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  3. I00–I99
  4. I60-I69
  5. Occlusion and stenosis of precerebral arteries, not resulting in cerebral infarction (I65)

Occlusion and stenosis of precerebral arteries, not resulting in cerebral infarction (I65)

ICD-10 code I65 covers conditions involving the occlusion and stenosis of precerebral arteries that do not cause cerebral infarction. These codes specify blockages or narrowings in arteries like the vertebral, basilar, and carotid arteries before they enter the brain, which can impair blood flow but have not yet led to a stroke.

This category includes detailed codes such as I65.01 for occlusion of the right vertebral artery, also known by terms like “vertebral artery thrombosis” or “embolism of right vertebral artery,” and I65.22 for the left carotid artery, linked with synonyms like “carotid artery stenosis” and “carotid artery embolism.” These codes help clarify specific artery involvement, whether unilateral, bilateral, or unspecified. Knowing these synonyms and specific artery distinctions assists health coders in accurately assigning the correct ICD-10 code for precerebral artery occlusions or stenoses that have not progressed to a cerebral infarction (stroke). As these conditions can be asymptomatic or prodromal, recognizing them early through precise coding supports targeted monitoring and treatment planning.

Instructional Notations

Includes

This note appears immediately under a three character code title to further define, or give examples of, the content of the category.

  • embolism of precerebral artery
  • narrowing of precerebral artery
  • obstruction (complete) (partial) of precerebral artery
  • thrombosis of precerebral artery

Type 1 Excludes

A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.

  • insufficiency, NOS, of precerebral artery G45
  • insufficiency of precerebral arteries causing cerebral infarction I63.0 I63.2

Clinical Terms

The following clinical terms provide additional context, helping users better understand the clinical background and common associations for each diagnosis listed in this section. Including related terms alongside ICD-10-CM codes supports coders, billers, and healthcare professionals in improving accuracy, enhancing documentation, and facilitating research or patient education.

Carotid Artery Thrombosis

Blood clot formation in any part of the CAROTID ARTERIES. This may produce CAROTID STENOSIS or occlusion of the vessel, leading to TRANSIENT ISCHEMIC ATTACK; CEREBRAL INFARCTION; or AMAUROSIS FUGAX.