Peripheral Artery Disease (PAD) & Ankle Brachial

Index (ABI)

Marge Lovell RN CCRC CVN BEd MEd

London Health Sciences CentreLondon, Ontario, Canada

Faculty/Presenter DisclosureFaculty/Presenter Disclosure

• Faculty: Marge Lovell• Program: 51st Annual Scientific Assembly

• Relationships with commercial interests:– NONE

Disclosure of Commercial Disclosure of Commercial SupportSupport

• This program has received NO financial support • This program has received NO in-kind support

• Potential for conflict(s) of interest:– NONE

Mitigating Potential BiasMitigating Potential Bias

• N/A

Objectives

• Provide an overview of PAD• Demonstrate the ABI technique• Provide Hands on Practice

• Peripheral Artery Disease (PAD, PVD)

A vascular disease in which the arteries supplying a limb are occluded/stenosis

The most common cause is atherosclerosis, resulting in plaque and thrombus deposition on the arterial wall, and lumenal stenosis or occlusion

Peripheral Arterial Disease• PAD is common and will become more

common in the next 2 decades.• PAD is associated with a marked increase

in global cardiovascular health risks:- Heart attack, stroke, and death- Claudication and functional impairment- Gangrene and amputation

• The current knowledge base permits significantly better: prevention, early diagnosis, integrated treatment, and rehabilitation.

Systemic Manifestations of Atherosclerosis

•TIA• Ischemic stroke

• Claudication

• Critical limb ischemia, rest pain, gangrene, amputation

• Renovascular hypertension

• Erectile dysfunction

•TIA• Ischemic stroke•TIA• Ischemic stroke

• Myocardial Infarction• Unstable angina pectoris

Incidence• More common in men• Estimated 27 million people in North

America & Europe suffer from PAD (16%) • 16.5 million are asymptomatic • In Canada: 1 in 4 people with PAD will

have MI or CVA• Common cause of disability, morbidity &

mortality• Under diagnosed and under treated Canadian Cardiovascular Consensus: PAD Executive Summary; Can J Cardiol 2005;

21(12):997-1006

ATHEROSCLEROSIS, A MULTIFACTORIAL DISEASE

EN

VIR

ON

ME

NTA

L FA

CTO

RS

GE

NE

TIC

FA

CTO

RS

AGESMOKING

OBESITY

DIET

FAMILY HISTORYSEDENTARYLIFESTYLE

GENDER

THROMBOGENIC FACTORS

VASCULARDISEASE

LIPIDSHYPERTENSION

DIABETES

Defining a Population “At Risk” for Lower Extremity P.A.D.

• Age > than 40 years with one additional risk factor (e.g., diabetes, smoking, dyslipidemia, hypertension, or hyperhomocysteinemia)

• Age 50 (male) 60 (female) with risk factor• Age 70 years and older• Leg symptoms with exertion (suggestive of

claudication) or ischemic rest pain• Abnormal lower extremity pulse examination• Known atherosclerotic coronary, carotid, or

renal artery disease

Canadian Cardiovascular Consensus: PAD Executive Summary; Can J Cardiol 2005; 21(12):997-1006

How Is PAD Diagnosed?

• History and physical History and physical examinationexamination

• ABIABI

• Vascular labVascular lab

Adapted American Diabetes Association. Diabetes Care. 2003:26;3333-3341.

Olson, KWP, et al. J of Vascular Nursing. 2004:22;72-77.

Questions to Ask Patients Presenting with Symptoms of PAD

1.Do you have pain in either leg when you walk?

3. How far can you walk without stopping?

4. What stops you when you are walking?

5. Do you walk?

6. Why not?

2. Do you have a similar pain when you are bending, sitting or lying down?

2. Do you have a similar pain when you are bending, sitting or lying down?

Physical Exam Findings of PAD

Lesho EP, et al. Am Fam Physician. 2004; 69:525-533.

The Physical Exam Should Be Performed With Patient’s Pants/Shoes Off

Limb examination (and comparison with the opposite limb) findings might include:

• Absent or diminished femoral or pedal pulses (especially after exercising the limb)

• Hair loss• Poor nail growth (brittle nails)• Dry, scaly, atrophic skin• Dependent rubor• Pallor with leg elevation after 1 minute at 60 degrees (normal

color should return in 10 to 15 seconds; longer than 40 seconds indicates severe ischemia)

• Ischemic tissue ulceration (punched-out, painful, with little bleeding), gangrene

• Arterial bruits

Concept of ABI

ABI has been found to be 95% sensitive and 99% specific for angiographically diagnosed PAD.

The systolic blood pressure in the leg should be approximately the same as the systolic blood pressure in the arm.

Therefore, the ratio of systolic blood pressure in the leg vs the arm should be approximately 1 or slightly higher.

Adapted from Weitz JI, et al. Circulation. 1996;94:3026-3049.

Arm pressure

Leg pressure

÷ ≈ 1

Equipment needed:Equipment needed:

1.1. Blood Pressure Blood Pressure CuffCuff

2.2. Hand-held 5-10 Hand-held 5-10 MHz Doppler MHz Doppler probeprobe

3.3. Ultrasound GelUltrasound Gel

American Diabetes Association. Diabetes Care 2003: 26; 3333–3341.

Measuring the Ankle-Brachial Index (ABI)Step 1: Gather Equipment Needed

Stabilizing handStabilizing hand

Calculating the ABIExample Calculation

66 mm Hg

120 mm Hg

Hiatt WR. N Engl J Med. 2001;344:1608-1621.

= 0.50 = 0.55

Right Leg ABIRight Leg ABI Left Leg ABILeft Leg ABI

60 mm Hg

120 mm Hg

Right Leg ABIRight Leg ABI

ABI InterpretationABI Interpretation

≤ ≤ 0.90 is diagnostic of peripheral arterial 0.90 is diagnostic of peripheral arterial diseasedisease

Interpreting the Ankle–Brachial Index: ABI

ABI Interpretation

• 1.0-1.4 Normal

• 0.91-0.99 Borderline   

• <0.90      Abnormal                                                        

• >1.4        Non-compressible

• 2011 ACCF/AHA Focused Update of the Guideline for the Management of Patients With Peripheral Artery Disease (Updating the 2005 Guideline)

A 65 year male, heavy smoker, hypertensive presents A 65 year male, heavy smoker, hypertensive presents with right gangrenous toe and rest pain: with right gangrenous toe and rest pain:

Calculate the ABICalculate the ABI

R Brachial Pressure: _160____

Dorsalis Pedis SBP: ___140____

Posterior Tibial SBP: ___138_____

Dorsalis Pedis SBP : __60_____

Posterior Tibial SBP : __58____

L/Brachial Pressure: __156___

R/ ABI= _____ L/ ABI= _____

ABI Interpretation: Normal, Borderline, Mild, Moderate, Severe, NoncompressibleCorrect answers are: R/ABI= 0.37 L/ABI= 0.87Severe PAD R/Side, mild PAD L/side

A 76 year old male, heavy smoker, hypertensive & A 76 year old male, heavy smoker, hypertensive & previous MI presents with right calf pain after 2 blocks: previous MI presents with right calf pain after 2 blocks:

Calculate the ABICalculate the ABI

R Brachial Pressure: _130____

AT SP: ___140____

PT SP: ___138_____AT SBP: __90_____

PT SBS: __96_____

L/Brachial Pressure: __134___

R ABI= _____ L ABI= _____

ABI Interpretation: Normal, Borderline, Mild, Moderate, Severe, NoncompressibleCorrect answers are: R/ABI= 0.71 L/ABI= 1.04Mild PAD R/ leg

A Risk Factor “Report Card” for all Individuals with Atherosclerosis

Tobacco smoking

Complete, immediate cessation

Hypertension BP less than 140/90

mmHg and Diabetics 130/80

Hypercholesterolemia LDL Cholesterol < 2.0

Diabetes Hb A1C : <7.0

Inactivity Follow guidelines

Antiplatelet therapy (like aspirin or Plavix) is: Antiplatelet therapy (like aspirin or Plavix) is: mandatorymandatory