I66.12 – Occlusion and stenosis of left anterior cerebral artery

ICD-10-CM 2027 diagnosis code · Cerebrovascular diseases

Billable code

ICD-10-CM code I66.12
Code
I66.12 (claims format: I6612)
Description
Occlusion and stenosis of left anterior cerebral artery
Billable
Yes – valid for HIPAA-covered transactions
Valid for
Dates of service October 1, 2026 – September 30, 2027 (FY2027)
Chapter
9. Diseases of the circulatory system (I00-I99)
Block
I60-I69 Cerebrovascular diseases
Parent codes
I66 › I66.1

Notes inherited from parent codes

Instructional notes at a category or block level apply to every code below it.

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 (not coded here):
  • Occlusion and stenosis of cerebral artery causing cerebral infarction (I63.3-I63.5)

Block I60-I69

Excludes1 (not coded here):
  • traumatic intracranial hemorrhage (S06.-)
Use additional code:
  • code to identify presence of:
  • alcohol abuse and dependence (F10.-)
  • exposure to environmental tobacco smoke (Z77.22)
  • history of tobacco dependence (Z87.891)
  • hypertension (I10-I1A)
  • occupational exposure to environmental tobacco smoke (Z57.31)
  • tobacco dependence (F17.-)
  • tobacco use (Z72.0)

Related codes in I66.1

Frequently asked questions

What is ICD-10 code I66.12?

I66.12 is the ICD-10-CM code for occlusion and stenosis of left anterior cerebral artery, in the block I60-I69 (Cerebrovascular diseases).

Is I66.12 a billable code?

Yes. I66.12 is a billable/specific code that can be used to indicate a diagnosis for reimbursement purposes.

What category does I66.12 belong to?

It belongs to category I66 – Occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction.

Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.