Cardiac Amyloidosis: A Hidden Cause of Heart Failure Is Now Treatable

Once considered rare, cardiac amyloidosis is now recognized as a common cause of heart failure. Until recently, no treatment was available for this condition. But groundbreaking drug therapies have greatly improved outcomes.

“We are much more attuned to looking out for cardiac amyloidosis, and we now have therapies,” says University Hospitals cardiologist Thomas O’Neill, MD. “Until recently, this was a disease that was important to diagnose for prognosis, but we had very little in the way of treatment.”

Understanding Cardiac Amyloidosis

Cardiac amyloidosis is the build-up of abnormal proteins in the heart muscle. This causes the heart wall to become thicker and stiffer, interfering with the heart’s ability to pump blood.

“My analogy to patients is when you have a bunch of Legos on the floor, it’s easy to vacuum them up,” says Dr. O’Neill. “That’s how our body cleans out extra proteins. But when the proteins link together, which we call amyloid, it’s like building a Lego car or Lego house. It’s a structure you can no longer vacuum.”

There are two types of cardiac amyloidosis:

• Transthyretin Amyloidosis (ATTR). The most common type. The liver produces too much transthyretin protein that starts accumulating in organs and tissues. Some cases are caused by a genetic mutation, but most are not. ATTR is more common in men over age 65, and 10 to 20 percent of cases occur in women.
• Light chain or AL amyloidosis. This type is less common and starts in the bone marrow. A specific kind of white blood cells, called plasma cells, make excess proteins that accumulate in organs and tissues.

Both types of cardiac amyloidosis can lead to heart failure, as well as heart rhythm disorders and valve disease.

Early Signs of Cardiac Amyloidosis

“The most common sign of cardiac amyloidosis is when the heart wall is very thick,” says Dr. O’Neill. “That could happen for different reasons, but in the case of amyloidosis, it’s not thickened muscle. It’s thickened due to protein deposits between the muscle cells.”

There are other symptoms that can point to amyloidosis, often years in advance, since the proteins accumulate in other parts of the body too. “We often find early symptoms in other parts of the body,” Dr. O’Neill says. “Sometimes, these conditions occur years or decades before the amyloidosis causes heart failure.”

Early signs of cardiac amyloidosis may include:

• Carpal tunnel syndrome in both hands or arms. “Carpal tunnel is common and not everyone with carpal tunnel has amyloidosis. But if somebody has had it on both sides and if they’ve had multiple surgeries, that’s unusual,” Dr. O’Neill says.
• Narrowing of the spine (spinal stenosis). Symptoms can include back pain, burning pain in the buttocks and down the leg, loss of feeling in the feet, and numbness, cramping, or weakness in the legs.
• Neuropathy. Pain, tingling, numbness, weakness in the extremities, when there is no known cause such as diabetes.
• Blood pressure that decreases significantly with age. “Blood pressure is likely to go up with age or remain the same. When blood pressure goes down, we might suspect amyloidosis,” says Dr. O’Neill.

Diagnosing Cardiac Amyloidosis

Echocardiograms can reveal if the heart muscle is thicker, Dr. O’Neill says. Patients may undergo echocardiograms for irregular heart rhythms or other reasons and sometimes this is how amyloidosis is discovered.

Other tests to diagnose cardiac amyloidosis may include:

• Electrocardiogram (EKG)
• Cardiac MRI
• Blood tests
• Heart tissue biopsy
• Cardiac PYP (nuclear imaging) test

New Treatments

For the light chain / AL amyloidosis, which originates in the bone marrow, treatment is similar to cancer treatment with chemotherapy or immunotherapy. Treatment will involve consultation with a hematologist.

For the more common ATTR amyloidosis, the Food and Drug Administration (FDA) has approved three drug therapies to treat. The new drugs – tafamidis, acoramidis and vutrisiran – can stop progression of the disease but won’t remove the amyloid proteins already deposited in the heart. The drug therapies work in different ways, either by preventing the proteins from clumping together or by stopping the liver from making the protein.

“The therapies are very good at preventing progression. Right now, we don’t have effective therapies to clean up the protein. That’s the future though,” Dr. O’Neill says. “That’s why the early diagnosis is so important. If we can diagnose someone before they develop heart failure symptoms, we can stop the disease right there.”

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The specialists at University Hospitals Harrington Heart & Vascular Institute provide patients with the highest quality, most advanced care and treatments.