Elsevier

JACC: Cardiovascular Imaging

Volume 7, Issue 2, February 2014, Pages 133-142
JACC: Cardiovascular Imaging

Original Research
CMR-Based Differentiation of AL and ATTR Cardiac Amyloidosis

https://doi.org/10.1016/j.jcmg.2013.08.015Get rights and content
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Objectives

This study was devised to describe the different cardiac magnetic resonance (CMR) appearances in light chain amyloid (AL) and transthyretin-related amyloidosis (ATTR).

Background

CMR is increasingly used to investigate patients with suspected amyloidosis. Global subendocardial late gadolinium enhancement (LGE) has been reported as typical of AL amyloidosis, whereas different patterns have been noted in ATTR amyloidosis.

Methods

We performed de novo analyses on original DICOM magnetic resonance imaging in 46 patients with cardiac AL amyloidosis and 51 patients with ATTR type who had been referred to a specialist amyloidosis center between 2007 and 2012 after CMR. Histological examination was performed in all cases, with immunohistochemistry, to confirm systemic amyloidosis.

Results

Patients' median age was 68 ± 10 years, and 74% were male. Left ventricular mass was markedly increased in ATTR amyloidosis (228 g [202 to 267 g]) compared with AL type (167 g [137 to 191 g]) (p < 0.001). LGE was detected in all but 1 cardiac amyloidosis patient (AL type) and was substantially more extensive in ATTR compared with AL amyloidosis. Ninety percent of ATTR patients demonstrated transmural LGE compared with 37% of AL patients (p < 0.001). Right ventricular LGE was apparent in all ATTR patients but in only 33 AL patients (72%) (p < 0.001). Despite these findings, survival was significantly better in cardiac ATTR amyloidosis compared with AL type. We derived an LGE scoring system (Query Amyloid Late Enhancement) that independently differentiated ATTR from AL amyloidosis and, when incorporated into a logistic regression model with age and wall thickness, detected ATTR type with 87% sensitivity and 96% specificity.

Conclusions

Transmural patterns of LGE distinguished ATTR from AL cardiac amyloidosis with high accuracy in this real-world analysis of CMR. Precise diagnosis of cardiac amyloidosis is crucial given the role of chemotherapy in AL type and with novel therapies for ATTR type currently in development.

Key Words

amyloid
cardiomyopathy
magnetic resonance imaging

Abbreviations and Acronyms

AL
light chain amyloid
ATTR
transthyretin-related amyloidosis
CI
confidence interval
CMR
cardiac magnetic resonance
DPD
99mTc-3,3-diphos- phono-1,2-propanodicarboxylic acid
LGE
late gadolinium enhancement
LV
left ventricular
LVEF
left ventricular ejection fraction
NT-proBNP
N-terminal pro–B-type natriuretic peptide
QALE
Query Amyloid Late Enhancement
RV
right ventricular
TTR
transthyretin

Cited by (0)

Dr. Dungu is supported by a British Heart Foundation Clinical Research Training Fellowship grant (FS/09/063/28026). All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.