ICD-10 Code I66.19 – Occlusion and stenosis of unspecified anterior cerebral artery (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I66.19 – Occlusion and stenosis of unspecified anterior cerebral artery
What it is
This code identifies a narrowing or blockage in an anterior cerebral artery, but the affected side is not specified. It refers to arterial cerebrovascular disease involving reduced blood flow in that vessel.
Clinical signs
Findings may include stroke or transient ischemic attack symptoms related to the anterior cerebral artery territory. Clinical features vary; refer to documentation for the exact neurologic deficits and laterality.
When to use this code
Use this code when the provider documents occlusion or stenosis of an anterior cerebral artery and does not identify the right or left side. It may also fit imaging-confirmed vascular narrowing or blockage when the record names the vessel but not laterality. Check documentation if the note is unclear.
Do not use for
Do not use this code for generalized cerebrovascular disease without a specified anterior cerebral artery finding. Do not use it when the documentation identifies a different artery or a different side-specific code.
Coding tip
Always confirm the artery and laterality in the report before assigning I66.19.