Mean Gradient, PHTN, Stress Echo

Question 1

What are the supportive parameters used to assess MS severity?

Answer 1

1. mPG

2. RVSP

Question 2

Limitations of mPG?

Answer 2

1. Suboptimal alignment with MS jet
2. Using PW instead of CW
3. Increased mPG without significant MS

Question 3

Why is CW Doppler preferred to PW Dopper in assessment of MS?

Answer 3

• PW displays maximum velocities around 2m/s (short pulses, PRF) => aliasing of signal whilst CW peak velocity not limited (continuous sampling)
• PW measured velocity at location of sample volume whilst CW detects highest velocity along the entire length of the beam

Question 4

When is mPG increased without significant MS?

Answer 4

• If significant MR, mPG is increases as SV MV = forward SV + regurgitant volume
• In this case, mPG is increased but DT is NOT prolonged so can assume gradient increase due to MR not MS

Question 5

How does pulmonary hypertension occur as a result of MS?

Answer 5

• PHTN with MS occurs secondary to elevation in LAP leading to passive backwards increase in pulmonary venous pressures

Question 6

Echo signs of PHTN?

Answer 6

1. Marked flattening of IVS

2. RV dilatation

Question 7

M-mode changes when mitral valve is stenotic?

Answer 7

1. Leaflet thickening
2. Abnormal pmvl motion (moves anteriorly due to leaflet tethrering and commissural fusion) - larger, more mobile amvl pulls pmvl during diastole
3. Absent mid-diastolic closure
4. Prolongation (less steep) of EF slope (DT equivalent)

Question 8

What is the role of stress echo in asymptomatic severe MS patients?

Answer 8

Determine if there are exercise induced MS symptoms

Question 9

What is the role of stress echo in symptomatic patients with mild MS?

Answer 9

Determine if degree of MS worsens i.e. if there is an increase in mPG or RVSP

Question 10

Stress echo in patients with severe MS?

Answer 10

• Significant increase in mPG (>15mmHg)

- Marked increase in RVSP (>60mmHg)

Question 11

Stress echo in patients with mild MS?

Answer 11

• Stable or only mild increase in mPG

- Only mild increase in PASP/RVSP