Peripheral Arterial Disease

Question 1

What is peripheral arterial disease (PAD)?

Answer 1

A term used to describe a narrowing or occlusion of the peripheral arteries, affecting the blood supply to the lower limbs.

Question 2

What is acute limb ischemia?

Answer 2

A sudden decrease in limb perfusion that threatens limb viability. In acute limb ischaemia, decreased perfusion and symptoms and signs develop over less than 2 weeks.

Question 3

What is chronic limb ischemia?

Answer 3

Chronic limb ischaemia can present as intermittent claudication (diminished circulation leads to pain in the lower limb on walking or exercise that is relieved by rest) or critical limb ischaemia (circulation is so severely impaired that there is an imminent risk of limb loss).

Chronic limb-threatening ischaemia is a more recent term describing clinical patterns with threatened limb viability related to several factors. It is characterised by chronic, inadequate tissue perfusion at rest and is defined by ischaemic rest pain with or without tissue loss.

Question 4

What is the most common cause of PAD?

Answer 4

Peripheral arterial disease of the lower limbs is most commonly caused by atherosclerosis which narrows the affected arteries. This limits blood flow to the affected limb.

Question 5

What is the most common cause of acute limb ischemia?

Answer 5

Most commonly due to thrombosis within a diseased artery when an atherosclerotic plaque ruptures (80–85%).

Question 6

What are the risk factors for PAD?

Answer 6

• Smoking
• Diabetes mellitus
• Hypertension
• Hyperlipidaemia
• Age >40 years
• History of CVD
• Low levels of exercise

Question 7

What are the signs of PAD?

Answer 7

May be no signs.

• Diminished or absent pulses

Question 8

What are the symptoms of PAD?

Answer 8

May be asymptomatic.

• Intermittent claudication
• Thigh or buttock pain when walking and is relieved by rest

Question 9

What investigations should be ordered for PAD?

Answer 9

• Ankle-Brachial Index (ABI)

Question 10

Why investigate ankle-brachial index (ABI)? And what may this show?

Answer 10

• ABI is the systolic pressure at the ankle, divided by the systolic pressure at the arm
• ABI ≤0.90

Question 11

How does acute limb ischemia present?

Answer 11

• Pain- constantly present and persistent
• Pulseless- ankle pulses are always absent
• Pallor (or cyanosis or mottling)
• Power loss or paralysis
• Paraesthesia or reduced sensation or numbness
• Perishing with cold

Question 12

How does intermittent claudication present?

Answer 12

Cramp-like pain in a muscle group after walking a predictable distance that is relieved by rest and reproduced by walking the same distance again- it is not present at rest or altered by position.

Symptoms usually occur in the distal extremity before the proximal extremity- the calves are more commonly affected than the thigh or buttock areas.

Question 13

How does critical limb ischemia present?

Answer 13

• Chronic rest pain
• There may sometimes not be a history of intermittent claudication
• Dependent rubor, pallor on elevation of the extremity, and reduced capillary refill
• Skin changes including ischaemic ulcers, non-healing foot wounds, and gangrene
• Absent foot pulses

Question 14

Briefly describe the various treatment options for PAD

Answer 14

• Risk factor modification
• Management of claudication
  
  • Supervised exercise programmes
  • Vasoactive drugs
  • Percutaneous transluminal angioplasty
  • Surgical reconstruction
  • Amputation

Question 15

What is included in risk factor modification?

Answer 15

All patients, regardless of their symptoms, should have aggressive risk factor modification including:

• Management of blood pressure
• Lipids
• Diabetes
• Smoking cessation

Antiplatelet (e.g. clopidogrel) also prescribed to reduce CVD risk.

Question 16

What vasoactive drugs can be used to treat painful claudication?

Answer 16

Symptom relief can be achieved with naftidrofuryl oxalate. Offer modest benefit and are only recommended in patients who do not wish to undergo revascularisation and if exercises fail to improve symptoms.

Question 17

How can revascularisation be achieved in PAD?

Answer 17

Endovascular revascularisation treatment may include either percutaneous transluminal balloon angioplasty (PTA) or bypass surgery.

Question 18

Briefly describe the management of acute limb ischemia

Answer 18

This is an emergency and may require open surgery or angioplasty. If diagnosis is in doubt, do urgent arteriography.

If the occlusion is embolic, the options are surgical embolectomy (Fogarthy catheter) or local thrombolysis, e.g. tissue plasminogen activatory t-pa, balancing the risk of surgery with the haemorrhagic complications with thrombolysis.

Anticoagulate with heparin after either procedure and look for the source of the emboli.

Question 19

What are the complications of PAD?

Answer 19

• Leg and foot ulcers
• Gangrene
• Permanent leg weakness and numbness

Question 20

What differentials should be considered for PAD?

Answer 20

1. Spinal stenosis
2. Arthritis

Question 21

How does PAD and spinal stenosis differ?

Answer 21

• Differentiating signs and symptoms: patients with history of back pain complain of hip, thigh, buttock, or leg pain. It is usually in a dermatomal distribution and may be associated with motor weakness. The pain may occur on standing alone and is relieved by position change such as sitting or stooping forwards (lumbar spine flexion).
• Differentiating investigations:
  
  • Ankle brachial index (ABI) will be normal and exercise ABI will show no decrease in post-exercise ABI
  • No significant disease seen with arterial imaging tests
  • Plain spinal x-ray: degenerative changes or spondylolisthesis
  • MRI spine: compression of the neural elements and soft tissue

Question 22

How does PAD and arthritis differ?

Answer 22

• Differentiating signs and symptoms: patients complain of hip, thigh, or buttock pain that is localised to hip and gluteal region. It can occur at rest or starts after exercise and is not quickly relieved.
• Differentiating investigations:
  
  • Ankle brachial index (ABI) will be normal and exercise ABI will show no decrease in post-exercise ABI
  • No significant disease seen with arterial imaging tests
  • X-ray of affected joint: new bone formation (osteophytes), joint space narrowing, and subchondral sclerosis and cysts