Doppler Segmental Pressures (LE) Flashcards
What are limitations of a Doppler segmental pressures exam
- cannot discriminate between stenosis and occlusion, or the precise area of obstruction
- cannot discriminate between CFA and external iliac disease
- may give falsely elevated Doppler on calcified vessels (patients with diabetes and end stage renal disease are common with this)
- wrong cuff size can give false pressures
- difficult to interpret multi-level diseases
- patients with CHF may have decreased ankle/brachial indices
Patients with these conditions may not be able to get pressure scans
(6)
DVT, dialysis access, lymphedema, stent, bypass graft, patients who had mastectomy
How long should patients rest before having this exam done
20 minutes
Ideally the cuff bladder should be placed over the______
Artery
It is VERY important that the width of the cuff is around ____% greater than the diameter of the limb
20%
With the four cuff (Bilateral) the cuffs are placed on the brachial (upper arm) and what other four areas?
High thigh (with a longer cuff for thighs)
Low thigh/above the knee (AK)
Below the knee (BK)/calf
At the ankle
With the three cuff method, the cuffs are placed at the brachial(upper arm), and what other 3 locations
One thigh cuff (19 X 40cm)
Below the knee/calf
At ankle
What is the average cuff size (excluding the thigh cuffs)
12 X 40 cm
For optimal Doppler signal the probe should be at a __ to __ degree angle to skin, with the blood flow moving ___ to the probe.
45-60 degree angle ( at the knee it may be closer to 90 degrees bc of vessel angulation)
Blood flowing towards the probe (Antegrade)
What is a sphygmomanometer
A hand held automatic cuff inflator
What is the order for a sphygmomanometer pressure exam, starting with
1. brachial artery
- At ankle (for PTA and DPA, **if necessary peroneal A.)
- Calf/BK (for PTA or DPA, use the HIGHEST pressure for this level)
- Above the knee/AK (same as calf, may need popliteal A. If difficult to obtain)
- High thigh/HT (same as above the knee)
Why are we performing segmental pressures from ankle to thigh?
To eliminate the possible underestimation of the systolic pressure measurements
Cuffs need to inflate ____ to ____ mmHg beyond last audible Doppler signal OR the same amount of mmHg higher than the highest brachial pressure
20-30 mmHg higher for both examples
For repeat measurements be sure to deflate completely and wait ____ minute(s) before repeat.
About one minute
To calculate ABI’s, divide the ankle pressure by _____
Ankle pressure divided by the HIGHER of the two brachial pressures
ABI use the following chart to detect severity > 1.0 = ? > 0.9-1.0 =? 0.8-0.9 = ? 0.5-0.8 = ?
> 1.0 = normal
0.9-1.0 = may be within normal limits
0.8-0.9 = mild arterial disease
0.5-0.8 = claudication (moderate disease)
Incompressible vessels will give false elevations making it inaccurate, what is the range on the ABI index to consider it incompressible?
> 1.3-1.5
T/F
Some authors think that an absolute ankle pressure of less than 50mmHg, rather than the ABI of .5 has a stronger weight for predicting symptoms at rest
TRUE
An ABI of greater than and equal to ___ represents SINGLE segment disease
Greater or equal to .5
ABI of less than .5 suggests ______ lesions
Multiple lesions
Segmental pressure drop between two consecutive levels needs to be greater than what mmHg in order to suggest SIGNIFICANT obstruction
Greater than 30 mmHg
** some authors suggest greater than 20 mmHg
If there is a pressure difference of greater than or equal to 20 or 30 mmHg between the right and left legs, this suggests?
Obstructive disease at or above the level in the leg with the lower pressure
With a 4 cuff technique, the HIGH THIGH is normally how much higher than the brachial pressure?
Normally greater than or equal to 30 mmHg in thigh than brachial
3 cuff methods, the thigh pressure should be what in comparison to the brachial pressure?
Should be similar in pressures
Toes pressures of less than or equal to 30 mmHg are present in foot/toe ulcers that [did or did not] heal
Did not heal
Toe pressures may be more reliable in what kind of patient
Diabetic patients
What does exercise during segmental pressure tests help to differentiate?
True VS false claudication
Name a few contraindications for ABI’s with exercise
Shortness of breath Severe hypertension Significant cardiac problems Stroke Walking problems
For the exercise portion of the ABI, the patient walks on a ____ ____ treadmill at a less than or equal to _____% elevation
Constant load treadmill at a < or equal to 12% elevation
What is the speed and maximum time the patient walks for this test
- 5mph for a max of 5 minutes
* *or until symptoms are too severe for patient to continue
With exercise ABI, we document these 3 things
Duration of walk
MPH
onset/location/progression of symptoms
Post-exercise pressures are obtained on both _____, then ______
Both ankles (abnormal first) Higher of the two brachials
Immediately after exercise, a normal ABI will ______ and an abnormal ABI will ______
Normal = ABI increases Abnormal = ABI decreases
With a decreased ABI post-exercise (aka abnormal), we obtain pressures every 2 minutes untill……
Untill pre-exercise pressures are attained
Post-exercise, _____ level disease will take 2-6 minutes for ABI to increase to the pre-exercise ABI. While _____ level disease takes 6-12 minutes.
SINGLE level disease takes 2-6 minutes
MULTI-level disease takes 6-12 minutes
T/F
Reactive hyperemia patients for the most part CANNOT walk
True
When a patient cannot walk (reactive hyperemia), what is the alternative method to exercise for an ABI
We inflate bilateral thigh cuffs (19 X 40) to a SUPRASYSTOLIC pressure level (usually 20-30mmHg above the higher BP), and maintain the pressure for 3-5 minutes
**this produces ischemia and vasodilation distal to the occluding cuffs
With the “non-exercise” technique of ABI, what is the range for a normal limb drop
Normal limbs may show a transient drop of 17-34%
With reactive hyperemia ( non-exercise) patients, a single level disease is < or = a 50% drop in ankle pressure, and a multi-level disease will have what
Multi-level disease is a >50% ankle pressure drop
Why is the treadmill testing the preferable test for exercise ABI
It produces a physiologic stress that reproduces a patients ischemic symptoms
