CPT 35645 Subclavian‑to‑Vertebral Bypass Reimbursement | OpenPayer

Summary & Overview

CPT 35645: Subclavian-to-Vertebral Artery Bypass with Synthetic Graft

CPT code 35645 represents a vascular surgical procedure that uses a synthetic graft to bypass an occlusion in a vertebral artery by creating a conduit from the subclavian artery around the blockage. This is a specialized revascularization technique used to restore posterior cerebral circulation when endovascular or native-artery repair is not feasible. The code matters nationally because it captures a high-acuity, operative intervention with implications for inpatient surgical utilization, vascular surgery reimbursement, and access to specialized perioperative care.

Key payers included in the discussion are Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the clinical context for the procedure, typical sites of service, and the kinds of reporting and benchmarking elements that payers commonly evaluate. The publication also outlines expected documentation elements tied to operative description and patient indications, and highlights where readers can expect variation across payers in authorization and coverage policies.

This summary prepares clinicians, coding professionals, and policy analysts to understand the clinical purpose of CPT code 35645, the settings where it is performed, and the payer landscape that affects authorization and claims handling.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicareCPT 35645vertebral artery bypasssubclavian arteryvascular surgerysynthetic graftinpatient surgeryrevascularizationoperative proceduresurgical codingarterial bypass

Billing Code Overview

CPT code 35645 describes a surgical bypass procedure in which a synthetic graft is used to reroute blood flow from the subclavian artery around an obstruction in a vertebral artery. The intent of the procedure is to restore adequate vertebral artery perfusion when native arterial flow is compromised.

Service Type: Surgical arterial bypass using synthetic graft

Typical Site of Service: Inpatient operating room or hospital-based vascular surgery suite, with perioperative hospitalization for monitoring and recovery.

Clinical & Coding Specifications

Clinical Context

A 68-year-old male with symptomatic vertebrobasilar insufficiency presents with recurrent transient ischemic attacks characterized by vertigo, diplopia, and ataxia despite optimal medical therapy, including antiplatelet agents and risk-factor control. Diagnostic vascular imaging (CT angiography or digital subtraction angiography) demonstrates significant atherosclerotic occlusive disease of the proximal vertebral artery with inadequate collateral flow and a patent ipsilateral subclavian artery.

The vascular surgery or neurovascular team evaluates the patient and determines that a surgical bypass from the subclavian artery to the vertebral artery using a synthetic graft is the appropriate revascularization strategy. Preoperative workflow includes vascular lab duplex, CTA/MRA or conventional angiography, cardiac risk stratification, and informed consent. In the operating room under general anesthesia, the surgeon exposes the subclavian and vertebral arteries, prepares a synthetic vascular conduit, and performs arterial anastomoses to bypass the occluded vertebral segment. Postoperative care includes monitored intensive care or step-down observation, antithrombotic management, duplex surveillance of the graft, and neurologic assessment prior to discharge. Typical site of service is an inpatient hospital operating room; ambulatory surgical center usage is uncommon due to the complexity and monitoring needs. Service type: open major vascular bypass procedure with prosthetic graft.

Coding Specifications

Modifier	Description	When to Use
`00`

CPT 35654: Axillary to Femoral Bypass Using Non-Vein Graft

CPT-35633-ILIAC-TO-MESENTERIC-ARTERY-BYPASS-SYNTHETIC-GRAFT

CPT 35633: Iliac-to-Mesenteric Artery Bypass with Synthetic Graft

CPT-35623-AXILLARY-TO-POPLITEAL-OR-TIBIAL-BYPASS-SYNTHETIC-GRAFT

CPT 35623: Axillary-to-Popliteal/Tibial Bypass with Synthetic Graft

CPT-35642-CAROTID-TO-VERTEBRAL-ARTERY-BYPASS-SYNTHETIC-GRAFT

CPT 35642: Carotid-to-Vertebral Artery Bypass with Synthetic Graft

CPT-35634-ILIAC-TO-RENAL-ARTERY-BYPASS-SYNTHETIC-GRAFT

CPT 35634: Iliac-to-Renal Artery Bypass Using Synthetic Graft

CPT-35600-ARTERIAL-GRAFT-HARVEST-ARM-FOR-CORONARY-BYPASS

CPT 35600: Arterial Graft Harvest from Arm for Coronary Bypass

CPT-35647-AORTO-FEMORAL-BYPASS-SYNTHETIC-GRAFT

CPT 35647: Aorto-Femoral Bypass with Synthetic Graft

CPT-35626-AORTIC-TO-SUBCLAVIAN-INNOMINATE-CAROTID-BYPASS-GRAFT

CPT 35626: Aortic-to-Subclavian/Innominate/Carotid Bypass with Synthetic Graft

CPT-35646-AORTO-FEMORAL-BYPASS-SYNTHETIC-GRAFT

CPT 35646: Aorto-Femoral Bypass with Synthetic Graft

CPT-35621-AXILLOFEMORAL-BYPASS-SYNTHETIC-GRAFT

CPT 35621: Axillofemoral Bypass Using Synthetic Graft

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Taxonomy Code	Specialty	Notes
2080R0004X	Vascular Surgery	Primary specialty performing open arterial bypass procedures.
2084P0800X	Neurological Surgery	May perform vertebral artery bypass in complex neurovascular cases.
207L00000X	Cardiothoracic Surgery	May be involved when proximal subclavian exposure requires thoracic expertise.
207K00000X	General Surgery (Vascular-focused)	General surgeons with vascular training may perform this bypass.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`I65.29`	Occlusion and stenosis of other cerebral arteries, not resulting in cerebral infarction	Commonly used for significant vertebral artery stenosis causing ischemic symptoms without completed stroke.
`I66.8`	Occlusion and stenic of other cerebral arteries, including vertebral, with cerebral infarction	Used when vertebral artery occlusion has resulted in cerebral infarction in the vertebrobasilar distribution.
`I67.6`	Nonpyogenic thrombosis of intracranial venous system	Included when thrombotic processes affect posterior circulation requiring revascularization (less common).
`G45.8`	Other transient cerebral ischemic attacks and related syndromes	Used for symptomatic vertebrobasilar TIAs prompting revascularization.
`I73.9`	Peripheral vascular disease, unspecified	May be used as a comorbidity code reflecting systemic atherosclerotic disease influencing management.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`36901`	Insertion of arterial sheath and catheter, arterial; for angiography, diagnostic	Performed preoperatively for diagnostic angiography or intraoperative catheter access if endovascular assessment is used.
`36247`	Selective catheterization, vertebral artery, unilateral, radiological supervision and interpretation	Used for diagnostic catheter angiography of the vertebral artery during preoperative planning or hybrid procedures.
`35566`	Endarterectomy, with patch graft, of other named arteries (e.g., subclavian)	Performed when concurrent subclavian artery disease requires endarterectomy during the same operative session.
`35820`	Arterial repair or reconstruction, with or without patch graft; extra-anatomic bypass	Related technique for arterial bypass or reconstruction in the cervicothoracic region.
`93975`	Duplex scan of extracranial arteries; complete bilateral study	Used preoperatively and postoperatively to assess vertebral and subclavian artery flow and graft patency.

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