/ Updated October 17th, 2022

Facts You Need To Know About Transthyretin Amyloid Cardiomyopathy (ATTR-cm)

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Facts About ATTR-cm

Transthyretin Amyloid Cardiomyopathy, or ATTR-cm, is a rare, life-threatening condition that affects the heart. Until recently, the condition was a relatively unknown and vague disease.

There are only two types of ATTMR-cm: hereditary transthyretin amyloid cardiomyopathy (hATTR-cm) and wild-type transthyretin amyloid cardiomyopathy (wATTR-cm)

Although there is no cure for this condition, there are measures and medications used to improve your quality of life and prolong your survival rate.

Until a few years ago, transthyretin amyloid cardiomyopathy (ATTR-cm) was a vague and unknown disease that was frequently misdiagnosed. This is mainly because it shared a lot of clinical features and symptoms with other heart diseases. Lately, however, it gained a lot of recognition among healthcare professionals and its prevalence among populations subsequently increased with increased awareness and diagnosis.

Learn about transthyretin amyloid cardiomyopathy (ATTR-cm) and some quick informative facts on the disease, types, causes, symptoms, diagnosis, treatment, and more in this article.

What Is Transthyretin Amyloid Cardiomyopathy (ATTR-cm)?

Transthyretin Amyloid Cardiomyopathy (ATTR-cm) is a rare, serious, and life-threatening condition that affects the heart. It occurs due to abnormally folded proteins called Transthyretin or TTR for short. Under normal conditions, this protein transports vitamin A and thyroxine hormone (from the thyroid gland) into the blood. But for ATTR-cm patients, this protein is misfolded and aggregates in the form of amyloid fibrils then deposits on the walls of the hearts, nerves, and other organs.

It's important to note that this is a progressive condition that can go undetected for years leading to major organ damage and other fatal serious complications like heart failure. Thus, early diagnosis and treatment are pivotal in improving the life expectancy and quality of life for patients with ATTR-cm.

Transthyretin Amyloid Cardiomyopathy (ATTR-cm) has 4 other alternative names, these include the following:

Cardiac amyloidosis
Amyloidosis ATTR
Transthyretin cardiac amyloidosis (ATTR-CM)
TTR amyloidosis

There Are Only Two Types of Transthyretin Amyloid Cardiomyopathy (ATTR-cm)

There are two types of ATTR-cm, and they differ in their etiologies. These types include the following:

Hereditary Transthyretin Amyloid Cardiomyopathy (hATTR-cm). This type generally runs in families, and it's caused by a mutation in the transthyretin (TTR) gene, which produces a faulty protein that misfolds and deposits amyloid fibrils on the heart, nerves, kidneys, and other organs. This faulty gene is inherited from generation to generation which is why it's recommended for those who carry the mutated variant of the TTR gene to seek genetic counseling before deciding to conceive.

Symptoms of hereditary transthyretin amyloid cardiomyopathy (hATTR-cm) start at any time between the ages of 20-80.

Risk factors for hereditary transthyretin amyloid cardiomyopathy (hATTR-cm) include the following:

A family history of ATTR-CM or heart failure
Old age (more than 50 years old), even though symptoms can appear between 20-80 years old
Sex, males have it more than females
Race, where it's more predominantly found in African Americans

Wild-type Transthyretin Amyloid Cardiomyopathy (wATTR-cm). This type is not inherited and doesn't run in families, but it's mostly associated with age. However, it also results from clumped proteins. It most commonly affects the normal functions of the heart and nerves and may cause other comorbidities like carpal tunnel syndrome (a condition that affects the hands causing pain, numbness, and tingling).

Symptoms of wild-type transthyretin amyloid cardiomyopathy (wATTR-cm) start after age 65.

Risk factors for wild-type transthyretin amyloid cardiomyopathy (wATTR-cm) include the following:

Old age (above 65 years old)
Males are more prone to getting wATTR-cm than females

It's Difficult to Pinpoint Symptoms of Transthyretin Amyloid Cardiomyopathy

Symptoms of transthyretin amyloid cardiomyopathy closely resemble that of other conditions like heart failure which is why they are frequently misdiagnosed. These symptoms include the following:

Shortness of breath
Increased heart rate (arrhythmias)
Chest pains
Coughing and wheezing
Edema (swelling) in the legs
Enlarged liver or spleen
Confusion and disorientation
Trouble thinking
Dizziness
Stomach bloating
Fatigue and tiredness
Fainting

These symptoms can differ from patient to patient. While some may experience severe symptoms, others may experience mild or no symptoms at all. This typically depends on the following parameters:

Age and overall health of the patient
Physical and medical history
Other underlying medical conditions
Type of the disease (hereditary or wild-type ATTR-cm)

Diagnosis of Transthyretin Amyloid Cardiomyopathy (ATTR-cm) Is Very Challenging

Diagnosing transthyretin amyloid cardiomyopathy can be very challenging. For the hereditary (hATTR-cm) type as their symptoms mimic other conditions, and for the wild-type (wATTR-cm), patients may experience no symptoms until the disease progresses to later stages (heart failure).

Dr. Philip Weintraub, a cardiologist at NYU Langone Health explains, "When one makes a diagnosis here, one must be meticulous and careful in looking at the other organs, including the eye, to make sure that this condition is not going on behind someone's back."

In fact, a study published in the Orphanet Journal of Rare Diseases in 2022, revealed that patients with transthyretin amyloid cardiomyopathy (ATTR-cm) suffered from reduced survival rate and extremely high medical costs which poses a financial and clinical burden. Thus, the authors recommend the following "To reduce the clinical and economic burdens, carefully examining manifestations of disease in patients can help with early diagnosis and treatment."

The first step to a conclusive diagnosis is to suspect the disease, after that your healthcare provider may prescribe the appropriate tests to confirm the diagnosis. Due to a lack of awareness of transthyretin amyloid cardiomyopathy, it's believed that less than 1% of patients with ATTR-cm are diagnosed.

Below is a list of the diagnostic tests available for transthyretin amyloid cardiomyopathy:

Echocardiogram a type of ultrasound scan to check the heart and neighboring blood vessels
Electrocardiogram a test to check your heart's electrical activity and rhythm, it's also referred to as ECG
Cardiac MRI
Taking a biopsy from the heart muscle a medical procedure where a small sample from the heart muscle is excised and examined under the microscope
Screening for mutated TTR gene (for the hereditary type hATTR-cm)

"Recently we've learned that amyloid is more prevalent than we once thought," Dr. Weintraub tells SurvivorNet. "And so therefore we need to diagnose it. Its presence can be isolated using what's called a MUGA scan, that can demonstrate certain properties that are lost in terms of the heart's ability to relax."

Treatment of Transthyretin Amyloid Cardiomyopathy Is Still a Work In Progress

There is no cure for transthyretin amyloid cardiomyopathy (ATTR-cm), but certain medications and measures may be taken to improve patient's quality of life and prolong their survival rate, these include the following:

Medications that stop disease progression by preventing further protein build-up
Medications to relieve symptoms caused by other comorbidities like heart failure or carpal tunnel syndrome
Tafamidis or Vyndamax Drugs that specifically target the TTR gene to stop proteins from misfolding
Inotersen or Tegsedi Drugs to slow the production of amyloid protein by the liver
Organ transplantation surgery (Liver, kidney, or heart transplant) depending on the affected organ

The life expectancy for patients with ATTR-cm ranges between 2-6 years from the moment of diagnosis. On the other hand, there are considerable efforts put into discovering promising new treatments through clinical trials that can improve these odds.

"ATTR cardiomyopathy is an evolving condition, until a few years ago, we did not really have anything to treat the disease in and of itself," said Dr. Aeshita Dwivedi, a cardiologist at Lenox Hill Hospital.

Dr. Dwivedi continues, "All we could do was really treat the symptoms of heart failure. More recently, we have been fortunate to have newer drugs that can impact the disease process."

The Bottom Line

Transthyretin amyloid cardiomyopathy is a rare, progressive, and possibly fatal disease often mistaken for other heart conditions. Both types of the disease occur due to abnormal TTR protein production which misfolds and accumulates leading to organ damage and other serious complications.

Early diagnosis and treatment play a crucial role in prolonging patients' lives as well as improving their quality of life. So far, the facts remain challenging for transthyretin amyloid cardiomyopathy (ATTR-cm). However, with efforts directed toward raising awareness, patient education, and new treatment options there's still hope to find a cure someday.

Questions to Ask Your Doctor

Which type of transthyretin amyloid cardiomyopathy (ATTR-cm) do I have?
What are the treatment options available for ATTR-cm?
Will I need organ transplantation at any point during my disease?
How can I increase my survival rate?
What are the risks associated with each treatment?
Do I need to change anything in my daily routine to improve my quality of life?
How can I avoid any complications?
Where can I contact other patients with ATTR-cm that are going through the same thing I'm going through?
Are there any clinical trials suitable for me?

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