Chronic Limb Ischaemia

Question 1

What is chronic limb ischemia?

Answer 1

Chronic limb ischaemia is peripheral arterial disease that results in a symptomatic reduced blood supply to the limbs.

Question 2

What causes chronic limb ischemia? And where does it commonly affect?

Answer 2

It is typically caused by atherosclerosis (rarely vasculitis) and will commonly affect the lower limbs (however the upper limbs and gluteals can also be affected).

Question 3

What are the risk factors for chronic limb ischemia?

Answer 3

• Smoking
• Diabetes mellitus
• Hypertension
• Hyperlipidaemia
• Increasing age
• Family history
• Obesity and physical inactivity

Question 4

Briefly describe the Fontaine classification of chronic leg ischaemia

Answer 4

Question 5

Briefly describe Buerger’s test

Answer 5

Buerger’s test involves lying the patient supine and raising their legs until they go pale and then lowering them until the colour returns (or even becoming hyperaemic). The angle at which limb goes pale is termed Buerger’s angle; an angle of less than 20 degrees indicates severe ischaemia.

Question 6

What is Leriche syndrome?

Answer 6

Leriche syndrome is a form of peripheral arterial disease affecting the aortic bifurcation. It specifically presents with buttock or thigh pain and associated erectile dysfunction.

Question 7

What is critical limb ischemia?

Answer 7

Critical limb ischaemia is the advanced form of chronic limb ischaemia.

It can be clinically defined in three ways:

• Ischaemic rest pain for greater than 2 weeks duration, requiring opiate analgesia
• Presence of ischaemic lesions or gangrene objectively attributable to the arterial occlusive disease
• ABPI less than 0.5

Question 8

How does critical limb ischemia present on examination?

Answer 8

On examination, the limbs may be pale and cold, with weak or absent pulses. Other signs include limb hair loss, skin changes (atrophic skin, ulceration, or gangrene), and thickened nails.

Question 9

What differentials should be considered for patient presenting with limb ischemia symptoms?

Answer 9

1. Spinal stenosis (‘neurogenic claudication’)
2. Acute limb ischemia

Question 10

Briefly describe the examination for chronic limb ischemia

Answer 10

• Weak peripheral pulses
  
  • Radial
  • Brachial
  • Carotid
  • Aorta
  • Femoral
  • Popliteal
  • Dorsalis Pedis
  • Femoral
• Pallor
• Cold
• Skin changes (ulceration, hair loss)
• Buerger’s Test
• Ultrasound doppler to more accurately assess pulses

Question 11

What investigations are required for chronic limb ischemia?

Answer 11

• Ankle-Brachial Pressure Index (ABPI)
• Arterial Doppler
• Angiography (CT or MRI)

Question 12

Briefly describe the Ankle-Brachial Pressure Index (ABPI)

Answer 12

The ankle-brachial pressure index (ABPI) is used to confirm the diagnosis and quantify severity of chronic limb ischaemia.

The ratio of systolic blood pressure in the ankle (around the lower calf) vs the arm e.g. an ankle SBP of 80 and an arm SBP of 100 gives a ratio of 0.8.

Results:

• >0.9 is normal
• 0.6 – 0.9 is mild disease
• 0.3 – 0.6 is moderate to severe disease
• <0.3 is severe disease to critical ischaemic
  *

Question 13

What is the medical management of chronic limb ischemia?

Answer 13

Most patients with chronic limb ischaemia require cardiovascular risk factor modification:

• Lifestyle advice (smoking cessation, regular exercise, weight reduction)
• Statin therapy (ideally atorvastatin 80mg OD)
• Anti-platelet therapy (ideally clopidogrel 75mg OD)
• Optimise diabetes control

Enrollment into a local supervised exercise programme has been shown to improve walking distance and claudication distance, and should be used as first line therapy in any patient without critical limb ischaemia

The course of chronic limb ischaemia is variable and many patients’ symptoms do improve on lifestyle changes and medical management alone.

Question 14

What is the surgical management of critical limb ischemia?

Answer 14

Any patients with critical limb ischaemia should be urgently referred for surgical intervention.

There are two main surgical options available:

• Angioplasty with or without stenting
• Bypass grafting, typically used for diffuse disease or in younger patients

A combination such as surgery to clean a specific lesion allowing access for angioplasty to another region.

Question 15

According to NICE, when should surgical management be offered in chronic limb ischemia?

Answer 15

NICE guidance states that surgical intervention can be offered in suitable patients if

• Risk factor modification has been discussed
• Supervised exercise has failed to improve symptoms

Question 16

When are amputations considered in chronic limb ischemia?

Answer 16

Amputations are considered for any patients who are unsuitable for revascularisation with ischaemia causing incurable symptoms or gangrene leading to sepsis.

Question 17

What are the complications of chronic limb ischemia?

Answer 17

Chronic limb ischaemia can result in sepsis (secondary to infected gangrene), acute-on-chronic ischaemia, amputation and reduced mobility and quality of life.