ICD-10 Code I65.1 – Occlusion and stenosis of basilar artery (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I65.1 – Occlusion and stenosis of basilar artery
What it is
I65.1 identifies narrowing or blockage of the basilar artery, a major vessel supplying the brainstem and posterior brain. Use it when the record documents atherosclerotic occlusion or stenosis of this artery.
Clinical signs
Clinical features vary; refer to documentation. Commonly reported findings may include symptoms of posterior circulation ischemia such as dizziness, diplopia, ataxia, weakness, or altered consciousness, supported by imaging or vascular studies.
When to use this code
Use this code when the provider documents basilar artery occlusion or stenosis as the diagnosis being managed or evaluated. It is appropriate for confirmed vascular narrowing or blockage, including incidental imaging findings if documented as clinically relevant. Code it from the chart, not from symptoms alone.
Do not use for
Do not use this code for nonspecific cerebrovascular symptoms without documented basilar artery disease. Check documentation if the condition is due to embolism, dissection, or another named vessel disorder, because a different code may apply.
Coding tip
Verify that the basilar artery is specifically named in the assessment or imaging report before assigning I65.1.