CABG: Bypass Problematic Coding Scenarios

CABG: Bypass Problematic Coding Scenarios

Proper claims payment is certain when you map out the best route.

Coding coronary artery bypass graft (CABG) surgery is far easier when you understand why the procedure is medically necessary. Just pretend you’re going on a road trip: You have a car (coding resources) and you know where you’re going (filing a claim) — that’s a good start. But without a roadmap (or GPS), you’ll never find your way. Here’s your roadmap to coding CABG.

What Is CABG?

Each heartbeat delivers oxygenized blood through the aorta to all the other arteries in the body. Two coronary arteries are the first to receive this oxygen-rich blood, providing oxygen to the heart muscle (myocardium). Yes, you read that correctly. Although we can code for and have modifiers for five coronary arteries, they all originate with the right and left main coronary arteries.

Of note, the applicable coronary modifiers don’t apply to CABG codes; they are intended for use with percutaneous coronary interventions (PCI).

The primary reason for coronary artery bypass grafting is occlusion. Occlusion occurs when fatty deposits, called plaques, build up inside an artery. The characteristics of plaque would make a great article by themselves, but the short story is plaques clog arteries. When this happens in the arteries supplying the myocardium, you will see it documented as coronary atherosclerosis.

Coronary atherosclerosis can lead to partial or complete blockage of the coronary arteries, causing symptoms such as angina (chest pain caused by a blockage) or a heart attack. To alleviate symptoms and prevent a heart attack, a surgeon will bypass the diseased area in a coronary artery. Think of it as taking a detour on a highway to avoid a traffic jam, as shown below.

The bypass is accomplished by using autologous vein(s) and/or artery(ies) attached above and below the blocked portion of the coronary artery. Just like driving, there are some rules of the road for CABG.

Coding Rules for CABG

The CABG CPT® codes are published in lists preceded by easy-to-follow guidelines. Now we come to the heart of this article (pun intended): coding for the bypass of the portion of a coronary artery with atherosclerosis.

When you review the codes in CPT®, think of them as shopping lists. As you review the CABG report, identify what was used to perform the bypass: how many veins, how many arteries, or if it was a combination. Once you have the number, keep in mind these rules:

  • If only veins are used, only use the veins list (33510–33516).
  • If only arteries are used, only use the artery list (33533–33536).
  • Your shopping list may include these arteries: internal mammary, gastroepiploic, epigastric, radial, and others.
  • If a combination is used, use the add-on list (+33517–+33523) for the vein(s) and the artery list (33533–33536).

Also use the lists in the chart below when coding CABG to prevent taking a wrong turn somewhere.

Drive it Home

Good CABG coding starts with knowing the rules of the road (guidelines). Pay attention to parenthetical notes and be aware of other codes that may apply to the case, such as harvesting veins by endoscopy (+33508).

Resources: staff (2014). “Medical gallery of Blausen Medical 2014” WikiJournal of Medicine

U.S. National Library of Medicine


Norma Panther
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