I63.532

Billable

Cerebral infarction due to unspecified occlusion or stenosis 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 blocked or narrowed artery on the left side of the brain that supplies the back portion of the brain.

Coding Tips

•Confirm left-sided posterior cerebral artery occlusion or stenosis is documented before coding.
•Differentiate from bilateral involvement (I63.533) or unspecified side (I63.539).

Clinical Significance

This code identifies an acute ischemic stroke due to occlusion or stenosis of the left posterior cerebral artery where the specific mechanism (thrombosis versus embolism) is not documented. 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
✓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 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 when thrombosis is specifically documented I63.432 — Cerebral infarction due to embolism of left posterior 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 └I63.53Cerebral infarction due to unspecified occlusion or stenosis of posterior cerebral artery └I63.532Cerebral infarction due to unspecified occlusion or stenosis of left posterior cerebral artery

└I63.532Cerebral infarction due to unspecified occlusion or stenosis of left posterior cerebral artery