Chronic Limb Ischaemia

Question 1

What is intermittent claudication?

Answer 1

Defined as an aching pain in the leg muscles usually the calf. Precipitatd by walking a fixed distance know as the claudication distance and the pain i relieved by rest.

Question 2

Why does intermittent claudication tend to improve with time and exercise?

Answer 2

New collaterals open up and supply the muscle therefore improving muscle function

Question 3

How does it present depending on which vessel is affected?

Answer 3

Gluteal muscles - Aorto iliac
Quadriceps and hamstrings - ilio-femoral
Gastrocnemius, soleus and peronei - Femoro-popliteal

Question 4

What are the differentials for aching pain in the calves?

Answer 4

Vascular

• atheroma
• aortic occlusion = buttock, thigh and calf claudication, impotence in males, absent femoral pulses and below - LERICHES SYNDROME

Neurological 
Cauda equina 
- elderly
- atypical history 
- hx of chronic back pain 
- pain bilateral in S1 - S3 dermatonal distribution 
- all pulses palpable 
- Legs well perfused

Question 5

Which process causes intermittent claudication?

Answer 5

Atherosclerosis

Question 6

How does atherosclerosis occur?

Answer 6

1. endothelium becomes damaged due to HTN for example
2. Lipoproteins enter and modify and recruit leukocytes and foam cells form
3. Intima continues to thicken due to Smooth muscle cell proliferation and leukocyte recruitment
4. fibrous cap forms
5. Lumen narrows and less blood flow - angina and claudication

Question 7

Which investigations should be done if chornic limb iscahemia is suspected?

Answer 7

Bedside tests - BP, ECG, sats, RR, HR
Bloods - FBC to exclude polycythaemia
blood glucose - diabetic control
Lipids - hyperclipidaemia

Other investigations
ABPI - confirm diagnosis and quantify severity of limb ischaemia
Doppler USS - severity and anatomical location
CT angiography or MR angiography

Question 8

What are the stages of chronic limb ischaemia?

Answer 8

Stage 1 = Aysmptomatic
Stage 2 = Intermittent claudication
Stage 3 = Ischaemic rest pain
Stage 4 = Ulceration/gangrene or both

Question 9

What is the medical management for chronic limb ischaemia?

Answer 9

Lifestyle advice - diet, smoking cessation, alcohol reduction, exercise
Statin therapy
Antiplatelet therapy
Diabetic control

Question 10

When is surgical management considered for chronic limb ischaemia?

Answer 10

Risk factor modification hasnt made enough improvement
Supervised exercise has failed to improve symptoms
Critical limb ischaemia - urgent referral

Question 11

What types of surgery are offered for chronic limb ischaemia?

Answer 11

Angioplasty with stenting - single occluded artery
Bypass grafting - diffuse disease
Amputation - pts unsuitable for revasculariation, gangrene - sepsis

Question 12

What are the complications of chronic limb ischaemia?

Answer 12

Sepsis - secondary to infected gangrene 
Acute on chronic ischaemia 
Amputation 
Reduced mobility 
Reduced quality of life

Question 13

What is ABPI?

Answer 13

Ankle brachial pressure index
a value of less than 0.9 suggests reduced blood supply to the lower limbs
a value of 0.5 and lower is suggestive of severe peripheral vascular disease - rest pain, gangrene, ulceration
be wary of a value of more than 1.2 as calcification and hardening of the arteries can give a falsely high ABPI