LE and UE Doppler Segmental Pressures Flashcards
Limitations of Doppler segmental pressures?
a) Cannot discriminate between stenosis and occlusion, precise area, or discriminate between CFA and external iliac disease.
b) Calcified vessels render falsely elevated Doppler pressures
c) Uncompensated CHF may result in decreased ABI
d) Artifactually elevated high thigh pressures when narrow cuff used on thigh
e) Difficult to interpret in presence of multi-level disease
Patient should rest for how long prior to exam?
20 minutes
How is cuff artifact created?
cuff too large, BP falsely lower
cuff too narrow, BP falsely higher
Width of the cuff should be about what % greater than the diameter of the limb?
20%
Order of segmental pressures?
brachial, ankle (PTA and DPA), calf (use highest ankle pressure for the rest of the leg), above the knee, high thigh
Why is it important to inflate from the ankle up instead of the other way?
there isn’t enough time for the blood to completely flow normally into the leg so the obtained BP would likely be falsely lower than it should be.
TO obtain complete cessation of blood flow the cuffs should be inflated to what pressure beyond the last audible Doppler arterial signal or to what pressure above the highest brachial pressure?
20-30 mmHg
If pressure measurements need to be repeated the cuff should be fully deflated for how long prior to repeat inflation?
1 minute
How is an ABI calculated?
divide ankle pressure by the higher of the two brachial pressures
Another term for ABI?
ankle/arm pressure index
ABI numbers
>1.0 = normal >0.9-1.0 = asymptomatic or mild disease 0.5-0.9 = claudication (moderate)
Incompressible vessels considered to have an ABI greater than what?
1.3-1.5
Some authors feel an absolute ankle pressure of what, rather than the ABI of .5 has stronger weight for predicting symptoms at rest.
Strandness’ work suggests that an ABI of > _____ represents single segment disease;
0.5
A segmental pressure drop between two consecutive levels suggests obstruction?
> 30 mmHg
In the 4 cuff technique the thigh cuff is normally what pressure higher than the highest brachial pressure?
> 30 mmHg
The AK and BK pressures should be at least the same as the highest brachial.
In the 3 cuff technique the thigh pressure is similar to what?
the highest brachial pressure
Toe pressures of
30 mmHg
In diabetic patients what pressure is most reliable?
toe pressures
Exercise is useful during testing how?
a) compare resting values to those after exercise
b) helps differentiate between true and pseudo-claudication
c) determine presence/absence of collaterals
Contradictions of exercise include?
shortness of breath, hypertension, cardiac problems, stroke, walking problems
Technique for exercise after resting exam?
a) patient walks on treadmill at a treadmill at
post-exercise ABI’s normal and abnormal
a) Normal: ABI increases
b) Abnormal: ABI decreases minimally or to a severe amount
c) With drop after exercise, pressures obtained every 2 minutes until pre-exercise pressures are attained
What level of disease takes 2 to 6 minutes for the ABI’s to increase back to resting levels after they dropped to low or unrecordable levels after exercise?
single level disease
What level disease takes 6 to 12 minutes for the ABI’s to increase back to resting levels after they remained low or at unrecordable levels after exercise?
Multi-level disease
Reactive hyperemia alternative method to exercise, what does it involve?
Bilateral thigh cuffs inflated to suprasystolic pressure levels, usually 20-30 mmHg above the higher brachial BP, maintaining the pressure 3 to 5 minutes.
Produces ischemia and vasodilatation distal to the occluding cuffs.
With reactive hyperemia normal limbs may show a transient drop of?
17-34%
In reactive hyperemia there is a > ______ % pressure drop in ankle pressure with multi-level disease.
50%
What is the Allen test used for?
To evaluate patency of the palmar arch
How is the Allen test preformed?
a) manual compression of radial artery by technologist while patient clenches fist for less than 1 minute inducing pallor.
b) patient relaxes hand while continuing manual compression of the radial artery.
c) PPG on the index finger to document arterial pulsations before and after the clenched fist
Interpretation of Allen test of normal and abnormal?
Normal: reappearance of normal color to indicate ulnar flow to palmar arch
Abnormal: color does not reappear indicating ulnar artery occlusion or palmar arch obstruction
A > 15-20 mmHg drop from upper arm to forearm suggests?
a) brachial artery obstruction distal to the upper cuff
b) obstruction in both radial and ulnar arteries
c) obstruction in single forearm artery which had decreased pressure
A _____ mmHg difference from one brachial pressure to the other, suggests a > _____ % stenosis of subclavian artery and/or vessel under the cuff.
15-20 mmHg
50%
A difference of > _____ mmHg between radial and ulnar pressures suggests obstruction in vessel with lower pressure.
20 mmHg
