Acute + Chronic Limb Ischaemia Flashcards

1
Q

What is chronic limb ischaemia?

A
  • Peripheral arterial disease, typically of lower limbs causing reduced blood supply
  • 5% of males >50yrs have intermittent claudication
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2
Q

What are risk factors for chronic limb ischaemia?

A
  • Smoking
  • Diabetes mellitus
  • Age
  • Hyperlipidaemia
  • Family history
  • Hypertension
  • Obesity
  • Physical inactivity
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3
Q

What are the causes of chronic limb ischaemia?

A
  • Atherosclerosis
  • Vasculitis (rarely)
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4
Q

What are the clinical features as per the Fontaine classification, for chronic limb ischaemia?

A
  • Stage I → asymptomatic
  • Stage II → intermittent claudication
  • Stage III → ischaemic rest pain
  • Stage IV → ulceration +/- gangrene

The commonest presentation is with pain in the lower limb on exercise (claudication)

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5
Q

What is intermittent claudication?

A
  • cramping/aching pain in buttock or calf
  • after walking a fixed distance (claudication distance)
  • relieved quickly by rest
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6
Q

What is critical limb ischaemia?

A
  • Unremitting pain at rest (esp at night)
  • May be improved by hanging feet out of bed
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7
Q

What is Leriche’s syndrome/triad?

A
  • Aorto-iliac obstruction
    • → Buttock + thigh pain
    • → Male impotence
    • → Absent femoral pulses
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8
Q

What are signs of chronic limb ischaemia?

A
  • Pulseless
  • Pale
  • Cool
  • Paraesthesia
  • Poor wound healing
  • Nail dystrophy
  • Loss of hair
  • Pallor
  • Skin changes
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9
Q

What is the ABPI classification in limb ischaemia?

A
  • 1 = normal
  • 0.6-0.9 = claudication
  • 0.3-0.6 = rest pain
  • <0.3 = impending gangrene
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10
Q

Apart from ABPI, what investigations are done for chronic limb ischaemia?

A
  • FBC → anaemia may exacerbate
  • ESR → raised in arteritis
  • Blood glucose → DM
  • Lipids
  • ECG → 60% have evidence of coronary artery disease
  • Imaging for site, length + degree of stenosis
    • Duplex ultrasound (Gold standard)
    • Also, CT or MR angiography
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11
Q

How do you interpret doppler USS waveforms for the degree of stenosis?

A
  • Triphasic → normal
  • Biphasic → mild stenosis
  • Monophasic → severe stenosis
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12
Q

What is the conservative management for chronic limb ischaemia?

A
  • Stop smoking
  • Regular exercise
  • Weight loss
  • Foot care
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13
Q

What is the medical management of chronic limb ischaemia?

A
  • Lipid lowering drugs
  • Hypertension control
  • Diabetes control
  • Antiplatelets (clopidogrel / aspirin)
  • Peripheral vasodilator → nafridrofuryl oxalate
  • Analgesia
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14
Q

What are the two surgical options for chronic limb ischaemia?

A
  1. Endovascular - angioplasty +/- stent:
    • Cross the narrowing or blockage w/ wire, pass balloon over wire, stretch open artery + place stent if needed; less invasive/less risk - better for high risk pts; good for short lesions
  2. Open surgical reconstruction:
    • Use a conduit (vein or plastic pipe) to go around blockage + restore blood flow distally
    • May be anatomical - fem-pop, fem-distal, aorto-bifemoral
    • Or extra-anatomical - axillo-femoral, fem-fem crossover
    • Ultimately @ 1yr following attempted lower limb bypass operation, 12% of those who initially had critical limb ischaemia + 1% of those with intermittent claudication end up having a major amputation
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15
Q

What is acute limb ischaemia?

A
  • Sudden onset (<2 weeks)
  • Painful lack of blood flow to a limb
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16
Q

What are the presenting features of acute limb ischaemia (6Ps)?

A
  • Pain
  • Pallor
  • Paralysis
  • Paraesthesia
  • Perishingly cold
  • Pulseless
17
Q

What are causes of acute limb ischaemia?

A
  • Thrombosis in situ - plaque rupture in vessel w/ stenosis (same pathology as MI)
  • Embolism → arrhythmia, fat embolism, heart valve replacement, surgery/angio
  • Dissection (usually aortic)
  • Trauma
  • Stent/graft occlusion
  • Compartment syndrome
18
Q

How is a thrombus different to embolus in presentation for acute limb ischaemia?

A
  • Thrombus has slower onset (hours to days, not immediate)
  • History of intermittent claudication
  • Less severe
  • Absent contra-lateral foot pulses
19
Q

What investigations are done for acute limb ischaemia?

A
  • Bloods → FBC, U+Es, G+S, INR (pre-op bloods)
  • ECG → ?cause of embolus, pre-op assessment
  • Imaging → Duplex USS
20
Q

What is the management of acute limb ischaemia?

A
  • This is an emergency!
  • ABCDE
  • NBM + IV fluids
  • Unfractionated heparin to prevent extension
  • Antibiotics if infection
  • Further management depends on extent of occlusion:
    • if complete → urgent surgery → embolectomy/bypass
    • if not completeangiogram + observation