Learn Coronary Artery Anatomy According to CPT® and CCI

coding for coronary interventions

When your job is converting medical documentation into codes, your knowledge of medical anatomy has to be shipshape. But you’ve got the added complication that the code set you’re using may have its own definitions for specific terms. Case in point: CPT® guidelines set out five major coronary arteries with coronary artery branches for only three. Use this quick refresher to improve your coronary revascularization coding.

What Are the Major Coronary Arteries?

Codes 92920-92944 represent percutaneous revascularization services for coronary vessels. Also called cardiac catheterization and percutaneous coronary intervention (PCI), the services you’ll see include angioplasty, atherectomy, and stenting.

AMA CPT® guidelines with the PCI codes list these as the major coronary arteries:

  • Left main
  • Left anterior descending
  • Left circumflex
  • Right
  • Ramus intermedius.

The CPT® guidelines go on to state that you should report one code to represent all PCI procedures in a single major artery through native coronary circulation. So if there are PCI procedures in the proximal, mid, and distal segments of the same major artery, you still use just one code.

But when documentation shows treatment of one segment of a major artery through native circulation and treatment of another segment of that artery through a coronary artery bypass graft (CABG), you should report the PCI through the CABG separately.

Tip: The major arteries line up precisely with the following HCPCS modifiers:

  • LM (Left main coronary artery)
  • LD (Left anterior descending coronary artery)
  • LC (Left circumflex coronary artery)
  • RC (Right coronary artery)
  • RI (Ramus intermedius coronary artery).

You can use those modifiers to bypass National Correct Coding Initiative (CCI or NCCI) edits when clinical circumstances support the override, according to chapter 1 of the NCCI Policy Manual for Medicare Services.

What Are the Coronary Artery Branches?

For reporting purposes, CPT® recognizes up to two coronary artery branches for these vessels:

  • Left anterior descending: diagonals
  • Left circumflex: marginals
  • Right: posterior descending, posterolaterals.

But the left main and ramus intermedius don’t have branches recognized by CPT® for reporting.

As with the major arteries, you’ll use a single code to report all PCIs performed in a coronary artery branch. CPT® rules allow you to report PCI for up to two branches of a major artery, but PCI in a third branch is not reportable.

Watch out: The CCI manual alerts you that “Medicare does not pay separately for PCI in a branch of a major coronary artery as this payment is included in the payment for the PCI code for the corresponding major coronary artery.”

As an example, 92920 (Percutaneous transluminal coronary angioplasty; single major coronary artery or branch) has a Medicare national rate of $558.25. But +92921 (… each additional branch of a major coronary artery …) shows status B, which means bundled code, on the Medicare Physician Fee Schedule. Experts advise reporting the code despite the B status to help show how often branch services are performed and possibly support changes to payment structures in the future.

What About Bypass Grafts?

For CPT® reporting, each CABG represents a coronary vessel, but that’s not the end of the explanation for coding:

  • Count a sequential bypass graft that has more than one distal anastomosis as one graft.
  • Consider a branching bypass graft, like a Y graft, to be a coronary vessel for the main graft. Each branch off the main graft is an additional coronary vessel, according to CPT®.

What About You?

This blog was a quick look at what CPT® counts as coronary arteries, but there’s more to the coding story. If you’re a vascular or cardiology coder who reports these PCI services, what tips would you give coders who are just starting out?


Deborah works on a wide range of TCI SuperCoder projects, researching and writing about coding, as well as assisting with data updates and tool development for our online coding solutions. Since joining TCI in 2004, she’s covered the ins and outs of coding for radiology, cardiology, oncology and hematology, orthopedics, audiology, and more.

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