A 74-year-old man has progressive exertional dyspnea with bilateral carpal tunnel syndrome history. Echo shows concentric LV wall thickness of 16 mm with LVEF 55% and a restrictive filling pattern. ECG shows low voltage limb leads. Cardiac scintigraphy with technetium pyrophosphate shows grade 3 diffuse uptake, and serum free light chains with serum/urine immunofixation are negative. Which is the most appropriate next step?

• A Start tafamidis ✓
• B Start high-dose melphalan with autologous stem cell transplant
• C Perform endomyocardial biopsy before any therapy
• D Start sacubitril-valsartan and titrate to maximum dose

Explanation

Grade 2 or 3 pyrophosphate uptake with no monoclonal protein on light chain and immunofixation testing is diagnostic of transthyretin cardiac amyloidosis without needing biopsy. Tafamidis, a TTR stabilizer, reduces mortality and hospitalization in ATTR cardiomyopathy. Melphalan and transplant are treatments for AL amyloidosis, excluded here by negative monoclonal screening. Sacubitril-valsartan offers no disease-specific benefit and hypotension limits its use in amyloidosis.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.