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Cardiac Amyloidosis

A rare, underdiagnosed, life-threatening disease
associated with progressive heart failure

Home > Cardiac Amyloidosis

Amyloidosis is a group of diseases which are characterized by the build-up of abnormal deposits of amyloid fibrils

These amyloid fibrils composed of misfolded proteins called amyloid in organs throughout the body.1,2 Over time, these amyloid deposits may cause affected organs to stop working properly which can eventually lead to organ failure.1

There are several types of amyloidosis which are named based on the specific precursor protein.  One of the organs in the body that can be impacted by amyloid deposits is the heart.2,3,4 The most common types of amyloidosis affecting the heart, which is also known as cardiac amyloidosis, are light chain amyloidosis (AL) and transthyretin amyloidosis (ATTR).2,5,6,7 Each type of amyloidosis is characterized by the make-up of the amyloid protein that deposits in the body’s organs and tissues.1

Transthyretin amyloid cardiomyopathy (ATTR-CM) is a presentation of ATTR amyloidosis that primarily affects the heart.2,3,5 Over time, ATTR-CM causes the heart muscle to become stiff, eventually resulting in restrictive cardiomyopathy and progressive heart failure.2,3

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Causes and Symptoms of Transthyretin Amyloid Cardiomyopathy (ATTR-CM)

ATTR-CM occurs when transthyretin, a transport protein that naturally circulates in the blood, becomes unstable, dissociates, and misfolds.2,3 The misfolded protein can aggregate and form amyloid fibrils that build up in the heart as amyloid deposits, which cause the heart muscle to become stiff, eventually resulting in heart failure.2,3

People with ATTR-CM often present with symptoms similar to more common types of heart failure, which can lead to misdiagnosis.3,8 Symptoms include shortness of breath, fatigue, and swelling of the ankles.2,3,5 Often the disease is diagnosed only after symptoms have become severe.7

Receiving a correct diagnosis of ATTR-CM has historically been difficult because disease awareness is low.8 In fact, people living with ATTR-CM face delays in receiving the correct diagnosis, often waiting years after symptoms present.9

Education is vital to help recognize the signs and symptoms of ATTR-CM and improve diagnosis.

Two Sub-types of Transthyretin Amyloid Cardiomyopathy (ATTR-CM)

There are two forms of ATTR-CM, hereditary or variant (hATTR) and wild-type (wtATTR).10

The hereditary form of the disease is caused by a mutation in the transthyretin gene. It can occur in people as early as their 50s-60s.11

The wild-type form, which is thought to be more common, usually affects men after age 60.4,10,12

ATTR-CM is significantly under or misdiagnosed, making it difficult to estimate how many people are affected. It’s believed that only 1-2% of people with ATTR-CM are diagnosed.12

 

References
1. Sipe JD, Benson MD, Buxbaum JN, et al. Amyloid fibril proteins and amyloidosis: chemical identification and clinical classification International Society of Amyloidosis 2016 Nomenclature Guidelines. Amyloid. 2016;23(4):209-213.
2. Siddiqi OK, Ruberg FL. Cardiac amyloidosis: an update on pathophysiology, diagnosis and treatment. Trends Cardiovasc Med. 2017;1050-1738.
3. Maurer MS, Elliott P, Comenzo R, Semigran M, Rapezzi C. Addressing common questions encountered in the diagnosis and management of cardiac amyloidosis. Circulation. 2017;135(14):1357-1377.
4. Ando Y, Coelho T, Berk JL, et al. Guideline of transthyretin-related hereditary amyloidosis for clinicians. Orph J of Rare Diseases. 2013;8:31.
5. Rapezzi C, Merlini G, Quarta CC, et al. Systemic cardiac amyloidoses: disease profiles and clinical courses of the 3 main types. Circulation. 2009;120(13):1203-1212.
6. Narotsky DL, Castano A, Weinsaft JW, Bokhari S, Maurer MS. Wild-type transthyretin cardiac amyloidosis: novel insights from advanced imaging. Can J Cardiol. 2016;32(9):1166.e1-1166.e10.
7. Nativi-Nicolau J, Maurer MS. Amyloidosis cardiomyopathy: update in the diagnosis and treatment of the most common types.Curr Opin Cardiol. 2018;33(5):571-579.
8. Rapezzi C, Lorenzini M, Longhi S, et al. Cardiac amyloidosis: the great pretender. Heart Fail Rev. 2015;20(2):117-124.
9. Thirusha Lane, RN, Marianna Fontana, MD, Ana Martinez-Naharro, MD, et al. Natural history, quality of life, and outcome in cardiac transthyretin amyloidosis.Circulation. 2019;140:16–26.
10. Ruberg FL, Berk JL. Transthyretin (TTR) cardiac amyloidosis. Circulation. 2012;126(10):1286-1300. 3.
11. Swiecicki PL, Zhen DB,Mauermann ML, et al. Hereditary ATTR amyloidosis: a single-institution experience with 266 patients. Amyloid. 2015;22(2):123-131.
12. 2018 Internal Analysis, Data on File Pfizer Inc.