Vascular Surgery Flashcards
Define acute limb ischemia
Sudden decrease in arterial limb perfusion causing threat to limb viability - present within 2 weeks - no time for collaterals
Aetiology of acute limb ischemia
- Acute arterial embolism ( healthy vessel)
- Acute arterial thrombosis (diseased vessel)
- Acute arterial injury
Commonest sites of impaction of an embolus
- Femoral bifurcation 40%
- Aortic bifurcation
- Popliteal bifurcation
- Brachial bifurcation
- Carotid bifurcation
Major difference between acute embolic and thrombotic limb ischemia is?
Presence of collaterals in the case of a thrombotic event!
Mention causes of acute embolic ischemia
Cardiogenic:
MS with AF
MI (mural thrombus)
Sub acute bacterial endo on diseased valve
Noncardiogenic:
Air emboli
Fat emboli
Amniotic emboli
Malignant cell emboli
Parasitic emboli
Theraputic emboli
Paradoxical emboli
Large artery emboli: from athero, aneurysm
features found in acute embolic ischemia that helps differentiate a thrombotic cause
- Dramatic sudden onset of pain
- Normal pulse on the other limb
- Absence of previous claudication
- No skin trophic changes
- Symptoms of cause of emboli
- No arterial collaterals
Symptoms of acute ischemia
6P
1. Pain (cardinal)
2. Progressive coldness (cardinal)
3. Pallor
4. Pulselessness
5. Paresis then paralysis
6. Paresthesia
When does an acute embolic limb ischemia present with absent pulseless in both limbs?
Aorto-ileal emboli
Color change in acute limb ischemia
Pale -> reversible cyanosed then mottled (6-12hrs) -> fixed irreversible cyanosed
What is the catheter used in embolectomy?
Fogerty catheter
Why is heparin given in acute limb ischemia
To prevent clot propagation
Investigation of acute limb ischemia
- Site of impaction:
-Doppler / duplex
- angiography - Of cause:
- ECG, Echo, TEE
- xRay (fractures)
-US (aneurysm)
Urgent care of acute limb ischemia
- IV heparin
- Analgesia: Morphine
- Aide limb perfusion
- Stabilize patient
- Start Treating the cause
What are some measure to improve existing perfusion in ischemic limb
- Keep limb dependent
- Avoid external pressure
- Avoid extremes of temperature: cold (vasospam) heat (increase metabolic rate)
- Maximum oxygenation
- Correct hypotension
What explains a pale ischemic limb becoming pinkish?
Functional collaterals
Classification of acute limb ischemia
Viable <3hrs
Threatened 3-6 hrs
Irreversible: fixed colour and muscle turgid
Absolute Contraindications of thrombolitic therapy
- Cerebrovascular stroke withing previous 2 months
- Active bleeding/recent GI bleed within previous 10 days
- Intracranial trauma or neurosurgery within previous 3 months
Relative contraindications of thrombolytic therapy
- Uncontrolled hypertension
- Major surgery/ trauma within 10 days
- CPR within previous 10 days
Mention possible etiologies that could result in occlusion of arterial tree
Atherosclerosis
Diabetes
Burger’s ds
Raynaud’s
Aortic aneurysm
Thoracic outlet syndrome
What are the defining symptoms of critical limb ischemia
- Rest pain
- Gangrene
- Ulcer
Mention the Fontaines classification of chronic limb ischemia
1: asymptomatic
2: claudication ->
2a: when walking > 200 meters
2b: when walking < 200 meters
3: rest pain
4: gangrene / ulcer
Stage 3&4 of fontaines classification are also known as?
Critical limb ischemia
DD of intermittent claudication:
- Neurospinal claudication: lumbar disc/ spinal canal stenosis
- Venous claudication: chronic ileo-femoral DVT
Explain the rubber colour of foot in critical limb ischemia
When performing buerger’s test the limb is elevated until pale then dropped dependent presenting the red-purple colour (rubber colour) due to metabolite induced vasodilation quickly consuming oxygen when foot dropped -> pooled reduced hemoglobin gives the characteristic colour
