Carotid Stenosis Flashcards
(34 cards)
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
