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Aortic Aneurysm G039

Document
Last amended 
11 July 2017
Current RMA Instruments
Reasonable Hypothesis SOP
9 of 2012
Balance of Probabilities SOP
10 of 2012
Changes from previous Instruments

SOP Bulletin 156

ICD Coding
  • ICD-9-CM Codes: 441.1 – 441.9
  • ICD-10-AM Codes: I71.1 – I71.6, I71.8, I71.9
Brief description

An aortic aneurysm is a localised enlargement of the aorta (the main artery from the heart) due to dilatation (expansion) of the aortic wall.  Two thirds occur in the abdominal aorta with the remainder in the thoracic aorta (in the ascending or descending part, or the arch).

Confirming the diagnosis

The diagnosis may be provisionally made on physical examination, but requires confirmation by imaging (ultrasound, CT scan or MRI).  In true aneurysms there is at least a 50% increase in diameter compared to the expected normal diameter, with involvement of the full thickness (all three layers) of the aortic wall.

The relevant medical specialist is a vascular surgeon.

Additional diagnoses covered by SOP
  • Abdominal aortic aneurysm
  • Ruptured aortic aneurysm
  • Thoracic aortic aneurysm
Conditions not covered by SOP
  • Non-aneurysmal aortic atherosclerotic disease*
  • Dissection of the aorta# (see comments below)
  • False (pseudo) aneurysm of the aorta# (see comments below)

* Another SOP applies

# Non-SOP condition

Clinical onset

The condition is most commonly asymptomatic and found incidentally by physical examination or imaging.  Large aneurysms may produce pain in the abdomen, chest, or back, or symptoms due to compression of adjacent structures.  An aneurysm can present initially with rupture, resulting in a medical emergency or sudden death.

Clinical worsening

The natural history of an aortic aneurysm is for progressive expansion to occur.  Specialist opinion will generally be required to identify if there has been worsening beyond the normal course of the disease.  Treament in most cases is conservative, with elective surgery reserved for aneurysms of large size or high risk of rupture. 

Comments
  • True aortic aneurysm – involves bulging of all three layers of the aortic wall.
  • Dissecting aortic aneurysm – involves separation of the layers of the aortic wall,allowing blood to leak between the layers.
  • Pseudo or false aortic aneurysm - blood leaks out of the aorta but is confined next to the vessel by surrounding tissue.  Due to trauma, atherosclerosis or infection.