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

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