Vascular I - ABI

ABI

Noninvasive test comparing the systolic pressure at the ankle level to the systolic pressure at the brachial artery level

Indications

• Claudication/rest pain

• Absent pulses

• Ulceration

• Digital cyanosis/gangrene

• Pre-operative assessment

• Aneurysm

• Trauma

• Revascularization follow-up

Limitations

• Calcified vessels

• Overcompensated collateral

circulation

• Extensive bandages or casts

• Pressure cuffs will not fit on leg

• Skin integrity/ulceration

• Trauma, surgical site

Distal SFA (adductor canal)

Most common location of disease

To stabilize blood pressure

Why let a patient rest for 5-10 mins before an exam?

hydrostatic pressure

Pressure measurements taken while patient is sitting will be falsely elevated due to

Heart

Take pressures in the supine position with the limb at the same level as the

Ankle

– 10-12 cm width

– 2-3 cm bladder

– Wrap above medial malleolus

Brachial

Wrap the same size cuff that was used on the ankle

20–30 mmHg

Inflate cuff _____ above the last audible signal

2-4mmHg

Deflation of the cuff should be at a rate of _____ per second

Pedal pressure/highest brachial

To calculate ABI

>0.9

considered a normal ABI

Triphasic/Multiphasic

– Sharp upstroke

– Brief reversal

– Late diastolic forward flow

<20 mmHg

Systolic brachial pressures between arms differ

>1.3

ABI of _____ suggests arterial calcification

Occlusion

An absent signal indicates

Sever or distal disease

A monophasic waveform indicates

Mild disease or early obstruction

A Multiphasic/biphasic waveform indicates

Seg pressures and Doppler

Noninvasive test assessing arterial flow and pressure gradients between the arm and lower extremity

Bernouli’s principle

velocity ↑ as lumen narrows, pressure ↓

hemodynamic consequence

Seg pressures measure overall, ___ and not the anatomical stenosis

functional perfusion

Reflects ____ rather than visual plaque burden

Lesions

Seg pressures can also detect hemodynamically significant

10-12cm

For 4-cuff method use on arm, upper/lower thigh, calf and ankle for extremity pressures

18-20cm

3-cuff method instead uses an ____ cuff on thighLynn

8-10MHz

Use ______ CW Doppler probe

4MHz

for obese patients use a _____ probe

Direction, amplitude, phasicity

Record waveform and note

significant obstruction

>20–30 mmHg pressure drop indicates

<0.50

ABI of ____ means significant multilevel obstruction

TBI

Measures digital blood flow using PPG sensors and digital pressure cuffs

Micro vascular disease

Evaluates _____ and distal arterial disease

terminal microcirculation

Digital arteries represent _____ sensitive to spasm and temperature

2–2.5 cm cuff

Use ____ on mid-phalanx (digit base)

>0.7

Normal TBI value

Distal obstruction or vasospasm

TBI with Rounded peak, absent dicrotic notch

Total occlusion or probe displacement

Flat line

Abnormal

Pressure difference between the ankle and toes (>44 mmHg in younger patients and >64 mmHg in older patients) is

>30mmHg

associated with good healing potential

Toe ischemia

Absolute pressure <20 mmHg in toes