Abstracts
PO39
Monoclonal Gammopathy and Cardiac Amyloidosis Diagnosed by 99mTc-Pyrophosphate SPECT/CT: A Multicenter Observational Study
Introduction/Background/Significance: Cardiac amyloidosis is a progressive infiltrative cardiomyopathy associated with significant morbidity and mortality. Monoclonal gammopathies may coexist with different forms of systemic amyloidosis, including light-chain (AL) and transthyretin (ATTR) amyloidosis. Early differentiation between amyloid subtypes is essential for appropriate treatment. We evaluated the incidence and spectrum of cardiac amyloidosis detected by 99mTc-pyrophosphate SPECT/CT in patients with monoclonal gammopathy and related plasma cell disorders.
Materials and Methods/Case Presentation/Objective:
Results/Description/Main Outcome Measure(s): Seventy patients underwent SPECT/CT evaluation. Cardiac amyloidosis was confirmed in 29 patients (41%). Median age was 58 years, with 39 women and 31 men. Forty-two patients had multiple myeloma, three AA amyloidosis, eighteen ATTR amyloidosis, and seven AL amyloidosis. Cardiac involvement was identified in only 1 of 42 (2.3%) patients with multiple myeloma, whereas all patients with ATTR, AL, and AA amyloidosis demonstrated cardiac infiltration. ATTR amyloidosis showed the most extensive involvement (Perugini grade III in 13/18 patients), significantly higher than other groups (p=0.0001).
Conclusion(s).: Although cardiac amyloid infiltration was uncommon in patients with multiple myeloma alone, it was consistently observed in patients with established ATTR, AL, and AA amyloidosis. 99mTc-pyrophosphate SPECT/CT is a valuable, noninvasive imaging modality for the diagnosis and characterization of cardiac amyloidosis, particularly ATTR, facilitating timely diagnosis and appropriate therapeutic decision-making.
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Materials and Methods/Case Presentation/Objective:
This multicenter ambispective observational study included patients evaluated between September 2018 and May 2024 who underwent echocardiographic assessment during the work-up of monoclonal gammopathy. Patients with echocardiographic findings suggestive of cardiac amyloidosis underwent 99mTc-pyrophosphate SPECT/CT. Cardiac amyloidosis was defined as Perugini grade II or III uptake. Additional investigations included serum free light chains, serum and urine immunofixation, bone marrow examination, flow cytometry, and transthyretin testing when indicated.
Results/Description/Main Outcome Measure(s): Seventy patients underwent SPECT/CT evaluation. Cardiac amyloidosis was confirmed in 29 patients (41%). Median age was 58 years, with 39 women and 31 men. Forty-two patients had multiple myeloma, three AA amyloidosis, eighteen ATTR amyloidosis, and seven AL amyloidosis. Cardiac involvement was identified in only 1 of 42 (2.3%) patients with multiple myeloma, whereas all patients with ATTR, AL, and AA amyloidosis demonstrated cardiac infiltration. ATTR amyloidosis showed the most extensive involvement (Perugini grade III in 13/18 patients), significantly higher than other groups (p=0.0001).
Conclusion(s).: Although cardiac amyloid infiltration was uncommon in patients with multiple myeloma alone, it was consistently observed in patients with established ATTR, AL, and AA amyloidosis. 99mTc-pyrophosphate SPECT/CT is a valuable, noninvasive imaging modality for the diagnosis and characterization of cardiac amyloidosis, particularly ATTR, facilitating timely diagnosis and appropriate therapeutic decision-making.
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