I63.332

Billable

Cerebral infarction due to thrombosis of left posterior 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 posterior cerebral artery, which supplies the back portion of the left side of the brain.

Coding Tips

•Ensure documentation clearly indicates 'left' side and 'posterior cerebral artery' location
•Differentiate from I63.331 (right) and I63.333 (bilateral) based on documented laterality

Clinical Significance

This code identifies an acute ischemic stroke caused by thrombosis (in-situ clot formation) of the left posterior cerebral artery, requiring precise documentation of the clot mechanism. The posterior cerebral artery supplies the occipital lobe, medial temporal lobe, and thalamus. Infarction in this territory affects vision and memory. 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 posterior 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 homonymous hemianopia, visual agnosia, memory deficits, and thalamic sensory loss)
✓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

I63.432 — Cerebral infarction due to embolism of left posterior cerebral 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 └I63.33Cerebral infarction due to thrombosis of posterior cerebral artery └I63.332Cerebral infarction due to thrombosis of left posterior cerebral artery

└I63.332Cerebral infarction due to thrombosis of left posterior cerebral artery