ICD-10 Code I66.8 – Occlusion and stenosis of other cerebral arteries (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I66.8 – Occlusion and stenosis of other cerebral arteries
What it is
This code identifies narrowing or blockage of a cerebral artery that is not specifically named elsewhere in the category. Use it when documentation shows an affected brain artery, but the vessel is not one of the listed major arteries.
Clinical signs
Patients may present with stroke or transient ischemic attack symptoms such as sudden weakness, speech changes, or vision loss. Clinical features vary; refer to documentation for the specific artery involved and whether the event is acute or chronic.
When to use this code
Use I66.8 when the provider documents occlusion or stenosis of an “other” cerebral artery and does not name a more specific artery code. It is appropriate when imaging or clinical notes support arterial narrowing or blockage in the brain circulation. Check documentation if the vessel is unclear.
Do not use for
Do not use this code for carotid artery disease, vertebral artery disease, or cerebral infarction without documented occlusion or stenosis. If the note names a specific cerebral artery with its own code, use that code instead.
Coding tip
Confirm the artery name in the report; if the vessel is not specified, query the provider before assigning I66.8.