All ICD10 Codes

I66

Non-Billable
ChapterI00–I99
Rankcategory
Official Description

Occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction

Use a more specific code (3 billable, 3 non-billable)
I66.0Occlusion and stenosis of middle cerebral arteryhas subcodesI66.1Occlusion and stenosis of anterior cerebral arteryhas subcodesI66.2Occlusion and stenosis of posterior cerebral arteryhas subcodesI66.3Occlusion and stenosis of cerebellar arteriesI66.8Occlusion and stenosis of other cerebral arteriesI66.9Occlusion and stenosis of unspecified cerebral artery
Metadata & Insights
  • •Non-billable category (requires more specific sub-code).
  • •Chapter 9: Diseases of the Circulatory System (I00-I99).

CH9 Parent Instructions

Excludes2(Not included here. Code separately if applicable.)
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
  • systemic connective tissue disorders (M30-M36)
  • transient cerebral ischemic attacks and related syndromes (G45.-)

I60-I69 Parent Instructions

Excludes1(Not coded here. Use a different code.)
  • 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)

Instructional Notes

Includes
  • embolism of cerebral artery
  • narrowing of cerebral artery
  • obstruction (complete) (partial) of cerebral artery
  • thrombosis of cerebral artery
Excludes1(Not coded here. Use a different code.)
  • Occlusion and stenosis of cerebral artery causing cerebral infarction (I63.3-I63.5)

Clinical Hierarchy

BillableHas subcodes
CH9Diseases of the circulatory system (I00-I99)
I60-I69Cerebrovascular diseases (I60-I69)
I66Occlusion and stenosis of cerebral arteries, not resulting in cerebral infarctionNot billable
I66.0Occlusion and stenosis of middle cerebral arterySubcodes
I66.1Occlusion and stenosis of anterior cerebral arterySubcodes
I66.2Occlusion and stenosis of posterior cerebral arterySubcodes
I66.3Occlusion and stenosis of cerebellar arteriesBillable
I66.8Occlusion and stenosis of other cerebral arteriesBillable
I66.9Occlusion and stenosis of unspecified cerebral arteryBillable

Applicable Ancestor Context

The following parent sections contain instructions or notes that apply to I66:

blockI60-I69
Cerebrovascular diseases (I60-I69)
View context instructions
chapterCH9
Diseases of the circulatory system (I00-I99)
View context instructions

MS-DRG Classification

2026

No direct MS-DRG triggers identified.

Cross Reference

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