LE Arterial Stress Testing Flashcards
How does Stress Testing Work ?
why is it necessary?
Create hyperemic state to force vasodilatation: Exercise or Occlusion with a cuff
Well developed collaterals mask disease with normal ABI at rest
Collaterals carrying maximum flow, can not react to increased demand creating positive study
what types of Indirect Physiologic Tests are there? (4)
- Pressure assessment –ABI and/or segmental pressures
- Plethysmography - Pulse volume recording (PVR), Photoplethysmography (PPG)
- Doppler waveform analysis
- Exercise stress test
Why Physiologic Testing vs Duplex?
Short learning curve
Short exam time
Accurate for hemodynamically significant disease (>60%)
- -Negative exam at rest and stress r/o hemodynamically significant disease.
- -High sensitivity and specificity
Provide physiologic information
Equipment is inexpensive
what sizes are the blood pressure cuffs?
Bladder should be 20% wider than limb diameter
thigh = 18 x 36 cm
arms, calf, ankle = 10 or 12 x 23 cm
metatarsal (child-size) = 9 x 20 cm
digit = 2 or 2.5 x 5 cm
Non-uniform limb sizes = variations in pressures.
Bladders over arteries
what size cuffs for 3 and r cuff technique?
Arm cuffs – usually 12 cm (may user 10 cm)
3 cuff tech
HT 18 cm
Calf (below knee) 10 cm (or 12)
Ankle 10 cm (or 12)
4 cuff tech
HT 12cm
LT 12 cm
(same rest of the way down)
what are the doppler pressure sites?
Dorsalis Pedis
easily compressed
harder to locate
Posterior Tibial
Harder to compress
Easier to locate
Essential not to drift off vessel !
what are segmentsal useful for?
where does this study indicate probable inflow dx?
Useful in identifying regions of disease
Toe pressures often useful
This study indicates probable inflow
disease and femoro-popliteal disease
of the left leg.
what do you compare when looking at segmentals?
compare to contralateral limb
compare to adjacent segments
compare to brachial pressure
A 20 mmHg or greater pressure gradient (drop) is significant in the presence of an abnormal ABI
what is an ABI?
Bilateral ankle pressures divided by the higher brachial pressure
Highest ankle pressure value is used for reported ABI
describe ABI levels from normal to ischemic rest pain.
> 1.0 = normal (usually)
Exercise patient if clear claudication symptoms
< 0.96 = abnormal,
exercise patient if borderline
< 0.8 = probable claudication
Exercise patient if borderline
< 0.5 = multi-level disease or long segment occlusion
Exercise patient to determine extent of disease
< 0.3 = ischemic rest pain
Do not exercise patient
what is the ABI value exception for normals?
Brachial systolic pressure below 100 mmHg or above 200 mmHg: ankle pressure may be 25% lower than brachial pressure
Low brachial pressure due to proximal (subclavian) disease
High brachial pressure - HTN
what are teh Pressure limitations for calcified arteries?
diabetics
chronic steroid therapy
renal dialysis patients
segmental pressures unobtainable or excessively high (ABI > 1.4)
what are the methods of stress testing?
what would u do to Stress perfusion to
define extent of disease
how about to test True vascular claudication
or pseudo-claudication ?
use Treadmill
Reactive hyperemia*
Toe raises*
Treadmill
what are the symptoms of spinal stenosis?
Pain and difficulty when standing or walking, aggravated by activity.
Lean forward on shopping cart
Numbness, tingling, hot or cold feelings, weakness or a heavy and tired feeling in the legs.
Clumsiness, frequent falling, or a foot-slapping gait