Abdominal Aortic Aneurysms

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Abdominal Aortic Aneurysms

• Beyond Grey Hair and Back Pain
• Marty Schoen
• Thanks to Michael Watkins and Lawrence Young

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AAA Basics What is it?

• Most common between renal arteries and
  bifurcation
• Infrarenal Aorta is
• between 1.4 and
• 3.0cm
• Average Aorta size
• is 2.0cm

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AAA Basics What is it?

• Most aortas less than 5cm in diameter do not
  rupture

• Transverse 3rd vertebrae diameter is a good
  baseline for minimal rupture size

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AAA Basics How Often?

• ADAM study showed prevalence of AAA of 4cm in
  1.4 of vets 50-79
• Men affected 4x more

• 2x more common in whites
• Average age 69 year for men, 78 years for women

ADAM Aneurysm Detection and Management
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AAA Basics Mortality

• 15,000 lives per year taken due to rupture (13th
  leading cause of death)

• 40 of 5.5-6cm AAAs will rupture in 5 years
• Average survival if untreated is 17 months

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AAA Basics Mortality

• Small Aneurysms carry much less risk, 0.5 of
  4-5.5 cm rupture

• Therefore small AAAs can be monitored with
  ultrasound

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AAA Basics Risks?

• Smoking increases risk 8x in ADAM
• HTN present in 40 of patients

• Family history and presence of COPD are also
  cofactors
• Cholesterol may play a role

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NEWS FLASH!

• Diabetics were actually protected from AAA!
• Odds ratio of 0.52 (0.45-0.61)
• Patients with DVT were also protected
• Odds ratio of 0.67 (0.53-0.84)

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AAA Diagnosis

• An intact AAA produces only minimal symptoms, if
  any
• Most patients may know of painless, throbbing
  mass

• Back pain is rare, due to pressure on nerves,
  vertebral erosion

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AAA Imaging

• Ultrasound is most useful and least expensive
  mode of diagnosis

• Best used to assess progression of AAA size
• Average expansion of 0.4cm/year

Longitudinal Section of 2cm Aorta
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AAA Imaging

• CT and CTA are also very effective tools to
  outline size and shape of AAA
• Because of CT and MRI, aortograms are not
  performed as frequently

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AAA Assessment
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AAA Surgery

• Performed because of natural history of AAA
  expansion and risk of death
• There is also morbidity due to arterial
  thromboembolism to legs
• Therefore surgery is recommended in AAA over 5.5
  cm
• 2002 study showed no benefit to operate on small
  (4-5.5) aneurysms

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AAA Repair

• Two types of repair performed

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Open vs. Endovascular
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Anatomic Criteria

• Proximal neck length gt15mm
  diameter lt28mm
• Tube graft distal cuff length gt10mm
  diameter lt28mm
• Iliac artery diameter gt7mm and lt 15mm
• Minimal to moderate tortuosity
• No mural thrombus at attachment sites
• Minimal calcification
• No associated mesenteric occlusive disease

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Open Repair and Graft
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Potential Complications
Death Breathing Problems Pneumonia Airway
Spasm Ventilatory Failure Kidney Failure Bleeding

• Blood Clots Requiring Reoperation
• Reaction to Blood Transfusion
• Bowel Dysfunction
• Impotence
• Paraplegia due to loss of Spinal Artery

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Indications for Endovascular Repair

• High risk patientsexcessive morbidity and
  mortality
• Parodiinitially used endografts only in patients
  deemed not surgical candidates
• Advanced age
• FEV1 lt 800cc
• Renal insufficiency
• Multiple previous abdominal operations

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Tube Endograft Placement
Katzen, et al
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Uniiliac Endograft Placement
Semba, et al
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Bifurcated Endograft Placement
Katzen, et al
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AneuRx

• Medtronic
• Modular bifurcated with extension cuffs
• Graftthin walled polyester
• Stentouter self expanding Nitinol stents
• Delivery25F introducer sheath
• Mechanical deployment handle

May, et al
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Benefits

• Theoretical
• Reduced complications and mortality
• Decreased hospitalization
• Decreased cost
• Realized
• Same number of complications but different types
• Less systemic complications, same mortality
• Shorter respiratory support
• Decreased ICU and hospital stay
• Decreased blood loss
• Cost??

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Results of Endovascular Repair

• Several initial studies in small groups of
  patients showed no mortality benefit to
  endovascular repair (Blum et. al. 1997, May et.
  al 1997)
• Follow up study by Treharne in 1999 showed modest
  improvement using physiologic assessments
• Many questions in literature regarding efficacy
  of EAAA repair (Collin and Murie 2001 A Failed
  Experiment)

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Costs of EAAA repair

• Claire in 2000 studied 139 patients
• Determined that average savings of EAAA was
  approx 6,000 pounds before graft cost
• 9 days in hospital vs. 3 days
• To break even, grafts need to become cheaper,
  original devices were custom-made and expensive
  (10,000)
• Some thought the procedure was not worth extra
  cost and complications
• Lifelong CT follow-up to detect leaks is
  expensive!

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Complications of EAAA repair

• Systemic
• MI, CHF, arrhythmias, respiratory failure, renal
  failure
• Procedure related
• Dissection, malpositioning, renal infarction,
  thromboembolizaton, ischemic colitis
• Groin hematoma, wound infection
• Device related
• Migration, detachment, rupture, stenosis,
  kinking, endoleak

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Endoleaks

• Coined by White, et al, 1996
• Leak around proximal or distal attachment sites
• Persistent flow in aneurysm sac
• Incomplete exclusion
• Rates
• 0 to 44
• Risks
• Expansion
• Rupture

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Endoleak Classification

• Type Iperigraft
• Persistent flow at proximal or distal attachment
  sites
• Type IIretrograde flow from side branches
• Inferior mesenteric or lumbar arteries
• Subgroup A inflow only B in and outflow
• Type IIIgraft defect
• Type IVgraft porosity
• Primary or secondary

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Changes in Aortic Morphology

• Aneurysm diameter
• Growth in size associated with persistent
  endoleak
• Neck size
• Annual expansion 0.7mm 1st year, 0.9mm 2nd year
• May lead to migration and late endoleaks
• Aneurysm length
• Shortens gt5mm in 68 patients at 12mos
• Associated with kinking and dislocation

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EAAA in 2004

• There are many new grafts available, now they are
  Second Generation
• Data from EUROSTAR (4000 patients)
• Newer grafts have better 3-year mortality
• Fewer secondary interventions
• Fewer conversions of open repair
• Fewer graft rupture
• Shorter hospital stay

Torella et. al. 2004
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Summary

• Endograft AAA repair is still a developing field
  with promise
• Certain patient populations may benefit
• Long term trials are ongoing
• Lot of Baby-Boomers will need AAA repair
• STAY TUNED!