The mitral valve helps control blood flow between the upper and lower chambers on the left side of your heart. When this valve becomes severely narrowed or does not close properly, the heart may have to work harder to move blood efficiently. In some people, medicines and regular monitoring are enough for a period of time. In others, a procedure may eventually be needed.
Mitral valve replacement is considered when the valve is severely damaged and cannot be adequately treated with medicines or, in selected cases, valve repair. The timing depends on the type and severity of mitral valve disease, symptoms, heart function, valve anatomy and the risks and benefits of intervention.
Importantly, having mitral valve disease does not automatically mean that the valve needs to be replaced. In many patients, repair may be possible and may be preferred when a durable repair can be achieved. For a broader overview of valve replacement procedures, see Heart Valve Replacement Surgery.
What Is Mitral Valve Disease?
The mitral valve is located between the left atrium and left ventricle. It opens to allow blood to move into the left ventricle and closes to prevent blood from flowing backward.
Mitral valve disease mainly occurs in two forms:
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
- Mitral regurgitation: The valve does not close completely, allowing blood to leak backward.
- Mitral stenosis: The valve becomes narrowed, restricting blood flow from the left atrium into the left ventricle.
Both conditions can range from mild to severe. Mild disease may only require regular monitoring, while severe disease can eventually place significant strain on the heart.
When Is Mitral Valve Replacement Considered?
Replacement may be considered when mitral valve disease becomes severe and intervention is necessary, particularly when the valve cannot be repaired effectively or when replacement is considered the more appropriate option.
Factors that can lead to consideration of an intervention include:
- Severe mitral valve regurgitation or stenosis
- Symptoms caused by the valve disease
- Reduced heart-pumping function
- Progressive enlargement or weakening of the heart chambers
- Increased pressure in the lungs related to the valve problem
- Other complications associated with advanced valve disease
- A valve that is not suitable for a durable repair
The decision is individualized. A cardiologist and cardiac surgeon may review your symptoms, imaging results, overall health and the expected durability and risks of different treatment options.
Mitral Regurgitation: When Can Surgery Become Necessary?
Mitral regurgitation is one of the most common reasons patients require mitral valve intervention. In severe regurgitation, a significant amount of blood can flow backward into the left atrium each time the heart contracts.
Over time, this extra volume can cause the left atrium and left ventricle to enlarge and may eventually affect the heart's pumping ability.
Symptoms of severe mitral regurgitation
When severe mitral regurgitation causes symptoms, intervention is generally considered. Symptoms may include:
- Shortness of breath, especially during activity
- Reduced exercise tolerance
- Persistent tiredness
- Palpitations or an irregular heartbeat
- Difficulty breathing when lying down
- Swelling of the ankles or legs
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
What About Mitral Stenosis?
Mitral stenosis is different from mitral regurgitation. Instead of leaking, the valve becomes narrowed and makes it harder for blood to move from the left atrium into the left ventricle.
Severe mitral stenosis can cause:
- Shortness of breath
- Fatigue during physical activity
- Reduced exercise capacity
- Palpitations
- Swelling caused by fluid retention
In suitable patients, a catheter-based procedure to open the narrowed valve may be possible. Surgery, including valve replacement, may be considered when such an approach is unsuitable or when the valve anatomy and other clinical factors make surgery more appropriate.
Does Severe Mitral Valve Disease Always Require Replacement?
No. This is an important distinction. When intervention is needed for certain forms of primary mitral regurgitation, repair is generally preferred over replacement if a successful and durable repair is likely.
Repair preserves the patient's own valve and may avoid some of the long-term considerations associated with a prosthetic valve.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
However, repair is not possible or durable in every patient. Extensive valve damage, severe calcification, rheumatic disease or other anatomical factors may make replacement a more suitable option.
The decision between repair and replacement is therefore based on the individual valve anatomy and the experience of the treating Heart Team.
How Do Doctors Determine Whether Replacement Is Needed?
The evaluation usually combines your symptoms, physical examination and imaging findings.
Echocardiography
An echocardiogram is central to the assessment of mitral valve disease. It can show how the valve opens and closes, estimate the severity of leakage or narrowing, and assess the size and function of the heart chambers.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
Electrocardiogram
An ECG can identify abnormal heart rhythms and other electrical changes that may occur alongside mitral valve disease.
Additional imaging
Transesophageal echocardiography, cardiac CT or other imaging may be used when more detailed information about the valve is needed, particularly when planning repair, replacement or a catheter-based procedure.
Assessment of surgical risk
Your age, other medical conditions, previous heart procedures, kidney and lung function, heart function and overall health may influence which treatment is safest and most appropriate.
What Happens If Mitral Valve Disease Is Left Untreated?
Mild or moderate disease may remain stable for a long time and can often be monitored. Severe disease that is left untreated, however, can progressively affect the heart.
Depending on the type of mitral valve problem, complications can include heart failure, abnormal heart rhythms, increased pressure in the lungs and enlargement or weakening of the heart chambers.
This does not mean that every person with mitral valve disease needs immediate surgery. The goal is to identify the point at which the expected benefit of intervention becomes greater than the risks of waiting or proceeding too early.
What Factors Affect the Timing of Mitral Valve Replacement?
The timing of treatment can vary considerably from one person to another. Your cardiac team may consider:
- Severity and type of mitral valve disease
- Presence and severity of symptoms
- Left ventricular function and size
- Changes in the left atrium
- Presence of pulmonary hypertension or abnormal heart rhythms
- Whether the valve can be repaired successfully
- Your age and general health
- Risk associated with surgery or another intervention
- Expected long-term benefit of treatment
For severe valve disease, current guidelines emphasize evaluation by a multidisciplinary Heart Team because choosing between repair, replacement and catheter-based treatment can require several areas of expertise.
The Bottom Line
Mitral valve replacement may be needed when severe mitral valve disease is causing significant symptoms, affecting heart function or creating a risk of serious complications, particularly when the valve cannot be repaired effectively.
However, replacement is not automatically the first choice whenever treatment is required. For many patients with primary mitral regurgitation, a durable valve repair is preferred when it is technically possible. Some patients may also be suitable for catheter-based treatment rather than conventional surgery.
The right timing and type of intervention depend on the severity and cause of the valve disease, heart function, valve anatomy, symptoms and overall surgical risk. A careful evaluation by a multidisciplinary Heart Team helps determine whether monitoring, repair, replacement or another intervention is the most appropriate next step.
