Reduced myocardial 123-iodine metaiodobenzylguanidine uptake: a prognostic marker in familial amyloid polyneuropathy.

Abstract

BACKGROUND:

Transthyretin familial amyloid polyneuropathy is a hereditary form of amyloidosis characterized by sensorimotor and autonomic neuropathy, cardiac conduction defects, and infiltrative cardiomyopathy. Previous studies have suggested that myocardial sympathetic denervation assessed by 123-iodine metaiodobenzylguanidine (MIBG) imaging occurs early in disease progression. However, its prognostic significance was never evaluated. We aimed to study the long-term prognostic value of myocardial sympathetic denervation detected by MIBG imaging in transthyretin familial amyloid polyneuropathy.

METHODS AND RESULTS:

A total of 143 individuals with V30M transthyretin mutation underwent Holter, ambulatory blood pressure monitoring, echocardiography, and MIBG imaging. Time to all-cause death was compared with late heart-to-mediastinum MIBG uptake ratio (H/M; either in relation to the estimated lower limit of normal [1.60] or as a continuous variable) using Cox proportional hazards regression. Multivariable analyses were performed to test the prognostic accuracy of clinical, neurological, and cardiovascular parameters. During a median follow-up of 5.5 years, 32 (22%) patients died. Five-year mortality rate was 42% for late H/M <1.60 and 7% for late H/M ≥1.60 (hazard ratio, 7.19; P<0.001). Late H/M was identified as an independent prognostic predictor. Fifty-three patients were submitted to liver transplantation. In comparison with neurophysiological score-matched controls, transplanted patients had lower long-term mortality (hazard ratio, 0.32; P=0.012). Patients with late H/M<1.60 were at higher risk of unfavorable outcome but seemed to have benefited from liver transplantation.

CONCLUSIONS:

Cardiac sympathetic denervation as assessed by MIBG imaging is a useful prognostic marker in transthyretin familial amyloid polyneuropathy.

• Authors: Maria C Azevedo Coutinho, Nuno Cortez-Dias, Guilhermina Cantinho, Isabel Conceição, António Oliveira, Armando Bordalo e Sá, Susana Gonçalves, Ana G Almeida, Mamede de Carvalho, António Nunes Diogo
• Journal: Circulation. Cardiovascular imaging (Circ Cardiovasc Imaging) Vol. 6 Issue 5 Pg. 627-36 (Sep 2013) ISSN: 1942-0080 [Electronic] United States
• PMID: 23833285 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Validation Study)

Chemical References

• Prealbumin
• Radiopharmaceuticals
• 3-Iodobenzylguanidine

Topics

• 3-Iodobenzylguanidine
• Adult
• Aged
• Aged, 80 and over
• Amyloid Neuropathies, Familial (diagnostic imaging, genetics, mortality, therapy)
• Cardiomyopathies (diagnostic imaging, genetics, mortality, therapy)
• Echocardiography
• Electrocardiography, Ambulatory
• Female
• Genetic Predisposition to Disease
• Heart (innervation)
• Humans
• Kaplan-Meier Estimate
• Liver Transplantation
• Longitudinal Studies
• Male
• Middle Aged
• Multivariate Analysis
• Mutation
• Phenotype
• Prealbumin (genetics)
• Predictive Value of Tests
• Prognosis
• Proportional Hazards Models
• Prospective Studies
• Radionuclide Imaging
• Radiopharmaceuticals
• Reproducibility of Results
• Risk Factors
• Sympathetic Nervous System (diagnostic imaging)
• Time Factors
• Young Adult