I63.349

Billable

Cerebral infarction due to thrombosis of unspecified cerebellar artery

HCC Category Mapping

V28HCC 249 — Ischemic or Unspecified Stroke

0.289

V24HCC 100 — Ischemic or Unspecified Stroke

0.262

ESRDHCC 100 — Ischemic or Unspecified Stroke

0.000

What This Code Means

A stroke caused by a blood clot in a cerebellar artery, but the specific side (right, left, or both) is not specified in the documentation.

Coding Tips

•Query the provider or review imaging reports to determine laterality before using this unspecified code
•This code should be used only when laterality cannot be determined despite documentation review

Clinical Significance

This code identifies an acute ischemic stroke caused by thrombosis (in-situ clot formation) of the unspecified cerebellar artery, requiring precise documentation of the clot mechanism. The cerebellar arteries (posterior inferior, anterior inferior, and superior) supply the cerebellum. Infarction can cause life-threatening posterior fossa swelling. Accurate coding of the mechanism, artery, and laterality is critical for risk adjustment and tracking stroke subtypes for quality measures and secondary prevention strategies.

Documentation Requirements

✓Provider documentation of acute cerebral infarction (stroke) as a confirmed diagnosis, not rule-out or suspected
✓Identification of the affected artery as the cerebellar artery
✓Documentation of laterality (unspecified) supported by clinical findings and/or imaging
✓Documentation that thrombosis (in-situ clot formation) is the underlying mechanism, typically supported by vascular imaging such as computed tomography angiography or magnetic resonance angiography
✓Neurological examination findings consistent with the identified vascular territory (e.g., acute vertigo, ataxia, dysarthria, nausea/vomiting, nystagmus, and risk of brainstem compression from cerebellar edema)
✓Brain imaging (computed tomography or magnetic resonance imaging) confirming acute infarction
✓Timing of symptom onset to confirm acute presentation
✓Documentation of stroke severity (National Institutes of Health Stroke Scale score preferred)
✓Treatment administered (thrombolytics, thrombectomy, antiplatelet therapy, anticoagulation)

Commonly Confused Codes

I63.449 — Cerebral infarction due to embolism of unspecified cerebellar artery; use for embolic rather than thrombotic mechanism I69.3xx — Sequelae of cerebral infarction; use for residual deficits from a prior stroke during follow-up visits, not during the acute event G45.9 — Transient cerebral ischemic attack, unspecified; use when symptoms resolve completely within 24 hours with no evidence of infarction on imaging

Code Hierarchy

└I63Cerebral infarction └I63.3Cerebral infarction due to thrombosis of cerebral arteries └I63.34Cerebral infarction due to thrombosis of cerebellar artery └I63.349Cerebral infarction due to thrombosis of unspecified cerebellar artery

└I63.349Cerebral infarction due to thrombosis of unspecified cerebellar artery