Mitral valve stenosis

Symptoms

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Patients may feel fine with mitral valve stenosis, or may have minimal symptoms for decades. Mitral valve stenosis usually progresses slowly over time. See your doctor if you develop:

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• Shortness of breath, especially with exertion or when you lie down

• Fatigue, especially during increased physical activity

• Swollen feet or legs

• Heart palpitations — sensations of a rapid, fluttering heartbeat

• Dizziness or fainting

• Coughing up blood

• Chest discomfort or chest pain

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Mitral valve stenosis symptoms may appear or worsen anytime and the heart rate increases, such as during exercise. An episode of rapid heartbeats may accompany these symptoms. Or they may be triggered by pregnancy or other body stress, such as an infection.

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In mitral valve stenosis, pressure that builds up in the heart is then sent back to the lungs, resulting in fluid buildup (pulmonary congestion) and shortness of breath.

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Symptoms of mitral valve stenosis most often appear in between the ages of 15 and 40 in developed nations, but they can occur at any age even during childhood.

Mitral valve stenosis may also produce signs that doctor will find during your examination. These may include:

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• Heart murmur

• Fluid buildup in the lungs

• Irregular heart rhythms (arrhythmias)

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Causes

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Causes of mitral valve stenosis include:

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Rheumatic fever. A complication of strep throat, rheumatic fever can damage the mitral valve. Rheumatic fever is the most common cause of mitral valve stenosis. It can damage the mitral valve by causing the flaps to thicken or fuse. Signs and symptoms of mitral valve stenosis might not show up for years.

Calcium deposits. As people age, calcium deposits can build up around the ring around the mitral valve (annulus), which can occasionally cause mitral valve stenosis.

Other causes. In rare cases, babies are born with a narrowed mitral valve (congenital defect) that causes problems over time. Other rare causes include radiation to the chest and some autoimmune diseases, such as lupus.

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How the heart works

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The heart, the center of your circulatory system, consists of four chambers. The two upper chambers (atria) receive blood. The two lower chambers (ventricles) pump blood.

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Four heart valves open and close to let blood flow in only one direction through the heart. The mitral valve — which lies between the two chambers on the left side of the heart — comprises two flaps of tissue called leaflets.

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The mitral valve opens when blood flows from the left atrium to the left ventricle. Then the flaps close to prevent the blood that has just passed into the left ventricle from flowing backward. A defective heart valve fails to either open or close fully.

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Risk factors

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Mitral valve stenosis is less common today than it was, because the most common cause, rheumatic fever can be treated easy. However, rheumatic fever remains a problem in developing nations.

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Risk factors for mitral valve stenosis include:

• History of rheumatic fever

• Untreated strep infection

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Complications

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Like other heart valve problems, mitral valve stenosis can strain the heart and decrease blood flow. Untreated, mitral valve stenosis can lead to complications such as:

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Pulmonary hypertension. This is a condition in which there's increased pressure in the arteries that carry blood from the heart to your lungs (pulmonary arteries), causing the heart to work harder.

Heart failure. A narrowed mitral valve interferes with blood flow. This can cause pressure to build in the lungs, leading to fluid accumulation. The fluid buildup strains the right side of the heart, leading to right heart failure. When blood and fluid back up into the lungs, it can cause a condition known as pulmonary edema. This can lead to shortness of breath and, sometimes, coughing up of blood-tinged sputum.

Heart enlargement. The pressure buildup of mitral valve stenosis results in enlargement of the heart's upper left chamber (atrium).

Atrial fibrillation. The stretching and enlargement of the heart's left atrium may lead to this heart rhythm irregularity in which the upper chambers of the heart beat chaotically and too quickly.

Blood clots. Untreated atrial fibrillation can cause blood clots to form in the upper left chamber of the heart. Blood clots from the heart can break loose and travel to other parts of the body, causing serious problems, such as a stroke if a clot blocks a blood vessel of the brain.

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Prevention

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The best way to prevent mitral valve stenosis is to prevent its most common cause, rheumatic fever. You can do this by making sure you and your children see your doctor for sore throats. Untreated strep throat infections can develop into rheumatic fever. Fortunately, strep throat is usually easily treated with antibiotics.

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Diagnosis

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Your doctor will ask about your medical history and give you a physical examination that includes listening to your heart through a stethoscope. Mitral valve stenosis causes an abnormal heart sound, called a heart murmur. Your doctor also will listen to your lungs to check lung congestion (a buildup of fluid in your lungs) that can occur with mitral valve stenosis.

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Common tests to diagnose mitral valve stenosis include:

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Transthoracic echocardiogram. Sound waves directed at the heart from a wandlike device (transducer) held on the chest produce video images of the heart in motion. This test is used to confirm the diagnosis of mitral stenosis.

Transesophageal echocardiogram. A small transducer attached to the end of a tube inserted down the esophagus allows a closer look at the mitral valve than a regular echocardiogram does.

Electrocardiogram (ECG). Wires (electrodes) attached to pads on the skin measure electrical impulses from the heart, providing information about heart rhythm. You might walk on a treadmill or pedal a stationary bike during an ECG to see how your heart responds to exertion.

Chest X-ray. This enables the doctor to determine whether any chamber of the heart is enlarged and the condition of the lungs.

Cardiac catheterization. This test isn't often used to diagnose mitral stenosis, but it might be used when more information is needed to assess the condition. It involves threading a thin tube (catheter) through a blood vessel of the arm or groin to an artery in the heart and injecting dye through the catheter to make the artery visible on an X-ray. This provides a detailed picture of the heart.

Cardiac tests such as these help doctor distinguish mitral valve stenosis from other heart conditions, including other mitral valve conditions. These tests also help reveal the cause of mitral valve stenosis and whether the valve can be repaired.

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Treatment

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If there is a mild to moderate mitral valve stenosis with no symptoms, immediate treatment is not needed. Instead, doctors will monitor the valve to see if the condition worsens.

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Medications

No medications can correct a mitral valve defect. However, certain drugs can reduce symptoms by easing heart's workload and regulating its rhythm.

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Procedures

You may need valve repair or replacement to treat mitral valve stenosis, which may include surgical and nonsurgical options.

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Percutaneous balloon mitral valvuloplasty

 

In this procedure, also called balloon valvotomy, a doctor inserts a soft, thin tube (catheter) tipped with a balloon in an artery of the arm or groin and guides it to the narrowed valve. Once in position, the balloon is inflated to widen the valve, improving blood flow. The balloon is then deflated, and the catheter with balloon is removed.

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For some people, balloon valvuloplasty can relieve the signs and symptoms of mitral valve stenosis. However, you may need additional procedures to treat the narrowed valve over time.

Not everyone with mitral valve stenosis is a candidate for balloon valvuloplasty. Talk to your doctor to decide whether it's an option for you.

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Mitral valve surgery

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Surgical options include:

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Commissurotomy. If balloon valvuloplasty isn't an option, a cardiac surgeon might perform open-heart surgery to remove calcium deposits and other scar tissue to clear the valve passageway. Open commissurotomy requires that you be put on a heart-lung bypass machine during the surgery. You may need the procedure repeated if your mitral valve stenosis redevelops.

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Mitral valve replacement. If the mitral valve can't be repaired, surgeons may perform mitral valve replacement. In mitral valve replacement, surgeons removes the damaged valve and replaces it with a mechanical valve or biological valve. 

Biological tissue valves degenerate over time, and often eventually need to be replaced. People with mechanical valves will need to take blood-thinning medications for life to prevent blood clots. Your doctor will discuss with you the benefits and risks of each type of valve and discuss which valve may be appropriate for you.