CPT 35508 Carotid-to-Vertebral Bypass Reimbursement | OpenPayer

Summary & Overview

CPT 35508: Carotid-to-Vertebral Artery Bypass Graft

CPT code 35508 represents an open surgical carotid-to-vertebral artery bypass graft used to restore vertebrobasilar perfusion by bypassing an occluded vessel. This complex vascular procedure is important nationally because it addresses high-risk cerebrovascular insufficiency where endovascular options may be limited or have failed. The code captures a resource-intensive operative service with implications for hospital utilization, surgical specialty billing, and payer medical necessity review. Key payers covered in the national analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will learn the clinical context for use of 35508, typical sites of service, and payer coverage patterns. The publication also summarizes common modifiers and documentation elements used in billing, discusses expected surgical service lines and specialties involved, and highlights benchmarking considerations and policy factors that affect prior authorization and reimbursement. Data not available in the input is indicated where applicable.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicare35508CPTcarotid-to-vertebral bypassvascular surgeryrevascularizationoperating roominpatient surgerycerebrovascular

Billing Code Overview

CPT code 35508 describes a surgical vascular bypass in which the provider bypasses an occluded vessel by inserting a graft that connects the common carotid artery to a portion of the vertebral artery. This procedure restores blood flow to vertebrobasilar circulation by creating an alternative conduit around a blockage.

Service type: Open vascular bypass grafting to revascularize vertebral artery circulation
Typical site of service: Hospital operating room or inpatient surgical setting

Clinical & Coding Specifications

Clinical Context

A typical patient is an adult with symptomatic posterior circulation ischemia due to proximal vertebral artery occlusion or severe stenosis not amenable to endovascular repair. The patient often presents with recurrent vertebrobasilar transient ischemic attacks (dizziness, diplopia, ataxia) or stroke despite optimal medical therapy. Diagnostic workup includes vascular imaging (CTA, MRA, or digital subtraction angiography) confirming a proximal vertebral artery lesion and assessment of carotid and subclavian anatomy to determine suitability for a carotid-to-vertebral bypass.

The clinical workflow begins with preoperative evaluation by a vascular surgeon or neurosurgeon including neurologic assessment, cardiac clearance, and discussion of risks. Perioperative planning includes cross-sectional and catheter angiography to map donor (common carotid) and recipient (vertebral) targets. In the operating room under general anesthesia, the surgeon exposes the common carotid artery and the vertebral artery segment, harvests or prepares a suitable graft (autologous vein or prosthetic), and constructs the bypass graft from the common carotid artery to the vertebral artery to restore posterior circulation flow. Postoperative care involves neurologic monitoring, antiplatelet or anticoagulation management, surveillance duplex or CTA, and rehabilitation as indicated.

Coding Specifications

Modifier	Description	When to Use
`00`	Default/No modifier	Standard billing when no modifier is required.

Related Codes

CPT-35565-ILIAC-TO-FEMORAL-VEIN-BYPASS

CPT 35565: Iliac-to-Femoral Vein Graft Bypass

CPT-35540-AORTO-BIFEMORAL-VEIN-BYPASS-GRAFT

CPT 35540: Aorto‑bifemoral Vein Bypass Graft

CPT-35535-HEPATIC-TO-RENAL-ARTERY-BYPASS-VEIN-GRAFT

CPT 35535: Hepatic-to-Renal Artery Bypass with Vein Graft

CPT-35571-POPLITEAL-TO-TIBIAL-PERONEAL-BYPASS

CPT 35571: Popliteal to Tibial/Peroneal Arterial Bypass

CPT-35521-AXILLARY-TO-FEMORAL-VEIN-BYPASS

CPT 35521: Axillary-to-Femoral Vein Bypass

CPT-35563-ILIAC-ARTERY-TO-ILIAC-ARTERY-VEIN-BYPASS

CPT 35563: Iliac-to-Iliac Artery Bypass with Vein Graft

CPT-35556-FEMORAL-TO-POPLITEAL-VEIN-BYPASS-GRAFT

CPT 35556: Femoral to Popliteal Vein Bypass Graft

CPT-35536-SPLENIC-TO-RENAL-ARTERY-BYPASS-VEIN-GRAFT

CPT 35536: Splenic-to-Renal Artery Bypass with Vein Graft

CPT-35572-FEMOROPOPLITEAL-VEIN-HARVEST-FOR-VASCULAR-RECONSTRUCTION

CPT 35572: Femoropopliteal Vein Harvest for Vascular Reconstruction

CPT-35570-TIBIAL-PERONEAL-ARTERY-BYPASS

CPT 35570: Tibial and Peroneal Artery Bypass Procedures

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Taxonomy Code	Specialty	Notes
`207SX0000X`	Vascular Surgery	Primary specialty performing extracranial-to-vertebral bypass procedures.
`207L00000X`	Neurosurgery	Performs complex cerebrovascular bypass and posterior circulation reconstructions.
`2080P0222X`	Thoracic and Cardiac Surgery	May be involved when vascular graft selection or complex neck-thoracic exposure is required.
`207RP1001X`	Interventional Radiology (Diagnostic)	Provides preoperative angiography and imaging guidance; not usually the operating surgeon.
`207VG0100X`	General Surgery	Some general vascular surgeons with this taxonomy perform carotid and vertebral bypasses.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`I65.29`	Occlusion and stenosis of left carotid artery	Carotid disease may coexist and influence selection of donor vessel and overall cerebrovascular perfusion planning.
`I65.21`	Occlusion and stenosis of right carotid artery	As above; donor vessel suitability assessment.
`I67.89`	Other cerebrovascular disease	Includes vertebrobasilar insufficiency presentations prompting bypass consideration.
`G45.8`	Other transient cerebral ischemic attacks and related syndromes	Recurrent TIAs of posterior circulation are a common indication for revascularization.
`I63.9`	Cerebral infarction, unspecified	Ischemic stroke in posterior circulation can be an indication when due to vertebral flow-limiting lesions.
`I77.6`	Arterial stenosis	General code reflecting focal arterial narrowing relevant to bypass planning.
`H53.8`	Other visual disturbances	Diplopia or visual symptoms may be manifestations of posterior circulation ischemia prompting intervention.
`R42`	Dizziness and giddiness	Symptom commonly associated with vertebrobasilar insufficiency leading to evaluation for bypass.

If specific ICD-10 codes were supplied in the input they would be reported above.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`61645`	External carotid artery to posterior circulation bypass (hypoglossal-facial bypass not otherwise classified) — Note: placeholder for specialized cranial bypass codes	Data not available in the input.
`36215`	Selective catheter placement, vertebral artery, unilateral, with angiography; radiological supervision and interpretation	Commonly performed preoperatively for diagnostic digital subtraction angiography to delineate vertebral lesions and collateral flow.
`36216`	Selective catheter placement, bilateral vertebral arteries, with angiography; radiological supervision and interpretation	Used when bilateral vertebral imaging is required for operative planning.
`35301`	Bypass graft, femoral-popliteal, single segment; this is an example of peripheral bypass technique coding	Represents conceptually similar bypass graft techniques; not the same anatomic site but relevant to graft selection and technique coding.
`31725`	Ligation of thoracic great vessel (example thoracic vascular procedure)	Represents related thoracic vascular procedures sometimes necessary in complex multilevel reconstructions.

Note: If a related CPT code list was provided in the input it would be listed above. The table above identifies commonly associated diagnostic angiography and conceptually related bypass procedure codes used in preoperative or adjunctive care workflows.