Occlusion and stenosis of precerebral arteries, not resulting in cerebral infarction (I65) ICD-10-CM
The I65 code range covers occlusion and stenosis of precerebral arteries, not resulting in cerebral infarction with 14 ICD-10-CM diagnosis codes. 11 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
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.
Codes in the I65 Range 14 codes · 11 billable
- I65 Occlusion and stenosis of precerebral arteries, not resulting in cerebral infarctionNon-billable
- I65.0 Occlusion and stenosis of vertebral arteryNon-billable
- I65.01 Occlusion and stenosis of right vertebral artery
- I65.02 Occlusion and stenosis of left vertebral artery
- I65.03 Occlusion and stenosis of bilateral vertebral arteries
- I65.09 Occlusion and stenosis of unspecified vertebral artery
- I65.1 Occlusion and stenosis of basilar artery
- I65.2 Occlusion and stenosis of carotid arteryNon-billable
- I65.21 Occlusion and stenosis of right carotid artery
- I65.22 Occlusion and stenosis of left carotid artery
- I65.23 Occlusion and stenosis of bilateral carotid arteries
- I65.29 Occlusion and stenosis of unspecified carotid artery
- I65.8 Occlusion and stenosis of other precerebral arteries
- I65.9 Occlusion and stenosis of unspecified precerebral artery
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the I65 range.
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.
About the I65 Code Range
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.
Questions About This Page
How many billable codes are in the I65 range?
Of the 14 codes in this range, 11 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.
What does the I65 range classify?
The range classifies occlusion and stenosis of precerebral arteries, not resulting in cerebral infarction. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
