General Surgery Coding Alert

If your practice includes vascular surgery, you should be in the know about the expansion of diagnosis codes for aortic aneurysm (AA).

With changes in ICD-10-CM 2023, not only do you have to know the exact anatomic site of the aortic aneurysm, but also whether the site has ruptured. Read on for tips to help you choose the correct diagnosis code in every case.

Understand AA Basics

An aneurysm is a bulge or ballooning in part of the artery wall. This causes the wall of the artery to weaken and can eventually rupture which can be life threatening.

An aortic aneurysm occurs in the aorta, which is the main blood vessel leading from the heart to the abdomen, pelvis, and legs, says Carol Hodge, CPC, CPMA, CDEO, CCC, CEMC, CPB, CFPC, COBGC, senior documentation specialist at St. Joseph’s/ Candler Medical Group.

An aortic aneurysm is an enlargement, or dilatation, of the aorta to 1.5 times its normal size, adds Catherine Brink, BS, CPC, CMM, president of Healthcare Resource Management in Spring Lake, New Jersey.

There are three main types of aortic aneurysms based on their location on the aorta: thoracic, abdominal, and thoracoabdominal.

Drill Down to Anatomic Specifics

With the expansion of the AA codes, ICD-10-CM further pinpoints where the aneurysm occurs by adding a fifth character to the existing codes to provide more specificity, as follows:

• For thoracic codes the new fifth characters are 1 (ascending aorta), 2 (aortic arch), or 3 (descending aorta).
• For abdominal codes, the fifth characters are 1 (pararenal) 2 (juxtarenal), or 3 (infrarenal).
• For thoracoabdominal codes, the fifth characters are 1 (supraceliac), or 2 (paravisceral).

The new codes follow a pattern of expanding the existing “ruptured,” or “without rupture” code and adding a fifth character “0” to indicate that a more-specific anatomic site is not evident in the medical record, or the specific fifth character as indicated above.

For instance, here are the thoracic site-specific aortic aneurysm codes:

Old code, now converts to parent code that requires fifth character: I71.1 (Thoracic aortic aneurysm, ruptured)

New codes:

• I71.10 (Thoracic aortic aneurysm, ruptured, unspecified)
• I71.11 (Aneurysm of the ascending aorta, ruptured)
• I71.12 (Aneurysm of the aortic arch, ruptured)
• I71.13 (Aneurysm of the descending thoracic aorta, ruptured)

Old code, now converts to parent code that requires fifth character: I71.2 (Thoracic aortic aneurysm, without rupture)

New codes:

• I71.20 (Thoracic aortic aneurysm, without rupture, unspecified)
• I71.21 (Aneurysm of the ascending aorta, without rupture)
• I71.22 (Aneurysm of the aortic arch, without rupture)
• I71.23 (Aneurysm of the descending thoracic aorta, without rupture)

Avoid These Coding Pitfalls

When coding aortic aneurysm, the first thing you should note is the “Code first” instruction. For an aortic aneurysm due to syphilis, you must use A52.01 (Syphilitic aneurysm of aorta), or for an aortic aneurysm due to trauma you should turn to S25.09 (Other specified injury of thoracic aorta) or S35.09 (Other injury of abdominal aorta).

Avoid: You should not use any of the site-specific AA codes if the condition is due to syphilis or trauma.

Understand dissection: ICD-10-CM also provides codes for aortic dissection based on anatomic site (I71.00-I71.03). A dissection occurs due to a tear or damage to the inner lining of the aorta, leading to formation of two channels within the vessel. As blood travels or pools in the different channels, the dissection may result in decreased blood flow to parts of the body or to a catastrophic rupture. Read the op note carefully to determine if the surgeon is treating an aneurysm or a dissection.

Work with providers: Some of the challenge when reporting aortic aneurysms is teaching providers to document the exact location of the aneurysm using terminology present in the new ICD-10-CM codes, Hodge says.

Coders need to have a good understanding of anatomy and physiology of aorta aneurysms and location, Brink adds. The ICD-10-CM code is specific to location and whether the aneurysm has ruptured. The documentation by the provider should be specific for type and location of the aneurysm for you to be able to code correctly.