Mitral stenosis natural history


 * Associate Editor-In-Chief:

Overview
After the initial episode of rheumatic fever, there is a latent period of 20 years before the onset of symptoms in mitral stenosis. Complications of mitral stenosis are left and right heart failure, endocarditis and embolization (stroke and pulmonary embolism. Survival in asymptomatic patients is 80% at 10 years.  Once symptoms develop, if mitral stenosis is left untreated, survival at 10 years is only 15%. The majority of patients die due to complications of pulmonary hypertension(which is associated with a mean survival of 3 years after its onset) and right heart failure.

Natural history
The natural history of mitral stenosis secondary to rheumatic fever (the most common cause) is an asymptomatic latent phase following the initial episode of rheumatic fever. This latent period lasts an average of 16.3 &plusmn; 5.2 years. Once symptoms of mitral stenosis begin to develop, progression to severe disability takes 9.2 &plusmn; 4.3 years. In some areas of the developing world, the rate of progression is more rapid due to repeated infections, poorer treatment of the infections, or more virulent infections and the patient may be symptomatic as early as the late teens.

Death from mitral stenosis is due to the progressive increase in pulmonary capillary wedge pressure, pulmonary hypertension and subsequent right-sided heart failure. This is the mode of death in 60 percent of mitral stenosis cases that are not treated.

Other less frequent causes of death include :
 * Stroke (20%-30%)
 * Pulmonary embolism (10%)
 * Infective endocarditis (1-5%)

Complications
Complications of mitral stenosis are left and right heart failure, endocarditis and embolization.
 * Atrial fibrillation and other arrhythmias. It is the most common cause of disability from the disease in patients who were previously asymptomatic.
 * Pulmonary edema
 * Hemoptysis and pulmonary hemorrhage
 * Thromboembolic events (pulmonary embolism and stroke, mostly due to atrial fibrillation
 * Pulmonary hypertension
 * Right ventricular failure
 * Tricuspid regurgitation
 * Pedal edema
 * Ascites
 * Congestive hepatopathy

Asymptomatic Patients
Survival is >80% at 10 years

Symptomatic Patients Without Treatment
In individuals who were offered mitral valve surgery but refused, survival with medical therapy alone was 44 &plusmn; 6% at 5 years, and 32 &plusmn; 8% at 10 years after they were offered correction.

Presence of Pulmonary Hypertension
In the presence of pulmonary hypertension, the mean survival is less than 3 years.