Changes in Myocardial Light Chain Amyloid Burden After Plasma Cell Therapy

Area of Science:

• Cardiology
• Nuclear Medicine
• Oncology

Background:

• Current light chain (AL) amyloidosis therapies target plasma cells, but their impact on heart amyloid deposits is unclear.
• Understanding myocardial amyloid burden changes is crucial for assessing treatment efficacy.

Purpose of the Study:

• To evaluate longitudinal changes in myocardial amyloid burden following plasma cell-targeted chemotherapy.
• To correlate amyloid burden changes with cardiac biomarkers and remodeling.

Main Methods:

• Prospective study of 81 patients with biopsy-proven AL amyloidosis.
• Serial 18F-florbetapir PET/CT and cardiac MRI (including ECV) at baseline, 6, and 12 months.
• Molecular amyloid burden assessed by 18F-florbetapir %ID; biomarker response defined by NT-proBNP changes.

Main Results:

• Myocardial amyloid burden (%ID) significantly decreased by 6 and 12 months in AL amyloid cardiomyopathy patients.
• %ID reduction correlated with NT-proBNP response and was significant in biomarker responders.
• Extracellular volume (ECV) did not change in responders but increased in non-responders; %ID did not change in non-cardiomyopathy patients.

Conclusions:

• Plasma cell therapy effectively reduces myocardial AL amyloid burden, detectable by 6 months using 18F-florbetapir PET/CT.
• 18F-florbetapir %ID and ECV changes reflect different aspects of myocardial remodeling in AL amyloidosis.
• Molecular imaging provides valuable insights into treatment response in AL amyloidosis.