Abstract
Background: Amyloidosis is characterized by extracellular deposits of insoluble proteins that cause tissue damage. The three main types are monoclonal light chain (AL), wild-type transthyretin (wt-TTR) and mutated transthyretin (m-TTR) amyloidosis. Cardiac amyloidosis (CA) raises diagnostic challenges.
Objective: To assess the diagnostic accuracy of 99mTc-HMDP-scintigraphy for typing CA, differentiating CA from non-amyloid left ventricle hypertrophy (LVH), and predicting outcomes.
Methods: 121 patients with suspected CA underwent 99mTc-HMDP-scintigraphy in addition to standard investigations.
Results: CA was diagnosed in all AL (n = 14) and wt-TTR (n = 21). Among m-TTR (n = 34), 26 had CA, 4 neuropathy without CA and 4 were asymptomatic carriers. Of the 52 patients with non-amyloid heart disease, 37 had LVH and served as controls. 99mTc-HMDP cardiac uptake occurred in all wt-TTR, in m-TTR with CA except two and in one AL. A visual score ≥ 2 was 100% specific for diagnosing TTR-CA. Among TTR-CA, heart-to-skull retention (HR/SR) correlated with CA severity (LVEF and NT-proBNP). Median follow-up was 111 days (50;343). In a multivariate Cox model including clinical, echocardiographic and scintigraphic variables, NYHA III-IV and HR/SR > 1.94 predicted acute heart failure and/or death.
Conclusions: This preliminary study suggests that 99mTc-HMDP-scintigraphy may aid differentiation between transthyretin and AL-CA as well as CA from other LVHs. 99mTc-HMDP-scintigraphy appears to provide prognostic information in CA.
Acknowledgements
We thank all the physicians involved in the Amyloidosis Network of the Henri Mondor Hospital who participated in the assessment and care of the patients included in this study. We also thank A Wolfe MD for editing the English-language.
Declaration of interest
The authors report no conflict of interest.
Supplementary material available online