From the Guidelines
The next diagnostic test after an echocardiogram suggests cardiac amyloidosis should be cardiac magnetic resonance imaging (CMR) with gadolinium contrast, followed by tissue biopsy for definitive diagnosis. This approach is supported by the most recent guidelines and studies, including the 2022 AHA/ACC/HFSA guideline for the management of heart failure 1 and the 2021 ASNC/AHA/ASE/EANM/HFSA/ISA/SCMR/SNMMI expert consensus recommendations for multimodality imaging in cardiac amyloidosis 1. CMR can identify characteristic patterns such as global subendocardial late gadolinium enhancement and abnormal myocardial nulling, which are highly suggestive of amyloid infiltration. For definitive diagnosis, tissue sampling is required, which can be done through endomyocardial biopsy (the gold standard) or through less invasive alternatives like abdominal fat pad aspiration, bone marrow biopsy, or biopsy of an affected organ if extracardiac involvement is present.
Some key points to consider in the diagnostic workup of cardiac amyloidosis include:
- The use of nuclear scintigraphy using technetium-labeled bone tracers (particularly 99mTc-PYP, 99mTc-DPD, or 99mTc-HMDP) which is highly specific for transthyretin (ATTR) amyloidosis and can often diagnose ATTR without the need for biopsy when combined with serum and urine protein electrophoresis to rule out light chain amyloidosis 1.
- Genetic testing should also be performed to distinguish between hereditary and wild-type ATTR amyloidosis, as this distinction has significant implications for treatment and family screening 1.
- The importance of a comprehensive diagnostic approach, as treatment differs significantly based on the type of amyloidosis identified, and accurate diagnosis is crucial for optimal patient outcomes 1.
Overall, the diagnostic workup of cardiac amyloidosis requires a multimodal approach, incorporating imaging, biopsy, and genetic testing to establish an accurate diagnosis and guide treatment decisions.
From the Research
Diagnostic Approach
If an echo suggests cardiac amyloidosis, the next diagnostic steps may involve:
- Further non-invasive imaging methods such as:
- These methods can help confirm the diagnosis and characterize the type of amyloidosis
Imaging Modalities
The following imaging modalities can be used to diagnose and assess cardiac amyloidosis:
- Echocardiography: can detect increased left ventricular wall thickness and diastolic dysfunction 3, 4, 5
- Cardiovascular MRI: can provide tissue characterization and help diagnose cardiac amyloidosis 2
- Bone scintigraphy: can help diagnose transthyretin amyloidosis (ATTR) 2
Diagnostic Challenges
Diagnosing cardiac amyloidosis can be challenging due to non-specific symptoms and the need for a high index of suspicion 2, 6
- A multimodal investigative approach is often required to diagnose this condition 6