LE Arterial Stress Testing Flashcards

1
Q

How does Stress Testing Work ?

why is it necessary?

A

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

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2
Q

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

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

Why Physiologic Testing vs Duplex?

A

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

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4
Q

what sizes are the blood pressure cuffs?

A

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

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5
Q

what size cuffs for 3 and r cuff technique?

A


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)

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6
Q

what are the doppler pressure sites?

A

Dorsalis Pedis
easily compressed
harder to locate

Posterior Tibial
Harder to compress
Easier to locate

Essential not to drift off vessel !

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7
Q

what are segmentsal useful for?

where does this study indicate probable inflow dx?

A

Useful in identifying regions of disease
Toe pressures often useful

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

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8
Q

what do you compare when looking at segmentals?

A


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

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9
Q

what is an ABI?

A

Bilateral ankle pressures divided by the higher brachial pressure

Highest ankle pressure value is used for reported ABI

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10
Q

describe ABI levels from normal to ischemic rest pain.

A

> 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

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11
Q

what is the ABI value exception for normals?

A

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

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12
Q

what are teh Pressure limitations for calcified arteries?

A

diabetics

chronic steroid therapy

renal dialysis patients

segmental pressures unobtainable or excessively high (ABI > 1.4)

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13
Q

what are the methods of stress testing?

A
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14
Q

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

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

A

use Treadmill
Reactive hyperemia*
Toe raises*

Treadmill

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15
Q

what are the symptoms of spinal stenosis?

A

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

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16
Q

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.

A

collaterals

vasodilatation

no pressure change or an increase in pressure.

occlusive

17
Q

what is the purpose of exercise stress testing?

A

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.

18
Q

what are the Indications for Exercise

A

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

19
Q

what are the contraindications for stress testing?

A

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

20
Q

how do you do he treatmill stress test?

A

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)

21
Q

what do you do post exercise ASAP?

A

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

22
Q

what are teh 2 main criteria for claudication?

what are the others…

A

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.

23
Q

what are the 4 post excerise methods?

A

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

24
Q

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

A

Normal
Pressures should increase.

Abnormal
If pressures decrease it is abnormal

25
what is this?
Post exercise serial pressures
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
2-6 7-12 15 60
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.
PORH: Post Occlusive Reactive Hyperemia
28
how do you do a pohr?
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
29
what is pohr interpretation?
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
30
how can toe raises be helpful?
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
31
whta are the physiologic limitations of stress testing?
32
what would this pt be a good candidate for if they present claudication w/ exercise?
stress studies.
33
what can be said about this 90 yo female w/ gangrenous toes ?
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.
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
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.
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+
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
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
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