Epidemiology
Etiology
- Atherosclerosis in the aorta and peripheral arteries → insufficient tissue perfusion → PAD
- PAD usually coexists with coronary artery disease. Smoking is one of the most important risk factors for PAD!
Pathophysiology
Clinical features
- Intermittent claudication
- Femoropopliteal disease (most common): typically causes calf claudication
- Aortoiliac disease (Leriche syndrome)
- Level of the aortic bifurcation or bilateral occlusion of the iliac arteries
- Triad of bilateral buttock, hip, or thigh claudication, erectile dysfunction, and absent/diminished femoral pulses
- Worsens upon exertion
- Due to increased oxygen demand
Important
Given that the pathophysiology of PAD is similar to that of coronary artery disease (CAD), a diagnosis of PAD suggests the presence of clinically significant CAD. Multiple studies have confirmed this association, demonstrating PAD to be a CAD risk equivalent. c
Diagnostics
- Ankle-Brachial Index (ABI): The best initial test. It compares the systolic BP in the ankle to the systolic BP in the arm.
- Normal: 1.0 - 1.4.
- Diagnostic for PAD: < 0.9.
- Severe PAD: < 0.5 suggests severe disease; < 0.4 indicates CLI.
- > 1.4: Suggests non-compressible, calcified arteries, often seen in elderly or diabetic patients.
- Angiography (CTA/MRA): The gold standard for visualizing anatomy and planning revascularization.
Differential diagnostics
| Feature | Peripheral Artery Disease (PAD) | Thromboangiitis Obliterans |
|---|---|---|
| Etiology | Atherosclerosis | Inflammatory Vasculitis |
| Patient Profile | > 50 yrs with risk factors (HTN, DM, HLD) | < 45 yr heavy male smoker |
| Vessels | Large proximal arteries | Small/Medium distal arteries & veins |
| Key Finding | Intermittent claudication | Migratory thrombophlebitis, “Corkscrew collaterals” |
| Tx | Risk factor management, Revascularization | Complete smoking cessation |
Treatment
- Risk Factor Modification & Secondary Prevention (All Pts):
- Smoking cessation: Single most effective intervention.
- High-intensity statin (e.g., Atorvastatin 40-80 mg).
- Antiplatelet therapy (Aspirin OR Clopidogrel) to reduce MI/Stroke risk.
- Optimal control of BP, DM2 (A1c < 7%).
- First-line Symptomatic: Supervised graded exercise program (min. 12 weeks). c
- Collateral Formation: Intermittent ischemia → ↑ VEGF → angiogenesis (new collateral vessels bypass stenoses).
- Pt must walk until moderate claudication pain occurs → rest until resolved → repeat. Walking without reaching pain threshold does not trigger the ischemic stimulus needed for these adaptations.
- Second-line Symptomatic: Cilostazol (PDE-3 inhibitor, causes vasodilation & platelet inhibition). Add if lifestyle + exercise fail.
- Contraindication: Heart failure.
- Refractory/Surgical (Revascularization): Endovascular (PTA w/ stent) or surgical bypass.
- Indications: Critical Limb Ischemia (rest pain, gangrene, non-healing ulcers) OR severe claudication refractory to medical tx that significantly impairs quality of life.