ICD-10 Code I66.21 – Occlusion and stenosis of right posterior cerebral artery (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I66.21 – Occlusion and stenosis of right posterior cerebral artery
What it is
This code identifies narrowing or blockage of the right posterior cerebral artery, a vessel that supplies blood to the occipital lobe and parts of the temporal lobe. Use it when documentation specifies the right side and the artery involved.
Clinical signs
Clinical features vary; refer to documentation. Findings may include visual field loss, visual disturbance, or other neurologic deficits consistent with posterior circulation ischemia.
When to use this code
Use I66.21 when the record clearly states occlusion or stenosis of the right posterior cerebral artery. It may appear in stroke workups, imaging reports, or specialist notes describing arterial narrowing or blockage. You should code the documented laterality and vessel exactly.
Do not use for
Do not use this code for nonspecific cerebrovascular disease or for occlusion of a different cerebral artery. If the documentation does not identify the right posterior cerebral artery, check documentation.
Coding tip
Match the code to the exact artery and side named in the report; laterality matters.