I63.133 ICD-10-CM Code: Cerebral infarction due to embolism of bilateral carotid arteries
HCC Buddy Code Card
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FY 2026 Apr update / Diseases of the circulatory system (I00-I99) / Cerebrovascular diseases (I60-I69)
I63.133
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceCerebral infarction due to embolism of bilateral carotid arteries
A stroke caused by blood clots blocking both the right and left carotid arteries at the same time.
Buddy Insight
Cerebral infarction due to embolism of bilateral carotid arteries is an extremely rare and catastrophic stroke event where emboli block both carotid arteries, compromising blood flow to both cerebral hemispheres simultaneously.
CMS-HCC V28
MappedHCC 249
RAF 0.289
CMS-HCC V24
MappedHCC 100
RAF 0.262
ACA/HHS
00
RAF 0
ESRD/PACE
MappedHCC 100
RAF 0.0
RXHCC
00
RAF 0
Code Trumping
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Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for I63.133 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for I63.133 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for I63.133 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for I63.133 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for I63.133 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for I63.133 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for I63.133 in this effective period.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.
Is I63.133 an HCC code?
Yes. I63.133 maps to Ischemic or Unspecified Stroke under the CMS-HCC V28 risk adjustment model (and Ischemic or Unspecified Stroke under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for I63.133
For I63.133to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed I63.133 during that encounter, not just copy-forwarded from a problem list.
What This Code Means
I63.133 is the ICD-10-CM diagnosis code for cerebral infarction due to embolism of bilateral carotid arteries. A stroke caused by blood clots blocking both the right and left carotid arteries at the same time. I63.133 sits in the ICD-10-CM chapter for diseases of the circulatory system (i00-i99), within the section covering cerebrovascular diseases (i60-i69).
Under the CMS-HCC V28 risk adjustment model, I63.133 maps to Ischemic or Unspecified Stroke (HCC 249) with a community, non-dual, aged base RAF weight of 0.289. Under the older V24 model, I63.133 mapped to the same category but with a base RAF weight of 0.262, V28 recalibrated weights across the entire model. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
This is an extremely rare and severe presentation; confirm bilateral carotid involvement is clearly documented. Because I63.133 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for I63.133 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This is an extremely rare and severe presentation; confirm bilateral carotid involvement is clearly documented.
- •Ensure both arteries are affected by embolism and not just one artery with contralateral stenosis.
Clinical Significance
Cerebral infarction due to embolism of bilateral carotid arteries is an extremely rare and catastrophic stroke event where emboli block both carotid arteries, compromising blood flow to both cerebral hemispheres simultaneously. This condition is almost invariably associated with massive bilateral cerebral infarction and devastating neurological outcomes. It suggests a significant proximal embolic source and carries extremely high mortality.
Documentation Requirements
- ✓Imaging confirmation of bilateral cerebral infarction
- ✓Vascular imaging confirming embolic occlusion of both carotid arteries
- ✓Documentation explicitly stating bilateral carotid embolism
- ✓Comprehensive neurological examination documenting bilateral deficits
- ✓Emergent embolic source evaluation
- ✓Critical care documentation and prognosis discussion