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Operative management of acute limb ischaemia

The following are “Know” from the syllabus

  • Appreciate the role of endovascular treatment including thrombolysis
  • Embolectomy: - brachial - femoral

Thrombolysis

  • Indications
    • For acute thrombosis
      • Achieved by stimulating conversion of plasminogen to plasmin
        • A protease that degrades fibrin
        • Results in thrombus dissolution
      • Must be injected via angiography
        • AT THE SITE of thrombus
        • Otherwise ineffective and high risk of complications
    • Short segment thrombotic occlusions
      • Catheter directed followed by balloon angioplasty to underlying offending lesion
    • Ischaemic interval short
      • Can be used up to 1-2/52 post initial event
  • Agents Used
    • rTPA (Recombinant Tissue Plasminogen Activator)
      • Streptokinase
      • Urokinase (probably superior)
    • Heparin given concurrently
      • Prevents clot formation around catheter, prevents early re-thrombosis & for 48 hours after
    • Consider life-long Warfarin
      • or Aspirin + Clopidogrel if warfarin contraindicated
  • Technique
    • Need to deliver to site of thrombus
    • Intra-thrombus method
    • Initial bolus dose followed by infusion for up to 3 days
      • Duration is dictated by reassessment
    • Occasionally can be supplemented with percutaneous thrombectomy
      • Suction/aspiration or disruption and net catchment
      • Not really recommended for distal vessels and can cause further arterial damage

Embolectomy

  • Principles
    • Prepare the whole limb and lower abdomen and contralateral side to mid-thigh
      • Because you don’t know exactly where problem is
      • You can evaluate your success (foot in transparent plastic bag)
    • Embolectomy via Fogarty balloon catheter placed through a proximal arteriotomy
      • Sizes 2-7 available (Fogarty)
      • Check balloon with saline first
    • Catheter passed in 10cm increments
      • Gentle inflation
      • Resistance free withdrawal
    • Repeat until no more clot, and good back flow
      • Back flow not a reliable sign though
    • Heparinize distally 5000 IU in 250mL
    • Can use intraoperative direct arterial infusion of urokinase (50,000-250,000 units) in settings where cleared proximal disease but might be left with some stagnant thrombosis which can’t clear
    • For an aortic bifurcation saddle embolus
      • Will often do bilateral femoral cut-downs, clamp both sides and clear
      • To avoid forcing trash down one side
    • Always do arteriogram on completion

Femoral Embolectomy

  • Setup and Positioning
    • Fogarty size 3 or 4 for Femoral
      • Sizes 2-7 available – 2 – smallest
      • Check the balloon
    • Prepare both limbs and lower abdomen completely (can wrap feet in transparent plastic bags)
      • E.g. If you identify an aortic bifurcation saddle embolus will need to do bilateral femoral cut downs, clamping both sides before starting to clear so trash doesn’t get thrown down one side
    • Thigh abducted, knee on pillow
      • NB: Mid-inguinal point – ASIS Pubic Symphysis
        • Femoral Artery
      • NB: Mid-point of the inguinal ligament; ASIS to Pubic Tubercle
        • Femoral Nerve
  • Incision and Control
    • Longitudinal skin incision at mid-inguinal point
    • Divide skin, subcutaneous tissue
    • Superficial & deep fascia, vascular sheath
    • May come across superficial branches of GSV/ Femoral Artery
      • Control Common femoral artery, superficial femoral artery, PFA individually with vascular loops
        • Encircle vessels by working medial to lateral under vessels with right angles
        • Avoid damage to Femoral Vein
      • Identify PFA as the one with the branches
  • Embolectomy
    • Before opening – 5000 IU heparin (take into account body weight, renal function)
    • Just above bifurcation make
      • Transverse cut if artery normal & unlikely to need to re-construct
      • Longitudinal if diseased, will often need to close with patch to prevent stenosis
        • Transverse arteriotomies are more predisposed to flaps & you are limited with the size of the cut you can make (therefore problematic in small vessels)
        • Longitudinal arteriotomies: More prone to stricturing
          • Will accept up to 50% stenosis
    • Use size (3) 4 catheter mostly
    • Do proximal (common), then SFA then PFA
    • Catheter passed in 10cm increments, gentle inflation, resistance free withdrawal
    • Repeat until no more clot, good back flow
    • Check distal pulses
    • Check other side pulses
    • From here if placed distally
    • Generally can enter peroneal artery
    • If want ATA or PTA, make separate distal (below knee) incision
  • Closure and Considerations
    • Once finished
    • Flush with heparinized saline
    • Arteriogram can be done if facilities/ experience available but not if unexperienced in technique
    • Transverse arteriotomy closed with 4/0 or 5/0 Prolene
    • Consider about fasciotomy

Popliteal Embolectomy

  • Leg abducted, hip & knee flexed, externally rotated
  • Standard medial incision
  • Parallel to long axis of leg,
  • 1 finger breadth posterior to medial border of Tibia
  • Approximately 10cm long, preserve LSV
  • Fat, fascia & deep fascia divided
  • Medial head of gastrocnemius mobilized & retracted posteromedially
  • Soleus taken down off tibia to expose Tibioperoneal Trunk
  • Get individual control (sometimes take ATV to aid dissection)
  • Distal popliteal arteriotomy (usually longitudinal)
  • Use size (2) 3 catheter for embolectomy
  • Close with graft or vein patch https://www.youtube.com/watch?v=VJGAJ2GFrPE&ab_channel=HoustonMethodistDeBakeyCVEducation

Brachial Embolectomy

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