Abdominal aort anevrizması
Abdominal aort anevrizması
Doç Dr Evren Özçınar
Ankara Üniversitesi Kalp ve Damar Cerrahisi ABD
• Aneurysma a widening “
• Most common true aneurysm
• 15th leading cause of death in US
• 40,000 AAA repair annually in US
• RAA 8,500 hospital deaths yearly
– Underestimates incidence by 50%
• >50% diameter of aorta (best definition)
• 5% suprarenal
• 25% iliac involvement
• Juxtarenal : require suprarenal clamping
• Avg aortic diameter
• – 28mm thoracic
• – 20mm infrarenal
• >3cm aorta Considered aneurysmal
• >1.8mm iliac considered aneurysmal
• Computer models suggest asymmetry increases rupture risk
• 10% 20% have blebs/ outpouchings
• PATOGENESİS
• Originally considered atherosclerotic
• – Fails to differentiate from occlusive
• disease
• Etiology more accurately described as:
• – Degenerative or Non Non-specific
• concept centers on matrix proteins
• Aortic Wall contains concentric layers of smooth muscle, elastin and collagen
• Elastin principal load bearing element
• that resistes aneurysm formation
• Collagen acts as “safety net net” to
• prevent rupture after aneurysm forms
• Elastin
• – not synthesized in adult aorta
• – half half-life of 40 40-70 years
• Aorta has reduction in # of medial
• elastin layers from chest to infrrenal
• 58% less elastin in infra-renal aorta
• compared to thoracic aorta
• Aortic Wall contains concentric layers of smooth muscle, elastin and collagen
• Elastin principal load bearing element
• that resistes aneurysm formation
• Collagen acts as “safety net net” to
• prevent rupture after aneurysm forms
• Elastin
• – not synthesized in adult aorta
• – half half-life of 40 40-70 years
• Aorta has reduction in # of medial
• elastin layers from chest to infrrenal
• 58% less elastin in infra-renal aorta
• compared to thoracic aorta
• Increased matrix metalloproteinases in
• infra infra-renal aorta in wall of AAA
• – MMP MMP-9 : primary elastolytic enzemy
• – 3 fold increase in MMP MMP-9 in larger
• aneurysms (5 5-7cm)
• – Animal studies suggest Doxycycline may
• inhibit MMP activity
• Auto-immune mechanism
• Immunoreactive protein disproportionately
• expressed in abdominal aorta
• Aortic aneurysm antigenic protien (AAAP AAAP-40)
• is a microfibril associated autoantigen found
• in abdominal aorta
• Defective fibrillin and poor microfibillar
• intregrety causes Aneurysms in Marfan Marfan’s
• syndrome
• Chlamydia Pneumonia
• Additional etiologic considerations :
• – Absence of vasa vasorum in infra infra-renal
• AAA decreases nutrient supply and
• potentiate degradation
• Reflected waves from aortic bifurcation result in increased wall tension
• Diagnosis
• Ultrasound
• – Inexpensive, fast,safe
• – Diameter measurements
• İnterobserver variability <5mm in 85%
• – Cannot asses prox prox/dist extent
• -Underestimates size 2mm 2mm-4mm
• CTA
• – Radiation & contrast
• exposure
• – 91% <5mm
• İnterobserver varibility
• – Procedure planning
• – Examines entire abdomen
• MRI
• – Expensive
• Suitable for screening
• – Long latency period
• – Detectable at early stage
• – Disease more treatable at early stage
• – Test is accurate,inexpensive, safe and painless
• Treatment
• Periopterive management
• – Pre Pre-operative Antibiotics
• – Beta Beta-blockade
• – Bowel prep
• – Intravenous, arterial access, foley
• – Cardiac screening
• – Pulmonary artery catheter
• – Cell Saver
•