I63.312

Billable

Cerebral infarction due to thrombosis of left middle cerebral 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 blocking the left middle cerebral artery in the brain, which is one of the major blood vessels supplying the brain.

Coding Tips

•Verify documentation specifies 'left' side and 'middle cerebral artery' to distinguish from other cerebral artery locations
•Ensure thrombosis (clot) is documented as the cause; if embolism or other mechanism, use different I63.3 subcategory

Clinical Significance

This code identifies an acute ischemic stroke caused by thrombosis (in-situ clot formation) of the left middle cerebral artery, requiring precise documentation of the clot mechanism. The middle cerebral artery supplies the lateral cerebral cortex including motor and sensory areas for the face and upper extremity, as well as language areas (Broca's and Wernicke's) in the dominant hemisphere. 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 middle cerebral artery
✓Documentation of laterality (left) 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., contralateral hemiparesis (face and arm worse than leg), hemisensory loss, and aphasia (dominant hemisphere) or neglect (non-dominant hemisphere))
✓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

I63.412 — Cerebral infarction due to embolism of left middle cerebral artery; use when the clot originated elsewhere rather than forming in situ 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 └I63.31Cerebral infarction due to thrombosis of middle cerebral artery └I63.312Cerebral infarction due to thrombosis of left middle cerebral artery

└I63.312Cerebral infarction due to thrombosis of left middle cerebral artery