Thoracic fat pad biopsy in cardiac amyloidosis: diagnostic yield in an afro-caribbean population

Abstract Background Cardiac amyloidosis (CA) is associated with amyloid infiltration of the extra-cardiac tissue, which may occur in the early stages of the disease. This study evaluates the diagnostic utility of thoracic fat pad biopsy obtained during a pacemaker or ICD implantation as an alternative to the standard diagnostic criteria for systemic amyloidosis. Methods This exploratory, retrospective study included 27 patients with suspected or diagnosed CA who underwent pacemaker or defibrillator therapy. Results Of these, 16 patients were confirmed to have CA (15 with technetium-labeled bisphosphonate bone scintigraphy and 1 with protein electrophoresis and echocardiographic findings) while 11 were confirmed to be CA-negative. The thoracic fat pad biopsy demonstrated a specificity of 100% but a sensitivity of only 31%. Among patients with transthyretin (ATTR)-CA, the sensitivity remained similarly low, at 27%. These results are consistent with prior findings on abdominal fat pad biopsy in ATTR-CA, highlighting the limited diagnostic yield of this method. Conclusions Thoracic fat pad biopsy cannot be recommended as a standard diagnostic tool for CA, particularly in ATTR-CA, due to its poor sensitivity. However, in AL (amyloid light-chain) amyloidosis, this minimally invasive procedure may aid diagnosis without additional invasive interventions