Prompt diagnosis of a wild-type transthyretin cardiac amyloidosis: Role of multimodality imaging

Abstract

Amyloidosis cardiomyopathy is a rare and underdiagnosed disease characterized by amyloid fibril deposition in the myocardium. The diagnosis of cardiac amyloidosis is often delayed due to a lack of awareness and the necessity of biopsy to confirm the diagnosis. Recent advances in cardiovascular imaging modalities have enhanced earlier recognition of this disease. A 66-year-old man experiences progressive shortness of breath for two weeks. Laboratory testing was significant for an elevation of cardiac biomarkers (creatine kinase: 522 U/L, troponin I: 0.10 ng/mL) and NT-pro-BNP (5074 pg/mL). He was diagnosed with acute coronary syndrome and received stent deployment. Nonetheless, progressive shortness of breath recurred in 2 months. Transthoracic echocardiography (TTE) demonstrated an increased left ventricular (LV) wall thickness with apical sparing. Cardiac magnetic resonance (CMR) imaging demonstrated high native T1 value, increased extracellular volume fraction as well as diffused subendocardial late gadolinium enhancement. Technetium-99m pyrophosphate (99mTc-PYP) scintigraphy, endomyocardial biopsy (EMB), and the genetic study confirmed the diagnosis of wild-type transthyretin amyloidosis (ATTRwt). The nonspecific clinical manifestations, lack of diagnostic biomarkers, and the rarity of systemic amyloidosis usually lead to delayed diagnosis and treatment. Our objective is to emphasize the role of multimodalities imaging in reducing delays to the diagnosis of cardiac amyloidosis.