CPT 35637 Aorto‑Iliac Bypass Reimbursement | OpenPayer

Summary & Overview

CPT 35637: Aorto-Iliac Bypass Using Synthetic Graft

CPT code 35637 denotes an open vascular surgery in which a synthetic graft connects the aorta to bypass a blocked iliac artery, restoring blood flow to the lower extremity. This procedure is a key intervention for advanced iliac occlusive disease and peripheral arterial disease when endovascular options are unsuitable or have failed. Nationally, the code is significant for tracking utilization of open aorto-iliac bypass procedures, surgical complexity, and resource use for major vascular reconstructions.

Key payers referenced in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find clinical context for when CPT code 35637 is used, typical sites of service, and how the procedure fits within treatment pathways for iliac artery disease. The publication provides benchmarks and comparative measures where available, outlines common billing and documentation considerations, and summarizes recent policy and coding guidance relevant to open aorto-iliac bypass procedures.

This overview is intended for clinicians, coding professionals, and payers seeking a concise reference to CPT code 35637, its clinical role, and the policy and operational considerations that influence billing and utilization nationally.

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Billing Code Overview

CPT code 35637 describes a surgical procedure in which a provider uses a synthetic graft to bypass an iliac artery blockage by rerouting the connection from the aorta around the obstructed segment of the iliac artery. This procedure is a form of arterial bypass grafting intended to restore blood flow to the lower extremity when iliac occlusive disease prevents adequate perfusion.

Service type: Vascular surgery — open arterial bypass with synthetic grafting

Typical site of service: Inpatient surgical suite or hospital operating room, often performed by vascular surgery teams. Data not available in the input.

Clinical & Coding Specifications

Clinical Context

A 68-year-old male with progressive right lower-extremity claudication, diminished distal pulses, and an ankle-brachial index of 0.6 is evaluated for revascularization. Cross-sectional imaging (CT angiography) demonstrates an aortoiliac occlusive lesion with significant stenosis of the right common iliac artery not amenable to endovascular therapy due to long-segment disease and heavy calcification. The vascular surgery team schedules an open aorto-iliac bypass using a synthetic graft under general anesthesia. Preoperative workflow includes vascular laboratory testing, cardiac risk assessment, informed consent discussing risks (bleeding, infection, graft thrombosis), preoperative antibiotics, and marking of laterality. Intraoperative workflow includes midline laparotomy or retroperitoneal exposure, proximal aortic control, distal iliac exposure, construction of the proximal aortic anastomosis, tunneling of the synthetic graft, distal anastomosis to the iliac artery beyond the obstruction, hemostasis, and closure. Postoperative management includes ICU or step-down monitoring, anticoagulation or antiplatelet therapy per protocol, wound care, vascular ultrasound surveillance, and follow-up for graft patency and limb function.

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	When billing only the physician professional component (rare for this open surgical procedure when technical and professional are bundled).

CPT 35646: Aorto-Femoral Bypass with Synthetic Graft

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

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

CPT-35601-CAROTID-COMMON-ARTERY-BYPASS-SYNTHETIC-GRAFT

CPT 35601: Common Carotid Artery 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-35671-POPLITEAL-TO-TIBIAL-PERONEAL-BYPASS-SYNTHETIC-GRAFT

CPT 35671: Popliteal to Tibial/Peroneal Bypass with Synthetic Graft

CPT-35602-CAROTID-TO-CAROTID-PROSTHETIC-ARTERIAL-BYPASS

CPT 35602: Carotid-to-Carotid Bypass Using Prosthetic Graft

CPT-35621-AXILLOFEMORAL-BYPASS-SYNTHETIC-GRAFT

CPT 35621: Axillofemoral Bypass Using Synthetic Graft

CPT-35631-AORTO-VISCERAL-RENAL-BYPASS-SYNTHETIC-GRAFT

CPT 35631: Aortic-to-Visceral/Renal Bypass with Synthetic Graft

CPT-35666-FEMORAL-TO-TIBIAL-OR-PERONEAL-BYPASS-SYNTHETIC-GRAFT

CPT 35666: Femoral-to-Tibial/Peroneal Bypass with Synthetic Graft

CPT-35663-ILIAC-ARTERY-CROSS-FEMORAL-BYPASS-SYNTHETIC-GRAFT

CPT 35663: Iliac Artery Cross-Femoral Bypass with Synthetic Graft

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Taxonomy Code	Specialty	Notes
207K00000X	Vascular Surgery	Primary specialty performing open aorto-iliac bypass procedures.
207L00000X	General Surgery	General surgeons with vascular expertise may perform this operation in some centers.
2080P0005X	Cardiothoracic–Vascular Surgery	Cardiac/vascular surgeons who provide complex aortic and iliac bypass procedures.
208000000X	Interventional Radiology	Typically performs endovascular alternatives; may be involved in hybrid procedures.
207RP1001X	Surgical Physician Assistant	May assist intraoperatively under surgeon supervision.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`I70.2`	Atherosclerosis of native arteries of the extremities	Common underlying pathology causing iliac artery occlusion requiring bypass.
`I70.31`	Atherosclerosis of native arteries of the extremities with intermittent claudication, right leg	Typical presentation prompting revascularization when lifestyle-limiting.
`I70.32`	Atherosclerosis of native arteries of the extremities with intermittent claudication, left leg	Left-sided clinical correlate when disease affects left iliac distribution.
`I74.3`	Embolism and thrombosis of arteries of lower extremities	Acute-on-chronic thrombotic events that may necessitate bypass if endovascular options not suitable.
`I70.23`	Atherosclerosis of native arteries of the extremities with rest pain	Severe ischemia indication for urgent revascularization.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`35631`	Extra-anatomic aorto-bifemoral bypass, graft, synthetic	Alternative or additional open bypass procedure when disease involves femoral targets or bifurcation.
`35566`	Extra-anatomic axillobifemoral bypass, graft; with prosthetic graft	Alternative bypass for patients who are not candidates for intra-abdominal aortic exposure.
`34825`	Aortofemoral bypass graft, with synthetic graft; single limb	Related open aorto-femoral reconstruction when disease extends to femoral arteries.
`36245`	Selective catheter placement, arterial system; each first order abdominal, pelvic, or lower extremity branch, with angiography	Used preoperatively or intraoperatively for diagnostic angiography of aortoiliac vessels.
`93925`	Duplex scan of arterial inflow and outflow, lower extremity, bilateral study	Noninvasive vascular testing performed pre- and postoperatively to assess disease and graft patency.
`99100`	Anesthesia for procedures on the vascular system (modifier for qualifying circumstances)	Represents anesthesia services; commonly used when reporting high-risk anesthesia circumstances for major vascular surgery.

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