Peripheral Artery Disease

Peripheral artery disease (PAD) is atherosclerotic narrowing or occlusion of the arteries supplying the limbs, most often the lower extremities. It ranges from asymptomatic disease through intermittent claudication to chronic limb-threatening ischaemia, and it is both a cause of limb morbidity and a marker of systemic atherosclerosis that raises cardiovascular risk.

Definition

Peripheral artery disease is a chronic condition in which atherosclerotic plaque narrows or occludes the peripheral arteries, classically those of the lower limbs, reducing perfusion and producing symptoms that range from none to exertional claudication and, at the severe end, rest pain, tissue loss, and limb-threatening ischaemia.

Scope

This entry covers the pathophysiology of lower-extremity arterial occlusive disease, its clinical spectrum, the ankle-brachial index and imaging used to recognise it, and the broad strategies - risk-factor modification, supervised exercise, and open or endovascular revascularization - by which it is addressed. It is a reference topic within vascular surgery fundamentals and does not give individualized clinical advice.

Core questions

• How does a flow-limiting stenosis translate into claudication versus limb-threatening ischaemia?
• What is the role of the ankle-brachial index in recognising and grading PAD?
• When does revascularization add value beyond risk-factor and exercise therapy?
• Why is PAD an indicator of heightened cardiovascular and mortality risk?

Key concepts

• Atherosclerotic occlusive disease
• Intermittent claudication
• Chronic limb-threatening ischaemia
• Ankle-brachial index
• Supervised exercise therapy
• Endovascular versus open revascularization
• Systemic atherosclerotic risk marker

Mechanisms

Atherosclerotic plaque progressively narrows the lumen of limb arteries, so that resting flow may be preserved but the increased demand of exercise outstrips supply, producing the reproducible muscular pain of intermittent claudication. As stenosis or occlusion advances and collateral flow becomes inadequate, perfusion can fall below resting metabolic needs, giving ischaemic rest pain, non-healing wounds, and gangrene - the picture of chronic limb-threatening ischaemia. The ankle-brachial index, the ratio of ankle to brachial systolic pressure, provides an objective measure of the haemodynamic deficit, while the same atherosclerotic process in other beds explains why PAD signals elevated coronary and cerebrovascular risk (kullo-2016, gerhard-herman-2017).

Clinical relevance

PAD is a common cause of exertional leg symptoms and, when severe, of limb loss, and its recognition also flags patients at higher cardiovascular risk who may benefit from systemic risk-factor management. The entry describes how the disease is conceptualised and graded for educational reference and is not a substitute for individualized assessment or treatment decisions, which rest on current guidelines and clinical judgement (gerhard-herman-2017, aboyans-2018, conte-2015).

Epidemiology

PAD affects a large and growing population, with prevalence rising sharply with age and concentrated among people who smoke or have diabetes, hypertension, or dyslipidaemia; a substantial proportion of affected people are asymptomatic, which is why objective testing such as the ankle-brachial index is emphasised. Because it shares risk factors and pathology with coronary and cerebrovascular disease, PAD is associated with increased rates of myocardial infarction, stroke, and death (kullo-2016, aboyans-2018).

History

Recognition of arterial occlusive disease of the limbs and its surgical treatment developed alongside twentieth-century reconstructive vascular surgery, and over recent decades management has shifted toward integrated care that couples aggressive medical risk-factor modification and supervised exercise with selective open or endovascular revascularization, as codified in successive professional society guidelines (gerhard-herman-2017, aboyans-2018, conte-2015).

Debates

Endovascular-first versus open surgery for advanced disease

For chronic limb-threatening ischaemia and complex lesions the relative roles of endovascular therapy and open bypass remain debated, with choices guided by anatomy, conduit availability, and patient risk rather than a single dominant strategy.

Seminal works

• kullo-2016
• gerhard-herman-2017
• aboyans-2018
• conte-2015

Frequently asked questions

What is the ankle-brachial index?

It is the ratio of the systolic blood pressure measured at the ankle to that measured at the arm; a reduced ratio indicates a haemodynamically significant arterial narrowing in the leg and is a standard objective sign of peripheral artery disease.

Why is PAD considered more than a leg problem?

Because the atherosclerosis that narrows leg arteries usually reflects systemic disease, people with PAD are at increased risk of heart attack and stroke, so PAD is treated as a marker of overall cardiovascular risk as well as a cause of limb symptoms.