ICD-10 Code I66.1 – Occlusion and stenosis of anterior cerebral artery (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I66.1 – Occlusion and stenosis of anterior cerebral artery
What it is
I66.1 identifies narrowing or blockage of the anterior cerebral artery. Use it when documentation specifies this artery as the site of the occlusion or stenosis.
Clinical signs
Clinical features vary; refer to documentation. Findings may include acute neurologic deficits consistent with cerebral ischemia, but the code depends on documented vessel involvement rather than symptoms alone.
When to use this code
Use I66.1 when the provider documents occlusion or stenosis of the anterior cerebral artery, including imaging-confirmed arterial narrowing or blockage. It is appropriate for ischemic cerebrovascular disease involving that specific vessel. If the record does not name the artery, check documentation.
Do not use for
Do not use this code for hemorrhagic stroke, generalized cerebrovascular disease, or occlusion of a different cerebral artery. If the diagnosis is only suspected or unspecified, code according to the documented statement.
Coding tip
Match the code to the exact artery named in the record and confirm laterality or acuity details only if documented.