Pro Tips for Tackling Endoleaks and Lower Extremity Coding in 2025

When it comes to coding for complex interventional radiology procedures like endoleak embolization, the stakes are high. Inaccurate coding not only threatens compliance and reimbursement but can also compromise your organization’s financial stability and audit risk profile. The complex nature of endoleak treatment—combined with the subtle differences between CPT® codes like 37242 and 37244—demands a deep, current understanding of coding guidelines. Without proper training and clarity, even experienced coders can find themselves in dangerous waters. Our subject matter experts have identified this area as a high-priority focus.

From Type I to IV: A Coder’s Guide to Endoleaks and Embolization

When addressing an endoleak with embolization, it’s crucial to differentiate between codes 37242 and 37244. Contrary to common assumptions, an endoleak isn’t classified as a hemorrhage; rather, it represents a persistent “leakage” of blood into the aneurysm sac. This ongoing leakage can elevate pressure within the sac, potentially leading to a rupture if left unaddressed.

There are five types of endoleaks, thus the dictated report may indicate, for example, “Type 1 endoleak” or “Type 2 endoleak”; however, understand that  the type of endoleak does not have an impact on your coding. You are responsible for identifying the type of treatment and code accordingly. Doing so might mean coding for stent-graft extensions, embolization of additional branches or vessels, or turning the patient over to vascular surgery after the diagnostic angiogram to allow for an open surgical procedure.

• Type 1 Endoleak

What causes a Type I endoleak is a gap between the endograft and the vessel wall at the point where it should be sealed. This circumstance allows  blood to continue to leak into the aneurysm sac.

• Type II Endoleak

Type II endoleak is characterized when blood from a branch or side vessel that was not embolized continues to leak blood into the aneurysm. These are the most common types of endoleaks seen after abdominal aortic aneurysm repair. Embolizing this type of endoleak often requires a translumbar catheterization of the aorta, with subsequent catheterization into a lumbar artery or the IMA (36245). Or it may require catheterization into the SMA with subsequent maneuvering around the Arc of Riolan to get to the IMA (36247).

• Type III and IV Endoleaks

A Type III endoleak occurs when the graft is defective, or the components are misaligned. This enables blood flow to continue flowing to the aneurysm. Type IV endoleak results from an intentionally porous graft and occurs soon after some EVAR procedures. Type V endoleak is also called “endotension,” and the method/reason for this type of leak is unclear.

Code 37241 is specific to venous embolization for clinical indications other than hemorrhage, tumors, or organ ischemia or infarction. As noted above, 37241 should not be assigned for extremity incompetent veins or spider veins. Examples of appropriate clinical indications for 37241 include:

• embolization/sclerotherapy of gastric or esophageal varices varicoceles
• incompetent ovarian veins,
• venous or lymphatic malformations.

Note that it is not appropriate to report code 37241 for embolization of accessory (side) branches of an AV dialysis graft. Take special note of  code 36909 in the AV Dialysis Graft section for more information.

Understanding the Nuances of Embolization Coding for Uncommon Clinical Scenarios

Coders may be wondering what code should be reported for extenuating circumstances and arterial embolization. Arterial embolization for reasons other than hemorrhage, tumor, organ ischemia or infarction is reported with code 37242. As noted in the code description, arterial malformations, AV malformations, AV fistulas, aneurysms and pseudoaneurysms are appropriate clinical indications for 37242.

However, do not assign this code for injection of thrombin into an extremity pseudoaneurysm as that is appropriately coded as 36002.

When hepatic chemoembolization or radioembolization (Y-90) is planned, other arteries such as the gastroduodenal or left gastric may be embolized to keep the chemotherapy or isotope from reaching other organs. If these arteries are embolized at the same session as the hepatic chemoembolization or radioembolization, only one embolization code (37243) would be assigned although additional vascular catheterization codes could be added.

Your 2025 Coding Remains at Risk: These Are NOT All the Tips and Tricks Necessary for IR Success. With every dollar of reimbursement counting more than ever in the face of payment decline and complex changes, it’s imperative to make sure your CPT coding is correct and compliant. Master more coding topics and break down the complexity with 2025 Lower Extremity Interventional Radiology Coding Webcast on April 16, 2025 at 11:00 am CT.