Myocardial Amyloid Burden in Transthyretin Amyloidosis.

Summary

In 1,541 ATTR participants, calibrated CMR-ECV thresholds provided strong diagnostic discrimination (<30% excludes, ≥40% confirms cardiac involvement) and stratified mortality risk in a graded fashion. ECV independently predicted death across biomarker and imaging strata, supporting its use for staging and therapeutic planning as disease-modifying agents expand.

Key Findings

• ECV <30% effectively excludes and ≥40% confirms cardiac involvement; 30–39% reflects early infiltration.
• Over median 2.8 years, ECV independently predicted mortality (HR 1.22 per 10% increase), with monotonic risk across ECV categories.
• Prognostic value persisted across biomarker strata (hs-troponin, NT-proBNP), Perugini grades 1–3, and LV mass strata.

Clinical Implications

Integrate ECV thresholds into diagnostic algorithms and risk stratification to guide timing and selection of stabilizers, silencers, and clearance therapies, and to monitor response.

Limitations

• Observational design with potential selection bias and heterogeneity of CMR protocols across centers
• ECV thresholds may require local calibration and validation in non-ATTR infiltrative phenotypes

Future Directions

Prospective validation and incorporation into treatment algorithms; use ECV to select and monitor patients in trials of amyloid-clearing agents.