Peripheral Arterial Disease


  • The prevalence of peripheral artery disease (PAD) increases progressively with age, beginning after age 40. Risk factors for PAD are similar to those that promote the development of coronary atherosclerosis (ie, hyperlipidemia, smoking, hypertension, diabetes).
Pathophysiology
  1. Embolic
    • Fragments of thrombi or atheromatous material embolize & occlude peripheral vessels
    • 90% originate from heart (mural or valvular);
      • AMI, A. fib, mitral or aortic valve disease, prosthetic heart valves, chronic CHF, cardiomyopathies, endocarditis, bradycardia- tachycardia syndromes
      • May be seen septic with thromboemboli
    • Less common (1-2%) are atheromatous lesions of abd. aorta, or intraarterial injection of drugs (vasospasm and embolism)
    • Emboli lodge at bifurcations or at narrowed arteriosclerotic areas
    • Emboli stop blood flow through artery
    • Progressive arterial thrombus formation may occlude collaterals
  2. Thrombotic
    • Usually a gradual process: atherosclerosis
    • Collaterals often have time to develop
    • Low cardiac output can worsen ischemia distal to atherosclerosis
    • Usually not emergent
  3. Aortic dissection, trauma, or iatrogenic arterial manipulations also cause peripheral ischemia
  4. Location
    • Femoral (43%); iliac (18%); terminal aorta (15.5%); or popliteal (15%)
    • Brachial artery most common in upper ext.
    • Visceral, renal or superior mesenteric arteries (7-10%)
    • CNS (3-15%)
    • May be multiple embolic sites

 

Clinical/Exam:

  • History of walking impairment, extremity pain that might be due to ischemia, and the presence of non-healing wounds.
  • Patients with risk factors for PAD who report no or few symptoms should be asked about functional capacity and decline in activity over time.
  • Pain of one or more muscle groups, atypical pain, or no symptoms.
  • Intermittent claudication (derived from the Latin word for limp) is defined as a reproducible discomfort of a defined group of muscles that is induced by exercise and relieved with rest.
    • An imbalance between supply and demand of blood flow that fails to satisfy ongoing metabolic requirements.
  • Classic claudication is characterized by leg pain that is consistently reproduced with exercise and relieved with rest. The degree of symptoms of claudication depends upon the severity of stenosis, the collateral circulation, and the vigor of exercise.
  • The usual relationships between pain location and corresponding anatomic site of arterial occlusive disease can be summarized as follows:
    • Buttock and hip: Aortoiliac disease
    • Thigh: Aortoiliac or common femoral artery
    • Upper two-thirds of the calf: Superficial femoral artery
    • Lower one-third of the calf: Popliteal artery
    • Foot claudication: Tibial or peroneal artery
  • Severe decreases in limb perfusion can result in ischemic rest pain which involves the digits and forefoot and typically occurs at night. The pain may be more localized in patients who develop an ischemic ulcer or gangrenous toe. The pain may be relieved by dependent positioning of the foot.
  • Some patients with PAD have atypical symptoms as a result of comorbidities, physical inactivity, and alterations in pain perception. Compared with patients with classic claudication, those with leg pain on exertion and at rest are more likely to have diabetes, neuropathy, or spinal stenosis in addition to PAD.

Diagnosis/Test

  1. Embolic: most common
    • Sudden onset pain; distal pulses absent; usually asymmetric
    • Variable numbness, paresthesias, paralysis, pallor, coolness, pulselessness
    • Necrosis of skin, fat, muscle, bone possible
    • Sensorimotor deficits should have flow restored in 3-4hr
  2. Thrombotic
    • Present with pain or intermittent claudication
    • Decr or absent pulses, numbness, discoloration
    • Trophic changes: hair loss, thickened nails, atrophy, petechial lesions, ulcers, gangrene
  3. To confirm the diagnosis of arterial stenosis or occlusion:
    • Resting ankle-brachial systolic pressure index (ABI) in patients with lower extremity exertional symptoms and in those patients with risk factors for PAD.
    • An ABI of ≤0.90 has a high degree of sensitivity and specificity for a diagnosis of PAD.
  4. Segmental BP (thigh, knee, ankle)
  5. Doppler velocity measurements
  6. Arteriography

Algorithm for vascular testing in asymptomatic PAD

Algorithm for vascular testing in symptomatic PAD

Classification of acute extremity ischemia

  Viable Threatened Nonviable
Pain Mild Severe Variable
Capillary refill Intact Delayed Absent
Motor deficit None Partial Complete
Sensory deficit None Partial Complete
Arterial Doppler Audible Inaudible Inaudible
Venous Doppler Audible Audible Inaudible
Treatment Urgent work-up Emergency surgery Amputation
 

Etiology of lower extremity ischemia

Major causes
Atherosclerosis
Thombosed aneurysm
Arterial injury
Arterial dissection
Atheroembolism
Thromboembolism
Thromboangiitis obliterans (Buerger's disease)
Other causes
Aorto-iliac
  Retroperitoneal fibrosis
  Radiation fibrosis
  Tumor
Iliac
  Fibromuscular dysplasia
  Iliac endofibrosis (athletic injury)
Iliofemoral
  Pseudoxanthoma elasticum
Popliteal
  Popliteal entrapment
  Adventitial cystic disease
 

Differentiation of foot ulcers

Characteristic Arterial ulcer* Venous ulcer Neuropathic ulcer*
Location Over toe joints, malleoli (over the bony prominence), anterior shin, base of heel, pressure points Medial and lateral malleolar area above bony prominence, posterior calf, may be large, circumferential Plantar surface of foot over metatarsal heads, heel, pressure points
Appearance Irregular margins, base dry and often pale or necrotic (brown/black fibrous tissue) Irregular margins, pink or red base that may be covered with yellow fibrinous tissue, exudate common (may be heavy); ulcers can be large, sometimes circumferential Punched out ulcer, usually superficial but sometimes deep, red base
Ulcer within callus Rare No Calloused border, ulcer can be underlying a callus
Foot temperature Warm or cool Warm Warm
Pain Yes, may be severe Yes, usually mild but may be severe No
Arterial pulses Absent Present Present or absent
Sensation Variable Present Absent tactile, pain, temperature and vibratory sensations
Foot deformities No No Often
Skin changes Shiny, taut, loss of hair

Dependent rubor of leg and foot that becomes pale with leg elevation

Erythema, brown-blue hyperpigmentation can be spotty or diffuse: "stasis" changes; atrophie blanche (white sclerotic areas), edema; dry skin; varicose veins common; if lipodermatosclerosis is present, skin may be bound down; bilateral lower extremities often affected Waxy or shiny, loss of hair, may be taut; dry skin; may have non-pitting edema, especially on dorsal foot
Reflexes Present Present Absent
 

Treatment

ED Management

  1. Anticoagulation if acute deficit and on contraindications
  2. Emboli: immediate embolectomy with intraoperative arteriogram
  3. Thrombotic:
    • Usually have arteriography performed initially
    • If neuro deficits or tissue loss: immediate revascularization
    • If rest pain & no neuro deficits: anticoagulation & observation; elective revascularization
  4. Upper extremity involvement should prompt evaluation of axillary/subclavian arteries and aorta, as well as cardiac abnormalities
  5. Some success reported with fibrinolytic agents
 

Long-Term Medical Management

Management Summary
Risk factor modification Intervention
• Smoking cessation
• Hypertension
• Diabetes mellitus
• Antiplatelet therapy
  - Aspirin
  - Ticlopidine
  - Clopidogrel (Plavix)
• Exercise
• Cilostazol (Pletal)
• Lipid lowering agents
• Ramipril 10 mg qd

 

1. SUPERVISED EXERCISE THERAPY 
- A supervised exercise program is recommended as part of the initial treatment regimen.
- It should be performed for a minimum of 30 to 45 minutes at least three times per week for a minimum of 12 weeks.
- During each session, an exercise level that is of sufficient intensity to elicit claudication should be achieved.
- The value of an unsupervised exercise program is less well studied, but is generally recommended for patients who cannot participate in supervised exercise programs.
 
2. PHARMACOLOGIC THERAPY
Acute Managemnent in ED
  • Pain Control
  • Heparin (18 U/kg)
Symptom Relief
  • Pentoxifylline : 400 mg orally three times daily for at least 8 weeks
  • Cilostazol : 100 mg orally twice daily
    • Do not give to patients with CHF
Risk Modification
  • Stop Smoking
  • Lipid lowering agent
    • -Statins are indicated in all patients to achieve LDL <100 mg/dL
       
  • Control Diabetes
    • HgA1c <7.0%
       
  • Control BP w/ beta-blocker or ACEI
    •  diabetic <140/90 mmHg
       
  • Antiplatelet therapy with aspirin is recommended.
    • Clopidogrel is recommended as an effective alternative antiplatelet therapy to aspirin
    • Aspirin : 75-150 mg orally once daily
    • Clopidogrel : 75 mg orally once daily
Revascularization
  • Patients with lifestyle-limiting claudication who have had no improvement with exercise and symptom relief should be referred to a vascular specialist to have their arterial anatomy defined and assessed.
  • Endovascular revascularization is recommended for aortoiliac disease with stenosis <10 cm and chronic occlusions that are <5 cm.
  • For femoropopliteal artery stenosis, endovascular therapy is recommended if there is
    • Discrete stenosis <10 cm, -OR-
    • Calcified stenosis <5 cm.
  • For infrapopliteal artery lesions, endovascular treatment has been limited to threatened limb loss only.
    • Unlike femoropopliteal lesions or aortoiliac lesions, failed endovascular intervention can preclude surgical revascularization. Therefore, careful selection is essential.
  • Surgical revascularization is recommended for aortoiliac disease if
    • Stenosis >10 cm, -OR-
    • Chronic occlusion >5 cm, -OR-
    • Heavily calcified lesions, -OR-
    • Lesions associated with aortic aneurysm.
  • Surgical revascularization is recommended for common femoral artery disease if
    • Lesion >10 cm,  -OR-
    • Heavily calcified lesions >5 cm,  -OR-
    • Lesions involving the ostium of superficial femoral artery  -OR- 
    • Lesions involving the popliteal artery
Amputation
  • Patients with critical limb ischemia who are unsuitable for revascularization will be those unable to walk before the episode of critical limb ischemia, and who have a limited life expectancy.
 

Disposition

  1. Consult vascular service OR Interventional Radiology.
  2. Admit all acute disease.
  

 

 



 

 



Source: Uptodate.com

ITE 2013, Q87.
A 62-year-old male with a 20-year history of diabetes mellitus presents with bilateral calf and buttock pain that occurs after he walks 2 blocks. The symptoms are relieved with rest. On
examination his pedal pulses are not palpable and his ankle-brachial index is 1.45.

Which one of the following would be most appropriate?

A) Reassuring the patient that his ankle-brachial index is normal
B) MRI of the lumbar spine
C) A repeat evaluation in 6 months if the symptoms persist
D) MR or CT angiography of the lower extremities

 

theabfm.com
A 72-year-old male with a history of hypercholesterolemia and a 40-pack-year smoking history presents with a 4-month history of right calf pain that occurs after walking 4 blocks and is relieved by rest. A physical examination is notable for a blood pressure of 150/96 mm Hg and reduced right pedal pulses. Noninvasive vascular evaluation reveals an ankle-brachial index of 0.82 on the right and 1.22 on the left.

Which one of the following classes of antihypertensive drugs would be most appropriate for this patient?

A - β-Blockers
B - Calcium channel blockers
C - ACE inhibitors
D - α1-Blockers
E - Direct vasodilators

Exmpalantion: