Peripheral Artery Disease

Peripheral Artery Disease (PAD) is a vascular disorder characterised by the abnormal narrowing of arteries other than those supplying the heart or brain. It primarily affects the legs but can also involve arteries in the arms, neck, or kidneys. PAD is a form of peripheral vascular disease (PVD), specifically affecting arteries rather than veins.

Signs and Symptoms

PAD often manifests as leg pain during walking, known as intermittent claudication, which resolves with rest. Other symptoms include muscle atrophy, hair loss, smooth or shiny skin, cool skin to the touch, decreased or absent pulses in the feet, cold or numb toes, and ulcers that do not heal. Severe PAD can lead to complications such as very important limb ischaemia and gangrene, especially in individuals with diabetes.

Causes and Risk Factors

The primary cause of PAD is atherosclerosis, where fatty plaque builds up in the arteries. Major risk factors include cigarette smoking, diabetes, high blood pressure, and high blood cholesterol. Smokers and those with diabetes have significantly increased risks of developing PAD. Other contributing factors include chronic kidney disease and a sedentary lifestyle.

Diagnosis

Diagnosing PAD involves a combination of history taking, physical examination, and confirmatory tests such as the Ankle-Brachial Index (ABI), duplex ultrasonography, and angiography. An ABI of less than 0.90 is indicative of PAD. Imaging techniques like CT angiography and magnetic resonance angiography (MRA) are also employed for detailed visualisation of arterial blockages.

Classification

PAD severity is often classified using the Fontaine and Rutherford systems. The Fontaine stages range from asymptomatic (Stage I) to severe (Stage IV, characterised by ulcers or gangrene). The Rutherford classification includes categories from asymptomatic (Category 0) to major tissue loss (Category 6).

Treatment

Lifestyle Modifications

Treatment strategies for PAD focus initially on lifestyle changes. Smoking cessation and regular exercise are very important. Supervised exercise programmes can significantly improve walking distance and overall quality of life.

Medication

Medications include statins for cholesterol management, ACE inhibitors for blood pressure control, and cilostazol to improve symptoms of claudication. Antiplatelet drugs like aspirin or clopidogrel are recommended to reduce the risk of cardiovascular events.

Revascularisation

For severe cases, revascularisation procedures such as angioplasty, atherectomy, and bypass grafting may be necessary. Angioplasty involves widening the narrowed artery, while bypass grafting uses a vessel from another part of the body or synthetic material to bypass the blockage. In cases of gangrene, amputation may be required to prevent the spread of infection.

Guidelines

Current guidelines from the American College of Cardiology and American Heart Association recommend specific interventions based on the severity of PAD. For chronic limb-threatening ischaemia, balloon angioplasty is suggested for those with a short life expectancy or without an autogenous vein available for bypass.

Prognosis

Individuals with PAD are at a significantly elevated risk for cardiovascular events, including heart attacks and strokes. The severity of PAD, as measured by ABI, correlates with the risk of mortality from cardiovascular disease. While the likelihood of severe ischaemia requiring amputation is low, the risk of death from coronary events remains notably high.

Epidemiology

PAD affects approximately 3-7% of the general population, with prevalence increasing with age. It is particularly common among individuals with diabetes, affecting one in three diabetics over the age of 50. Despite its high prevalence, awareness of PAD is relatively low, underscoring the need for better education and screening practices.

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Self-assessment MCQs (single best answer)

What is the primary cause of Peripheral Artery Disease (PAD)?

Which symptom is most commonly associated with PAD?

Which risk factor significantly increases the likelihood of developing PAD?

What does an Ankle-Brachial Index (ABI) of less than 0.90 indicate?

Which classification system is used to categorise the severity of PAD?

What is the primary initial treatment strategy for PAD?

Which medication is commonly used to manage cholesterol levels in PAD patients?

What is the purpose of angioplasty in the treatment of PAD?

Which complication can occur in severe cases of PAD, especially in diabetics?

According to the American College of Cardiology and American Heart Association guidelines, what is recommended for chronic limb-threatening ischaemia in PAD patients?