3: Chronic Limb Ischaemia

Question 1

what is chronic limb ischaemia

Answer 1

a form of peripheral arterial disease that results in symptomatic reduction of blood supply to limbs

Question 2

what is the typical pathophysiology of chronic limb ischaemia

Answer 2

atherosclerosis

Question 3

what are the main risk factors of chronic limb ischaemia

Answer 3

• smoking
• diabetes
• HTN
• hyperlipidaemia
• inc age
• strong FHx
• obesity
• physical inactivity

Question 4

how is chronic leg ischaemia classified

Answer 4

Fontaine classification

Question 5

what is critical limb threatening ischaemia

Answer 5

clinical syndrome defined by the presence of peripheral arterial disease and rest pain, gangrene or lower limb ulceration **> 2 weeks **
- associated w amputation, increased mortality and decreased QoL
- ABPI < 0.5

Question 6

how might chronic limb ischaemia present

Answer 6

• affected limbs are colder
• evidence of arterial ulcers
• reduced or absent peripheral pulses in advanced cases
• femoral bruit

Question 7

what is Leriche syndrome and how does it present

Answer 7

form of peripheral arterial disease affecting aortic bifurcation
- presents w buttock or thigh pain
- associated w ED

Question 8

what are the 2 main ddx for patient presenting w limb ischaemia

Answer 8

1. spinal stenosis (neurogenic claudication): pain from back radiating down lateral aspect of leg + symptoms on movement and relieved by sitting
2. acute limb ischaemia: symptoms < 14 days

Question 9

what investigations are indicated in chronic limb ischaemia

Answer 9

• Buerger’s test
• ABPI
• FBC
• toe pressure
• CT angiogram
• Doppler USS
• Duplex

Question 10

what is Buerger’s test

Answer 10

• lying the patient supine and raising their legs until they go pale and then lowering them until the colour returns
• angle at which limb goes pale is termed Buerger’s angle; an angle of less than 20 degrees indicates severe ischaemia

Question 11

how is ABPI used to diagnose chronic limb ischaemia

Answer 11

• any ABPI value >1.2 interpret w caution as calcification and hardening of arteries can cause falsely high ABPI e.g. with increasing age

Question 12

how is toe pressure used in diagnosis of chronic limb ischaemia

Answer 12

> 30mm/Hg is sufficient to promote wound healing and pt can tolerate surgery

Question 13

how can doppler USS for chronic limb ischaemia be interpreted

Answer 13

• monophasic
• biphasic
• triphasic (normal)

Question 14

what is the medical management of chronic limb ischaemia

Answer 14

• lifestyle advice: smoking cessation, exercise, weight loss
• statin: atorvastatin 80mg OD
• anti-platelet: clopidogrel 75mg OD
• optimise DM control

Question 15

why is it important to encourage patients with chronic limb ischaemia to walk through the apin

Answer 15

encourage developement of new blood vessels and establishment of collateral circulation

Question 16

when can a patient with chronic limb ischaemia be offered surgical intervention

Answer 16

1. risk factor modification discussed
2. supervised exrecise has failed to improve symptoms

Question 17

what are the 2 main surgical options for chronic limb ischaemia

Answer 17

1. angioplasty: incise femoral triangle, insert probe and inflate balloon + stent
2. bypass: typically used for diffuse disease or in younger patients

Question 18

how do you decide whether to amputate a gangrenous limb

Answer 18

• dry gangrene: body will auto-amputate and not infected (shrunken)
• wet gangrene: superimposed infection and risk of spreading so must remove (swollen)

Question 19

what are the complications of chronic limb ischaemia (4)

Answer 19

• sepsis secondary to infected gangrene
• acute-on-chronic ischaemia
• amputation
• reduced mobility + QoL