From the Guidelines
The normal mitral valve area is between 4.0 to 5.0 cm2. This range allows for proper blood flow from the left atrium to the left ventricle during diastole when the heart relaxes 1. The mitral valve consists of two leaflets, the anterior and posterior, which open and close with each heartbeat to regulate blood flow. When the valve area decreases below 2.5 cm2, it typically occurs before the development of symptoms, and an area less than 1.5 cm2 may not produce symptoms at rest but can lead to symptoms with increased transmitral flow or decreased diastolic filling period 1.
Key Points to Consider
- The normal mitral valve area is crucial for understanding the progression and severity of mitral stenosis.
- Mitral stenosis is characterized by the narrowing of the valve area, leading to restricted blood flow and potential symptoms.
- The severity of mitral stenosis can be classified based on the valve area, with mild stenosis typically defined as a valve area between 1.5 and 2.0 square centimeters, moderate stenosis between 1.0 and 1.5 square centimeters, and severe stenosis when the area is less than 1.0 square centimeter.
- The valve area can be measured using various cardiac imaging techniques, including echocardiography, which is the most common non-invasive method used in clinical practice.
Clinical Implications
- Understanding the normal mitral valve area is essential for diagnosing and managing mitral stenosis.
- Patients with symptomatic mitral stenosis and favorable valve morphology may benefit from percutaneous mitral commissurotomy (PMC) or surgical intervention 1.
- Asymptomatic patients with high-risk features, such as increased risk of systemic embolism or hemodynamic decompensation, may also be considered for intervention 1.
Evidence-Based Recommendations
- The most recent and highest-quality study, the 2017 ESC/EACTS guidelines for the management of valvular heart disease, recommends intervention for patients with clinically significant mitral stenosis (valve area <1.5 cm2) 1.
- The guidelines also emphasize the importance of considering clinical characteristics, valve anatomy, and local expertise when deciding on the type and timing of intervention.
From the Research
Normal Mitral Valve Area
The normal mitral valve area is typically considered to be between 4.0-6.0 cm2 2. This range is based on studies that have measured the mitral valve orifice area in healthy individuals.
Measurement of Mitral Valve Area
Mitral valve area can be measured using various techniques, including two-dimensional echocardiography 3, 4. This non-invasive method allows for accurate measurement of the mitral valve orifice area, even in the presence of mitral regurgitation.
Factors Affecting Mitral Valve Area
The size of the mitral valve orifice can vary depending on several factors, including body surface area 3. In pediatric patients, the mitral valve area has been shown to correlate with body surface area, with a formula of MVA = 4.83 X BSA - 0.07 3.
Comparison of Measurement Techniques
Studies have compared the accuracy of different measurement techniques, including echocardiography and cardiac catheterization 5, 4. These studies have shown that echocardiography is a reliable and accurate method for measuring mitral valve area, with good correlation with invasive measurements.
Mitral Stenosis
Mitral stenosis is characterized by a narrowing of the mitral valve orifice, with a valve area typically less than 4.0 cm2 2. The severity of mitral stenosis can be classified based on the valve area, with severe stenosis typically defined as a valve area less than 1.0 cm2 2.