ICD-10 Code I65.1: Occlusion and Stenosis of Basilar Artery
ICD-10 code I65.1 designates occlusion and stenosis of the basilar artery, a major vessel in the posterior circulation of the brain that supplies the brainstem, cerebellum, and posterior cerebral hemispheres 1.
Clinical Significance
The basilar artery is part of the vertebrobasilar system and represents a critical vascular territory. When this vessel becomes occluded or stenosed, it can lead to:
- Posterior circulation stroke with potentially devastating neurological consequences
- Brainstem ischemia affecting vital functions
- Cerebellar infarction
- Posterior cerebral artery territory involvement
Basilar artery occlusions are specifically noted in stroke literature as being associated with worse clinical outcomes compared to other vessel locations 2. This makes accurate identification and coding of basilar artery pathology particularly important for both clinical management and research purposes.
Coding Context
This code falls within the broader ICD-10-CM classification system:
- Chapter I65: Occlusion and stenosis of precerebral arteries
- I65.1 specifically: Basilar artery involvement
The ICD-10-CM system, which encompasses approximately 68,000 codes, provides more precise disease coding compared to its predecessor ICD-9 1. For stroke research and clinical documentation, ICD-10 codes have demonstrated high validity, with studies showing positive predictive values exceeding 90% for ischemic stroke identification when properly applied 3, 4.
Clinical Application
When documenting basilar artery disease:
- The code applies to both occlusion (complete blockage) and stenosis (narrowing)
- It should be used when imaging (CT angiography, MR angiography, or conventional angiography) confirms basilar artery involvement
- For acute stroke presentations, this would typically be combined with codes from the I63.x series (cerebral infarction) to fully capture the clinical picture
The location of vessel occlusion should be clearly defined in clinical documentation, as stroke guidelines recommend reporting outcomes by level of occlusion to allow meaningful comparison across studies and treatment approaches 2.