What is the normal mitral valve gradient?

From the Guidelines

The normal mitral valve gradient is generally less than 5-6 mmHg. This value represents the pressure difference between the left atrium and left ventricle when the mitral valve is open, and it is crucial for efficient blood flow during diastolic filling 1. The mean diastolic gradient across a normal mitral valve is usually in the range of 1-3 mmHg at rest with normal heart rates.

Key Points to Consider

• The normal mitral valve gradient can be influenced by several factors, including prosthesis size, ventricular and atrial function, chamber compliances, relative chamber pressures, and the presence of patient-prosthesis mismatch (PPM) or any obstruction 1.
• Echocardiography, using Doppler techniques, is the standard method for measuring the mitral valve gradient and assessing blood flow velocities across the valve.
• An increase in the mean gradient above the normal range can indicate mitral stenosis or other pathology affecting the valve, with significant obstruction typically associated with a mean transmitral pressure gradient of 10 mmHg or higher 1.
• Serial measurements over time are essential for accurately assessing changes in mitral valve function and detecting potential issues early.

Clinical Implications

• Understanding the normal mitral valve gradient is vital for diagnosing and managing mitral valve disease, as it allows clinicians to identify abnormalities and monitor disease progression or response to treatment.
• The information from echocardiographic assessments, including the mitral valve gradient, should be interpreted in the context of the patient's overall clinical presentation and other diagnostic findings.
• Given the potential for variability and the influence of multiple factors on the mitral valve gradient, a gradient of less than 5-6 mmHg is considered normal, as indicated by the most recent and highest quality evidence 1.

From the Research

Normal Mitral Valve Gradient

The normal mitral valve gradient is a topic of interest in the field of cardiology.

• A study published in 2 found that a resting mean mitral diastolic gradient of ≤3 mm Hg is considered normal.
• Another study published in 3 also used a mean transmitral pressure gradient of ≥3 mmHg as a threshold for mitral annular calcification-related mitral valve dysfunction.

Mitral Valve Gradient Ranges

Different studies have reported various ranges for mitral valve gradients:

• A study published in 4 found that a peak exercise mean mitral gradient of > 15 mm Hg is indicative of significant mitral stenosis.
• The same study found that the mean mitral gradient increased from 7 +/- 2 mm Hg at rest to 19 +/- 6 mm Hg with exercise.
• A study published in 3 stratified patients by mean transmitral pressure gradient into low (3-5 mmHg), mid (5-10 mmHg), and high (≥10 mmHg) gradient groups.

Factors Affecting Mitral Valve Gradient

Several factors can affect the mitral valve gradient:

• Posterior mitral leaflet plication and the use of a complete mitral annuloplasty ring were associated with elevated mitral gradients in a study published in 2.
• Mitral valve area was an independent predictor of maximum exercise capacity in the same study.
• Concomitant mitral regurgitation was associated with excess mortality in low-gradient ranges (3-5 mmHg) but gradually lost prognostic importance at higher gradients, as reported in 3.