I63.40

HCC Category Mapping

What This Code Means

A stroke caused by a blood clot that traveled from elsewhere in the body and lodged in a cerebral artery, but the specific artery is not identified.

Coding Tips

• •Query the provider to identify which cerebral artery is affected to assign a more specific code
• •Review imaging reports and clinical documentation to determine the location of the embolism

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 unspecified other cerebral artery. This code covers cerebral arteries not individually classified, including smaller or variant vessels. 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 other cerebral artery
• ✓Documentation of laterality (unspecified) 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., variable neurological deficits depending on the specific vascular territory involved)
• ✓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