Mitral Stenosis Treatment - Timing Is Everything
With mitral stenosis (MS), the mitral valve (the valve that lies in between the heart's two left chambers) becomes thickened and immobile, failing to open completely and impeding blood flow. Since MS is fundamentally a mechanical problem, the ultimate solution must be a surgical one -- that is, some intervention to relieve the obstruction.If you have MS, the most critical question is deciding whether to perform surgery and when to perform it.
The timing of mitral valve surgery is very important. MS usually gets worse very slowly, and people with MS can remain entirely without symptoms for many years. You may think it's better just to get the procedure over with, but performing the surgery too early can expose you to unnecessary risk.
On the other hand, waiting too long to perform surgery can lead to irreversible heart damage, so that mitral valve surgery will no longer be effective. This can be a fatal mistake.
Deciding on the appropriate time to perform mitral valve surgery largely depends on your symptoms, as well as measurements of how well your mitral valve opens and the pressure within your pulmonary artery. These measurements can be done with an echocardiogram.
It is very important to pay close attention to any shortness of breath, fatigue, and changes in your ability to exert yourself. Your doctor will help by asking the right questions. (How many steps can you climb before becoming short of breath? How long does it take you to walk one block? Do you cough when you exert yourself? Etc.)
Deciding When the Time Is Right for You
With these considerations, let's look at some general "rules" for deciding when it's time for surgery.
If you have no symptoms at all and your MS is considered mild, the main decision you and your doctor will make is how often you should have repeat evaluations. Depending on your assessment, echocardiograms performed every year or 2 to 3 years may be necessary. If you experience shortness of breath or fatigue in between checks, go for a sooner-than-scheduled re-evaluation.
If you have mild MS and mild symptoms, your doctor may ask you to have an exercise echocardiogram - that is, a stress test during which an echocardiogram is performed. This test allows the doctor to estimate your pulmonary artery pressure during exercise.
If you develop elevated pulmonary artery pressure during exercise, your doctor may refer you for surgery. However, in general, patients with mild MS are referred for mitral valve repair only if they are candidates for percutaneous mitral balloon valvulotomy (PMBV), a relatively non-invasive mitral valve repair procedure.
If you have moderate to severe MS and also have symptoms, and your pulmonary artery pressure is elevated either at rest or during exercise, you should have surgery. In this case you will probably be referred for PMBV if that procedure is feasible. If it is not feasible, you will be referred for another mitral stenosis surgery -- an open procedure to either repair or replace your mitral valve.
If you have severe MS and very significant symptoms, the issue is no longer whether the MS is severe enough to perform surgery, but whether the MS has progressed beyond the point where surgery would be of any help. Making this decision can be relatively difficult, and it often involves a full cardiac catherization and close consultation and discussion between you, your cardiologist and the cardiac surgeon.
Can Drugs Help Mitral Stenosis?
Definitive therapy requires physically relieving the obstruction, but medical therapy can offer some advantages.Diuretics (water pills), usually the more powerful diuretics such as Lasix or Bumex, can help with shortness of breath or with fluid retention.
Using drugs to prevent rheumatic fever are important, especially in younger patients, if the MS is due to rheumatic heart disease.
In general, using drugs that help prevent endocarditis is no longer recommended for people with MS.
Since atrial fibrillation tends to cause worse symptoms in patients with MS than in patients without it, aggressive treatment to control symptoms should be used.
Preventing Blood Clots
People with MS have an increased risk of thromboembolism (blood clots within blood vessels or the heart that break off and cause tissue damage such as stroke). In MS, the thrombus tends to form in the left atrium. The risk of thromboembolism is greatly increased if atrial fibrillation is present.For this reason, anticoagulation with Coumadin is recommended in patients with MS who have any of the following:
- a history of a prior thromboembolic event, especially stroke
- left atrial thrombus (which can be detected by echocardiogram
- atrial fibrillation
- according to some experts, a greatly enlarged left atrium (also detected by echocardiogram)
Sources:
Bonow, RO, Carabello, BA, Chatterjee, K, et al. 2008 Focused update incorporated into the ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 1998 Guidelines for the Management of Patients With Valvular Heart Disease): endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. Circulation 2008; 118:e523.
