Occlusion and stenosis of bilateral middle cerebral arteries

This code signifies a narrowing or complete blockage affecting both middle cerebral arteries, which are major blood vessels supplying blood to large parts of the brain. This condition can lead to cerebral ischemia or infarction if blood flow is significantly compromised.

Use this code when documentation explicitly states occlusion or stenosis impacting both the left and right middle cerebral arteries. This diagnosis is often made via imaging studies such as MRA, CTA, or cerebral angiography.

• Ensure documentation specifies bilateral involvement; otherwise, a unilateral code (I66.01 or I66.02) would be more appropriate.
• Distinguish between occlusion (complete blockage) and stenosis (narrowing); this code covers both.
• If an infarction (stroke) has occurred as a result, code the stroke first, then this code as an associated condition.