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Week 2: Aortic Regurgitation > Indirect Signs of AR Severity > Flashcards

Indirect Signs of AR Severity Flashcards

1
Q

What are the five indirect clues to significant AR?

A
  1. Forward flow velocities
  2. Intensity of AR CW signal
  3. Shape of AR CW signal
  4. Flow reversal in descending/abdominal aorta
  5. Colour Doppler imaging (CDI)
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2
Q

AR: Significance of Increased Forward Flow Velocities (PW LVOT)

A
  • Increased forward flow velocities seen on PW Doppler at LVOT with AR
  • SV LVOT = forward SV + regurgitant volume
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3
Q

AR: Significance of Increased Forward Flow Velocities - Limitations

A
  • Increased LVOT velocities are also elevated in 1) high cardiac output states and 2) HOCM
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4
Q

AR: Significance of Intensity of AR Signal

A
  • CW Doppler signal intensity directly proportional to the number of red blood cells moving within Doppler beam
  • Intensity of regurgitant signal increases as severity of regurgitation increases
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5
Q

AR: Significance of Intensity of AR Signal - Limitations

A
  • AR intensity can be underestimated when Doppler beam is not parallel with AR jet
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6
Q

AR: Significance of Shape of AR CW Signal in Severe AR

A
  1. Pressure half time reflect pressure gradient between the aorta and LV during diastole
  2. In chronic severe AR, aortic pressure falls rapidly = short p1/2t
  3. P1/2t < 200ms = severe AR
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7
Q

AR: Significance of Shape of AR CW Signal - Limitations

A
  • P½t is highly dependent on chamber compliance and systemic vascular resistance
  • P½t can be short in absence of severe AR when there is poor LV complicance
  • P½t can be prolonged in chronic severe AR when there is a compliant LV (LV can accept large volume of blood without significant increase in LVEDP)
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8
Q

What signs indicate restrictive filling?

A
  • Transmitral inflow; big E-wave and little or no A-wave
  • E/A > 2
  • DT < 160ms
  • Elevated LVEDP
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9
Q

What is meant by restrictive filling?

A
  • Marked reduction in LV compliance i.e. the LV is very stiff and non-compliant
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10
Q

What does short P½t without severe AR suggest?

A

Reduced LV compliance (increased LVEDP)

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11
Q

What does prolonged P½t with severe AR suggest?

A

Compensated/compliant LV; able to accept a large volume of blood without significant increase in LVEDP

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12
Q

AR: Significance of Diastolic Flow Reversal in Descending Aorta

A
  • Pan diastolic flow reversal in descending aorta = significant AR
  • CFI shows red flow towards Tx in diastole from suprasternal notch
  • If end-diastolic velocity > 1.8m/s = moderate to severe AR
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13
Q

AR: Significance Diastolic Flow Reversal in Abdominal Aorta

A
  • Pan diastolic flow reversal
  • CFI shows blue flow away from Tx in diastole (subcostal abdonimal aorta)
  • Sign of severe AR
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14
Q

AR: Significance of Flow Reversal - Limitations

A
  • False positive when there is a diastolic pressure gradient between the aorta and another low pressure chamber
  • E.g. aorta-LA fistula (communication between aorta and LA)
  • E.g. PDA
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15
Q

AR: Significance of Colour Flow Imaging (Jet Height)

A
  • Origin of regurgitant jet height is compared to LVOTd during diastole
  • Fills < 25% of LVOTd = mild
  • AR fills entire LVOTd during diastole = severe AR
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16
Q

What is the Vena Contracta?

A
  • Vena contracta is the narrowest neck of flow region at the level of the aortic valve immediately below the flow convergence region
17
Q

AR: Significance of Colour Flow Imaging - Limitations: Technical Factors

A
  1. Gain and filter settings
  2. Tx frequency
  3. PRF
  4. Incident angle
  5. Frame rate
  6. Attenuation
  7. Suboptimal images
18
Q

AR: Significance of Colour Flow Imaging - Limitations: Physiological Factors

A
  1. Driving pressure
  2. Eccentric jets
  3. Size and shape of orifice
  4. Chamber compliance
  5. Regurgitant volume
  6. Coexistent jets
19
Q

AR: Significance of Colour Flow Imaging - Limitations: Other Limitations

A
  1. Effect of angle: need to pan through valve

2. Billiard ball phenomenon: over-estimation of regurgitation

20
Q

Other signs of severe AR?

A
  1. Reduced mitral deceleration time
  2. Diastolic mitral regurgitation
  3. Premature mitral valve closure
  4. Premature aortic valve opening
21
Q

What is considered the best indirect clue of significant AR?

A

Flow reversals

22
Q

Other signs of AR: Reduced Mitral Deceleration Time

A
  • Rapid and sharp rise of LVEDP => shortened p½t and reduced DT
  • In the absence of other causes, increased LVEDP, DT < 160ms and E/A > 2 = severe AR
23
Q

Other signs of AR: Diastolic mitral regurgitation

A
  • Normally, MR occurs during systole

- If diastolic MR seen = severe AR

24
Q

Other signs of AR: Premature mitral valve closure

A
  • Marked increase in LVEDP such that LV pressure during diastole exceeds LAP = early MV closure
25
Q

Other signs of AR: Premature aortic valve opening

A
  • Really marked increase in LVEDP such that LVEDP rises to a pressure greater than diastolic aortic pressure = AV opens early

Week 2: Aortic Regurgitation (3 decks)

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