Diagnosing Transthyretin Cardiac Amyloidosis*Screen for AL
Order the following tests1,2†
Also known as transthyretin amyloid cardiomyopathy (ATTR-CM).Electrophoresis alone is insufficient without immunofixation.3
- Serum kappa/lambda free light chains
- Serum protein electrophoresis with immunofixation
- Urine protein electrophoresis with immunofixation
Perform a PYP Scan‡
|AL test results2,3
|AL possible—refer to a hematology specialist for evaluation
|AL unlikely—refer to PYP results to determine if ATTR cardiac amyloidosis is possible
Order a PYP scan
- The ACC advises utilization of PYP cardiac imaging to diagnose ATTR cardiac amyloidosis2
Not FDA approved for the diagnosis of ATTR cardiac amyloidosis. Please consult individual labeling for risks.
99mTc-PYP radionuclide imaging as a diagnostic modality§
- Both planar and SPECT imaging should be evaluated for diffuse uptake of PYP in the myocardium3
Multisocietal expert consensus recommendations highlight the importance of PYP cardiac imaging in diagnosing ATTR cardiac amyloidosis3
99mTc-PYP planar and SPECT/CT fusion showing myocardial uptake4||
99mTc-PYP radioactive tracer is a highly sensitive, noninvasive diagnostic imaging technique
- Used as an adjunct to diagnosis after ruling out AL, though not FDA approved for the diagnosis of ATTR cardiac amyloidosis
SPECT imaging is necessary for studies that show planar myocardial uptake because it can help differentiate myocardial uptake from blood or overlying bone uptake3
|| Illustrative representation.
If clinical suspicion is high in spite of a negative or inconclusive scan, a biopsy should be considered.Interpretation3STEP 1
- The recommended time between injection of 99mTc-PYP and scan is 3 hours to maximize specificity¶
- Both planar and SPECT imaging should be reviewed and interpreted, irrespective of the timing of acquisition
- Evaluate planar and SPECT images to confirm diffuse radiotracer uptake in the myocardium
- Differentiate myocardial radiotracer uptake from residual blood pool activity on SPECT images
- If myocardial tracer uptake is visually present on SPECT, proceed to Step 2, semi-quantitative visual grading. If no myocardial tracer uptake is present on SPECT, the visual grade is 0
Semi-quantitative grading to distinguish AL from ATTR cardiac amyloidosis (1- or 3-hour approach)3#
Examine planar and SPECT images for tracer uptake in the myocardium relative to ribs and grade using the following scale:
PYP imaging is used as an adjunct to diagnosis after ruling out AL. AL is ruled out by testing for presence of monoclonal protein via serum and urine protein electrophoresis with immunofixation and serum free light chain assay.
Heart/contralateral lung (H/CL) uptake ratio assessment (when applicable)3
Circular target regions of interest (ROI) are drawn over the heart on the planar images and are mirrored over the contralateral chest to account for background and ribs.
Quantitation of cardiac 99mTc-PYP|| uptake using H/CL ratio4# Adapted from 2021 Expert Consensus Recommendations for Multimodality Imaging in Cardiac Amyloidosis.Next: See clinical data for VYNDAMAXContinueLoadingYou are now leaving PfizerPro
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it has provided or reviewed. PP-PFE-GBR-3859. November 2021
Not FDA approved for the diagnosis of ATTR cardiac amyloidosis. Please consult individual labeling for risks.The recommended time between injection of 99mTc-PYP and scan is 2 or 3 hours. The 1-hour approach is optional; if excess blood pool activity is noted, 3-hour imaging is recommended.Illustrative representation.AL=amyloid light-chain; ATTR=transthyretin amyloidosis; CT=computerized tomography; PYP=pyrophosphate; SPECT=single photon emission computed tomography.
- An H/CL ratio is calculated as the fraction of heart ROI mean counts to contralateral lung ROI mean counts. If discordant or the visual grade is equivocal, H/CL ratio may be helpful to classify equivocal visual Grade 1 vs 2 as positive or negative
- H/CL ratios of ≥1.5 at 1 hour can accurately identify ATTR cardiac amyloidosis if myocardial PYP uptake is visually confirmed on SPECT and systemic AL amyloidosis is excluded. An H/CL ratio of ≥1.3 at 3 hours can identify ATTR cardiac amyloidosis
- NOTE: Diagnosis of ATTR cardiac amyloidosis cannot be made solely based on H/CL ratio alone with PYP. H/CL ratio is not recommended if there is absence of myocardial uptake on SPECT
References: Maurer MS, Bokhari S, Damy T, et al. Expert consensus recommendations for the suspicion and diagnosis of transthyretin cardiac amyloidosis. Circ Heart Fail. 2019;12(9):e006075.Heidenreich PA, Bozkurt B, Aguilar D, et al. 2022 AHA/ACC/HFSA guideline for the management of heart failure: a report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation. 2022;145(18):e876-e894. Dorbala S, Ando Y, Bokhari S, et al. ASNC/AHA/ASE/EANM/HFSA/ISA/SCMR/SNMMI expert consensus recommendations for multimodality imaging in cardiac amyloidosis: part 1 of 2—evidence base and standardized methods of imaging. Circ Cardiovasc Imaging. 2021;14(7):e000029.Data on file. Pfizer Inc., New York, NY.