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

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, post-traumatic, .

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

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 defficiencydecreases 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

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.

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

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

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 aneurysmTreatment 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 aneurysmTreatment 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

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 70-80/0).

-Techniques: cito laparotomy, proximal and distal clamping, changes the aortic aneurysm with dacron prosthetic graft.

False aneurysm

Normal wall

Leakage part of the wall

Fatal rupture

Proximal and distal control using vascular clamps

Proximal control

Distal control

Leakage

Dacron