Date amended:
External
Statements of Principles
Current RMA Instruments

Reasonable Hypothesis SOP

54 of 2020

Balance of Probabilities SOP

55 of 2020

Changes from previous Instruments

ICD Coding
  • ICD-9-CM Codes: 433.10, 442.81, 440.8
  • ICD-10-AM Codes: I65.2, I70.8, I72.0, I77.0
Brief description

This SOP covers a range of conditions affecting the carotid arteries.  The most common form of disease is atherosclerosis, causing arterial narrowing or blockage.  Dissection and aneurysm of a carotid artery are also covered by the SOP.  Rarely, narrowing or blockage may result from another pathological process.  In all cases the condition must be severe enough to require treatment to warrant designation as a disease.  The SOP also concerns only disease of the carotid arteries themselves (common, internal and external) and not any downstream effects. If there has been a cerebrovascular accident, chronic vascular brain compromise, or a retinal infarction then the separate RMA instruments for cerebrovascular accident, vascular dementia, or retinal vascular disease should be applied.

Confirming the diagnosis

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

The relevant medical specialist is a general physician or vascular surgeon.

Additional diagnoses covered by SOP
  • Carotid artery aneurysm
  • Carotid artery dissection
  • Carotid artery stenosis
  • Carotid artery arteriovenous fistula
Conditions excluded from SOP
  • (Minor) carotid artery atherosclerosis not causing stenosis/occlusion sufficient to require treatment – not a disease or injury
  • Cerebrovascular accident* / stroke
  • Transient (cerebral) ischaemic attack* - CVA SOP

* another SOP applies

Clinical onset

The condition may be asymptomatic and be detected on medical examination.  There may be outcomes, in the form of downstream effects (such as transient ischaemic attacks), that lead to investigation and detection of the condition on imaging.  Vertigo and syncope (feeling faint) are not caused by carotid disease so do not indicate a clinical onset.

Clinical worsening

Worsening of carotid artery disease would require evidence of progression of narrowing, occlusion, dissection or aneurysm beyond the normal (appropriately treated) course.  The occurrence of a stroke or new development of TIAs or other ischaemic manifestations represent onset of that relevant disease or injury, not worsening of carotid artery disease.