MCMedicalCodingSoftware
Free trial
I66.1

I66.1: Occlusion and stenosis of anterior cerebral artery

Non-billable headerICD-10-CM

I66.1 is a non-billable header ICD-10-CM code for occlusion and stenosis of anterior cerebral artery. It cannot be billed on its own: choose one of the more specific child codes below.

Excludes1 inherited from the categories above I66.1

A category’s note binds every code beneath it.

Written on I66: Occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction

  • Occlusion and stenosis of cerebral artery causing cerebral infarction (I63.3-I63.5)

Risk adjustment

No CMS-HCC V28 category: this code does not change a RAF score.

Code history

Unchanged in every release from FY2024 to FY2027.

Code to one of these instead I66.1

4 child codes. Green means billable.

Other codes under I66

ICD-10-CMFY2027· effective October 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release: see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.