Carotid Stenosis Flashcards
Define critial stenosis?
narrowing of the arterial lumen resulting in a hemodynamically significant reduction in volume, pressure and flow
Aorta critical stenosis?
90% of its cross-sectional area must be encroached upon before there is a reduction in pressure and flow distally
Smaller vessels critical stenosis
In smaller vessels, such as the carotid arteries, the critical stenosis varies from 70-90% cross sectional area reduction
What will you hear when entering a stenotic zone?
- Velocity increases
- doppler sounds will become high pitched or “whistling”
Doppler sounds as you exit the stenotic zone and encounter post stenotic turbulence?
- garbled sound
What sound will you hear distal to a stenosis?
Sound becomes more low pitched again but weaker in amplitude
Doppler sound in the setting of complete occlusion of the ICA?
Thumping sound will be heard adjacent to it
Carotid Intima Media Thickness (CIMT)?
<0.9mm
How to measure PSV within a stenosis? (3)
- Sample prox to stenosis
- Highest velocity should be taken and recorded within the stenosis (3 times)
- Just distal to stenosis document the post stenotic turbulence
Higher ratio =?
- when is ratio useful?
Greater stenosis
- useful in situations of decreased heart functions where the velocities are globally low throughout
Diameter reduction: ?
Mild?
hemodynamically significant?
Critical?
Mild- 30%
Hemodynamically sig.- 50%
Critical- 70%
Calculation of diameter reduction?
1- (residual/original) x 100
What qualifies a hemodynamically significant lesion? (diameter reduction)
> 50% diameter reduction
What is area reduction?
- Transverse vessel
1-(residual/original )X100
Area reduction hemodynamically significat lesion? (%)
> 75% area reduction
Area reduction
mild?
hemo sig.?
critical?
Mild- 50%
HS- 75%
Critical- 90%
NASCET criteria for grading ICA stenosis: <15%?
deceleration spectral broadening with a peak systolic velocity (PSV) <125 cm/s
NASCET criteria for grading ICA stenosis: 16-49%?
pansystolic spectral broadening with a PSV <125 cm/s
NASCET criteria for grading ICA stenosis: 50-69%?
- pansystolic spectral broadening with a PSV of >125 cm/s
- end diastolic velocity (EDV) <110 cm/s
- ICA/CCA PSV ratio >2 but <4
NASCET criteria for grading ICA stenosis: 70-79%?
- pansystolic spectral broadening with PSV >270 cm/s or
- EDV >110 cm/s
- ICA/CCA PSV ratio >4
NASCET criteria for grading ICA stenosis: 80-99%?
EDV >140 cm/s
NASCET criteria for grading ICA stenosis: Complete occlusion?
No flow or terminal thump
Sono role- ask about patient history including?
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
Indications on requisition or history from referring physician?
Headaches Bruit heard on auscultation by physician Present stroke TIA Vertigo/dizziness Amaurosis fugax Limb weakness-indicate which side and upper or lower limb
What is carotid bruit?
- more common with what % stenosis?
- sign?
- 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
D/D of carotid bruit? (6)
- A murmur radiating from a stenosed aortic valve
- External carotid artery disease
- Intraluminal turbulence in the internal carotid artery
- Arteriovenous malformations
- External compression from thoracic outlet syndrome
- Scarring due to neck surgery
Tumor
Calculation for ICA stenosis ratio
Prox ICA PSV/distal CCA PSV ratio
What indicates hemodynamically significant stenosis?
- if ratio is 2 or more
- Velocity doubles from CCA to ICA
- PSV of the ICA is >125cm/s
What indicates hemodynamically significant stenosis?
- if ratio is 2 or more
- Velocity doubles from CCA to ICA
- PSV of the ICA is >125cm/s
Carotid endarterectomy- CEA?
- when is it used?
- 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
How is calcified plaque indication on report?
with x’s
How is total occlusion indication on report?
Completely fill in the lumen
What is trickle flow?
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
collateral flow documentation?
- ICA occlusion
- SSS
- CCA occlusion
- OA direction in the setting of high grade or complete occlusion of ICA
- reversed vertebral flow and brachial artery systolic pressures in the setting of SSS
- reversed ECA flow in the setting of CCA occlusion
