From the Guidelines
Mitral stenosis is graded based on valve area, mean pressure gradient, and pulmonary artery pressure, with severity categorized as mild, moderate, or severe. The grading of mitral stenosis is crucial for determining the appropriate management strategy and predicting outcomes. According to the most recent guidelines 1, echocardiography is the preferred method for diagnosing mitral stenosis and assessing its severity.
Key Factors in Grading Mitral Stenosis
- Valve area: This is a critical factor in determining the severity of mitral stenosis. A valve area of >1.5 – 2.5 cm2 is considered mild, between 1.0 and 1.5 cm2 is moderate, and <1.0 cm2 is severe 1.
- Mean pressure gradient: The mean pressure gradient across the mitral valve is another important factor. A mean gradient of <7 mmHg is considered mild, between 8 and 15 mmHg is moderate, and >15 mmHg is severe 1.
- Pulmonary artery pressure: The pulmonary artery pressure is also taken into account, with <35 mmHg considered mild, between 35 and 50 mmHg considered moderate, and >50 mmHg considered severe 1.
Importance of Accurate Grading
Accurate grading of mitral stenosis is essential for guiding treatment decisions and predicting outcomes. Symptoms such as dyspnea, fatigue, and palpitations typically correlate with the severity of stenosis, and regular echocardiographic assessment is necessary for monitoring disease progression.
Diagnostic Tools
Echocardiography is the primary diagnostic tool for mitral stenosis, and it provides valuable information on valve area, mean pressure gradient, and pulmonary artery pressure. The use of echocardiography allows for accurate grading of mitral stenosis and informs management decisions.
From the Research
Mitral Stenosis Grading
Mitral stenosis can be graded using various echocardiographic parameters and scoring systems. The following are some of the methods used to grade mitral stenosis:
- Doppler-derived measurements of mitral pressure half-time to calculate mitral valve area 2
- Planimetry to determine mitral valve area, which can be performed using two- or three-dimensional imaging 2
- Wilkins score, which has been used for over 30 years to predict balloon mitral valvuloplasty outcomes 3, 4, 5
- Newer scoring systems, such as the Nunes quantitative scoring system and the Sutaria scoring system, which have been proposed to improve predictive accuracy 4, 5
- Commissural calcium score and commissural area ratio, which can be used in combination with the Wilkins score to predict procedural outcomes 5
Echocardiographic Parameters
Echocardiographic parameters used to grade mitral stenosis include:
- Mitral valve area 2, 3, 4
- Mitral valve morphology, including leaflet displacement and commissural area ratio 4, 6
- Subvalvular involvement 4
- Left atrial systolic strain, which can predict adverse outcomes in patients with mitral stenosis 2
Scoring Systems
Various scoring systems have been developed to grade mitral stenosis, including:
- Wilkins score, which assigns points for leaflet mobility, leaflet thickening, calcification, and subvalvular involvement 3, 4, 5
- Nunes quantitative scoring system, which assigns points for mitral valve area, leaflet displacement, and commissural area ratio 4
- Sutaria scoring system, which assigns points for leaflet mobility, leaflet thickening, and calcification 5
- Integrated approach, which combines the Wilkins score with other parameters, such as commissural calcium score and commissural area ratio, to predict procedural outcomes 5