Cardiac amyloidosis (CA) is a serious condition characterized by the extracellular deposition of amyloid fibrils within heart tissue, leading to infiltrative cardiomyopathy and heart failure with preserved ejection fraction (HFpEF). While CA's features have been recognized for years, its prevalence in elderly patients with HF is increasingly noted. The disease is classified into transthyretin (ATTR) or light chain (AL) amyloidosis.
ATTR CA can result from a genetic mutation in the TTR gene (ATTRv) or age-related deposition from wildtype ATTR (ATTRwt). Cardiac involvement in AL amyloidosis is attributed to extracellular amyloid fibril deposition in the myocardium or direct cardiotoxicity from fibril aggregates. Accurate evaluation of CA is now possible using cardiac magnetic resonance imaging and bone scintigraphy tracers.
Advancements in Diagnosis and Typing
Typing of amyloid fibrils, a critical determinant of therapy, has improved with the wider availability of laser capture and mass spectrometry of histologic specimens. This advancement allows for specific and accurate evaluation of CA, facilitating tailored treatment strategies.
Emerging Therapeutic Strategies
Treatment strategies for CA have recently undergone transformative changes, leading to progress in outcomes for certain patients. Novel, disease-modifying strategies evaluated in clinical trials include RNA inhibitors, fibril formation stabilizers and inhibitors, and immunotherapeutic targeting of amyloid deposits. These approaches hold promise for improving outcomes in systemic and cardiac amyloidoses.
Challenges and Future Directions
Survival in CA has improved markedly as novel chemotherapy agents have become available, but challenges remain in advanced disease. Broadening the amyloid-specific therapeutic landscape may further improve outcomes. The focus is on developing therapies that target the underlying mechanisms of amyloid fibril formation and deposition.
