Lower limb aneurysms

Popliteal aneurysms

Majority are true
Definition
- 1.5-2cm popliteal artery external diameter
Risk factors
- Almost all in men
- Smoking
- HTN
- CAD
Presentations
- Incidental finding
- Pulsatile mass
- Acute limb ischaemia (thrombosis or embolism)
- Chronic claudication or blue toe syndrome
Natural history
- 30% will develop thromboembolism by three years
Examination
- Unreliable
Imaging
- Duplex USS first-line
- Intra-arterial arteriography is gold-standard
Intervention
- 2cm or greater in diameter
- Any symptomatic
Surgical bypass
- Proximal and distal ligation
- Bypass with saphenous vein graft
- Thrombectomy or tPA may be required in emergent situation if no suitable outflow vessel
Endovascular stent graft
- Identical indications
- Long-term results are unknown
- Generally reserved for high-risk patients

Many false
- Infected femoral pseudoaneurysm
  - Most commonly secondary to inadvertent intra-arterial injection of ilicit drugs
  - Tender, pulsatile groin mass, cellulitis, open draining punctate skin lesion, signs of systemic infection, sequelae of arterial embolisation or occlusion
  - Generally treated by ligating femoral artery and debriding
True aneurysms (arteriosclerotic)
- Commonly a/w aneurysms in other locations (60%)
- Most commonly found in CFA
- Pathogenesis probably relates to inflammation and atherosclerotic degeneration of arterial wall
- Presentation
  - Pulsatile mass
  - Compressive symptoms - oedema and neuropathy
  - Commonly asymptomatic
  - Complications less commonly seen than with popliteal
- Diagnosis
  - Duplex USS
  - CTA is good
- Repair
  - >3cm
  - Symptomatic
  - Complicated
  - Rapidly-enlarging
  - Emergent repair in acute limb ischaemia due to thromboembolism/rupture
- Surgical repair
  - Ligation of inflow and outflow
  - Placement of dacron graft from external iliac to distal CFA
- Endovascular repair
  - Not currently recommended - frequent hip flexion risks stent fracture
Pseudoaneurysms after arterial access
- Natural history is unclear, but the vast majority probably close on their own
- Up to a third will require repair
- Small uncomplicated pseudoaneurysms can be followed with serial USS
- >3cm or symptomatic should have treatment
  - USS guided compression or thrombin injection
  - Open surgical repair if these are failed