The Four Vascular Territories: Why Anatomy Has Become a Reimbursement Skill in 2026
The first article in this series argued that the 2026 Lower Extremity Revascularization overhaul delivered something bigger than 46 new CPT codes: it delivered 46 new documentation expectations. This article gets specific about where those expectations live: the four vascular territories that now organize every lower extremity intervention you report.
Territory assignment sounds like an anatomy refresher. It's actually a reimbursement decision, because each territory carries its own code family, its own bundling rules, and its own traps. One primary intervention code may be reported per territory, which means knowing where a territory begins and ends is now, quite literally, knowing what you can bill.
By the MD Billing Vascular Coding Team
A few ground rules apply everywhere before we walk the anatomy. Catheter placement is included in the intervention codes. So is all imaging, with ultrasound guidance (76937) still separately billable when documented. If a lesion crosses from one vessel into another, only one vessel is reported. Lesions themselves divide into straightforward (stenosis, a partial narrowing) and complex (occlusion, 100%), and that single distinction changes the code in every territory. IVUS (37252/37253) remains separately reportable, with pullback IVUS coded as a single unit of 37252.
Now, the territories, from inflow to toe.
Iliac territory (common, internal, and external iliac)
The iliac family covers angioplasty alone (37254 straightforward / 37256 complex, with add-on codes 37255 and 37257 for each additional artery) and stent with angioplasty (37258 / 37260, add-ons 37259 / 37261). Lithotripsy is an add-on here (37262), layered onto angioplasty. One quirk to flag for your coders: atherectomy in the iliacs still lives outside the new family entirely, reported with Category III code 0238T. A charge ticket that funnels iliac atherectomy into the new codes will be wrong all year.
Femoral-popliteal territory
Anatomically this territory contains several named vessels. For coding purposes it contains exactly two: the common femoral and profunda femoris count as *one* vessel, and the superficial femoral and popliteal count as *one* vessel. Documentation that treats them as four separate targets invites overreporting, and automated review will notice.
This is also the fullest code family: angioplasty alone (37263/37265), stent with angioplasty (37267/37269), atherectomy with PTA (37271/37273), and atherectomy with stent (37275/37277), each with additional-artery add-ons, and lithotripsy as add-on 37279 across the board. The straightforward/complex split runs through all of it, which makes the operative note's lesion characterization (stenosis percentage or documented occlusion) the highest-leverage sentence in the record.
Tibial-peroneal territory
Anterior tibial, posterior tibial, and peroneal arteries, coded through the 37280 to 37295 family across the same four intervention types. Two rules distinguish this territory. First, the tibioperoneal trunk is considered part of the posterior tibial or peroneal arteries and is not coded separately unless it's treated alongside the anterior tibial, or it's the only vessel treated. Second, lithotripsy is bundled here. Not an add-on, not reportable. Included. A biller who reflexively appends a lithotripsy code below the knee is generating denials, or worse, payments that won't survive an audit.
Inframalleolar territory
The dorsalis pedis and plantar arteries, with the pedal arch folded into them unless the arch is the only vessel treated. The code family is deliberately narrow: only angioplasty is separately reported here: 37296/37298 with add-ons 37297/37299. Atherectomy performed at this level isn't separately billable, however real the work was. Foot-level cases are where enthusiasm for capturing everything most often collides with the framework's limits.
Why this is a billing-partner problem, not a memorization problem
Four territories, four rule sets, and at least five places where the intuitive answer is the wrong one. Your physicians shouldn't have to carry this table in their heads, but someone touching your claims absolutely must, and must also recognize when an operative note doesn't contain enough anatomical precision to apply it. That's the real test of a billing operation in 2026: not whether they loaded the new codes into their system (everyone did), but whether they can catch the tibioperoneal trunk coded separately, the iliac atherectomy on the wrong code, and the lithotripsy billed in a bundled territory before the payer does.
If you're not certain your current biller would catch all five, that uncertainty is data. MD Billing's vascular coding practice is built around exactly these rules, and our free revenue cycle assessment will audit a sample of your 2026 LER claims against them. Take it at mdbilling.com, or contact us.
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