CPT code 35301 – Thromboendarterectomy by neck incision

Key takeaways

CPT code 35301 covers open thromboendarterectomy through a neck incision at the carotid, vertebral, or subclavian artery. Endovascular repairs use other codes.

The patch graft and any temporary shunt are bundled into 35301 and must not be coded separately.

TCAR and carotid artery stenting with embolic protection are both billed with CPT 37215, not 35301.

Bilateral cases take LT/RT with modifier 58 when staged, or modifier 50 for same-session surgery, depending on payer rules.

In 2026, 35301 carries 30.71 facility RVUs, worth about $1,025.74 nationally before geographic adjustment.

CPT code 35301: official descriptor and procedure overview

CPT code 35301 describes thromboendarterectomy, including patch graft when performed, carotid, vertebral, or subclavian artery, by neck incision. The American Medical Association, which maintains the CPT code set, places 35301 in the Surgery section under Cardiovascular/Arteries and Veins, within the endarterectomy code range.

The approach requirement matters most in practice. The code applies only when the surgeon removes plaque through an open incision in the neck. Any catheter-based or endovascular approach maps to a different code family, whatever the vessel.

What CPT 35301 covers: anatomical sites and procedure components

Three arterial sites are eligible under CPT code 35301, all accessed via the same cervical (neck) incision approach. Coders sometimes assume 35301 covers any endarterectomy performed near the neck, but it does not. The vessel and the approach must both match.

• Common and internal carotid artery: The most frequent use of 35301. The surgeon removes the atheromatous plaque from the carotid bifurcation or isolated internal carotid artery through a cervical incision.
• Vertebral artery: Endarterectomy of the proximal vertebral artery via a neck incision. Less common but still within scope when performed as an open procedure.
• Subclavian artery: Accessible via neck incision in certain anatomical configurations. Subclavian endarterectomy from a chest approach uses a different code family.

Patch graft bundling: When the surgeon closes the arteriotomy with a patch (bovine pericardial, Dacron, or saphenous vein), that service is included in 35301. No additional CPT code applies. The descriptor’s “including patch graft, if performed” wording sets this bundling rule, and payers enforce it.

Intraoperative shunting: Placement and removal of a temporary carotid shunt during CEA is also included in 35301. Shunting does not warrant a separate claim line.

What CPT 35301 does not include: exclusions and separate coding

CPT code 35301 excludes all endovascular approaches and all endarterectomies performed at sites outside the cervical vessels. These are among the most common miscoding sources in vascular surgery billing.

TCAR deserves special attention. It uses a neck incision, the same anatomical access as 35301, but the technique is endovascular. A stent is placed via catheter, with flow reversal for embolic protection. TCAR is therefore billed with CPT 37215, not 0075T or 35301. Submitting 35301 for a TCAR procedure is a frequent denial trigger in vascular coding.

CPT 35301 vs related codes: carotid endarterectomy and endarterectomy site selection

Choosing between 35301 and its neighboring codes takes two checks: how the artery was treated, then which vessel. The diagram below runs those checks in order, and the table after it covers the codes coders confuse most often.

Coders working across the 35301-35390 range can check diagnosis pairings in a CPT-to-ICD-10 crosswalk. Read it alongside the operative report to confirm the vessel, the approach, and whether the reoperation add-on applies.

Modifiers for CPT code 35301

CPT code 35301 uses modifiers to capture laterality, bilateral procedures, staged surgeries, and increased complexity. Modifier selection drives many denials, particularly on bilateral CEA cases, where payer rules differ.

Bilateral CEA: Same-session bilateral carotid endarterectomy is rare, but when it happens, modifier 50 on 35301 signals the bilateral procedure. CMS assigns 35301 bilateral surgery indicator 1, so Medicare pays 150% of the single-procedure amount. That’s 100% for the first side and 50% for the second.

Commercial payers handle bilateral cases differently, so check each payer’s bilateral surgery policy before submitting. For staged procedures, where each side is done in a separate session within the global period, add modifier 58 to the second claim. It marks a planned staged procedure and opens a new global period.

Documentation requirements for CPT 35301

Incomplete operative documentation is the leading cause of audit findings and downcoding on 35301 claims. The operative report must name the vessel, approach, technique, and graft use that support the code. A complete operative note is also what gets the claim paid on first submission.

• Vessel(s) operated on: Name the specific artery – common carotid, internal carotid, vertebral, or subclavian. Generic references to “the carotid” without specifying common vs internal can create ambiguity under audit.
• Incision site and approach: Confirm the neck incision explicitly. State that the procedure was performed via an open cervical approach. That wording supports 35301 over 37215.
• Plaque and thrombus description: Document the atheromatous plaque or thrombus encountered, its extent, and the degree of stenosis addressed. Payers and auditors use this to validate medical necessity.
• Patch graft material (if used): Record the patch type (bovine pericardial, Dacron, saphenous vein) and that it was used for arteriotomy closure. Although patch graft is bundled, its documentation prevents auditors from questioning whether a separately coded service occurred.
• Shunt use: Note whether an intraoperative shunt was placed and removed. Document the reason for shunting if used (e.g. EEG changes, stump pressure).
• Closure technique: Describe arteriotomy closure, primary or patch, and any hemostasis steps. Capturing these elements at the point of care keeps incomplete notes from reaching the billing team.

Prior authorization for 35301 typically requires submission of the carotid duplex ultrasound or CTA/MRA report showing the degree of stenosis. Medicare and most commercial payers apply the NASCET methodology for stenosis measurement. Keep imaging reports in the billing file and attach them proactively to prior auth requests.

ICD-10 diagnosis codes that support CPT 35301 medical necessity

Payers validate medical necessity for CPT code 35301 by checking the paired ICD-10-CM diagnosis code against local coverage determinations (LCDs). Pair 35301 only with the diagnosis code that reflects the documented operative indication, never one picked for billing convenience.

Asymptomatic stenosis: Medicare coverage for asymptomatic carotid stenosis typically requires stenosis of 60-70% or greater by NASCET methodology, per the MAC’s local coverage determination. Payers may also require a neurologist or vascular surgeon to attest that the risk/benefit analysis supports intervention. Coverage thresholds are jurisdiction-specific and change with annual updates. Check the applicable LCD and the patient’s eligibility before scheduling the procedure.

Medicare reimbursement rate for CPT 35301

CPT code 35301 is reimbursed by Medicare under the Physician Fee Schedule (MPFS), which is updated annually by CMS. Rates vary by location through the Geographic Practice Cost Index (GPCI). The CY 2026 values below come from the CMS relative value file. Use the CMS Physician Fee Schedule lookup to retrieve current rates for a specific locality and setting.

At the 2026 conversion factor of $33.4009, the 30.71 facility RVUs work out to a national rate of about $1,025.74. Surgeons in a qualifying APM use the $33.5675 factor instead, which gives about $1,030.86. Because CEA is performed in a facility, the facility rate is the standard reference for surgeon billing.

The facility bills separately for hospital overhead, supplies, and staff costs. The GPCI adjustment matters too. A vascular surgeon in a high-cost metro area receives noticeably more than the national average for the same code.

The 90-day global surgical package means that standard follow-up E/M visits within 90 days of the procedure date are bundled into the 35301 payment. Visits for unrelated conditions, significant new problems, or complications requiring a return to the OR may still be billed separately with the appropriate modifier.

Common denial reasons for CPT 35301 and how to avoid them

CPT code 35301 denials follow predictable patterns, and each one has a fix that happens before submission.

Our guide to medical billing denial codes lists the CARC reason codes payers typically attach to these denials. Appeal timelines vary by payer, so check your payer contract for deadlines.

For a medical necessity or documentation denial, attach the operative report, imaging, and prior auth documentation to the appeal. For coding errors, submit a corrected claim rather than an appeal where payer rules allow.

How claims management software prevents CPT 35301 denials

Many 35301 denials trace back to a claim assembled by hand. The coder reads the operative note in one system, keys the claim in another, and has to remember each payer’s modifier rules. A missing LT or RT modifier, or a TCAR case coded as 35301, slips through that handoff.

Practice management software like Pabau keeps the note, the codes, and the claim in one place. Its claims management software flags a missing modifier or an unsupported ICD-10 pairing before the claim leaves the practice. Clean claims then go out as 837 files through Pabau’s Claim.MD clearinghouse integration.

Payments come back as electronic remittance advice, so your team can match each 35301 payment against the expected facility rate. Denials are tracked by reason, so a repeat pattern points you to the operative note template instead of another round of appeals.

Get CPT 35301 claims right first time

Pabau checks 35301 modifiers and diagnosis pairings before submission, then sends clean claims through its Claim.MD integration. Your team spends less time on vascular surgery rework and appeals.

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Conclusion

A 35301 claim stands or falls on one line of the operative note: an open thromboendarterectomy through a neck incision. When that line is explicit and the vessel and side are named, the code holds up under audit.

The fixes worth making first are cheap. Add the approach, vessel, and patch material to your operative note template. Then route every TCAR and stenting case to 37215 before the claim form is opened.

The trade-off is a few extra fields for the surgeon to complete. Set against a facility payment of about $1,026 that one missing modifier can hold up for weeks, it pays for itself.

Book a demo to see how Pabau checks 35301 modifiers and diagnosis pairings before your vascular surgery claims go out.

Continue your research

Coding a TCAR or carotid stent instead? CPT code 37215 covers carotid artery stenting with embolic protection, including TCAR.

Need to understand how clearinghouse routing works for surgical codes? Medical claims clearinghouse guide explains how claims move from EHR to payer and where errors occur.

Want to reduce claim rework across your entire code set? Claim.MD clearinghouse overview covers the payer network, eligibility checks, and ERA processing Pabau uses.

Managing credentialing requirements alongside surgical billing? Getting credentialed with insurance companies covers the enrollment steps that unlock reimbursement for new vascular surgeons.

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