From the Guidelines
The normal range for mitral valve velocity assessed by transthoracic echocardiography (TTE) is typically less than 1.9 m/s for the peak early diastolic velocity (E velocity) in most normally functioning mitral valves. This value is based on the most recent and highest quality study available, which provides guidelines for the imaging assessment of prosthetic heart valves, including mitral valve velocity assessment 1.
Key Points to Consider
- The normal mean transmitral gradient is generally less than 5-6 mmHg, and increasing grades of stenosis are associated with increasing transmitral velocities and gradients.
- Prosthesis size, ventricular and atrial function, chamber compliances, relative chamber pressures, and the presence of patient-prosthesis mismatch (PPM) or any obstruction can influence transmitral velocities.
- The presence of tachycardia or significant mitral regurgitation (MR) can also affect transmitral flow velocities, highlighting the need for comparing serial values in the same patient over time.
Clinical Implications
- An early mitral peak velocity of 2.5 m/s or higher and a mean transmitral pressure gradient of 10 mmHg or higher suggest the presence of severe mitral prosthetic obstruction.
- Significant mitral prosthetic valve obstruction is usually associated with increased transprosthetic mean gradient (12 mmHg or higher) during stress echocardiography.
- A change from immediate postoperative values or an increase in mean gradient of more than 5 mmHg with similar heart rates is suggestive of the occurrence of valve obstruction, as noted in the study 1.
From the Research
Mitral Valve Velocity Assessment
The normal range for mitral valve velocity assessed by transthoracic echocardiography (TTE) can be determined by several factors, including peak early diastolic velocity.
- Peak early diastolic velocity (E velocity) is a key index of mechanical prosthetic mitral valve function, with a value of > or =1.9 m/s indicating potential valve dysfunction 2.
- The pressure half-time (PHT) method is also used to assess mitral valve area, but its accuracy may be limited in certain patient populations, such as older patients or those in atrial fibrillation 3.
- A PHT of less than 130 milliseconds is associated with a good valve opening, but this method should be used cautiously, especially after percutaneous mitral commissurotomy (PMC) 3.
Diagnostic Considerations
When assessing mitral valve velocity using TTE, it is essential to consider the following:
- The use of beta-blockers may affect mitral valve function, particularly in patients with mitral stenosis 4, 5.
- Accurate characterization of normal mitral valve anatomy and function is crucial for understanding the pathophysiology of mitral valve disease 6.
- Advances in noninvasive cardiac imaging techniques, such as three-dimensional echocardiography and cardiac magnetic resonance, can provide high spatial resolution images and accurate assessment of mitral valve anatomy and function 6.