From Echocardiography in ICU

Mechanical mitral valves are difficult to assess from transthoracic windows. The metallic structure of the valve reflects the ultrasounds, creating a dead zone behind the valve, and many artifacts around it. Assessment of mechanical mitral valve position and function is challenging and should be realized by a trained cardiologist.

The important parameters to assess in a patient with mechanical mitral valve are:

-position of the valve

-valve motion

-regurgitations: intra or para-prosthetic --> TEE will be more accurate if any doubt exists

-valve thrombosis

Parasternal long axis. Note the mechanical mitral valve, normally seated. There is concentric left ventricle hypertrophy. 
Parasternal long axis with color. There are many artifacts created by the high reflectivity of the metallic valve.

 

Apical 4 chamber. You can see the motion of the leaflets. The left atrium is almost completely shadowed by the artifacts from the valve.

Apical 4 chamber with color on the mitral valve. The forward flow across the valve is normally accelerated, but regurgitation can not be assessed. 
Apical 2 chamber
Apical 2 chamber with color.