Transcript How is an Abdominal Aortic Aneurysm

Aortic Aneurysm
Hendro Sudjono Yuwono MD PhD
Sub-Dept.Vascular Surgery
Dept.Surgery UNPAD/RSHS
Anatomy
Abdominal aorta:
normal Ø 16-22 mm
Common Iliac
artery:normal Ø half
of aorta.
Artery: palpation
Abdominal aorta
Abdominal Aortic Aneurysm (AAA)
64 years old male
Head
AAA
Head
Aortic (Ao) Aneurysm
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Aneurysm: abnormal dilatation of artery or vein. Ao
aneurysm- abn.dilatation of Ao.
Mostly involve Aorta esp.Abd.Ao or Iliac
Other arteries: popliteal,femoral,subclavian, splenic,
carotid, circulus of Willis.
Most aneurysms are 2ndary to atheromatous
degeneration; other types: infected (syphilitic, mycotic,
salmonella, staphylococcus), post-stenotic, posttraumatic, .
True anerysm:the aneurysm wall is the vessel itself.
False aneurysm: the aneurysm wall is surrounding
connective tissue.
Pathophysiology
Predisposing Factors to abdominal aortic aneurysm formation
Inadequate vasa vasorum
Fewer elastic lamellae: elastase >>,
smoking circulating proteolytic activity
Reflected pressure waves
Calcification
Multifactorial development of arterial
aneurysm
Genetic abnormality
Aging and natural degeneration
of Elastin
Atherosclerotic damage to
elastin and collagen
Increased proteolytic enzyme
activity
Abdominal Ao aneurysm
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Incidence:
2% of population over age of 50 years
Mostly elderly males (♂:♀=4:1)
Etiology:
-majority are 2ndary to atherom deposit:atherosclerotic damage to elastin
and collagen.
-occasionally autoimmune inflammatory aneurysm (e.g.vasculitis
Takayasu)
-intrinsic weakness in the aortic wall. -Copper defficiencydecreases
collagen
-genetic predisposition: lower amounts of type III collagen
-smoking: circulating proteolytic activity >>, As in COPD-impaired
pulmonary elasticity, proteolytic>, lower antielastase activity.
-hypertension.
Aortic Atherosclerotic development
Abdominal Ao aneurysm
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Pathology: -Most begin a few cm bellow origin of Renal arteries
-Occasionally extend above renal arteries: Thoraco-abd.aneurysm occurs
-Often contain organising thrombus.
-Inflammatory aneurysm may be stuck to adjacent retroperitoneal structures,
inflammation and fibrosis extends to the adventitial layer and to surrounding tissue in aortic
bed.
-Atheromal deposit within aortic wall.
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Complications:
-rupture with massive retroperitoneal bleeding.
-Thrombus formation with distal embolism  ‘blue toe syndrome’
-Distal arteries occlusion
-Aorto-Caval Fistula with high output cardiac failure.
-Aortoenteric fistula especially into duodenum
Ao-Caval Fistula
Abdominal Ao aneurysm
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How is an Abdominal Aortic Aneurysm
(AAA) detected?
An aneurysm may be detected during routine
abdominal examination, but many cannot be
felt. Or may be diagnosed by chance when
they are examined for another problem.
Occasionally, a patient may become aware of
a feeling of pulsation in the abdomen. On
rare occasions, a lump can be visible.
Dissecting Aneurysm
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Usually begin with an intimal tear, often in the
ascending aorta allowing blood to enter the
medial layer and track within
De Bakey classification Ao dissection
Abdominal Ao aneurysm
Treatment
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Not all aneurysms need an operation. The risk of rupture and
therefore the need for an operation depends on the size of the
aneurysm (the risk of rupture increases as the aneurysm gets
bigger).
If the aneurysm is large (Ø more than 55mm, but may be less), it
may be safer to have an operation to repair it than to leave it
alone.
Because the operation itself carries some risk, the exact size at
which your surgeon will advise an operation will also depend on
any other health problems that you may have. For instance, if
you have heart, lung, or kidney problems an operation may be
more risky for you than for some other patients.
Once repaired, the risk of rupture disappears !
Abdominal Ao aneurysm
Treatment
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Ideally, an operation is advised when the threat of the
aneurysm bursting (which is usually fatal) is more than the
risk of an operation.
If your aneurysm is smaller than the size at which operation
is needed, your surgeon will arrange further ultrasound scans
(usually once a year) to monitor the rate of growth.
Aortic aneurysms generally grow slowly. At Ø >50mm (about
2 inches), the rate of growth is between 1-4mm per year.
When aneurysms are > than 50mm in diameter, the rate of
growth increases to 4-6mm per year.
If an aortic aneurysm ruptures, the chances of survival are
not good. Overall only 2 in 10 will survive. Half the patients
with aortic rupture will die before they reach hospital.
Abdominal Ao aneurysm
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Treatment:
Indication of surgical treatment (operation):
-Aortic Ø > 3-4 cm, with abdominal pain
-Rupture (or leakage) : symptoms & signs: sudden abdominal
pain, subconyunctiva becomes pale, shock (blood pressure 7080/0).
-Techniques: cito laparotomy, proximal and distal clamping,
changes the aortic aneurysm with dacron prosthetic graft.
False aneurysm
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Normal wall
Leakage part of the wall
Fatal rupture
Proximal and distal control
using vascular clamps
Proximal control
Leakage
Distal control
Dacron