I63.432

Billable

Cerebral infarction due to embolism 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

•Confirm left-sided involvement is documented in imaging or clinical notes
•Distinguish from right-sided or bilateral posterior cerebral artery involvement

Clinical Significance

This code identifies an acute ischemic stroke caused by embolism (a clot originating from a distant source such as the heart or proximal vasculature) lodging in the left posterior cerebral artery. 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 embolism is the underlying mechanism, with workup for embolic source (echocardiogram, cardiac monitoring for atrial fibrillation, carotid evaluation)
✓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

I63.332 — Cerebral infarction due to thrombosis of left posterior cerebral artery; use for thrombotic rather than embolic 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 └I63.4Cerebral infarction due to embolism of cerebral arteries └I63.43Cerebral infarction due to embolism of posterior cerebral artery └I63.432Cerebral infarction due to embolism of left posterior cerebral artery

└I63.432Cerebral infarction due to embolism of left posterior cerebral artery