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Non-Aneurysmal Aortic Atherosclerotic Disease G003

Last amended 
29 June 2015
Current RMA Instruments:
Reasonable Hypothesis SOP
15 of 2012
Balance of Probabilities SOP
16 of 2012
Changes from Previous Instruments:

SOP Bulletin 157

ICD Coding:
  • ICD-9-CM Codes: 440.0,444.0,444.1
  • ICD-10-AM Codes: I70.0, I74.0

For this SOP the presence of atherosclerosis in itself is not sufficient.  There must be clinical manifestations.  This SOP applies to the abdominal aorta only for atherosclerotic occlusion, but to any part of the aorta for a penetrating ulcer (i.e. the ascending, arch, descending (thoracic) or abdominal aorta).

Is specific diagnostic evidence required to apply the SOP?Yes.

Imaging evidence is required to establish the presence of atherosclerosis.

Are there sub-factors that require specific information? – No.
Additional diagnoses covered by SOP
  • Penetrating ulcer of the aorta
Conditions not covered by SOP
  • Aortic aneurysm, ICD codes 441.1-441.9
  • Asymptomatic atherosclerosis of the aorta (N.I.F.)
Unconfirmed diagnosis

If, after applying the above information, you are unable to confirm the diagnosis, you should then:

  1. seek medical officer advice about further investigation, or;
  2. generate a diagnostic report, or;
  3. re-encode the condition, if appropriate.

The following investigations may be useful in establishing the diagnosis.

  • A report from a vascular surgeon
  • Arteriography, CT or MRI report
Classification Tree:

Atherosclerosis is a large blood vessel arterial disease which can cause obstruction of blood flow and subsequent ischaemic damage to the end organs supplied by the affected blood vessels.

Atherosclerosis involves the deposition of cholesterol in inner most wall of the artery (intima), which leads to inflammation associated with fibrosis and calcium deposits.  This provides the appearance in the vessel wall of porridge (athero-) with hard flakes (-sclerosis), which gives the disease its name of atherosclerosis.

The atherosclerosis affects the blood vessels by acting as a space occupying lesion within the blood vessel wall, progressively with time, encroaching on the lumen of the artery. Additionally atherosclerosis can cause complications of in situ thrombosis overlying an atherosclerotic plaque, an aneurysm, or embolism of plaque or thrombosis.

Local vessel effects of atherosclerosis:
  • Lumen:
    • Thrombosis
    • Embolism – of plaque; of in situ thrombosis.
    • Nidus (nest) – for infective organisms.
  • Wall (mural)
    • obstruction – stenosis, occlusion.
    • weaken wall – dissection; aneurysm.
End organ effects of atherosclerosis:
  • Transient reversible ischaemia.
  • Infarction – death of tissue due to insufficient blood supply.

End organ damage normally manifests as decreased function of the end organ and or pain (angina).

The atherosclerotic RMA instruments are:

  • Brain – Cerebrovascular accident (brain organ ischaemic manifestations); Vascular dementia (brain organ ischaemic manifestations.
  • Eye – retinal vascular disease (requires eye end organ manifestations)
  • Carotid artery – Carotid arterial disease (requires decreased blood flow manifestations)
  • Aortic arch – Aortic aneurysm & Non-aneurysmal aortic atherosclerotic disease (Only for penetrating ulcer)
  • Coronary arteries - Ischaemic heart disease (requires heart end organ ischaemic manifestations)
  • Thoracic aorta – Aortic aneurysm & Non-aneurysmal aortic atherosclerotic disease (Only for penetrating ulcer)
  • Upper limb arteries – Atherosclerotic peripheral vascular disease (requires decreased blood flow manifestations)
  • Mesenteric arteries – Non-SOP.
  • Abdominal aorta – Aortic aneurysm & Non-aneurysmal aortic atherosclerotic disease (requires decreased blood flow manifestations)
  • Renal artery – renal artery atherosclerotic disease (requires renal end organ manifestations)
  • Lower limb arteries – Atherosclerotic peripheral vascular disease (requires decreased blood flow manifestations)

General risk factors for atherosclerosis are:

  • Family history
  • Increasing age
  • Smoking
  • Hypertension
  • Dyslipidaemia – High cholesterol; High LDL, low LDL.
  • Diabetes mellitus (both types)
  • Sedentary lifestyle
  • Obesity
  • Hyperhomocysteinaemia
  • Chronic renal disease
  • Periodontitis
  • Ionising radiation to the blood vessel
Additional SOP word definitions:

Aneurysm – dilated artery. A dilated vein is called a varix with the plural being varices.

Aorta – ascending, arch, thoracic, and abdominal parts. The descending aorta includes the thoracic and the abdominal parts.

Claudication – lameness in the limbs due to ischaemia. Literally claudication means limping. It is often used in relation to the lower limbs where the claudication is originally intermittent associated with increased physical activity, and then with progression of time the claudication can be present at rest.

Dyslipidaemia – this means an abnormal lipid or fat level in the blood and in the case of atherosclerosis chiefly refers to an abnormality of blood cholesterol and cholesterol carriers in the blood being LDL [light density lipoprotein] and HDL [high density lipoproteins]. Atherosclerosis risk factor is associated with an elevated blood total cholesterol, low HDL and high LDL. This is the lipid profile.

Haemodynamic instability – This is vascular shock.

Intima – the innermost layer of the artery. The blood vessel is composed of intima (inner layer), media (middle layer) and adventitia (outer layer).

Intramural – means inside the wall of the blood vessel.

Mural – wall of the blood vessel.

Occlusion – Obstruction of the blood vessel either partial or total.