Aortic stenosis, heart murmurs, and amyloidosis might seem like separate heart conditions, but they can actually be closely related. For people living with amyloidosis and their loved ones, understanding the links between these conditions can help you recognize symptoms, ask the right questions, and feel more in control of your health.

This article explains how aortic stenosis and amyloidosis are connected and what you need to know about both conditions. You’ll also learn about the risks of having both conditions, how they’re diagnosed, and what treatment options may be available.

What Is Aortic Stenosis?

Aortic stenosis, also called aortic valve stenosis, is a condition that affects the heart’s aortic valve. The aortic valve controls blood flow from the heart to the rest of the body. When someone has aortic stenosis, their aortic valve becomes too stiff or narrow. This means the heart must work harder to push blood through the narrow valve. Over time, this added strain can cause the heart muscle to thicken and weaken.

If left untreated, aortic stenosis can lead to serious problems, such as heart failure, most commonly left-sided. Left-sided heart failure can cause fluid to back up into the lungs, causing shortness of breath.

Aortic stenosis mostly happens in older adults. It’s often caused by age-related changes in the heart. However, some people are born with the condition, and others may develop it after having rheumatic fever.

A heart murmur is often one of the first signs of aortic stenosis. Heart murmurs can be heard through a stethoscope as a whooshing or swishing sound while listening to the chest. If a murmur is heard, the next step is an echocardiogram. This is a painless test that uses sound waves to take pictures of the heart. It shows how well the heart is pumping, how thick the heart muscle is, and how narrow the aortic valve has become. It also measures the ejection fraction, which shows how much blood the heart pumps out with each beat.

What Are ATTR Amyloidosis and Cardiac Amyloidosis?

Cardiac amyloidosis is a disease where misfolded proteins, called amyloids, build up in the heart. These proteins clump together and collect in the heart tissue. Over time, these clumps make the heart stiff and less able to fill with and pump blood. This leads to a type of heart problem called restrictive cardiomyopathy. There are several types of amyloidosis, but two are most commonly linked to heart problems:

• AL amyloidosis, caused by abnormal immune cells that make harmful proteins
• ATTR amyloidosis, caused by a protein called transthyretin (TTR)

In this article, we’ll focus on ATTR amyloidosis. When this type of amyloidosis affects the heart, it’s called transthyretin cardiac amyloidosis, or ATTR-CM. In ATTR-CM, the TTR protein breaks apart and forms sticky amyloid fibrils that build up in the heart.

There are two main types of ATTR-CM:

• Wild-type ATTR — This form is not inherited and mostly affects older adults, especially men. It can develop slowly over time.
• Hereditary ATTR — This form runs in families and is caused by a mutation (change) in the TTR gene. It may appear earlier in life and can affect the nerves as well as the heart.

ATTR-CM can lead to symptoms such as:

• Shortness of breath (from left-sided heart failure)
• Swelling in the legs (from right-sided heart failure)
• Irregular heart rhythms (such as atrial fibrillation)
• Feeling very tired

Because these symptoms are common in older adults, ATTR-CM is sometimes mistaken for other diseases. Many people live with it for years before getting the right diagnosis.

The good news is that doctors are getting better at spotting ATTR-CM, and there are new tests that make it easier to diagnose. More importantly, there are now treatments that can slow down the disease and help people feel better, especially when it’s caught early.

How Are Aortic Stenosis and ATTR Amyloidosis Connected?

Aortic stenosis and ATTR-CM are both common in people over age 65, and often happen at the same time. In fact, studies show that between 5 percent and 15 percent of older adults who need a procedure to treat aortic stenosis also have ATTR-CM.

Why is that? Both conditions become more common with age. ATTR-CM may even help cause or worsen aortic stenosis by depositing amyloid buildup in the aortic valve, making it stiffer.

To treat aortic stenosis, doctors often replace the damaged valve with a procedure called transcatheter aortic valve replacement (TAVR). In TAVR, a new heart valve is placed using a thin tube called a catheter through a blood vessel, usually in the leg. It’s less invasive than open-heart surgery and is especially helpful for older adults and those who aren’t good candidates for open-heart surgery.

Sometimes, ATTR-CM doesn’t show up clearly on imaging tests until after TAVR has improved heart function. That’s because a weak heart’s output can make it harder to detect the buildup of amyloid. Once the valve is fixed and the heart works better, ATTR-CM may become easier to spot in tests.

If someone still has symptoms like fatigue or swelling even after having a TAVR procedure, it may be a sign of ATTR-CM. In these cases, your doctor may order special tests to check for amyloidosis, such as scintigraphy (bone scan) or a cardiac magnetic resonance imaging (MRI) scan.

Knowing whether a person has both aortic stenosis and ATTR-CM is important because it can change the treatment plan. People living with both aortic stenosis and ATTR-CM may respond differently to treatment and may benefit from both a valve replacement and medications that help slow the progression of ATTR-CM.

Signs That May Suggest Cardiac Amyloidosis in Someone With Aortic Stenosis

Since both aortic stenosis and ATTR-CM can cause shortness of breath, it can be hard to tell them apart. However, there are other signs that can help doctors determine whether someone has both conditions. These can include:

• A history of carpal tunnel syndrome or back/spine problems
• Symptoms of right-sided heart failure, like swelling in the legs or enlarged neck veins
• Kidney problems

How Do Doctors Diagnose These Conditions Together?

When it’s not clear what’s causing a person’s symptoms — or if doctors suspect there might be more than one condition— several tests will be used to make an accurate diagnosis. One common test is echocardiography. This is an ultrasound of the heart. It can show if the heart walls are thick or stiff, how well the valves are working, and how well the heart is pumping.

Doctors may also use an electrocardiogram (ECG or EKG). This test measures the heart’s electrical activity. If amyloid is damaging the heart cells, the signals shown on the ECG may be weak. When this happens in someone with thick heart walls, it can be a sign of ATTR-CM.

Another helpful test is a cardiac MRI. This is a scan that gives a detailed picture of the heart muscle. When combined with special tools, cardiac MRIs can help doctors see if amyloid has built up in the heart tissue.

A bone scan, also called scintigraphy, is another test that can help. In this test, a small amount of radioactive material is injected into a vein. It travels through the bloodstream and into the heart and bones. In people with ATTR-CM, heart cells soak up some of the material, just like bones do. This shows up clearly on scintigraphy.

This type of scan can often confirm ATTR-CM without needing a biopsy (a sample of heart tissue). That’s because an ATTR-CM heart looks similar to bone on scintigraphy, while a healthy heart does not absorb the radioactive material.

In some cases, blood tests can also help. High levels of certain compounds can be a sign of heart damage caused by amyloid buildup.

Managing Treatment and Living With Overlapping Conditions

Learning that you or a loved one has both aortic stenosis and ATTR-CM can feel overwhelming. But the good news is that there are treatments available, and getting an early diagnosis can make a big difference.

Treating Aortic Stenosis

The main treatment for aortic stenosis is to replace the damaged heart valve. There are two ways to do this:

• Transcatheter aortic valve implantation (or replacement) — This is a less invasive procedure done through a blood vessel in the leg. It’s often the best choice for older adults and people with ATTR-CM.
• Surgical aortic valve replacement — This is open-heart surgery. It may be too risky for some people, especially those with both conditions.

Treating ATTR-CM

There’s no cure for ATTR-CM yet, but there are several medications that can slow the disease and improve symptoms. Some people may also need a pacemaker or defibrillator if the heart’s electrical system is affected.

In very advanced cases, doctors may consider a heart transplantation — sometimes along with a liver transplant, since the protein that causes ATTR-CM is made in the liver. In other cases, palliative care (care focused on comfort and quality of life) may be considered. What’s right for you will depend on your age, overall health, and personal preferences.

Finding these conditions early can make a big difference. Early diagnosis can help doctors choose treatments that are safer and more effective, and avoid ones that might cause more harm than good.

Talk With Others Who Understand

On MyAmyloidosisTeam, the social network for people with amyloidosis and their loved ones, members come together to ask questions, share advice, and connect with others who understand life with any type of amyloidosis.

Have you been diagnosed with aortic stenosis and ATTR-CM? What was the path to diagnosis like for you? Share your experience in the comments below, or start a conversation by posting on your Activities page.