Conference Coverage

A 2-Step Approach May Spare Biopsy in Suspected Cardiac Amyloidosis

Edited by:
Ashton L. Stahl

Key Highlights

  • The retrospective study included 287 patients at 9 US amyloidosis centers.
  • The 2-step pathway potentially avoided endomyocardial biopsy in 44.6% of patients.
  • The pathway potentially spared biopsy in 79% of patients with transthyretin amyloid cardiomyopathy.

A 2-step diagnostic approach potentially spared endomyocardial biopsy (EMB) in nearly 45% of patients with suspected cardiac amyloidosis and monoclonal protein abnormalities, without misclassifying any light chain cardiomyopathy (AL-CM) cases. The authors presented the findings at the 2026 American Heart Association (AHA) Scientific Sessions.

According to the abstract, abnormal serum free light chain ratios (FLCR) and monoclonal proteins occur in 10% to 40% of patients with transthyretin amyloid cardiomyopathy (ATTR-CM). These abnormalities often reflect coexisting monoclonal gammopathy of undetermined significance and prompt EMB to exclude AL-CM.

The researchers conducted a retrospective multicenter study at 9 US amyloidosis centers. Eligible patients had suspected cardiac amyloidosis, cardiac amyloid radionuclide imaging (CARI), abnormal unadjusted FLCR and/or monoclonal protein on immunofixation, and EMB as the diagnostic gold standard.

The pathway first applied age- and estimated glomerular filtration rate (eGFR)–adjusted FLCR to reclassify patients. The second step used logistic regression to identify predictors of AL-CM and develop a diagnostic score. The researchers evaluated whether this approach could identify ATTR-CM despite evidence of monoclonal gammopathy and allow biopsy deferral without missing AL-CM.

Study Findings

The study included 287 patients: 56.4% had ATTR-CM and 43.6% had AL-CM. The mean age was 72.3 ± 9.9 years, and 80.1% were men. Reclassification using age- and eGFR-adjusted FLCR in the first step would have deferred EMB in 15% of patients.

For the second step, the logistic regression model incorporated Perugini grade on CARI, an absolute difference in serum free light chains (dFLC) of at least 12.5 mg/dL, and age younger than 78 years. A score of 1 or lower correctly identified ATTR-CM, potentially sparing an additional 85 patients, or 29.6% of the cohort, from EMB. Overall, biopsy was potentially avoidable in 44.6% of patients, including 79% of ATTR-CM cases. No AL-CM cases were misclassified, and the reported negative predictive value was 1.000.

Clinical Implications

According to the researchers, integrating adjusted FLCR with a model incorporating age, absolute dFLC, and Perugini grade could reduce unnecessary invasive procedures in routine practice. The reported biopsy avoidance reflects the pathway's application in this retrospective cohort.

Expert Commentary

“This strategy has the potential to reduce unnecessary invasive procedures in routine practice,” the researchers concluded.

Reference

Ansari B, Barrera NI, Teruya S, et al. A two-step endomyocardial biopsy-sparing approach to distinguish transthyretin amyloid cardiomyopathy from light chain cardiomyopathy in patients with monoclonal protein abnormalities. Abstract MDP2074. Presented at: American Heart Association Scientific Sessions 2026; November 9, 2026.