Color Flow Doppler to Assess Cardiac Valve Competence

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Color Flow Doppler to Assess Cardiac Valve Competence

Resident Clinical Pearl (RCP) April 2019

Dr. Scott Foley – CCFP-EM PGY3 Dalhousie University, Halifax NS

Reviewed by Dr. David Lewis

 

 

Background:

When colour Doppler is initiated, the machine uses the principals of the Doppler effect to determine the direction of movement of the tissues off which it is reflecting.

The Doppler effect is the change in frequency of a wave in relation to an observer who is moving relative to a wave source. It was named after the Austrian physicist Christian Doppler who first described the phenomenon in 1842. The classic example is the change in pitch of a siren heard from an ambulance as it moves towards and away from an observer.

These principles are applied to POCUS in the form of colour Doppler where direction of flow is reflected by the colour (Red = moving towards the probe, Blue = moving away from the probe), and the velocity of the flow is reflected by the intensity of the colour (brighter colour = higher velocity).
*Note: the colour does not represent venous versus arterial flow.

 

The use of colour Doppler ultrasound can be useful in the emergency department to determine vascular flow in peripheral vessels as well as through the heart. It is one way to determine cardiac valve competency by focusing on flow through each valve.

 

Obtaining Views:

To optimize valve assessment, proper views of each valve must be obtained. It is best to have the direction of the ultrasound waves be parallel to the direction of flow. External landmarks for the views used are seen below:

  • Mitral Valve and Tricuspid Valve: The best view for each of these is the apical 4 chamber view. If unable to obtain this view, the mitral valve can be seen in parasternal long axis as well.
  • Aortic Valve: The best view is the apical 5 chamber or apical 3 chamber but are challenging to obtain. Instead, the parasternal long axis is frequently used.
  • Pulmonic Valve: Although not commonly assessed, the parasternal short axis can be used.
  • Visit 5minutesono.com for video instruction on obtaining views

Parasternal long axis: MV, AV

Parasternal short axis: PV, TV

Apical 4 chamber: TV, MV

 

Assessing Valvular Competency:

How to examine valvular competency:

  1. Get view and locate valve in question
  2. Visually examine valve: opening, closing, calcification
  3. Use colour Doppler:
    1. Place colour box over valve (as targeted as possible (resize select box) to not include other valves)
    2. Freeze image and scroll through images frame by frame
    3. Examine for pathologic colour jets in systole and diastole
  4. Estimating severity:
    1. Grade 1 – jet noticeable just at valve
    2. Grade 2 – jet extending out 1/3 of atrium/ventricle
    3. Grade 3 – jet extending out 2/3 of atrium/ventricle
    4. Grade 4 – jet filling entire atrium/ventricle

See video tutorial below for more

Mitral Regurgitation A4C

Tricuspid Regurgitation A4C

Aortic Stenosis PSLA

Bottom line:

Color flow Doppler on POCUS is a straightforward way to assess for valvular competency in the Emergency Department. A more detailed valvular assessment requires skill, knowledge and experience.

 

Useful Video Tutorials:

Mitral Regurgitation

 

Aortic Stenosis vs Sclerosis

Tricuspid Valve

References:

  1. https://www.radiologycafe.com/medical-students/radiology-basics/ultrasound-overview
  2. By Patrick J. Lynch and C. Carl Jaffe – http://www.yale.edu/imaging/echo_atlas/views/index.html, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=21448310
  3. 5minutesono.com
  4. ECCU ShoC 2018 powerpoint, Paul Atkinson, David Lewis
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