ATTR-CM (transthyretin amyloid cardiomyopathy) is a rare heart condition that can lead to heart failure. However, with an early and accurate diagnosis, ATTR-CM is often treatable.
But ATTR-CM is not just a disease of the heart. The amyloid fibrils can build up in the nervous system, causing various forms of neuropathy, and can also build up in various organs of the body. This means that getting a definitive diagnosis requires a thorough examination, testing, and review of symptoms.Read More
Here are five of your top questions about ATTR-CM answered:
1. How does ATTR-CM occur?
ATTR-CM occurs when the protein transthyretin, which transports thyroid hormone and vitamin A through the bloodstream, becomes misshapen and forms amyloid fibrils that settle in the heart. As a result, the heart stiffens and becomes unable to relax sufficiently to fill with blood and/or squeeze enough blood out of the heart to meet the body’s needs.
2. How is ATTR-CM diagnosed?
One of the challenges of treating ATTR-CM is that it’s typically hard to diagnose, as symptoms often duplicate the early stages of heart failure. Therefore many doctors are not looking for ATTR-CM.
As a result, a person with this rare condition is often misdiagnosed, or often diagnosed too late. With new imaging techniques becoming more readily available however, there are currently more accurate assessments taking place that don’t rely on invasive tissue biopsy procedures.
“ATTR cardiomyopathy is, unfortunately, an under-diagnosed condition,” says New York cardiologist Aeshita Dwivedi, MD, who explains that greater awareness of ATTR-CM is indeed leading to more diagnoses, which is also resulting in people starting treatment earlier in the disease process, which is crucial.
Getting an ATTM-CR Diagnosis
Typically, an individual experiencing signs of heart failure might be evaluated for ATTR-CM. Common symptoms include:
- Awareness of a laboring or racing heart
- Coughing when lying down
- Fluid retention or swelling, particularly in the lower limbs
- Shortness of breath
“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 that this condition is not going on behind someone’s back,” says New York cardiologist Dr. Philip Weintraub.
The most common way to diagnose ATTR-CM is to start with an ECG (electrocardiogram) and a physical exam. An electrocardiogram measures the electrical activity of the heart. An echocardiogram, or “echo,” uses sound waves to create images of a beating heart. An MRI, magnetic resonance imaging, employs a combination of high-powered magnets and special x-rays to produce detailed images of soft tissue, such as heart muscle. Certain radioactive tracers or contrast dyes can help solidify an ATTR-CM diagnosis with this specific test.
A Multigated Acquisition Scan (MUGA) uses a radioactive tracer and special camera to measure the pumping ability of the ventricles, which helps determine whether reduced pumping function may be related to a type of cardiomyopathy or other cause. Overall, a biopsy, which removes a small piece of heart muscle tissue, is still the “gold standard for ATTR-CM diagnosis,” according to a 2020 review of the condition’s diagnostic and treatment guidelines in the Journal of the American College of Cardiology (JACC).
“To do a cardiac biopsy, it’s usually done under conscious sedation, meaning you’re in a ‘twilight’ and not general anesthesia,” Dr. Dwivedi says. “We can thread the catheter through a vein and into the heart and take a small piece of the heart to look under the microscope.”
The JACC review also notes that samples should be taken from four different locations to increase the chances of identifying the malformed transthyretin proteins.
3. How is ATTR-CM treated?
Since it is difficult for doctors to treat ATTR-CM directly, they mainly focus on managing symptoms, which are very much like those associated with heart failure. These include:
- Arrhythmia (heart rhythm disturbance)
- Decreased exercise tolerance
- Shortness of breath
“ATTR cardiomyopathy is an evolving condition, and until a few years ago, we did not really have anything to treat the disease in and of itself,” says Dr. Dwivedi. “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.”
4. What drugs, if any, are available for ATTR-CM?
In 2019, the FDA approved tafamidis (Vyndamax), a once-daily oral medication that blocks the breaking up of transthyretin proteins and the subsequent formation of amyloid fibrils. The drug currently costs more than $200,000 annually, though most insurance providers should cover it or a large portion of it. There is currently no generic version.
Another form for tafamidis, called Vyndaqel, is also a once-per-day regimen, but each dose includes four pills. The two forms of tafamidis treat both kinds of ATTR-CM: the hereditary type caused by a mutation of a transthyretin gene and the wild type, which has no genetic component and is triggered by unknown causes.
Tafamidis doesn’t cure the disease or reverse its course. But the drug can slow its progress by interfering with the breakdown of transthyretin proteins and the subsequent formation of amyloid fibrils.
5. What lifestyle changes should I make as a result of ATTR-CM?
While tafamidis and other treatments may help extend life and improve quality of life for people with ATTR-CM, there is still unfortunately nothing that can totally reverse this heart condition.
When your heart becomes too weak to effectively pump blood throughout the body, not surprisingly, you will need to make a number of lifestyle changes.
Some of what you will need to know can be learned by participating in a cardiac rehabilitation program. If you have been diagnosed with ATTR-CM, ask your doctor about prescribing you rehab to learn about diet, exercise, medication adherence and other aspects of living with a heart condition.
Dr. Dwivedi explains that when confronted with the signs of ATTR-CM, like those of heart failure, it’s essential that you begin working closely with your cardiologist and follow the doctor’s advice about medication, checkups, lifestyle, and give thoughtful consideration to discussions of procedures, such as having a pacemaker or pump implanted.
“Number one would be to see your doctor regularly,” Dr. Dwivedi says. “It is important to seek medical care for this condition, because we have good options and can change lives. Second would be talk to your doctor if any of your symptoms change. You would rather know sooner rather than later, before things get worse and when you may need hospitalization.”
She also recommends shifting to a heart-healthy diet that includes limited sodium intake and fats, a diet that will help you achieve and maintain a healthy weight. Exercise is also important, though your capacity for physical activity will be limited. Be sure to discuss your exercise limits and concerns with your doctor or a cardiac rehab specialist.
“Getting your steps in for the day and doing moderate activities is very important,” Dr. Dwivedi says. If exercise is new to you and you are unsure where to start, reach out to your doctor for a supervised exercise program for you to get comfortable being active.
It’s also so important to take your medications. “The medications have been shown to benefit this patient population significantly and can change lives,” Dr. Dwivedi adds.
Contributing by SurvivorNet Staff.