Assessment of right ventricular myocardial stiffness by cardiac elastography in patients with transthyretin amyloidosis

Amyloidosis is a group of diseases characterized by the deposition of misfolded protein fragments, forming insoluble fibrils in organs and tissues. Transthyretin (ATTR) amyloidosis, particularly cardiac amyloidosis (CA), leads to myocardial stiffness and heart failure. Right ventricular (RV) involvement is common in CA, but assessing RV stiffness noninvasively is challenging. This study aimed to evaluate RV stiffness using shear wave elastography (SWE) and correlate the findings with clinical, laboratory, and echocardiographic parameters. In this prospective, single-center, cross-sectional study, 60 patients were divided into three groups: 20 with cardiac ATTR amyloidosis (ATTR-CM), 20 with non-cardiac ATTR amyloidosis (ATTR non-CM), and 20 healthy controls. Myocardial stiffness was measured using SWE in the free wall of the RV. Pearson's and Spearman's correlation coefficients were used for statistical analysis, with significance set at p < 0.05. RV SWE values showed a strong positive correlation with functional class and a moderate correlation with BNP and troponin I levels. A significant negative correlation was found between RV SWE values and the 6-minute walk test distance. SWE also correlated with echocardiographic variables like interventricular septum thickness and RV basal diameter. An SWE cutoff of ≥ 4.6. kPa was associated with cardiac involvement, showing 65 % sensitivity and 76 % specificity. SWE is a valuable noninvasive technique for assessing RV stiffness in CA patients, correlating well with clinical and echocardiographic parameters. An RV SWE value of ≥ 4.6 kPa could aid in early detection of cardiac involvement in ATTR amyloidosis, improving diagnosis and management.