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Aortic Stenosis


Guy P. Armstrong

, MD, Waitemata District Health Board and Waitemata Cardiology, Auckland

Reviewed/Revised Nov 2023 | Modified Dec 2023
Topic Resources

Aortic stenosis is a narrowing of the aortic valve opening that blocks (obstructs) blood flow from the left ventricle to the aorta.

  • The most common cause in people younger than 70 years is a birth defect that affects the valve.

  • In people over 70, the most common cause is thickening of the valve cusps (aortic sclerosis).

  • People may have chest tightness, feel short of breath, or faint.

  • Doctors usually base the diagnosis on a characteristic heart murmur heard through a stethoscope and on results of echocardiography.

  • People see their doctors regularly so their condition can be monitored, and people with symptoms may undergo replacement of the valve.

The aortic valve is in the opening between the left ventricle and the aorta. The aortic valve opens as the left ventricle contracts to pump blood into the aorta. If a disorder causes the valve flaps to become thick and stiff, the valve opening is narrowed (stenosis). Sometimes the stiffened valve also fails to close completely and blood from the aorta leaks back through the aortic valve into the heart (aortic regurgitation Aortic Regurgitation Aortic regurgitation is leakage of blood back through the aortic valve each time the left ventricle relaxes. Aortic regurgitation is due to deterioration of the aortic valve and the surrounding... read more ) each time the left ventricle relaxes.

In aortic stenosis, the muscular wall of the left ventricle usually becomes thicker as the ventricle works harder to pump blood through the narrowed valve opening into the aorta. The thickened heart muscle requires an increasing supply of blood from the coronary arteries, and sometimes, especially during exercise, the blood supply does not meet the needs of the heart muscle. The insufficient blood supply can cause chest tightness, fainting, and sometimes sudden death. The heart muscle may also begin to weaken, leading to heart failure Heart Failure (HF) Heart failure is a disorder in which the heart is unable to keep up with the demands of the body, leading to reduced blood flow, back-up (congestion) of blood in the veins and lungs, and/or... read more Heart Failure (HF) . The abnormal aortic valve can rarely become infected (infective endocarditis Infective Endocarditis Infective endocarditis is an infection of the lining of the heart (endocardium) and usually also of the heart valves. Infective endocarditis occurs when bacteria enter the bloodstream and travel... read more Infective Endocarditis ).

Causes of Aortic Stenosis

In North America and Western Europe, aortic stenosis is mainly a disease of older people—the result of scarring and calcium accumulation (calcification) in the valve cusps. In such cases, aortic stenosis becomes evident after age 60 but does not usually cause symptoms until a person is age 70 or 80 years.

In people under 70 years, the most common cause is a birth defect Overview of Heart Defects About one in 100 babies is born with a heart defect. Some are severe, but many are not. Defects may involve abnormal formation of the heart's walls or valves or of the blood vessels that enter... read more , such as a valve with only two cusps Bicuspid Aortic Valve A bicuspid aortic valve is an aortic valve that has two cusps (leaflets) instead of the normal three. (See also Overview of Heart Defects.) The aortic valve is the valve that opens with each... read more instead of the usual three (bicuspid valve) or a valve with an abnormal funnel shape. The narrowed aortic valve opening may not be a problem during infancy, but problems occur as a person grows. The valve opening remains the same size, but the heart grows and enlarges further as it tries to pump increasing amounts of blood through the small valve opening. Over the years, the opening of a defective valve often becomes stiff and narrow because calcium accumulates.

Spotlight on Aging: Aortic Sclerosis

Sometimes calcium accumulates on the aortic valve, and the valve thickens. But the thickening does not interfere with blood flow through the valve. This disorder is called aortic sclerosis. About 1 out of 4 people older than 65 years have this disorder.

Symptoms of Aortic Stenosis

People who develop aortic stenosis as a result of a birth defect may not develop symptoms until adulthood.

People who have severe aortic stenosis may faint during exertion because blood pressure may fall suddenly. Fainting usually occurs without any warning symptoms (such as dizziness or light-headedness).

Diagnosis of Aortic Stenosis

  • Physical examination

  • Echocardiography

Doctors usually base the diagnosis on a characteristic heart murmur (abnormal heart sound) heard through a stethoscope and on results of echocardiography Echocardiography and Other Ultrasound Procedures Ultrasonography is a type of medical imaging that uses high-frequency (ultrasound) waves to produce a moving image of internal organs and other tissues. Echocardiography is ultrasonography of... read more Echocardiography and Other Ultrasound Procedures . Echocardiography is the best procedure for assessing the severity of aortic stenosis (by measuring how small the valve opening is) and the function of the left ventricle.

Treatment of Aortic Stenosis

  • Valve replacement

Adults who have aortic stenosis but no symptoms should see their doctor regularly and should avoid overly stressful exercise. Echocardiography Echocardiography and Other Ultrasound Procedures Ultrasonography is a type of medical imaging that uses high-frequency (ultrasound) waves to produce a moving image of internal organs and other tissues. Echocardiography is ultrasonography of... read more Echocardiography and Other Ultrasound Procedures is done periodically, at intervals determined by the severity of the stenosis, to monitor heart and valve function.

Before surgery, heart failure is treated with diuretics (see table ). Treating angina is often difficult because nitroglycerin, which is used to treat angina in people who have coronary artery disease, can rarely cause dangerously low blood pressure and worsen the angina in people with aortic stenosis.

Sometimes, in children and young adults who were born with a defective valve, the valve can be stretched open using a procedure called balloon valvotomy. In this procedure, a catheter with a balloon on the tip is threaded through a vein or artery into the heart (cardiac catheterization Cardiac Catheterization and Coronary Angiography Cardiac catheterization is a procedure that can measure heart function through a catheter inserted into a vein or artery and guided into the heart. Coronary angiography, which can be done during... read more Cardiac Catheterization and Coronary Angiography ). Once across the valve, the balloon is inflated, separating the valve cusps.

In people who have aortic stenosis that causes any symptoms (particularly shortness of breath on exertion, angina, or fainting), or if the left ventricle begins to fail, the aortic valve is replaced. Replacement of the abnormal valve is the best treatment for nearly everyone, and the prognosis after valve replacement is excellent. Aortic valve replacement was traditionally done via open-heart surgery. (See the video .)

Increasingly, older people can have their valve replaced through a catheter threaded up the femoral artery in a procedure called transcatheter aortic valve implantation (TAVI). TAVI is generally better than medical therapy and similar to surgical valve replacement for these people.

People with an artificial valve must take antibiotics before a surgical, dental, or medical procedure (see table ) to reduce the risk of an infection on the valve (infective endocarditis).

Prognosis for Aortic Stenosis

Aortic stenosis progresses faster as severity increases, but the rate of progression varies, so affected people, particularly sedentary older adults, need to be checked regularly. Blood flow may become significantly compromised without triggering symptoms.

Once symptoms develop, prompt valve replacement is needed to relieve symptoms and improve survival.

In people with severe aortic stenosis, death may occur suddenly, so doctors advise these people to limit physical exertion.

More Information

The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

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