Abstract
PurposeCardiac amyloidosis is a rare disorder, but it may lead to potentially life-threatening restrictive cardiomyopathy. Cardiac manifestations frequently occur in primary amyloidosis (AL) and familial amyloidosis (ATTR), but are uncommon in secondary amyloidosis (AA). Echocardiography is the method of choice for assessing cardiac amyloidosis. Amyloid deposits impair the function of sympathetic nerve endings. Disturbance of myocardial sympathetic innervations may play an important role in the remodelling process. 123I-MIBG can detect these innervation changes.MethodsPatients with biopsy-proven amyloidosis underwent general work-up, echocardiography and 123I-MIBG scintigraphy. Left ventricular internal dimensions and wall thickness were measured, and highly refractile cardiac echoes (sparkling) were analysed. Early (15 min) and late (4 h) heart-to-mediastinum ratio (HMR) and wash-out rate were determined after administration of MIBG.ResultsIncluded in the study were 61 patients (30 women and 31 men; mean age 62 years; 39 AL, 11 AA, 11 ATTR). Echocardiographic parameters were not significantly different between the groups. Sparkling was present in 72 % of ATTR patients, in 54 % of AL patients and in 45 % of AA patients. Mean late HMR in all patients was 2.3 ± 0.75, and the mean wash-out rate was 8.6 ± 14 % (the latter not significantly different between the patient groups). Late HMR was significantly lower in patients with echocardiographic signs of amyloidosis than in patients without (2.0 ± 0.70 versus 2.8 ± 0.58, p < 0.001). Wash-out rates were significantly higher in these patients (−3.3 ± 9.9 % vs. 17 ± 10 %, p < 0.001). In ATTR patients without echocardiographic signs of amyloidosis, HMR was lower than in patients with the other types (2.0 ± 0.59 vs. 2.9 ± 0.50, p = 0.007).ConclusionMIBG HMR is lower and wash-out rate is higher in patients with echocardiographic signs of amyloidosis. Also, 123I-MIBG scintigraphy can detect cardiac denervation in ATTR patients before signs of amyloidosis are evident on echocardiography.
Highlights
Amyloidosis comprises a group of diseases characterized by deposition of protein fibrils with a cross-β-pleated sheet molecular structure
It is frequent in primary amyloidosis and familial amyloidosis, Eur J Nucl Med Mol Imaging (2012) 39:1609–1617 but uncommon in secondary amyloidosis
The purpose of this study was to determine if 123I-MIBG scintigraphy is able to identify cardiac sympathetic denervation in patients with different types of early stage amyloidosis
Summary
Amyloidosis comprises a group of diseases characterized by deposition of protein fibrils with a cross-β-pleated sheet molecular structure. The deposition of these amyloid fibrils results in loss of organ function. About 50 % of all amyloidosis patients experience some cardiac manifestations related to the disease [1]. It is frequent in primary amyloidosis (immunoglobulin light chain, or AL type) and familial amyloidosis (transthyretin, or ATTR type, which leads to familial amyloidotic polyneuropathy, FAP), Eur J Nucl Med Mol Imaging (2012) 39:1609–1617 but uncommon in secondary amyloidosis (serum amyloid A protein, or AA type). Symptoms are milder and progression is slower, when compared to AL amyloidosis
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