Background

Atherosclerotic occlusive disease is a **systemic, progressive condition** characterized by plaque formation within the arterial wall. It is the **leading cause of vascular morbidity and mortality** worldwide, affecting coronary, carotid, and peripheral arteries.

* **Global burden:** >200 million people affected by peripheral arterial disease (PAD) globally, ~40 million in Europe. Prevalence increases with age and comorbidities [@fowkes2013].
* **Geographic distribution and health disparities:** Higher incidence in high-income countries due to longevity; rising prevalence in low- and middle-income countries due to diabetes and smoking. Within developed nations, significant racial and ethnic disparities persist in PAD outcomes, with minority populations experiencing higher rates of advanced disease and limb loss [@repella2025].
* **Natural history:** Many remain asymptomatic; 20–30% develop claudication, ~5–10% progress to **chronic limb-threatening ischemia (CLTI)**, associated with high amputation and mortality rates [@criqui2015]. In patients with diabetes mellitus (DM), PAD often presents with more distal, multi-segmental involvement and a higher risk of rapid progression to limb-threatening stages [@acc2025-i].[@acc2026-c].
* **Systemic risk:** Patients with PAD have a **2–4× increased risk** of myocardial infarction, stroke, and cardiovascular death [@hiatt2015]. Emerging evidence highlights the role of lipoprotein(a) [Lp(a)] as an independent, genetically determined risk factor for atherosclerotic progression, though its clinical implementation in risk stratification remains a significant gap [@yang2026].

**Associated vascular beds:** Atherosclerosis rarely affects a single territory. Screening and surveillance should extend to:
* **Carotid arteries:** see [[Cerebrovascular Disease|Ch. 7]] for management of extracranial carotid stenosis
* **Renal and mesenteric arteries:** see [[Renal and Mesenteric Artery Disease|Ch. 11]] for evaluation and treatment