How is peripheral arterial disease (PAD) diagnosed and managed, including lifestyle modifications, pharmacologic therapy, and criteria for revascularization?

Diagnosis and Management of Peripheral Arterial Disease

Diagnosis

The ankle-brachial index (ABI) is the essential first-line diagnostic test for PAD and should be obtained without any imaging in patients with suspected disease. 1, 2

When to Measure ABI

Obtain resting ABI in patients meeting any of these criteria:

• Age ≥65 years 1
• Age 50-64 years with atherosclerosis risk factors (smoking, diabetes, dyslipidemia, hypertension) or family history of PAD 1
• Age <50 years with diabetes plus one additional atherosclerosis risk factor 1
• Leg symptoms with exertion or ischemic rest pain 1
• Abnormal lower extremity pulse examination 1
• Known atherosclerotic disease in other vascular beds (coronary, carotid, renal) 1

ABI Interpretation

• ≤0.90 = PAD confirmed 1, 2
• 0.91-0.99 = Borderline 1
• 1.00-1.40 = Normal 1
• >1.40 = Noncompressible vessels (requires toe-brachial index) 1

Additional Diagnostic Testing

If resting ABI is normal or borderline but claudication symptoms persist, perform exercise treadmill ABI testing to unmask PAD. 1, 2

In patients with diabetes or renal failure with normal resting ABI, measure toe pressure or toe-brachial index. 1

Imaging: Only When Revascularization is Considered

Duplex ultrasound is the first-line imaging method to confirm PAD lesions and should only be ordered when revascularization is being considered, not for routine diagnosis. 1, 2

For symptomatic patients with aortoiliac or multisegmental/complex disease being considered for revascularization, CTA and/or MRA are recommended as adjuvant imaging techniques. 1

A common pitfall is ordering imaging prematurely—imaging is unnecessary until you've established that the patient has failed medical therapy and requires anatomic definition for revascularization planning. 2

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Medical Management

All patients with confirmed PAD (ABI ≤0.90) must receive comprehensive optimal medical therapy regardless of symptom status, as they face cardiovascular event rates equivalent to or higher than patients with coronary artery disease. 1

Core Pharmacologic Therapy

Antiplatelet therapy:

• Aspirin 75-325 mg daily OR clopidogrel 75 mg daily to reduce myocardial infarction, stroke, and vascular death 1, 3, 4

High-intensity statin therapy:

• Required for ALL PAD patients regardless of baseline lipid levels 1, 3
• Target LDL <100 mg/dL (or <70 mg/dL for very high-risk patients) 5

ACE inhibitors or ARBs:

• Recommended for cardiovascular risk reduction in PAD patients 1, 3
• Particularly beneficial for blood pressure control and systemic atherosclerosis protection 1

Antihypertensive therapy:

• Target BP <140/90 mmHg 5

Diabetes management:

• Target HbA1c <7% 1, 5

Lifestyle Modifications

Smoking cessation:

• The single most important intervention—use physician counseling, nicotine replacement therapy, and/or bupropion 3, 4

Supervised exercise training (SET):

• First-line therapy for claudication—prescribe at least 3 times weekly for 30-60 minutes per session, minimum 12 weeks duration 1, 3
• Patients should exercise to moderate-severe claudication pain to maximize benefit 1
• SET improves pain-free walking distance, maximum walking distance, 6-minute walking distance, quality of life, and cardiorespiratory fitness 1
• When SET is unavailable, home-based exercise training should be offered, though it is inferior to supervised programs 1

Claudication-specific pharmacotherapy:

• Cilostazol improves walking distance and quality of life 3, 6
• Ramipril has evidence for improving walking distance 7, 3

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Criteria for Revascularization

Intermittent Claudication

Revascularization should only be considered for patients with lifestyle-limiting claudication who have failed guideline-directed medical therapy (including structured exercise and optimal pharmacotherapy) for at least 3 months. 1

Before revascularization:

• Confirm hemodynamic significance with segmental Doppler pressures, exercise ABI testing, and/or translesional gradients 1
• Anatomic imaging (duplex ultrasound, CTA, or MRA) must be analyzed in conjunction with symptoms and hemodynamic tests 1

The choice between endovascular and surgical revascularization depends on:

• Anatomic location of lesions 1
• Lesion complexity (stenosis vs. occlusion, length) 1
• Patient-specific procedural risk-benefit ratio 1

Critical Limb-Threatening Ischemia (CLTI)

Patients with CLTI (chronic ischemic rest pain, ulcers, or gangrene) require prompt revascularization to prevent limb loss. 1

• Mortality rates reach 20% within 6 months and exceed 50% at 5 years if left untreated 1
• Immediate anatomic assessment and revascularization planning (endovascular or surgical) is indicated 1
• Use the WIfI classification system (Wound, Ischemia, foot Infection) to estimate amputation risk in patients with chronic wounds 1

Acute Limb Ischemia

Acute limb ischemia is a vascular emergency requiring immediate vascular surgery consultation. 1

• Recognize the five "Ps": pain, pulselessness, pallor, paresthesias, paralysis 1
• Emergent diagnostic testing and assessment of limb viability must be performed 1

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Additional Screening Consideration

Consider screening duplex ultrasound for abdominal aortic aneurysm (AAA) in patients with symptomatic PAD, as AAA prevalence is significantly higher in this population. 2, 5

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Critical Pitfalls to Avoid

Do not order imaging (duplex, CTA, MRA) for routine PAD diagnosis—the ABI establishes the diagnosis and initiates medical therapy without imaging. 2

Do not withhold medical therapy while awaiting specialist consultation—all PAD patients require immediate antiplatelet therapy, high-intensity statins, and cardiovascular risk reduction regardless of revascularization plans. 1

Do not assume normal pulses exclude PAD—many PAD patients have atypical or no leg symptoms, and the ABI is more sensitive than pulse examination. 1, 4

Do not proceed to revascularization without first attempting a 3-month trial of supervised exercise and optimal medical therapy (except in CLTI or acute limb ischemia). 1