I63.521

Billable

Cerebral infarction due to unspecified occlusion or stenosis of right anterior 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 narrowing or blockage of the right anterior cerebral artery, which supplies the front and inner portions of the brain.

Coding Tips

•Confirm right-sided involvement is documented; anterior cerebral artery involvement may present with lower extremity weakness
•Distinguish from middle cerebral artery involvement, which has different clinical presentations

Clinical Significance

This code identifies an acute ischemic stroke due to occlusion or stenosis of the right anterior cerebral artery where the specific mechanism (thrombosis versus embolism) is not documented. The anterior cerebral artery supplies the medial surfaces of the frontal and parietal lobes, including the motor and sensory cortex for the lower extremity. 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 anterior cerebral artery
✓Documentation of laterality (right) supported by clinical findings and/or imaging
✓If the mechanism (thrombosis vs. embolism) can be determined from imaging or clinical workup, a more specific code should be assigned
✓Neurological examination findings consistent with the identified vascular territory (e.g., contralateral leg weakness greater than arm weakness, personality changes, urinary incontinence, and abulia)
✓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

I63.321 — Cerebral infarction due to thrombosis of right anterior cerebral artery; use when thrombosis is specifically documented I63.421 — Cerebral infarction due to embolism of right anterior cerebral artery; use when embolism is specifically documented 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 └I63.5Cerebral infarction due to unspecified occlusion or stenosis of cerebral arteries └I63.52Cerebral infarction due to unspecified occlusion or stenosis of anterior cerebral artery └I63.521Cerebral infarction due to unspecified occlusion or stenosis of right anterior cerebral artery

└I63.521Cerebral infarction due to unspecified occlusion or stenosis of right anterior cerebral artery