Peripheral Arterial Disease

Question 1

Define peripheral arterial disease (PAD) from both a functional and anatomical standpoint.

Answer 1

Anatomical:
o Structural atherosclerotic narrowing of any non-coronary vessel which limits blood flow to limbs
Functional:
o Arterial narrowing causing mismatch between organ supply and demand causing intermittent symptoms of claudication and/or tissue ischemia

Question 2

Discuss the prevalence of PAD and associated risk of coronary artery disease.

Answer 2

• Prevalence increases with age
• High cost for health care
• Once patients with PAD become symptomatic, atherosclerosis has progressed to advanced level
o PAD confers additional mortality risk

Question 3

Identify risk factors that have the highest positive predictive value for developing PAD.

Answer 3

• **Tobacco
o Single most modifiable cause
• **Diabetes
o Due to endothelial and smooth muscle cell dysfunction
• HT
o Especially with stroke
• Hyperlipidemia
o Correction via diet/drugs → major improvement on rates of stroke, MI
• Inflammatory mediators
o Homocysteine, fibrinogen, CRP, Lipoprotein (a), renal disease
• Age, gender (male), ethnicity (African-American)
• Obesity and physical inactivity

Question 4

Discuss the elements of a vascular focused history and physical examination

Answer 4

History
o Risk factors for atherosclerosis
o Family history
o Symptoms of transient ischemic attacks or stroke
o Angina or angina equivalent
o Postprandial abdominal pain
o Pain at rest localized to lower leg or foot
o Poorly healing or nonhealing wounds of leg or foot
o Exertional limitation of the lower extremity muscles or history of walking impairment

Physical
o Bilateral arm BP
o Cardiac exam
o Palpation of abdomen for aneurysmal disease
o Auscultation for bruits
o Examine legs and feet
o Pulse examinations: carotid, radial/ulnar, femoral, popliteal, dorsalis pedis, posterior tibial
• Scale: 0 = absent; 1 = diminished; 2 = normal; 3= bounding (aneurysm or AI)

Question 5

Discuss diagnostic studies used to detect lower extremity PAD

Answer 5

o Intermittent limb claudication induced by exercise, relieved by rest
o Atypical features: fatigue, heaviness, dysesthesia or cold sensation
o Not nocturnal cramps

Techniques:
• ABI exam
• Pulse volume recordings (compare bilateral waveforms) = As decrease arterial circulation, PVR lowers in amplitude and widens
• Color Duplex ultrasoundography
• Exercise ABI test when ABI is normal or borderline but have symptoms consistent with claudication
• Arterial Duplex Ultrasound testing: Diagnose anatomic location and degree of stenosis
• Can use to select candidates for endovascular intervention (stent, PTA), surgical bypass, and to select sites of surgical anastomosis
• Magnetic Resonance Angiography (MRA):
• No ionizing radiation, excellent arterial picture
• Can’t use if patients are claustrophobic, have a pacemaker/implantable cardioverter-defibrillator, obese
• Computed Tomographic Angiography:
• Requires ionizing radiation, excellent arterial picture

Question 6

Discuss diagnostic studies used to identify abdominal aortic aneurysms.

Answer 6

Aortic aneurysm
• Localized dilation of an artery >50% normal diameter or >2x size more proximal artery
• More common in men
• Occurs most often in infra-renal aorta
• High mortality (75-90%) if rupture
o Mesenteric artery disease
• Results in abdominal pain after eating and weight loss

Diagnose:
• Ultrasound (look at diameter and velocity)
• With elevated velocities → MRA or CT

Question 7

Discuss diagnostic studies used to detect renal PAD

Answer 7

o Renal artery disease (stenosis, HT)
• Atherosclerotic etiology
• Also from fibromuscular dysplasia: congenital arterial abnormality of fibrous, muscular, and elastic components

o Diagnose:
• Ultrasound (look at diameter and velocity)
• With elevated velocities → MRA or CT

Question 8

Discuss diagnostic studies used to detect carotid PAD

Answer 8

o Can manifest as transient ischemic attacks or stroke
o Stroke:
• Ischemic from clot (85% of all strokes)
• Hemorrhagic (bleed around or into brain)

• Diagnose
• Carotid bruit on physical exam
• Do ultrasound of carotid arteries
• Confirm abnormalities with MRA or CT

Question 9

Identify normal and abnormal ankle-brachial indices and explain their clinical significance.

Answer 9

Perform ABI exam:
o Patient in supine position
o Pressures measured with arterial Doppler and correct size BP cuff
o Measure systolic pressure in R and L brachial arteries, followed by R and L ankle arteries
• ABI: ratio of higher brachial systolic pressure and the higher of either dorsalis pedis or posterior tibial ankle systolic pressure for each leg
• ABI = (ankle systolic pressure) / (higher brachial artery systolic pressure)
Interpretation
o ≤ 0.90 is diagnostic of PAD
o ≥ 1.30 is noncompressible (artery is calcified)

Question 10

Describe therapeutic goals and general approaches to treatment of PAD.

Answer 10

Limb outcomes:
o Improved ability to walk (increase in peak walking distance, improve quality of life)
o Prevention of progression to CLI and amputation

Cardiovascular morbidity and mortality outcomes
o Decrease in morbidity from non-fatal MI and stroke
o Decrease in cardiovascular mortality from fatal MI and stroke

Question 11

Describe lifestyle changes and medications used in the treatment of PAD

Answer 11

***Get patient walking → grow new collateral arteries → heal themselves
• Stop smoking
• Lose weight
• Antiplatelet therapy
• Control of diabetes (hemoglobin A1c risk of surgery
o Carotid endarterectomy to remove plaque