CPT code 35691 represents an open vascular surgical procedure that exposes the vertebral artery, divides it, and anastomoses it to the carotid artery beyond an occlusive lesion to restore posterior cerebral blood flow. The code matters nationally because it describes a technically complex revascularization aimed at preventing ischemic events in patients with vertebrobasilar insufficiency or proximal vertebral artery occlusion, with implications for surgical capacity, hospital resource use, and specialty reimbursement.

Key payers in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise clinical context for the procedure, the typical site of service, and the service type. The publication provides benchmarks and coding guidance context, highlights common billing modifiers associated with complex surgical services, and summarizes payer coverage patterns where available.

This overview is intended for health policy analysts, hospital revenue cycle teams, and vascular surgery clinicians seeking a clear national summary of the code, its clinical purpose, and the areas to consider when reviewing reimbursement, utilization, and documentation practices. Data not available in the input will be noted where relevant.