Aortic stenosis is a narrowing of the aortic valve. The aortic valve controls the blood flow between the heart’s main pumping chamber and main artery (aorta).

Aortic stenosis occurs when the aortic valve becomes narrow and blocks the flow of blood from the heart to rest of the body. When the aortic valve gets very narrow, the heart must work harder to pump blood around the body.

As a result, the heart muscle gets thicker, stiffer and, over time, weaker. This weakness of the heart muscle is called heart failure.

When symptoms occur, they often start during times of labor and effort and include:

• Shortness of breath
• Chest pain (angina)
• Passing out (syncope)
• Fatigue (feeling tired)
• Reduced ability to exercise or be active
• Sudden death

Once symptoms begin, they often get worse. If not diagnosed and treated, they can cause severe heart problems.

Over time, if the heart muscle gets very weak and there is heart failure, symptoms can also include swelling in the ankles, shortness of breath with exertion and when resting, and an inability to lie flat.

What causes Aortic Stenosis

There are three main causes of aortic stenosis.

The first and most common cause is buildup of calcium on a normal aortic valve that occurs as patients get older.

Second, about 2% of people are born with an aortic valve with an abnormal valve structure. Normal aortic valves have three leaflets, also called cusps. In a small portion of the population, the aortic valve has two cusps (bicuspid aortic valve) and, more rarely, one or four cusps. In these cases, the blood flows more roughly over the valve and causes calcium buildup and narrowing of the valve (stenosis) at an earlier age (50 to 60 years old, instead of 70 to 80 years old).

Third, a less likely cause of aortic stenosis is inflammation caused by rheumatic fever, a condition that is more common in underdeveloped countries.

Aortic stenosis is often found during an exam when the doctor listens to the heart and hears a heart murmur. But the loudness of the murmur doesn’t reflect the severity of stenosis.

Other tests will be ordered to confirm the diagnosis and to determine the type of damage or issue with your heart valve. Tests include:

• Electrocardiogram (ECG): Calcium buildup linked to this condition may cause issues with the electrical system of the heart. This test also can reveal whether your heart muscle has grown thicker by showing changes in the electrical activity of the heart.
• Chest X-ray: The heart size often is normal, but other physical changes may be seen. For example, there might be a rounding of the heart border and tip of the heart (apex) because of a thickened heart muscle. Often, an enlarged aorta is seen just above the aortic valve.
• Echocardiogram (heart ultrasound): A heart ultrasound is used to look at the structure and function of the heart. It is a fast and painless study that uses ultrasound waves to produce heart images. Your doctor may be able to identify the cause of aortic stenosis and look for other conditions you may have. He or she also can find out how narrow your aortic valve is and look for narrowing or leaks of the other valves.
• Cardiac Computed tomography (CAT scan): This test takes multiple X-rays to make detailed pictures of the heart. It is sometimes used to look for calcium deposits on the aortic valves and to guide certain procedures such as TAVR (a minimally invasive surgical procedure to repair an aortic valve).
• Cardiac Catheterization (heart catheterization or coronary angiogram): A heart catheterization is done to find out if you have disease of the heart muscle, valves or coronary (heart) arteries. During the procedure, the pressure and blood flow in your heart can be measured. A contrast dye visible in X-rays is injected through a catheter that is threaded from a blood vessel in your wrist or groin. X-ray images show the dye as it flows through the heart arteries and can show whether they are blocked. A coronary angiogram can be used to identify patients who also might benefit from surgery on the blood vessels around the heart along with an aortic valve replacement procedure.

Patients with aortic stenosis can do well over many years without symptoms or limitations at rest or when active.

At some point, however, the aortic valve obstruction will begin to cause symptoms. This is usually when the aortic stenosis has advanced from mild or moderate to severe. If you have severe aortic stenosis, you may feel:

• More tired and exhausted
• Be short of breath with activities
• Develop chest discomfort with activities
• Lightheaded or even pass out

“Watchful observation” is recommended while patients have no symptoms. Once symptoms are present, replacing the valve may be considered. The less invasive procedure is also referred to as transcatheter aortic valve implantation, or TAVI.

Surgery: The valve can be replaced either through surgery or using a less invasive procedure called transcatheter aortic valve replacement (TAVR). Both approaches reduce symptoms and help patients live longer. At present, no medical therapy can “unclog” an obstructed aortic valve.

During a surgical aortic valve replacement (SAVR), you would be put under general anesthesia, and you would be placed on a ventilator while on a heart-lung bypass machine. A surgeon would then cut open your breastbone (called a sternotomy) to get to the heart. In some patients, less invasive approaches can be used. The aortic stenosis valve is cut out, and replaced by the new valve. Recovery in the hospital usually takes about five days.

TAVR (also known as TAVI): Transcatheter aortic valve replacement, or implantation, has emerged as an alternative approach to treat certain patients with aortic stenosis. TAVR does not require sternotomy or a heart-lung bypass machine. The replacement valve is usually inserted using a catheter into an artery in the leg, then threaded through arteries to the heart. Once within the diseased aortic valve, the folded TAVR valve is opened with a balloon and the old valve pushed to the side. Recovery in the hospital is usually about one to two days.

Overall, TAVR has been an exciting development in treating patients with aortic stenosis, but there are limitations:

• There is almost always a leak between the old and the new TAVR valve; however, this is usually not a major concern.
• Pushing the old aortic valve to the side can damage the electrical wiring of the heart and may require a pacemaker.
• Most important, the durability of TAVR valves compared with surgical valves is unclear. The TAVR valves may not last as long.

It is important to talk with your heart doctor and heart surgeon to weigh the options for treatment of your aortic stenosis and decide what is right for you.

There are steps you can take to strengthen your heart and guard against developing aortic stenosis. These include:

• Make heart-healthy choices: Although not proved, factors that can cause calcium buildup in the arteries of the heart (called atherosclerosis) also can cause calcium buildup on the aortic valve. For general health, it is always a good idea to exercise daily. Also, if you have high blood pressure, high cholesterol, diabetes, or kidney problems, you should speak to your doctor to get these conditions treated. If you smoke, you should quit smoking and talk to your doctor about ways to help you stop.
• Keep up with dental checkups: Infection in your gums can sometimes cause an infection of the heart valves and cause aortic stenosis. Bacteria can hide in your gums, and you can make sure your gums are healthy by going to the dentist regularly.
• Treat infections: The bacteria that cause strep throat can sometimes cause rheumatic fever if left untreated. Rheumatic fever often happens in children and young adults and can be easily treated with antibiotics. If rheumatic fever is not treated, it can cause aortic stenosis years later.

Patients with aortic stenosis can live full and rewarding lives. However, they may need to be monitored by a heart specialist with office visits and periodic testing.

In many cases, aortic stenosis is discovered in patients before they develop any symptoms. These patients are told to watch for certain symptoms such as chest pain or discomfort, difficulty breathing, or lightheadedness or fainting spells. These symptoms could indicate a worsening of the condition, but they can occur for other reasons as well. Any of these symptoms should be reported at once to your family doctor or heart specialist.

Based on the severity of your condition, your doctor may limit your activity, but many patients can exercise and do most activities without restriction. However, you should increase activity or start an exercise or walking program only under the guidance of your doctor.

Because aortic stenosis tends to progress over time, even patients without symptoms will require routine testing to monitor their condition. This would typically include an ultrasound of the heart (called an echocardiogram) and other tests, such as an exercise stress test.

On occasion, more invasive testing such as heart catheterization may be needed. Your heart specialist will work with you to set a schedule for monitoring and testing. Together, you will decide when and if treatment is needed.

If you’ve been diagnosed with aortic valve stenosis, there are several key questions that you should ask your heart specialist during your next visit. These questions will ensure that you and your doctor have discussed your major risk factors so that you can become or stay as healthy as possible.

• I feel lightheaded at times; can this be associated with aortic stenosis?
• How often should my physician monitor my aortic valve for changes in its area?
• What is the appropriate timing for cardiac surgery to treat aortic valve stenosis?
• What symptoms of aortic valve stenosis would push me towards having my valve repaired?
• Am I a good candidate for less invasive treatment approaches for aortic valve stenosis, such as a TranscatheterAortic Valve Replacement (TAVR)?
• Are there any medications that I should stop taking after being diagnosed with aortic stenosis?
• Should I limit my physical activity because of aortic valve stenosis?
• Is my valve bicuspid (meaning it has two leaflets)? If so, how does this predispose me to aortic stenosis?
• What changes happen to the heart after having aortic stenosis over time?
• Can aortic valve stenosis lead to chest pain?
• What symptoms of aortic valve stenosis should prompt me to seek immediate medical care?