Criteria
Mayo staging system for immunoglobulin light chain (AL) amyloidosis (2012)[94]
Based on the following three prognostic markers:
N-terminal pro-B-type natriuretic peptide (NT-proBNP) ≥1800 ng/L
Cardiac troponin T (cTnT) ≥0.025 micrograms/L
Difference between involved and uninvolved serum free light chains (dFLC) ≥180 mg/L.
Each prognostic marker is assigned a score of 1. Stage is determined based on the total score:
Stage I: total score = 0
Stage II: total score = 1
Stage III: total score = 2
Stage IV: total score = 3
Conversion tables for use of B-type natriuretic peptide (BNP) instead of NT-proBNP, and for use of cardiac troponin I (cTnI) or high-sensitivity cTnT (hs-cTnT) instead of cTnT, have been published.[62][105]
Mayo staging system for immunoglobulin light chain (AL) amyloidosis (2004) with European modifications[93][95]
Based on the following risk factors:
N-terminal pro-B-type natriuretic peptide (NT-proBNP) ≥332 ng/L
Cardiac troponin T (cTnT) ≥0.035 microgram/L; or cardiac troponin I (cTnI) ≥0.1 microgram/L
Stage is determined based on the presence of these risk factors (an NT-proBNP cutoff of 8500 ng/L is used to subclassify stage III):
Stage I: no risk factors
Stage II: 1 risk factor
Stage IIIA: 2 risk factors (with NT-proBNP 332 to <8500 ng/L)
Stage IIIB: 2 risk factors (with NT-proBNP ≥8500 ng/L)
Conversion tables for use of B-type natriuretic peptide (BNP) instead of NT-proBNP, and high-sensitivity cTnT (hs-cTnT) instead of cTnT or cTnI, have been published.[62][105]
Haematological treatment response criteria for AL amyloidosis[106]
Complete response (CR): normal serum free light chain (FLC) levels with a normal kappa/lambda ratio and negative serum and urine immunofixation
Very good partial response (VGPR): difference between involved and uninvolved serum FLC (dFLC) <40 mg/L
Partial response (PR): dFLC decrease ≥50%
No response: response is less than PR
A modification to this criteria has been proposed that uses negative serum and urine immunofixation, along with involved FLC ≤20 mg/L or dFLC ≤10 mg/L, as a criteria for CR (i.e., instead of a normal serum FLC ratio), which may provide improved survival discrimination.[107]
ASNC/AHA/ASE/EANM/HFSA/ISA/SCMR/ SNMMI expert consensus recommendations: diagnostic criteria[108]
Histological diagnosis of cardiac amyloidosis: Endomyocardial biopsy (amyloidogenic light chain, amyloidogenic transthyretin [ATTR], other subtypes)
Endomyocardial biopsy positive for cardiac amyloidosis with Congo red staining with apple-green birefringence under polarised light; typing by immunohistochemistry and/or mass spectrometry at specialised centres.
Histological diagnosis of cardiac amyloidosis: Extracardiac biopsy (ATTR)
ATTR cardiac amyloidosis is diagnosed when the following criteria are met:
Extracardiac biopsy proven AL amyloidosis, and
Typical cardiac imaging features.
Histological diagnosis of cardiac amyloidosis: Extracardiac biopsy (amyloidogenic light chain)
Amyloidogenic light chain cardiac amyloidosis is diagnosed when the following criteria are met:
Extracardiac biopsy proven AL amyloidosis, and
Typical cardiac imaging features, or
Abnormal cardiac biomarkers: abnormal age-adjusted NT-pro BNP or abnormal Troponin T/I/Hs-Troponin (with all other causes for these changes excluded).
Clinical diagnosis of ATTR cardiac amyloidosis: 99mTc-PYP, DPD, HMDP
ATTR cardiac amyloidosis is diagnosed when the following criteria are met:
99mTc-PYP, DPD, HMDP Grade 2 or 3 myocardial uptake of radiotracer, and
Absence of a clonal plasma cell process as assessed by serum FLCs and serum and urine immunofixation, and
Typical cardiac imaging features.
Typical imaging features of cardiac amyloidosis: any of the following imaging features (with all other causes for these cardiac manifestations, including hypertension, reasonably excluded)
Echocardiography (ATTR/amyloidogenic light chain)
Left ventricular (LV) wall thickness >12 mm
Relative apical sparing of global LS ratio (average of apical LS/average of combined mid+basal LS >1)
≥ Grade 2 diastolic dysfunction.
Cardiac magnetic resonance (ATTR/amyloidogenic light chain)
LV wall thickness >upper limit of normal for sex
Global extracellular volume >0.40
Diffuse late gadolinium enhancement
Abnormal gadolinium kinetics typical for amyloidosis, myocardial nulling prior to blood pool nulling.
PET: 18F-florbetapir or 18F-florbetaben PET (ATTR/amyloidogenic light chain)
Target to background (LV myocardium to blood pool) ratio >1.5
Retention index >0.030 minute^-1.
European society of cardiology working group on myocardial and pericardial disease: invasive (all types) cardiac amyloidosis diagnostic criteria[109]
Cardiac biopsy positive for amyloid, or
Extracardiac biopsy positive for amyloid, plus
Echocardiographic/cardiac magnetic resonance criteria.
Echocardiographic and cardiac magnetic resonance criteria are:
Echocardiography; unexplained LV thickness (≥12 mm) plus 1 or 2:
Characteristic echocardiography findings (≥2 of the following must be present):
Grade 2 or worse diastolic dysfunction
Reduced tissue Doppler s', e', and a' waves velocities (<5 cm/second)
Decreased global longitudinal LV strain (absolute value <-15%).
Multiparametric echocardiographic score ≥8 points:
Relative LV wall thickness (IVS+PWT)/LVEDD >0.6 (3 points)
Doppler E wave/eʹ wave velocities >11 (1 point)
Tricuspid annular plane systolic excursion ≤19 mm (2 points)
Left ventricular global longitudinal strain absolute value ≤-13% (1 point)
Systolic longitudinal strain apex to base ratio >2.9 (3 points).
Cardiac magnetic resonance
Characteristic CMR findings (a and b must be present):
Diffuse subendocardial or transmural late gadolinium enhancement
Abnormal gadolinium kinetics
ECV ≥0.40% (strongly supportive, but not essential/diagnostic).
European society of cardiology working group on myocardial and pericardial disease: non-invasive (ATTR only) cardiac amyloidosis diagnostic criteria[109]
Grade 2 or 3 cardiac uptake at diphosphonate scintigraphy, plus
Negative serum free light chains and negative serum and urine immunofixation, plus
Echocardiographic/cardiac magnetic resonance criteria (per European society of cardiology working group on myocardial and pericardial disease: invasive (all types) cardiac amyloidosis diagnostic criteria).
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