Aortic Stenosis: Effects of Heart Valve Narrowing

Aortic stenosis is a condition that causes the heart's aortic valve to narrow. The aortic valve connects the heart's main pumping chamber (left ventricle) to the aorta. Aortic stenosis can occur due to a congenitally abnormal aortic valve or due to degeneration of the valve.

It's a fairly common condition, particularly in adults over age 65 years. You may not have any symptoms early on, but your healthcare provider may be able to hear a heart murmur. In later stages, when symptoms are present, valve replacement is necessary.

This article will discuss the stages of aortic stenosis and treatment options.

Why Does Aortic Stenosis Happen?

Narrowing of the aortic valve can happen for several reasons. Some more common causes include degenerative valve disease, congenital valve disease, and rheumatic heart disease. The most common type of aortic stenosis is degenerative aortic stenosis due to wear and tear on the valve over many years. Usually, this doesn't happen until around 60 years old, with symptoms appearing between 70 and 80 years old.

Aortic Valve Stenosis

Congenital (present at birth) malformations of the aortic valve are actually quite common, with up to an estimated 2% of people born with a bicuspid valve that has just two cusps (flaps) instead of the normal three cusps. Over time, increased stress on the valve leads to calcification and narrowing. People with congenital aortic valve narrowing may begin to have symptoms as soon as 30 years old.

Lastly, rheumatic heart disease can cause aortic stenosis. Rheumatic heart disease happens years after rheumatic fever, a condition related to untreated strep infections. While it is rare in the United States, in other parts of the world it's a common cause of heart valve disease. Rheumatic heart disease typically affects the mitral valve, but the aortic valve can also be affected.

Classification of Aortic Stenosis

According to the American Heart Association/American College of Cardiology, valvular heart disease is classified based on echocardiogram (heart ultrasound) findings and presence or absence of symptoms. Aortic stenosis starts as mild but becomes more severe and causes symptoms over time.

Progressive Aortic Stenosis

Progressive aortic stenosis is a term that includes mild and moderate aortic stenosis. There is some narrowing of the valve, but the valve is still able to allow enough blood to pass from the heart to the body without causing symptoms. A murmur is heard on physical examination, but progressive aortic stenosis can be monitored over time and does not require immediate treatment.

Severe Aortic Stenosis

Severe aortic stenosis, on the other hand, is when the valve becomes so narrow that blood flow out of the heart is significantly impaired. This typically leads to symptoms like exercise intolerance (the body's inability to exercise), shortness of breath, chest pain, light-headedness or even fainting.

Often, people with severe aortic stenosis have symptoms. Sometimes, when someone with severe aortic stenosis does not notice symptoms, it is because they have decreased their activity levels without realizing it. If you have severe aortic stenosis but no symptoms, a cardiologist can perform a treadmill stress test, during which exertion can bring out any unnoticed symptoms.

It's important to pay attention to any symptoms, because once symptoms are present, it's time to get the valve fixed. In some cases the valve should be fixed sooner, and this depends on the severity based on echocardiogram measurements as well as any other heart surgeries that may be needed.

Receiving an Aortic Stenosis Diagnosis

The murmur of aortic stenosis is very specific, so the condition is usually first suspected with physical examination. However, the details of the valve and the severity of aortic stenosis require an echocardiogram, or heart ultrasound, for further characterization.

If you have been diagnosed with aortic stenosis, it's important to follow up with a cardiologist for regular screening and/or treatment. For progressive aortic stenosis, your cardiologist will perform echocardiograms every so often (every year or three to five years, depending on how narrow the valve is) to monitor progression and heart function. Pay attention to any of the following symptoms and report them to your heart team. Note that it's not the severity of symptoms but the presence of any symptoms, even if mild, that is important. Symptoms may include:

• Chest discomfort
• Shortness of breath
• Fatigue or weakness
• Exercise intolerance
• Palpitations
• Light-headedness or fainting

A heart valve replacement is needed if aortic stenosis becomes very severe or if symptoms develop.

Aortic Stenosis Progression and Effect on Life Expectancy

Progression of aortic stenosis varies based on the type of aortic stenosis and the severity at diagnosis. Those with severely narrowed valves experience the most rapid progression. Once aortic stenosis is severe, the two-year survival rate is 30% to 50% without valve replacement.

Those with mild aortic stenosis may take years to progress to severe disease or require a valve replacement. That is why echocardiograms to monitor progression can be spaced out every three to five years for those with mild aortic stenosis.

Treatment of Aortic Stenosis

Aortic stenosis historically required open heart surgery to correct. However, over the past several decades, a less invasive procedure called transcatheter aortic valve replacement (TAVR) has become a preferred treatment option for many people. The type of valve replacement you receive depends on several factors, including your age and whether or not there is other valve disease present.

There are two types of prosthetic heart valves that may be used: mechanical (artificial) or bioprosthetic. Mechanical valves last longer, but they require open heart surgery. People with these valves need to take lifelong anticoagulant (blood-thinning) medication.

Bioprosthetic valves are made from either porcine (pig) or bovine (cow) tissue and can be surgically implanted with TAVR. These valves do not require long-term medication, but it may be recommended short-term after implantation.

Surgical Aortic Valve Replacement

Surgical aortic valve replacement requires open heart surgery to implant a new valve. A heart surgeon can place a mechanical or bioprosthetic valve, the choice of which depends on individual patient factors.

Surgical valve replacement may be preferred over TAVR for younger patients because mechanical valves are known to last longer, and mechanical valves cannot be placed with TAVR. However, open heart surgery is more invasive than TAVR, and the recovery period is longer.

TAVR

In TAVR, a bioprosthetic aortic valve is implanted using a catheter-based technique. A catheter is typically placed through an artery in the groin but in some cases may be placed through arteries in the neck or upper chest.

Once in the proper position in the aortic valve, a balloon is inflated, pushing the old valve aside and leaving the new valve in place. TAVR is a great option for people with aortic stenosis who have frailty or other medical conditions. TAVR is often preferred in people older who are 65 years old or older.

Postoperative Care

Postoperative care differs based on the type of procedure. If a surgical aortic valve was implanted through open heart surgery, recovery is longer and can take about four to eight weeks. In either case, you may benefit from cardiac rehab, a supervised exercise program for people with heart disease or recovering from heart surgery.

Speak with your heart team about any exercise, driving, or other activities restrictions. You will also receive instructions on how to care for any surgical wounds.

Lifestyle and Medical Management

No medications or treatments have been shown to slow the progression of aortic stenosis. However, it's recommended that people with heart disease follow a heart-healthy lifestyle, which includes:

• Eating heart-healthy diet high in fruits, vegetables, legumes, whole grains, and low in salt and processed foods
• Getting regular physical exercise
• Quitting smoking and avoiding secondhand smoke
• Avoiding alcohol or drinking alcohol in moderation
• Keeping cholesterol, blood pressure, and blood sugar controlled

How to Find a Cardiologist You Trust

It can be intimidating to receive a diagnosis of aortic stenosis, and finding a cardiologist and heart team that you trust with your care is important. Cardiologists are physicians who have completed internal medicine residency training and three years of additional fellowship training in cardiovascular disease. Interventional cardiologists who perform TAVRs have one to two years of additional procedural training.

Many health centers have specialized valve teams with expertise and experience managing complex valvular heart disease. Cardiologists and heart surgeons work together to determine the best course of action regarding valve replacement. Look for a care team that is experienced in managing aortic stenosis and who takes the time to explain your condition and answer your questions.

Summary

Aortic stenosis is narrowing of the heart valve that allows blood to exit the heart to supply the body with blood and oxygen. Severe narrowing of this valve causes symptoms including exercise intolerance, chest pain, shortness of breath, and light-headedness. Once aortic stenosis is severe and causing symptoms, life expectancy is reduced and replacement of the valve is necessary.

Valve replacement can be performed through open heart surgery or a less invasive technique called transcatheter aortic valve replacement (TAVR). A specialized heart team will determine the best treatment plan for individual patients.