Mitral Stenosis

What is Mitral Stenosis?

In mitral stenosis, valve leaflets become diffusely thickened by fibrosis and calcification. The mitral commissures fuse, the chordae tendineae fuse and shorten, the valvular cusps become rigid, and the apex of the valve becomes narrowed, obstructing blood flow from the left atrium to the left ventricle.

As a result of these changes, left atrial volume and pressure increase and the atrial chamber dilates. The increased resistance to blood flow causes pulmonary hypertension, right ventricular hypertrophy and, eventually, right-sided heart failure. Also, inadequate filling of the left ventricle reduces cardiac output.

Causes of Mitral Stenosis

Mitral stenosis most commonly results from rheumatic fever. It may also be associated with congenital anomalies.

Signs & Symptoms of Mitral Stenosis

Often there are no signs or symptoms of mitral stenosis until you are between 30 and 40 years of age. The following are signs and symptoms of MS:

• Coughing up blood-tinged sputum (spit).
• Coughing when lying down.
• Difficulty sleeping flat or with just one pillow.
• Feeling dizzy.
• Fainting.
• Hoarseness
• Swelling of the feet and ankles.
• Loss of stamina.
• Palpitations (awareness of your heartbeat).

Diagnostic Tests

Cardiac catheterization shows a diastolic pressure gradient across the valve. It also shows elevated pulmonary artery wedge pressure (greater than 1 5 mm Hg) and pulmonary artery pressure in the left atrium with severe pulmonary hypertension. It detects elevated right ventricular pressure, decreased cardiac output, and abnormal contraction of the left ventricle. However, this test may not be indicated in patients who have isolated mitral stenosis with mild symptoms.

Chest X-rays show left atrial and ventricular enlargement (in severe mitral stenosis), straightening of the left border of the cardiac silhouette, enlarged pulmonary arteries, dilation of the upper lobe pulmonary veins, and mitral valve calcification.

Echocardiography discloses thickened mitral valve leaflets and left atrial enlargement.

Electrocardiography reveals left atrial enlargement, right ventricular hypertrophy, right axis deviation, and (in 40% to 50% of cases) atrial fibrillation.

Treatment

In valvular heart disease, treatment depends on the nature and severity of associated symptoms. In asymptomatic mitral stenosis in a young patient, penicillin is an important prophylactic. If the patient is symptomatic, treatment varies. Heart failure requires bed rest, digoxin, diuretics, a sodium-restricted diet and, in acute cases, oxygen. Small doses of beta-adrenergic blockers may also be used to slow the ventricular rate when digitalis glycosides fail to control atrial fibrillation or flutter. Synchronized cardioversion may be used to correct atrial fibrillation in an unstable patient.

If hemoptysis develops, the patient requires bed rest, salt restriction, and diuretics to decrease pulmonary venous pressure. Embolization mandates anticoagulants along with symptomatic treatments.

A patient with severe, medically uncontrollable symptoms may need open-heart surgery with cardiopulmonary bypass for commissurotomy or valve replacement.

Percutaneous balloon valvuloplasty may be used in young patients who have no calcification or subvalvular deformity, in symptomatic pregnant women, and in elderly patients with end-stage disease who couldn't withstand general anesthesia. This procedure is performed in the cardiac catheterization laboratory.

Prevention Tips

The most effective 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 when you have a sore throat. Untreated strep throat can develop into rheumatic fever. Fortunately, strep throat is easily treated with antibiotics. Mitral stenosis itself often cannot be prevented, but complications can be prevented. Inform your health care provider of any history of heart valve disease before medical treatment and also follows these steps.

• Stop smoking
• Lose weight if you are overweight.
• Learn ways to reduce or manage stress.
• Limit your salt intake if the health care provider suggests a low-salt diet. 
• Exercise regularly according to your health care provider's advice.