4.03 Vascular Surgery - Peripheral Vascular Disease Flashcards
What is acute limb ischaemia?
The sudden decrease in limb perfusion that threatens the viability of the limb, commonly caused by complete or partial occlusion of the arterial supply to the limb.
What are the three main causes of acute limb ischaemia?
- Embolisation - a thrombus from a proximal source travels distally to occlude the artery (most common).
- Thrombosis in situ - an atheroma plaque in the artery ruptures and a thrombus forms on the plaque’s cap (presenting as acute or acute-on-chronic).
- Trauma - including compartment syndrome (less common).
What are the clinical features of acute limb ischaemia?
Hint: 6Ps
- Pain
- Pallor
- Paraesthesia
- Paralysis
- Perishingly cold
- Pulseless
What are the differentials for acute limb ischaemia?
- critical chronic limb ischaemia
- acute DVT
- spinal cord or peripheral nerve compression
What investigations are warranted for suspected acute limb ischaemia?
- bloods including serum lactate to assess the level of ischaemia, and Group&Save
- Doppler ultrasound scan
- CT angiography
What is the management of acute limb ischaemia?
- high flow oxygen
- IV heparin infusion
- surgical intervention
NB acute limb ischaemia is a surgical emergency and complete arterial occlusion can lead to irreversible tissue damage within 6 hours.
What are the surgical interventions possible to manage acute limb ischaemia?
- embolectomy
- thrombolysis
- bypass surgery
- angioplasty
What are the signs of irreversible limb ischaemia, and what is the management?
- mottled non-blanching appearance
- hard woody muscle
Irreversible limb ischaemia warrants urgent amputation or taking a palliative approach.
What are the complications of acute limb ischaemia?
- mortality (~20%)
- reperfusion injury
Outline the pathophysiology of reperfusion injury following surgical intervention of acute limb ischaemia.
- Sudden increase in capillary permeability results in compartment syndrome
- Damaged muscle cells release: K+ (hyperkalaemia); H+ (acidosis); myoglobin (AKI)
What is chronic limb ischaemia?
Peripheral arterial disease that results in a symptomatic reduced blood supply to the limbs.
What are the risk factors for chronic limb ischaemia?
- smoking
- diabetes mellitus
- hypertension
- hyperlipidaemia
- increasing age
What is the cause of chronic limb ischaemia?
Peripheral arterial disease, commonly caused by progressive atherosclerosis reducing blood supply ot the lower limbs.
What are the clinical features of chronic limb ischaemia?
- asymptomatic
- intermittent claudication
- ischaemic rest pain
- ulceration or gangrene
What test can be used to diagnose chronic limb ischaemia?
Buerger’s test - involves lying the patient supine and raising their legs until they go pale, and then lowering them until the colour returns.
The angle at which the limb goes pale is termed Buerger’s angle - an angle of <20° indicates severe ischaemia.
What is Leriche syndrome?
A form of peripheral arterial disease that affects the aortic bifurcation, presenting with buttock or thigh pain and is associated with erectile dysfunction.
What are the clinical features of critical limb ischaemia?
- pale and cold limbs
- weak or absent pulses
- limb hair loss
- atrophic skin
- ulceration
- gangrene
- thickened nails
