LE Arterial Stress Testing

Question 1

How does Stress Testing Work ?

why is it necessary?

Answer 1

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

Question 2

what types of Indirect Physiologic Tests are there? (4)

Answer 2

1. Pressure assessment –ABI and/or segmental pressures
2. Plethysmography - Pulse volume recording (PVR), Photoplethysmography (PPG)
3. Doppler waveform analysis
4. Exercise stress test

Question 3

Why Physiologic Testing vs Duplex?

Answer 3

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

Question 4

what sizes are the blood pressure cuffs?

Answer 4

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

Question 5

what size cuffs for 3 and r cuff technique?

Answer 5


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)

Question 6

what are the doppler pressure sites?

Answer 6

Dorsalis Pedis
easily compressed
harder to locate

Posterior Tibial
Harder to compress
Easier to locate

Essential not to drift off vessel !

Question 7

what are segmentsal useful for?

where does this study indicate probable inflow dx?

Answer 7

Useful in identifying regions of disease
Toe pressures often useful

This study indicates probable inflow
disease and femoro-popliteal disease
of the left leg.

Question 8

what do you compare when looking at segmentals?

Answer 8


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

Question 9

what is an ABI?

Answer 9

Bilateral ankle pressures divided by the higher brachial pressure

Highest ankle pressure value is used for reported ABI

Question 10

describe ABI levels from normal to ischemic rest pain.

Answer 10

> 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

Question 11

what is the ABI value exception for normals?

Answer 11

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

Question 12

what are teh Pressure limitations for calcified arteries?

Answer 12

diabetics

chronic steroid therapy

renal dialysis patients

segmental pressures unobtainable or excessively high (ABI > 1.4)

Question 13

what are the methods of stress testing?

Answer 13

Question 14

what would u do to Stress perfusion to
define extent of disease

how about to test True vascular claudication
or pseudo-claudication ?

Answer 14

use Treadmill
Reactive hyperemia*
Toe raises*

Treadmill

Question 15

what are the symptoms of spinal stenosis?

Answer 15

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

Question 16

Substantial ______ provide adequate perfusion to the ankle at rest, thus a normal ABI.
o
With exercise (walking or toe raises) or reactive hyperemia limb blood flow is increased, causing __________.
o
Normal arterial flow will result in _______
o
When _______ lesions are present flow can not be increased adequately through the collaterals, so a pressure drop will occur.

Answer 16

collaterals

vasodilatation

no pressure change or an increase in pressure.

occlusive

Question 17

what is the purpose of exercise stress testing?

Answer 17

Differentiate borderline normal from abnormal
o
Differentiate true vascular claudication from “pseudo-claudication”.
o
In patients with combined neuropathy and vascular disease, determine which condition is limiting walking.

Question 18

what are the Indications for Exercise

Answer 18

Intermittent claudicators with normal or boarderline resting ABI

ABI 0.85 - 0.4 to determine extent of disease

(we don’t do if resting ABI is abnormal)

If known neurologic or MS disease and PAD, determine which is limiting walking

Question 19

what are the contraindications for stress testing?

Answer 19

Ischemic rest pain or ischemic limb ulceration

ABI < .4

Questionable cardiac status

cardiac arrest

Severe pulmonary disease

respirator arrest

Poor ambulators

DO NOT LEAVE THEM ALONE WHILE EXERCISING

Question 20

how do you do he treatmill stress test?

Answer 20

treadmill speed = 1.5 or 2 mph

10-12 percent grade

5 minutes = standard walking time, or until symptoms occur

Document when symptoms occur and where (calf, thigh, etc)

Question 21

what do you do post exercise ASAP?

Answer 21

ankle pressures

Some references also do brachial, use the one highest at rest

Some references monitor ABI until they return to baseline

Some references do PT and DP waveforms

Adv: reproduces symptoms, controlled environment that can be quantified and monitored

Question 22

what are teh 2 main criteria for claudication?

what are the others…

Answer 22

Normal response - ankle systolic pressure increases or stays same & Pressure drop abnormal

Repeat ankle pressure every 1-2 minutes until back to baseline or up to 10 minutes

Usually when a patient is forced to stop due to pain, the pressure will be 60 mmHg or less, this confirms a vascular etiology

If symptoms occur without significant drop in pressure, consider nonvascular cause of symptoms.

Question 23

what are the 4 post excerise methods?

Answer 23

Method # 1
one bilateral ABI
PVR or Doppler waveforms

Method # 2
serial ABI’s for 5-10 minutes
optional ankle waveforms

Method # 3
Post exercise ABI
Post exercise ankle pressures
Compare to baseline.

Method # 4
Serial ankle pressures for 5- 10 minutes, or until back to baseline

Question 24

if a pressure is ___ it should increase. otherwise it is ___

Answer 24

Normal
Pressures should increase.

Abnormal
If pressures decrease it is abnormal

Question 25

what is this?

Answer 25

Post exercise serial pressures

Question 26

Return to baseline in ___ minutes = single level disease

Return to baseline ____ minutes = multiple levels of disease

Ischemic rest disease = pressure will remain low for > ___minutes

Remember – it should drop to <___ mmHg to be considered ischemic

Answer 26

2-6

7-12

15

60

Question 27

what is Indicated for patients that can not exercise

Occlusion of artery puts limb in hyperemic state, so vasodilatation occurs

Not useful to differentiate spinal stenosis, MSK, etc.

Answer 27

PORH: Post Occlusive Reactive Hyperemia

Question 28

how do you do a pohr?

Answer 28

Pt is supine with cuffs at thighs, ankles and brachials

Occlude proximal or distal thigh for 3-5 minutes

Occlude Pressure is 20 mm Hg above limb pressure

*Record post occl. ankle pressure
Painful exam, poor patient acceptance

Question 29

what is pohr interpretation?

Answer 29

Normal pressure drop of 17-34% that returns to baseline within 1 minute.

Pressure drop of 35-50% indicates single level disease

Pressure drop of >50% indicates multiple level disease

Question 30

how can toe raises be helpful?

Answer 30

Substitute for PORH

Esp. helpful in testing the less severe leg when bilateral disease

Toes raises for 1 minute

Post exercise pressures

Interpretation criteria is the same as walking

Question 31

whta are the physiologic limitations of stress testing?

Question 32

what would this pt be a good candidate for if they present claudication w/ exercise?

Answer 32

stress studies.

Question 33

what can be said about this 90 yo female w/ gangrenous toes ?

Answer 33

contraindicated to excercise her due to ABI’s
look at society of ultrasound professional guidelines and print

ABIs abnormal bilaterally, severe on right.
Severe aorto-iliac and femoro-popliteal disease on right.
Moderate AI and femoro-popliteal disease on left.
Severe ischemia right foot
Stress studies contraindicated.

Question 34

what can you say abou this 78 yr. old female presented with recent onset Rt. hip and leg pain soon after walking.
Walking limited to 1 blk.\
No Hx of CVA, HT, DM, or vascular surgeries
Hx of bilateral SFA disease

Answer 34

ok to excercise w/ toe raises. results below.

Although patient experienced a mild decrease in ankle pressures post ex, it was not of a magnitude to explain leg pain on a vascular basis.

Patient subsequently found to have spinal stenosis at L-5 level by CT scan.

Question 35

what can be said about this 34 year old male
Acute onset Rt calf claudication
Study date 6/16/99
Hx of Aorto-Rt femoral bypass 3/98
Rt pulses CFA, POP, DP, PT all 0

Lt pulses all 2+

Answer 35

do not excersice. report immediately that pulses are 0 for appropriate intervention

what can be said about the below?

underlying problem w/ graft is still there. although his thrombus was removed he still has stenosis

Question 36

53 year old male presents with Hx of left buttock, thigh, calf claudication limiting walking to 2 blks.

HX smoking 1-2 ppd

Hx of Hypertension, angina

Hx of coronary angioplasty with stent

Answer 36

contraindicated for excercising due to current/recent angina

Rt leg normal

Severe aorto-iliac disease on left

Exercise contraindicated for the left and because of his CARDIAC STATIS.

If want to test the right, toe raises or PORH