Echocardiography in the Diagnosis of Mitral Regurgitation

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Echocardiography in the Diagnosis of Mitral
Regurgitation
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• Dysfunction or altered anatomy of any one of the
  components of the mitral valve apparatus can
  result in mitral regurgitation.

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Etiology and Presumed Mechanisms of MR
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2-D Criteria

• The left ventricle ejects blood both forward into
  the aorta against systemic vascular resistance
  and backward into the low-resistance left atrium.
  
• Since the left ventricle effectively pumps
  against the low afterload early in the disease
  course, the increase in left ventricular stroke
  volume is achieved mainly by more complete left
  ventricular emptying (an increase in ejection
  fraction) rather than by left ventricular
  dilation.

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2-D Criteria

• 2-D and M-mode echo are useful in detecting the
  underlying cause of mitral regurgitation
• The left ventricle is expected to appear
  hyperdynamic on 2D imaging when mitral
  regurgitation is present.

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2-D Criteria

• With chronic regurgitation, progressive left
  ventricular dilation eventually occurs as the
  regurgitant volume increases the LV is
  hyperdynamic. So accurate LV measurements should
  be taken.
• The left atrium gradually dilates to accommodate
  the regurgitant volume while maintaining a normal
  left atrial pressure. So the LA should be
  measured.

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2-D Criteria

• With acute MR, the regurgitant volume is
  delivered into a small, noncompliant left atrium,
  resulting in a significant increase in left
  atrial pressure.
• Echocardiographic evaluation of the patient with
  mitral regurgitation includes noninvasive
  measurement of pulmonary artery pressure from the
  tricuspid regurgitant jet velocity and estimate
  of RA pressure

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2-D Criteria

• This is performed because, pulmonary artery
  pressure rises passively in response to both the
  chronic mildly elevated left atrial pressure seen
  with chronic mitral regurgitation and the acute
  severe elevation seen with acute regurgitation.
• When left atrial pressure is chronically
  elevated, pulmonary vascular resistance may
  increase

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CM-mode and M-mode

• Can help in the evaluation of the time of the MR
  relative to the systolic cycle
• LA and LV size are usually dilated although could
  be normal in mild MR
• Can cause early systolic closing of the aortic
  valve
• Rounded E point
• Hyperdynamic LV motion

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Evaluation of Hemodynamic Severity

• The amount of regurgitant flow must be determined
• The effect of the regurgitation on the left
  ventricle, i.e., the degree of left ventricular
  volume loading, must be assessed
• The effect of the regurgitation on left atrial
  and pulmonary venous pressure, i.e., the degree
  of LA/pulmonary venous loading, must be determine

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Doppler/color Doppler

• Multiple Doppler parameters can be used to assess
  the quantity of mitral regurgitant flow. These
  include both semi-quantitative parameters such as
  
• peak velocity of forward flow across the MV
  during diastole, which increases as the
  regurgitant volume increases,
• area, and length of the regurgitant jet as assess
  by color Doppler,
• width of the regurgitant jet by the point of
  valve leaflet apposition (vena contracta)
• and the intensity of the spectral Doppler
  velocity profile

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Doppler/color Doppler

• All these parameters correlate with angiographic
  estimations of severity when MR is either mild or
  severe.
• However, in patients with moderate degrees of MR
  these parameters have been less definitive

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Doppler/color Doppler

• CW may be useful in quantitative assessment of
  severity (increase density of the envelop)
• The velocity of the mitral regurgitation tends to
  be lower lt5m/sec with increasing severity because
  the increase LA pressure reduces the transmitral
  systolic gradient
• Acute MR the jet will peak in early systole

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Doppler/color Doppler
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Doppler/color Doppler

• In MR, antegrade flow (mitral inflow) velocity
  may be increased with severe regurgitation.
• Peak mitral diastolic velocity (E point) gt1.5
  m/sec with normal pressure ½ time is severe MR

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Doppler/color Doppler

• In the parasternal views use pulsed color Doppler
  flow in the LA for systolic turbulence and to
  evaluate the Vena Contracta
• Vena Contracta gt0.5cm is considered significant

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Doppler/color Doppler

• mapping technique of flow disturbance from
  parasternal and apical views provide estimation
  of severity using pulsed and more commonly color
  Doppler

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Doppler/color Doppler

• MR should be assessed in all views
• Parasternal long and short axis
• All three apical views
• Subcostal long axis

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Doppler/color Doppler
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Doppler/color Doppler

• In color flow imaging of MR, the area of the
  regurgitant jet relative to the size of the LA is
  most predictive of regurgitant severity
  determined by angiography

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Doppler/color Doppler

• Jet area is more reliable than jet length method
  in mapping. It is done by planimetry of the
  regurgitant jet in the LA and RA then dividing by
  the left or right atrial areas

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Doppler/color Doppler

• Pulmonary Vein Flow reversal
• Use the right upper pulmonary vein
• Place the PW Doppler cursor at least .5 to 1 cm
  into the pulmonary vein
• Open the Doppler gate to 1 cm
• Set the Doppler spectral sweep speed to 100 msec

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Doppler/color Doppler
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Example