2026 ICD-10-CM Diagnosis Code I65.1Occlusion and stenosis of basilar artery

ICD-10-CM Codes›I00–I99›I60-I69›I65

ICD-10-CM I65.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

I65.1 is a billable ICD-10-CM diagnosis code for occlusion and stenosis of basilar artery. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Occlusion or stenosis of precerebral or cerebral arteries without infarction.

Code Identity

ICD-10-CM Code
I65.1
Billable Status
Yes — Valid for Submission
Code Describes
Occlusion and stenosis of basilar artery
Short Description
Occlusion and stenosis of basilar artery
Same as the full description in the CMS dataset.
Parent Code
I65
Occlusion and stenosis of precerebral arteries, not resulting in cerebral infarction

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI60-I69Cerebrovascular diseases
CategoryI65Occlusion and stenosis of precerebral arteries, not resulting in cerebral infarction
This CodeI65.1Occlusion and stenosis of basilar artery

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Asymptomatic occlusion of artery
  • Asymptomatic occlusion of basilar artery
  • Asymptomatic stenosis of basilar artery
  • Asymptomatic stenosis of intracranial artery
  • Basilar artery embolism
  • Basilar artery occlusion
  • Basilar artery occlusion without infarction
  • Basilar artery stenosis
  • Basilar artery thrombosis
  • Occlusion of branch of basilar artery
  • Occlusion of distal basilar artery
  • Occlusive embolus of basilar artery
  • Pontine artery occlusion
  • Pontine artery thrombosis

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Embolism(multiple) (paradoxical)
      • basilar (artery)
    • Occlusion, occluded
      • artery
        • basilar

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR CIR023
Occlusion or stenosis of precerebral or cerebral arteries without infarction
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Vascular Diseases

Your vascular system is your body's network of blood vessels. It includes your:

The full article covers:

  • What are vascular diseases?
  • What causes vascular diseases?
  • Who is at risk for vascular diseases?
  • What are the symptoms of vascular diseases?
  • How are vascular diseases diagnosed?
  • How are vascular diseases treated?
  • Can vascular diseases be prevented?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert I65.1 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
433.00 Ocl bslr art wo infrct
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About I65.1Overview

Is I65.1 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report occlusion and stenosis of basilar artery on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What is the ICD-9 equivalent of I65.1?

Under the General Equivalence Mappings, occlusion and stenosis of basilar artery converts to ICD-9-CM 433.00 (ocl bslr art wo infrct). The mapping is a direct match.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.