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ICD-10-CM 2027 diagnosis code

I66.2Occlusion and stenosis of posterior cerebral artery

Not billable — use a more specific code

I66.2 is a header code, so it can't be reported by itself. Choose one of the 4 more specific codes beneath it.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About I66.2

I66.2 is the ICD-10-CM diagnosis code for occlusion and stenosis of posterior cerebral artery. It belongs to category I66 (occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction), block I60-I69 (cerebrovascular diseases) and chapter 9 (diseases of the circulatory system). It is a header code, so it can't be reported by itself; one of its 4 subcodes must be used instead.

Within I66 (occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction), I66.2 is specifically for occlusion and stenosis of posterior cerebral artery. Related codes cover middle cerebral artery (I66.0), anterior cerebral artery (I66.1), cerebellar arteries (I66.3), other cerebral arteries (I66.8) and unspecified cerebral artery (I66.9).

To report this condition, pick the subcode that matches the documentation: I66.21 (artery), I66.22 (artery), I66.23 (arteries) and I66.29 (artery).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Specific codes under I66.2

Notes that apply from higher levels

Instructions written at a parent level also apply to I66.2.

› From I66 Occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction
Includes
  • embolism of cerebral artery
  • narrowing of cerebral artery
  • obstruction (complete) (partial) of cerebral artery
  • thrombosis of cerebral artery
Excludes1
  • Occlusion and stenosis of cerebral artery causing cerebral infarction (I63.3-I63.5)

Broader instructions also apply from I60-I69 Cerebrovascular diseases and Chapter 9: Diseases of the circulatory system.

Alphabetic index entries

1 entries

Terms in the official ICD-10-CM index that lead to I66.2.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about I66.2

Is I66.2 billable?

No. I66.2 is a header code. Report one of its more specific subcodes instead.