Understanding Aortic Valve Stenosis

What is Aortic Valve Stenosis?

Aortic valve stenosis is a condition where the aortic valve in your heart becomes narrowed, making it harder for blood to flow from your heart to the rest of your body. Think of your aortic valve as a door between the heart's main pumping chamber (left ventricle) and the body's main artery (aorta). When this "door" doesn't open fully due to stenosis, your heart has to work much harder to pump blood through the narrowed opening.

The aortic valve normally has three leaflets (flaps) that open and close with each heartbeat. In aortic stenosis, these leaflets become stiff, thick, or calcified (hardened with calcium deposits), preventing them from opening properly during each heartbeat.

Understanding the Stages of Aortic Stenosis

Medical professionals classify aortic stenosis into different stages to help guide treatment decisions:

Stage A - At Risk: You may have a bicuspid aortic valve (born with two leaflets instead of three) or early valve scarring, but the valve still functions normally with no symptoms.

Stage B - Progressive: The valve shows mild to moderate changes with some calcification and reduced movement, but you still have no symptoms. This stage includes both mild stenosis (with blood flow velocities of 2.0-2.9 meters per second) and moderate stenosis (velocities of 3.0-3.9 meters per second).

Stage C - Asymptomatic Severe: The valve is severely narrowed with significant calcification and blood flow velocities of 4 meters per second or higher, but you don't yet experience symptoms. This stage is further divided into those with normal heart function (C1) and those with reduced heart function (C2).

Stage D - Symptomatic Severe: You have severe valve narrowing and are experiencing symptoms. This stage includes several subtypes: high-gradient stenosis (D1), low-flow low-gradient stenosis with reduced heart function (D2), and paradoxical low-flow stenosis with normal heart function (D3).

Recognizing the Symptoms

Many people with aortic stenosis don't experience symptoms until the condition becomes severe. When symptoms do appear, they typically include:

Shortness of breath during physical activity or even at rest which occurs because your heart cannot pump enough blood to meet your body's oxygen demands during exertion.

Chest pain or pressure (angina) during physical activity happens because your heart muscle isn't getting enough blood flow through the coronary arteries, especially when the heart is working harder.

Fatigue and decreased exercise tolerance develop as your heart struggles to maintain adequate blood flow to your muscles during activity.

Dizziness or fainting (syncope) during exertion can occur when blood flow to the brain is insufficient, particularly dangerous as it may happen without warning.

Heart failure symptoms may develop in advanced cases, including swelling in your legs, ankles, or feet, and difficulty breathing when lying flat.

It's important to understand that once symptoms appear, the condition typically progresses more rapidly, making timely medical evaluation crucial.

How Aortic Stenosis is Diagnosed

Physical Examination: Your doctor may detect aortic stenosis by hearing a heart murmur during a routine examination. However, physical examination alone cannot accurately determine the severity of the condition.

Echocardiography (Heart Ultrasound): This is the most important diagnostic test for aortic stenosis. An echocardiogram uses sound waves to create images of your heart and can measure how well your aortic valve opens, calculate the valve area, and assess blood flow velocities. The test is painless and provides detailed information about valve anatomy, the degree of narrowing, and how well your heart is functioning.

Exercise Testing: For patients without symptoms, supervised exercise testing may be performed to see if symptoms develop during physical activity and to assess how well your heart responds to increased demands.

Additional Testing: In some cases, your doctor may recommend cardiac catheterization (inserting a thin tube into your heart through blood vessels) to get more detailed pressure measurements, especially if there are questions about the severity of stenosis or if you're being considered for treatment.

Blood Tests: Certain blood markers, such as B-type natriuretic peptide (BNP), may be elevated in aortic stenosis and can provide additional information about heart function.

Understanding Severity Measurements

Doctors use specific measurements to determine how severe your aortic stenosis is:

Mild stenosis: Blood flow velocity across the valve is 2.0-2.9 meters per second, with a mean pressure gradient of less than 20 mmHg.

Moderate stenosis: Velocity is 3.0-3.9 meters per second, with a mean gradient of 20-39 mmHg.

Severe stenosis: Velocity is 4.0 meters per second or higher, with a mean gradient of 40 mmHg or more, and typically an aortic valve area of 1.0 square centimeters or less.

Very severe stenosis: Velocity reaches 5.0 meters per second or higher, with a mean gradient of 60 mmHg or more.

Treatment Options and Timing

Watchful Waiting and Medical Management: If you have mild to moderate aortic stenosis without symptoms, your doctor will likely recommend regular monitoring with periodic echocardiograms and clinical evaluations. During this time, it's important to manage other cardiovascular risk factors such as high blood pressure and high cholesterol.

Valve Replacement: When aortic stenosis becomes severe and symptomatic, valve replacement is typically recommended. There are two main approaches:

Surgical Aortic Valve Replacement (SAVR): This involves open-heart surgery to remove the diseased valve and replace it with either a mechanical valve (made of durable materials that last a lifetime but require blood-thinning medications) or a biological valve (made from animal tissue that doesn't require long-term blood thinners but may need replacement after 10-20 years).

Transcatheter Aortic Valve Replacement (TAVR): This newer procedure involves inserting a replacement valve through a catheter, usually through a blood vessel in your leg, without the need for open-heart surgery. TAVR has become an increasingly popular option for many patients, including those at high surgical risk and, more recently, those at intermediate and even low surgical risk.

When Treatment Becomes Necessary

The timing of treatment depends on several factors:

Symptomatic severe stenosis typically requires prompt valve replacement, as symptoms indicate that the heart is no longer compensating effectively for the valve narrowing.

Asymptomatic severe stenosis may require intervention if you develop reduced heart function, abnormal exercise test results, or if the stenosis is very severe with high velocities.

During other heart surgery: If you need coronary artery bypass surgery or other heart surgery and have moderate to severe aortic stenosis, your surgeon may recommend replacing the aortic valve at the same time.

Living with Aortic Stenosis

Regular follow-up is essential. Your doctor will recommend periodic echocardiograms to monitor the progression of your condition. The frequency of these tests depends on the severity of your stenosis and ranges from every year for severe stenosis to every 3-5 years for mild stenosis.

Activity recommendations vary depending on the severity of your condition. People with mild stenosis can usually participate in normal activities, while those with severe stenosis may need to avoid strenuous physical activity until the valve is treated.

Infection prevention is important because damaged heart valves are at higher risk for infection. Your doctor may recommend antibiotics before certain dental or medical procedures.

Medication management focuses on treating related conditions like high blood pressure and coronary artery disease. While no medications can reverse aortic stenosis, proper management of other cardiovascular conditions is important for overall heart health.

What to Expect Going Forward

The progression of aortic stenosis varies from person to person. Some people may have mild stenosis that progresses slowly over many years, while others may experience more rapid progression. Factors that may influence progression include age, the underlying cause of the stenosis, and other cardiovascular risk factors.

Once symptoms develop, the condition typically progresses more rapidly, and without treatment, the prognosis is generally poor. However, with appropriate and timely treatment, particularly valve replacement, most people can return to normal or near-normal activity levels and have an excellent long-term outlook.

Regular communication with your healthcare team is essential. Don't hesitate to report any new symptoms, particularly shortness of breath, chest pain, or dizziness, as these may indicate that your condition is progressing and treatment timing may need to be reconsidered.

Understanding your condition empowers you to participate actively in your care and make informed decisions about your treatment options. Your healthcare team, including your cardiologist and potentially a cardiac surgeon, will work with you to determine the best treatment approach based on your individual circumstances, overall health, and personal preferences.

August 2025

Prepared by Professor Eric Lim for PEACHealth with background research and drafting assistance by LLM.