if 99mTc-PYP was positive (transthyretin amyloidosis (ATTR)) or serum free light chain assay (immunoglobulin light-chain amyloidosis (LCA)). We compared RV-PA and other different echocardiography parameters with T-test and x2 between patients with CA and HCM. We performed areas under the ROC curve to determinate the best cut-off points for diagnosing amyloidosis. Results Out of 38 patients, 19 were diagnosed with CA (7 ATTR and 12 LCA) and 19 HCM. There was no difference in gender or age in both groups (table 1). The left ventricular wall thickness (LVWT), relative wall thickness (RWT), left ventricular ejection fraction (LVEF) and left ventricular longitudinal strain (LVGLS) were higher in HCM; the left atrial volume index (LAVI), PASP and LVEF/LVGLS ratio were higher in CA; the TAPSE, right ventricular fractional area change (RVFAC) (%) and TAPSE/PASP ratio were lower in CA. The TAPSE/PASP ratio <0.39 was cut-off value for diagnosing amyloidosis (table 2), it was superior to the LVEF/LVGLS and equal to the LVGLS. Conclusion The RV-PA coupling, estimated by the ratio TAPSE/PASP, is a good echocardiogram parameter to differentiate CA from HCM. It is a highly reproducible parameter and has the advantage that it can be used on echocardiogram equipment that does not have strain software.