peripheral vascular disease

**Definition/terminology:** PVD is a broad term for disorders of the non-cardiac, non-intracranial circulation. It includes arterial disease (PAD), venous disease (DVT, chronic venous insufficiency), and vasculitides and vasospastic disease. On boards, "PVD" usually means PAD, which is atherosclerosis of the aorto-iliac, femoropopliteal, or tibial vessels.

**Risk factors:** Smoking (strongest modifiable risk factor), diabetes mellitus, hypertension, hyperlipidemia, age >50, CKD, and family history. PAD is a coronary artery disease (CAD) equivalent, so these patients have high risk of MI and stroke.

**Pathophysiology:** Atherosclerotic plaque causes a fixed stenosis. During exercise, muscle oxygen demand exceeds supply, which causes ischemic pain (claudication). At rest, perfusion is adequate until the disease is severe.

**Clinical features:** - **Intermittent claudication:** Reproducible pain with walking that is relieved by rest within minutes. The site is distal to the stenosis: calf for femoropopliteal disease, buttock/thigh for aorto-iliac disease. - **Leriche syndrome (aortoiliac disease):** Claudication of the buttock/thigh, erectile dysfunction, and diminished femoral pulses. - **Chronic limb-threatening ischemia (CLTI):** Rest pain (often at night, relieved by dangling the leg), non-healing ulcers, and gangrene. - **Exam:** Diminished or absent pulses, bruits, hair loss, shiny atrophic skin, pallor on elevation, dependent rubor, cool extremity, and delayed capillary refill. - **Arterial vs venous ulcers:** Arterial ulcers are painful, punched-out, on distal toes/pressure points, with a pale base and no edema. Venous ulcers are irregular, shallow, at the medial malleolus, with edema and hemosiderin deposition, and are less painful.

**Diagnosis:** - **ABI** (ankle SBP / brachial SBP): normal 1.0–1.4; ≤0.90 is diagnostic of PAD; 0.4–0.9 is typical of claudication; <0.4 suggests severe ischemia/rest pain. >1.4 suggests noncompressible calcified vessels (diabetes, CKD), so use toe-brachial index or pulse volume recordings. - **Imaging:** Duplex ultrasound first, then CT or MR angiography. Conventional angiography is the gold standard and is used before intervention.

**Management:** - **Risk-factor modification:** Smoking cessation, BP control, glycemic control, and foot care in diabetics. - **Medical therapy:** Antiplatelet (aspirin or clopidogrel), high-intensity statin, and ACE inhibitor/ARB for hypertension. Low-dose rivaroxaban plus aspirin may be added in select patients. - **Claudication therapy:** Supervised exercise therapy is first-line. Cilostazol (PDE-3 inhibitor) improves walking distance but is contraindicated in heart failure. Pentoxifylline is less effective. - **Revascularization:** Indicated for lifestyle-limiting claudication that fails therapy and for CLTI. Options are endovascular angioplasty/stenting or surgical bypass.

**Acute limb ischemia (distinguish from chronic PAD):** The 6 P's are pain, pallor, pulselessness, paresthesia, paralysis, and poikilothermia. Causes are embolism (e.g., from atrial fibrillation, with a sudden onset and no prior claudication) or thrombosis on a chronic plaque. Treatment is immediate heparin and urgent revascularization (embolectomy, thrombolysis, or bypass). Complications include compartment syndrome and reperfusion injury (hyperkalemia, myoglobinuria).

**Differential for leg pain with walking:** - **Neurogenic claudication (lumbar spinal stenosis):** Pain is relieved by sitting or leaning forward, and pulses are normal. - **Venous claudication:** Bursting pain with swelling, relieved by elevation. - **Others:** Thromboangiitis obliterans (Buerger disease; young male smokers, distal small-vessel segmental inflammation), and Raynaud phenomenon (vasospasm).

**High-yield pearls:** PAD is a CAD equivalent. The most common cause of death in PAD patients is MI or stroke. Smoking cessation is the single most important intervention. Diabetics have a higher risk of infrapopliteal disease, noncompressible vessels, and amputation. Buerger disease is treated by smoking cessation.