Myocardial stiffness assessed by real-time 3D shear wave elastography discriminates accurately ATTR from AL cardiac amyloidosis
T Meki, A Zaroui, O Pedreira, M Kharoubi, R Lacoste-Badie, C Papadacci, M Tanter, E Messas, T Damy, M PernotAbstract
Background
Cardiac amyloidosis (CA) results from myocardial amyloid deposition, causing increased stiffness and diastolic dysfunction. Differentiating the two main types, Light-Chain (AL) and Transthyretin (ATTR), is critical: ATTR progresses slowly and responds to targeted therapies, whereas AL is rapidly progressive, directly cardiotoxic, and requires urgent chemotherapy. Currently, standard echocardiography cannot reliably differentiate AL from ATTR-CA. We hypothesized that myocardial stiffness, quantitatively assessed using transthoracic 3D shear wave elastography (3D-SWE), can distinguish between these etiologies.
Methods
72 patients with confirmed CA underwent echocardiography, bone scintigraphy, biopsy, blood tests, and 3D-SWE at a Hospital (France). Ten 3D-SWE acquisitions were performed per target myocardial segments: the anterior free wall of the right ventricle (RV), the basal anteroseptal (AS) wall in the parasternal long-axis view, and the apex in the apical four-chamber view. Shear wave velocity (SWV) was quantified within a 10x16x16 mm³ myocardial volume of each segment during diastasis using ECG gating (Fig A).
Results
The cohort comprised 44 patients with ATTR-CA (80±7 years), 24 with AL-CA (66±10 years), and 4 with non-typable CA (87±8 years) based on standard diagnostic criteria. All patients successfully underwent 3D-SWE scanning. While standard echocardiographic parameters failed to discriminate between the AL and ATTR groups, SWV was significantly higher in ATTR-CA compared to AL-CA patients in both the AS wall (p<0.001) and RV free wall (p<0.001), though not at the apex. A multiparametric diagnostic algorithm combining patient age, NT-proBNP levels, and median SWV in the AS and RV walls successfully classified all typable patients, achieving 100% sensitivity and 100% specificity within this cohort.
Conclusion
Myocardial stiffness measured by 3D-SWE can accurately discriminate between ATTR and AL cardiac amyloidosis, overcoming the limitations of standard echocardiography. This non-invasive approach demonstrates excellent accuracy and holds tremendous promise as a front-line tool for expediting type-specific CA diagnosis and monitoring.Myocardial stiffness of AL and ATTR CA