Cardiology > Peripheral Arterial Disease (PAD)

Background

Peripheral Arterial Disease (PAD) is a chronic atherosclerotic condition characterized by narrowing or occlusion of arteries, primarily in the lower extremities, leading to impaired blood flow. The resulting ischemia causes claudication, rest pain, poor wound healing, and, in advanced stages, critical limb ischemia and potential limb loss. 

II) Classification/Types 

By Severity (Fontaine Classification): 

• • Stage I: Asymptomatic 

• • Stage IIa/IIb: Intermittent claudication (IIa = >200 m walking distance; IIb = <200 m) 

• • Stage III: Rest pain 

• • Stage IV: Ulcers or gangrene 

By Anatomic Location: 

• • Aortoiliac (inflow disease) 

• • Femoropopliteal 

• • Tibial or peroneal (outflow disease) 

By Clinical Presentation (Rutherford Classification): 

• • Categories 0–6 (from asymptomatic to major tissue loss) 

III) Pathophysiology 

Atherosclerotic plaque accumulation in peripheral arteries causes luminal narrowing and decreased perfusion. This leads to exertional muscle ischemia, impaired oxygen delivery, and eventual tissue necrosis if untreated. Endothelial dysfunction, inflammation, and thrombosis contribute to disease progression. 

IV) Epidemiology 

• • Sex: Slight male predominance 

• • Age: Increases with age; most common in those >60 years 

• • Geography: Higher prevalence in high-income countries with widespread risk factors 

• • Comorbidities: Strongly associated with diabetes, smoking, hypertension, and dyslipidemia 

• • Prevalence: Affects approximately 8–12 million people in the U.S. 

Etiology

I) Causes 

• • Atherosclerosis (most common) 

• • Thromboembolism 

• • Vasculitis (e.g., Buerger disease, Takayasu arteritis) 

• • Trauma 

• • Radiation-induced vascular injury 

• • Fibromuscular dysplasia 

II) Risk Factors 

• • Age >50 years 

• • Smoking (strongest modifiable risk factor) 

• • Diabetes mellitus 

• • Hypertension 

• • Dyslipidemia 

• • Chronic kidney disease 

• • Hyperhomocysteinemia 

• • Sedentary lifestyle 

Clinical Presentation

I) History (Symptoms) 

• • Intermittent claudication (leg pain with exertion, relieved by rest) 

• • Rest pain (in advanced disease) 

• • Numbness or weakness in legs 

• • Coldness in lower limb 

• • Non-healing ulcers, gangrene (critical limb ischemia) 

• • Erectile dysfunction (Leriche syndrome) 

II) Physical Exam (Signs) 

Peripheral Vascular Exam: 

• • Diminished or absent peripheral pulses 

• • Cool, pale extremities 

• • Prolonged capillary refill 

• • Dependent rubor, pallor on elevation 

• • Ulcers (typically on toes or pressure points) 

• • Muscle atrophy, hair loss, thickened nails 

• • Bruits over affected arteries 

Vital Signs: 

• • May be normal or show signs of hypertension or associated cardiovascular disease 

Differential Diagnosis (DDx)

• • Chronic venous insufficiency 

• • Spinal stenosis (neurogenic claudication) 

• • Diabetic neuropathy 

• • Deep vein thrombosis 

• • Compartment syndrome 

• • Cellulitis or skin ulcers of other etiology 

Diagnostic Tests

Initial Tests: 

• • Ankle-Brachial Index (ABI): 

• • • Normal: 1.0–1.4 

• • • Borderline: 0.91–0.99 

• • • PAD: <0.90 

• • • Severe PAD: <0.40 

• • Doppler Ultrasound: 

• • • Localizes stenosis, measures flow velocity 

Advanced Imaging: 

• • CT Angiography (CTA): 

• • • Excellent for visualizing vessel anatomy and stenosis 

• • MR Angiography (MRA): 

• • • Non-contrast option in renal impairment 

• • Digital Subtraction Angiography (DSA): 

• • • Gold standard for detailed vessel imaging, used for intervention planning 

Laboratory Tests: 

• • Lipid profile 

• • Hemoglobin A1c 

• • Renal function 

• • CBC (to rule out anemia, infection in ulcers) 

Treatment

I) Medical Management: 

Lifestyle Modification: 

• • Smoking cessation (most critical) 

• • Structured exercise therapy (at least 30–45 minutes, 3x/week) 

• • Foot care and hygiene 

Pharmacologic Therapy: 

• • Antiplatelet agents: Aspirin or clopidogrel for cardiovascular risk reduction 

• • Statins: High-intensity statin for atherosclerosis 

• • Cilostazol: For claudication symptom relief (not for heart failure patients) 

• • Antihypertensives: ACE inhibitors or ARBs preferred 

• • Diabetes control: Tight glycemic control to reduce progression 

II) Interventional/Surgical: 

Endovascular Therapy (First-line in many cases): 

• • Balloon angioplasty with or without stenting 

• • Atherectomy in select cases 

Surgical Options: 

• • Bypass grafting (e.g., femoral-popliteal bypass) for long-segment occlusions 

• • Amputation in cases of irreversible critical limb ischemia 

Indications for Intervention: 

• • Lifestyle-limiting claudication unresponsive to medical therapy 

• • Critical limb ischemia 

• • Tissue loss or gangrene 

Patient Education, Screening, Vaccines

Education: 

• • Importance of smoking cessation 

• • Regular walking programs improve symptoms and prognosis 

• • Daily foot inspection, moisturizing, avoiding trauma 

• • When to seek urgent care (new ulcers, rest pain, color changes) 

Vaccinations: 

• • Influenza (annually) 

• • Pneumococcal vaccine 

• • COVID-19 vaccine 

• • Tetanus booster if ulcers or injury present 

Screening: 

• • ABI in patients ≥65 years or ≥50 years with diabetes or smoking 

• • Cardiovascular risk assessment (PAD is a coronary artery disease equivalent) 

Consults

• • Vascular Surgery: For critical limb ischemia or need for revascularization 

• • Podiatry: For foot care and ulcer prevention 

• • Cardiology: If concurrent CAD, arrhythmias, or heart failure 

• • Endocrinology: For poorly controlled diabetes 

• • Wound Care: In presence of ulcers 

• • Smoking Cessation Program: For tobacco users 

Follow-Up

Monitoring: 

• • Regular ABI every 6–12 months 

• • Foot exams at each visit 

• • Monitor for claudication progression, rest pain, ulceration 

• • Reinforce lifestyle modifications 

• • Adjust medications based on lipid and BP targets 

• • Early recognition of critical limb ischemia to prevent amputation