Peripheral Artery Disease

Clinical Orientation

A 68-year-old man with diabetes and a 50-pack-year smoking history reports that his left calf cramps after walking two blocks. The pain resolves when he stops and rests. His left foot is cooler than his right, hairless, and the dorsalis pedis pulse is absent. He has a non-healing sore on his left great toe. This chapter answers: What mechanism links PAD to bedside findings, tests, red flags, and nursing priorities?

What Goes Wrong?

Atherosclerosis in the periphery — same disease, different location. The same process that causes CAD causes PAD: endothelial injury → lipid accumulation → plaque → stenosis or occlusion. PAD affects the arteries supplying the lower extremities (most commonly), but can affect upper extremities, mesenteric, and renal arteries.

Stages of PAD:

1. Asymptomatic (many patients)
2. Claudication: Reproducible muscle pain/cramping with exertion, relieved by rest. Calf most common (superficial femoral artery). Thigh/buttock = iliac disease.
3. Rest pain: Pain at rest, especially at night when legs are elevated (gravity no longer assists flow). Burning in toes/forefoot — relieved by dangling legs.
4. Tissue loss: Non-healing ulcers, gangrene. Critical limb ischemia.

The 6 Ps of acute arterial occlusion:

• Pain (sudden, severe)
• Pallor (pale)
• Pulselessness
• Poikilothermia (cold — "poikilo" = varied, temperature takes on ambient temperature)
• Paresthesia (tingling → numbness — nerve ischemia)
• Paralysis (late — irreversible damage imminent)

What the Nurse May See

Chronic PAD: Diminished or absent pulses. Bruit over stenotic artery. Cool, hairless, shiny skin. Thickened toenails. Pallor with elevation, dependent rubor (redness when dangling — from maximal vasodilation). Claudication distance reproducible.

Acute limb ischemia: Sudden onset of the 6 Ps. Limb threatened — irreversible damage in 4-6 hours without revascularization.

Compare sides. PAD is often asymmetric. Document pulse quality (0=absent, 1+=diminished, 2+=normal, 3+=bounding). Use Doppler if pulses not palpable.

Tests and Monitoring

• Ankle-brachial index (ABI): Ankle systolic BP / brachial systolic BP. Normal: 0.9-1.3. PAD: <0.9 (mild 0.7-0.9, moderate 0.4-0.7, severe <0.4). >1.3 suggests calcified, noncompressible vessels (common in diabetes, CKD).
• Segmental pressures and pulse volume recordings: Localize the level of stenosis.
• Duplex ultrasound, CT angiography, MR angiography: Imaging to define anatomy.

Nursing Priorities

1. Vascular assessment: Palpate pulses (dorsalis pedis, posterior tibial, popliteal, femoral). Compare sides. Document skin temperature, color, hair distribution, ulcers.
2. Foot care: Critical in PAD + diabetes. Inspect feet daily. Proper footwear. Never go barefoot. Podiatry for nail and callus care. Report any break in skin immediately — poor perfusion = poor healing.
3. Risk factor modification: Smoking cessation — single most important intervention. Antiplatelet therapy (aspirin or clopidogrel). Statin therapy. Blood pressure control. Diabetes management.
4. Exercise therapy: Supervised walking programs improve collateral circulation and walking distance. Walk to the point of claudication pain, rest, then continue.
5. Acute limb ischemia: Notify provider immediately. Keep limb level or slightly dependent (gravity assists flow). Protect from pressure and cold. Do NOT elevate. Prepare for possible angiography and revascularization.

Red Flags

Patient Teaching

• "The arteries in your legs are narrowed by the same process that causes heart attacks. When you walk, your leg muscles need more oxygen, but the narrowed arteries can't deliver it — that's the cramping pain. Resting lets the demand drop and the pain goes away. Stop smoking — it's the single most important thing you can do to prevent this from getting worse."
• Foot care: daily inspection, proper shoes, no barefoot, report any wound immediately.