Arterial Disease of the Limbs Flashcards
What is the pathophysiology of critical limb ischaemia?
Usually athersclerotic disease of the arteries supplying the lower limb
Sometimes can be from vasculitis or Buerger’s disease
What are the risk factors for critical limb ischaemia?
Same as for atherosclerosis:
- Male
- Age
- Smoking
- Hypercholesterolaemia
- Hypertension
- Diabetes
What are the symptoms of critical limb ischaemia and how are the classified?
Fontaine classification
I - asymptomatic, incomplete vessel obstruction
II - mild claudication in limb
(IIa - pain walking >200m)
(IIb - pain walking <200m)
III - Pain at rest, mostly in feet
IV - necrosis/gangrene
What questions might you ask in a history in suspected critical limb ischaemia?
Exercise tolerance Effect of incline Change over time Relieved by rest? Where in the leg? Bilateral?
Resting pain?
- type
- relieving factors
Tissue loss
- duration
- history of trauma
- peripheral sensation
Presence of risk factors
What would you look for in an examination in suspected critical limb ischaemia?
Expose both legs
Look for ulceration, pallor, hair loss
Feel
- capillary refill
- temperature
- pulses
- peripheral sensation
Auscultate
- handheld doppler
- feel dorsalis pedis and posterior tibial pulses
What other special tests may be done in critical limb ischaemia?
Ankle brachial pressure index
= ankle pressure over brachial pressure
> 1? Usually symptom free
0.5-0.95? Usually intermittent claudication
0.3-0.5? Usually pain at rest
<0.2? Usually gangrene and ulceration
Buerger’s test
- elevate legs - pallor and severe ischaemia <20 degrees
- hang feet over the edge of bed - slow to regain colour or dark red
- normally 1/3rd capillaries, in CLI autoregulation is lost, all capillaries are open
How do you manage critical limb ischaemia?
Best medical therapy
- Antiplatelet
- Statin
- BP control
- Diabetic control
- Lifestyle changes
Consider angioplasty/stent/bypass
Consider endovascular reconstruction
What investigations may be done in suspected critical limb ischaemia? What are there pros/cons?
Duplex
- dynamic
- no radiation/contrast
- not good in the abdomen
- operator dependent, time consuming
CTA/MRA
- detailed - allows treatment planning
- NICE first line
- use contrast/radiation
- can overestimate calcification
Digital subtraction angiogram
What are the various amputations that might be done?
Digit Transmetatarsal Symes (Rare) Below Knee Through Knee Above Knee Hip disarticulation Hindquarter
How do mobility and energy requirements vary with Above and Below knee amputations?
Inside
- 80% mobility with Below, 40% with above
Outside
- 65% mobility with below, 43% with above
Energy requirements
- increase 63% with below
- increase 117% with above
What might cause acute limb ischaemia?
Embolus/Thrombus
Trauma
Dissection
Acute aneurysm thrombosis
How might acute limb ischaemia present?
6 ‘P’s
- Pain
- Pallor
- Perishingly cold
- Paraesthesia
- Paralysis
- Pulseless
History of chronic limb ischaemia
Risk factors
Cardiac history
Compare to contralateral limb
What happens in compartment syndrome?
Muscle ischaemia, inflammation, oedema, venous obstruction
Tense, tender calf
Rise in creatinine kinase
Risk of renal failure
What investigations might be done in acute limb ischaemia?
ECG
Bloods
NBM
Determine if limb is salvageable or not
What is the treatment for acute limb ischaemia?
Salvageable?
Yes:
- (embolus) embolectomy
- (thrombosis in situ) endovascular thrombectomy or open embolectomy +/- bypass
No?
- amputate or palliate
