Occlusion and stenosis of left vertebral artery

This code signifies a narrowing or complete blockage of the left vertebral artery, a major blood vessel supplying blood to the brainstem, cerebellum, and posterior cerebrum. This condition can lead to vertebrobasilar insufficiency, causing symptoms such as dizziness, vertigo, ataxia, and visual disturbances.

Apply this code when documentation explicitly identifies an occlusion or stenosis affecting the left vertebral artery. This diagnosis is typically supported by imaging studies such as duplex ultrasound, CT angiography, or MR angiography, along with clinical findings consistent with vertebrobasilar compromise.

• Ensure laterality is clearly documented as "left" to avoid coding an unspecified or right-sided vertebral artery condition.
• Distinguish between occlusion (complete blockage) and stenosis (narrowing); this code covers both.
• Consider sequencing this code as a primary diagnosis if it is the reason for the encounter, or as a secondary diagnosis if it contributes to the patient's overall condition.