Carotid Stenosis

Question 1

Define critial stenosis?

Answer 1

narrowing of the arterial lumen resulting in a hemodynamically significant reduction in volume, pressure and flow

Question 2

Aorta critical stenosis?

Answer 2

90% of its cross-sectional area must be encroached upon before there is a reduction in pressure and flow distally

Question 3

Smaller vessels critical stenosis

Answer 3

In smaller vessels, such as the carotid arteries, the critical stenosis varies from 70-90% cross sectional area reduction

Question 4

What will you hear when entering a stenotic zone?

Answer 4

• Velocity increases

- doppler sounds will become high pitched or “whistling”

Question 5

Doppler sounds as you exit the stenotic zone and encounter post stenotic turbulence?

Answer 5

• garbled sound

Question 6

What sound will you hear distal to a stenosis?

Answer 6

Sound becomes more low pitched again but weaker in amplitude

Question 7

Doppler sound in the setting of complete occlusion of the ICA?

Answer 7

Thumping sound will be heard adjacent to it

Question 8

Carotid Intima Media Thickness (CIMT)?

Answer 8

<0.9mm

Question 9

How to measure PSV within a stenosis? (3)

Answer 9

1. Sample prox to stenosis
2. Highest velocity should be taken and recorded within the stenosis (3 times)
3. Just distal to stenosis document the post stenotic turbulence

Question 10

Higher ratio =?

- when is ratio useful?

Answer 10

Greater stenosis

- useful in situations of decreased heart functions where the velocities are globally low throughout

Question 11

Diameter reduction: ?
Mild?
hemodynamically significant?
Critical?

Answer 11

Mild- 30%
Hemodynamically sig.- 50%
Critical- 70%

Question 12

Calculation of diameter reduction?

Answer 12

1- (residual/original) x 100

Question 13

What qualifies a hemodynamically significant lesion? (diameter reduction)

Answer 13

> 50% diameter reduction

Question 14

What is area reduction?

Answer 14

• Transverse vessel

1-(residual/original )X100

Question 15

Area reduction hemodynamically significat lesion? (%)

Answer 15

> 75% area reduction

Question 16

Area reduction
mild?
hemo sig.?
critical?

Answer 16

Mild- 50%
HS- 75%
Critical- 90%

Question 17

NASCET criteria for grading ICA stenosis: <15%?

Answer 17

deceleration spectral broadening with a peak systolic velocity (PSV) <125 cm/s

Question 18

NASCET criteria for grading ICA stenosis: 16-49%?

Answer 18

pansystolic spectral broadening with a PSV <125 cm/s

Question 19

NASCET criteria for grading ICA stenosis: 50-69%?

Answer 19

• pansystolic spectral broadening with a PSV of >125 cm/s
• end diastolic velocity (EDV) <110 cm/s
• ICA/CCA PSV ratio >2 but <4

Question 20

NASCET criteria for grading ICA stenosis: 70-79%?

Answer 20

• pansystolic spectral broadening with PSV >270 cm/s or
• EDV >110 cm/s
• ICA/CCA PSV ratio >4

Question 21

NASCET criteria for grading ICA stenosis: 80-99%?

Answer 21

EDV >140 cm/s

Question 22

NASCET criteria for grading ICA stenosis: Complete occlusion?

Answer 22

No flow or terminal thump

Question 23

Sono role- ask about patient history including?

Answer 23

Previous stroke
Smoker, prior or now
Elevated BP-HBP
Elevated cholesterol-hyperlipidemia
Diabetic
Family history of any of the above
Other-refer to requisition for information

Question 24

Indications on requisition or history from referring physician?

Answer 24

Headaches
Bruit heard on auscultation by physician
Present stroke
TIA
Vertigo/dizziness
Amaurosis fugax
Limb weakness-indicate which side and upper or lower limb

Question 25

What is carotid bruit?

• more common with what % stenosis?
• sign?

Answer 25

• Noise caused by turbulent blood flow in the carotid artery
• heard via stethoscope placed over carotid bifurcation
• more common with 90-90% stenosis
• confetti sign

Question 26

D/D of carotid bruit? (6)

Answer 26

1. A murmur radiating from a stenosed aortic valve
2. External carotid artery disease
3. Intraluminal turbulence in the internal carotid artery
4. Arteriovenous malformations
5. External compression from thoracic outlet syndrome
6. Scarring due to neck surgery
   Tumor

Question 27

Calculation for ICA stenosis ratio

Answer 27

Prox ICA PSV/distal CCA PSV ratio

Question 28

What indicates hemodynamically significant stenosis?

Answer 28

• if ratio is 2 or more
• Velocity doubles from CCA to ICA
• PSV of the ICA is >125cm/s

Question 28

What indicates hemodynamically significant stenosis?

Answer 28

• if ratio is 2 or more
• Velocity doubles from CCA to ICA
• PSV of the ICA is >125cm/s

Question 29

Carotid endarterectomy- CEA?

- when is it used?

Answer 29

• Surgical procedure to remove plaque
• used to reduce risk of stroke
• artery narrowed by more than 70%, the procedure is considered especially if patient is symptomatic

Question 30

How is calcified plaque indication on report?

Answer 30

with x’s

Question 31

How is total occlusion indication on report?

Answer 31

Completely fill in the lumen

Question 32

What is trickle flow?

Answer 32

Considered to be pre-occlusive with just a trickle of flow within lumen
Decrease the color velocity scale (PRF)
Increase the color gain
Increase the sample volume size to the lumen width

Question 33

collateral flow documentation?

• ICA occlusion
• SSS
• CCA occlusion

Answer 33

1. OA direction in the setting of high grade or complete occlusion of ICA
2. reversed vertebral flow and brachial artery systolic pressures in the setting of SSS
3. reversed ECA flow in the setting of CCA occlusion