Discordant Numbers

Question 1

What are the three potential causes for discordant data?

Answer 1

1. Measurement error
2. Body size
3. Flow state

Question 2

Formula for Indexed Stroke Volume?

Answer 2

SVi = (LVOT area x LVOT VTI) / BSA

Question 3

What is defined as a low flow state?

Answer 3

Low flow state iSV ≤ 35ml/m2

Question 4

What is defined as a normal flow state?

Answer 4

Normal flow state iSV 36 - 57ml/m2

Question 5

What is defined as a high flow state?

Answer 5

High flow state iSV ≥ 58ml/m2

Question 6

Low flow state: What are the two types of low flow, low gradient AS?

Answer 6

• Classical LF-LG AS = depressed EF (<50%)

- Paradoxical LF-LG AS = preserved EF (>50%)

Question 7

What are the two possible types of Classical LF-LG AS (LVEF<50%)?

Answer 7

• True severe AS => LV unable to generate high pressure gradients
• Pseudo-severe AS => poor LV systolic function, unable to open AV (sick LV)

Question 8

Pathophysiological Consequences of Paradoxical LF-LG AS (EF≥50%)?

Answer 8

1. Impaired intrinsic LV function
2. Reduced LV forward flow
3. Increased post valvular afterload

Question 9

“Common” features of Paradoxical LF-LG AS (EF≥50%)?

Answer 9

1. Small LV
2. Concentric LVH
3. Restricted LV filling (big E small A wave)

Question 10

What is the role of dobutamine stress echo in AS?

Answer 10

• DSE used for classical LF-LG AS to determine if true severe AS or pseudo severe AS

Question 11

DSE findings in true severe AS?

Answer 11

1. Both AV VTI and LVOT VTI will increase (Vmax ≥4m/s)

2. AVA will still be ≤1.0cm^2 as both of these parameters have increased

Question 12

DSE findings in pseudo severe AS?

Answer 12

1. LVOT VTI will increase
2. AV VTI will decrease due to increased blood volume opening the AV wider
3. AVA > 1.0cm^2

Question 13

Paradoxical LF-LG AS (EF≥50%): Causes of (1) Impairment of Intrinsic LV Function

Answer 13

1. Restrictive filling
2. Reduced longitudinal strain
3. BBB or pacing induced LV desynchronization
4. LV diastolic dysfunction
5. Pericardial constriction

Question 14

Paradoxical LF-LG AS (EF≥50%): Causes of (2) Reduced LV Forward Flow

Answer 14

1. MR
2. MS
3. TR
4. Pulmonary HTN
5. RV dysfunction
6. AF

Question 15

Paradoxical LF-LG AS (EF≥50%): Causes of (3) Increased Post Valvular Afterload

Answer 15

1. Poor central or peripheral arterial compliance

2. Severe HTN

Question 16

DSE for patients with small restrictive LVs?

Answer 16

• Not recommended

- Patients may be at risk of haemodynamic deterioration

Question 17

Examples of irreversible high flow states?

Answer 17

1. Severe AR

2. Haemodialysis

Question 18

Examples of reversible low flow states?

Answer 18

1. Anemia
2. Hyperthyroidism
3. AV shunts
4. Infection
5. Fever

Question 19

Parameters for severe AS in high flow states?

Answer 19

• A high gradient (≥4m/s) generally indicates severe AS

Question 20

Step-wise approach to Classical LF-LG AS (EF<50%)?

Answer 20

1. Confirm measurement accuracy
2. Confirm low flow status (index SV)
3. Assess LV systolic function (LVEF)
4. Confirm AS severity by DSE

Question 21

Step-wise approach to Paradoxical LF-LG AS (EF≥50%)?

Answer 21

1. Confirm measurement accuracy
2. Confirm low flow status (index SV)
3. Identify cause for low flow state
4. AS severity by AVA (and other clues)

Question 22

Step-wise approach to AS in High Flow State?

Answer 22

1. Confirm measurement accuracy
2. Confirm high flow state (index SV)
3. Define if high flow status is reversible
4. If not reversible = severe AS. If reversible = reassess at normal flow.

Question 23

What is afterload?

Answer 23

• Afterload is the pressure that the heart must work against to eject blood during systole
• As aortic and pulmonary pressures increase, the afterload increases on the left and right ventricles respectively