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I66.12

I66.12: Occlusion and stenosis of left anterior cerebral artery

Billable / specific codeICD-10-CMleft

I66.12 is a billable, specific ICD-10-CM code for occlusion and stenosis of left anterior cerebral artery. It is valid for submission on a claim.

Check I66.12 with the rest of the claim: free scrubber

Excludes1 inherited from the categories above I66.12

A category’s note binds every code beneath it.

Written on I66: Occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction

  • Occlusion and stenosis of cerebral artery causing cerebral infarction (I63.3-I63.5)

Risk adjustment

No CMS-HCC V28 category: this code does not change a RAF score.

Medicare coverage

I66.12 is named in 38 Medicare coverage policies: 38 listing it as supporting medical necessity. Which one applies depends on your Medicare contractor.

  • A52868Billing and Coding: Transesophageal Echocardiography (TEE)
  • A52992Billing and Coding: Non-Invasive Cerebrovascular Arterial Studies
  • A56423Billing and Coding: Cardiology Non-emergent Outpatient Stress Testing
  • A56476Billing and Coding: Cardiac Radionuclide Imaging

Code history

Unchanged in every release from FY2024 to FY2027.

Other codes under I66.1

ICD-10-CMFY2027· effective October 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release: see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.