Occlusion and stenosis of unsp posterior cerebral artery

This code signifies a blockage or narrowing within a posterior cerebral artery, the specific branch of which is not documented. This condition restricts blood flow to the occipital lobe, thalamus, and parts of the temporal lobe, potentially leading to visual disturbances, sensory deficits, or memory issues.

Apply this code when documentation indicates an occlusion or stenosis of a posterior cerebral artery, but the specific segment (e.g., P1, P2, P3) is not identified. This is appropriate for diagnoses like "posterior cerebral artery stenosis, unspecified" or "occlusion of PCA, site unknown."

• Ensure the documentation explicitly states "unspecified" or lacks detail regarding the specific posterior cerebral artery segment.
• Distinguish from codes for specified segments (e.g., I66.21-I66.23) if more precise information is available.
• Always sequence this code after any acute cerebrovascular event (e.g., I63.x) if it represents a sequela or underlying cause.