You are here

Carotid Arterial Disease G020

Last amended 
28 June 2015

Current RMA Instruments:

Reasonable Hypothesis
37 of 2012
Balance of Probabilities
38 of 2012
Changes from Previous Instruments:

SOP Bulletin 158

ICD Coding:
  • ICD-9-CM Codes: 433.10, 442.81, 440.8
  • ICD-10-AM Codes: I65.2, I72.0, I70.8

Carotid arterial disease is any arterial disease affecting the carotid arteries. This SOP concerns only the artery and not the downstream effects. If there was a cerebrovascular accident or a chronic vascular brain compromise or a retinal infarction then the separate RMA instruments for cerebrovascular accident, vascular dementia or retinal vascular disease should be utilised.

The presence of atherosclerosis in the carotid artery, not causing stenosis or occlusion sufficient to require treatment, is not covered by this SOP and is not a disease or injury(see further comments below).

Is specific diagnostic evidence required to apply the SOP? – No.

However, imaging, in the form of a duplex Doppler ultrasound, an MRI, a CT scan or an angiogram will generally be required to demonstrate the required pathology and loss of function.

Are there sub-factors that require specific information? – No.

However, note that the trauma factor (g)(i) is sided, so the carotid arterial disease which would be covered, is that pertaining to the side of trauma. Similarly there are some other factors which are locally specific and hence would only apply to the affected segment of artery.

Additional diagnoses covered by SOP
  • Carotid artery aneurysm
  • Carotid artery dissection
  • Carotid artery stenosis
Conditions excluded from SOP
  • Cerebrovascular accident / stroke, ICD-9-CM codes 434.01, 434.11
  • Transient (cerebral) ischaemic attack, ICD-9-CM codes 435
Unconfirmed diagnosis

If, after applying the above information, you are unable to confirm the diagnosis, you should then seek medical officer advice about further investigation.


The carotid artery supplies blood to the brain in conjunction with the two vertebral arteries. There are two carotid arteries anatomically sited on either side of the neck. The common carotid artery bifurcates at the level of the thyroid cartilage into the external carotid supplying blood to the face and the internal carotid continuing into the skull to supply the brain.

The left common carotid arises from the aortic arch where as the right common carotid arises from the brachiocephalic artery. This means that the left common carotid has part of the artery in the thoracic cavity where as the right carotid system begins behind the right sternoclavicular joint.

The scope of carotid arterial disease includes pathological effects of atherosclerosis but is not restricted to atherosclerosis.

Note, that for occlusion or stenosis due to atherosclerosis, dissection or another pathological process involving that artery the definition is restricted to disease which requires treatment (of the occlusion or stenosis).

  • Aneurysm – Oxford dictionary states ‘morbid dilatation of an artery’. A varix and varicose are morbid dilatations of vein and veins.
  • Dissection – This a tear of the inner most layer of the blood vessel (intima), with blood tracking between the intima and middle layer (media) causing a stenosis and occlusion of the internal blood flow. The ‘tracking blood’ acts as the surgical knife dissecting between the intima and media of the artery along the length of the blood vessel.
  • Occlusion – Oxford dictionary states ‘stop up, close, obstruct’. Though this does include stenosis, it is generally considered as a more severe form.
  • Stenosis – Oxford dictionary states ‘Narrowing of a passage in the body’.