Stent-graft placement (endovascular repair) in the treatment of abdominal aortic aneurysms

• stent-graft placement (endovascular repair) is a minimally invasive alternative to open repair of abdominal aortic aneurysms
  • graft is mounted on a stent, which is inserted into the aorta via catheters in the femoral arteries
  • stent-graft is deployed under X-ray guidance and positioned across the aneurysm
  • additional endovascular or surgical interventions may be necessary to complete the procedure e.g. insertion of stents into the iliac arteries, occlusion of selected arteries and femoro-femoral bypass grafts (1)
  • endovascular repair requires that the aneurysm has an adequate (1.2cm) 'neck' below the renal arteries for stent fixation
    • approximately 65+% of patients with AAA are judged suitable for endovascular repair and many clinicians believe that endovascular techniques should be the first line therapy for all patients with AAA who have suitable aneurysm morphology (2)
    • advantages of this technique are the avoidance of transperitoneal manipulation and aortic cross clamping.
    • principle disadvantage of endovascular repair is that the patient must be kept under either US or CT surveillance to ensure continued endograft integrity
      
      
• NICE suggest that endovascular stent-grafts are recommended as a treatment option for patients with unruptured infra-renal abdominal aortic aneurysms, for whom surgical intervention (open surgical repair or endovascular aneurysm repair) is considered appropriate (3)
• NICE state (4) - consider aneurysm repair for people with an unruptured abdominal aortic aneurysm (AAA), if it is:
  • symptomatic
  • asymptomatic, larger than 4.0 cm and has grown by more than 1 cm in 1 year (measured inner-to-inner maximum anterior-posterior aortic diameter on ultrasound)
  • asymptomatic and 5.5 cm or larger (measured inner-to-inner maximum anterior-posterior aortic diameter on ultrasound) Open surgical repair, standard endovascular aneurysm repair or conservative management (4): * Consider aneurysm repair for people with an unruptured abdominal aortic aneurysm (AAA), if it is:
    • open surgical repair should be offered for people with unruptured AAAs meeting the criteria * unless it is contraindicated because of their abdominal copathology, anaesthetic risks, and/or medical comorbidities
    • consider endovascular aneurysm repair (EVAR) for people with unruptured AAAs who meet the criteria * and who have abdominal copathology, such as a hostile abdomen, horseshoe kidney or a stoma, or other considerations, specific to and discussed with the person, that may make EVAR the preferred option
    • consider EVAR or conservative management for people with unruptured AAAs meeting the criteria * who have anaesthetic risks and/or medical comorbidities that would contraindicate open surgical repair
    • symptomatic
    • asymptomatic, larger than 4.0 cm and has grown by more than 1 cm in 1 year (measured inner-to-inner maximum anterior-posterior aortic diameter on ultrasound)
    • asymptomatic and 5.5 cm or larger (measured inner-to-inner maximum anterior-posterior aortic diameter on ultrasound)

Reference:

• (1) NICE (March 2006).Stent-graft placement in abdominal aortic aneurysm.
• (2) British Heart Foundation (Factfile 2/2008). Abdominal aortic aneurysms.
• (3) NICE (February 2009). Endovascular stent-grafts for the treatment of abdominal aortic aneurysms
• (4) NICE (March 2020).Abdominal aortic aneurysm: diagnosis and management