Easy coding of coronary artery bypass graft:

In my experience, I have seen many coders suffering a lot to understand the concepts of CABG coding. A small topic with limited number of codes, but often creates chaos when coders start to assign the CABG codes. This article will summarize the key facts in determining the CABG graft codes.

For better understanding, let me break the article into sets of questions as below:

What is a coronary artery?

Arteries that supply blood to the heart muscle are referred to as coronary arteries. When these arteries get clogged with plaque or atherosclerosis, it is termed as arteriosclerotic coronary artery disease. (ASCAD).

What are the types of coronary arteries?

Two major coronary arteries branch off from the aorta near the point where the aorta and the left ventricle meet. The two major branches are:

Left Main Coronary Artery (also called the left main trunk)

The left main coronary artery branches into:

  • Circumflex artery
  • Left Anterior Descending artery (LAD)

Right Coronary Artery (RCA)

The right coronary artery branches into:

  • Right marginal artery
  • Posterior descending artery

What is a coronary artery bypass graft?

A coronary artery bypass graft (CABG) is a surgical procedure used to treat coronary heart disease. It diverts blood around narrowed or clogged parts of the major arteries to improve blood flow and oxygen supply to the heart.

A coronary artery bypass graft involves taking a healthy blood vessel from another part of the body (usually the chest, leg or arm) and attaching it to the coronary artery above and below the narrowed area or blockage.

What is procurement?

The new blood vessel taken from other parts of the body to restore normal blood flow is known as a graft and the process of obtaining the graft is known as “harvesting” or “procurement”. The surgeon may harvest an artery, a vein or both. The number of grafts needed will depend on the severity of coronary heart disease and the number of coronary blood vessels narrowed.

What is arterial grafting?

When healthy arteries from other parts of the body are used to provide the bypass grafts, it is known as arterial grafting.

Examples include: Left internal thoracic (mammary) artery – LITA or LIMA, Right internal thoracic (mammary artery) – RITA, RIMA, Radial artery, Right gastroepiploic artery, Inferior epigastric artery, Ulnar artery, Splenic artery

Frequently harvested arteries include LIMA, RIMA and radial artery.

What is venous grafting?

When healthy veins from other parts of the body are used to provide the bypass grafts, it is known as venous grafting.

Examples include: Greater saphenous vein, shorter saphenous vein and Cephalic vein.

Frequently harvested veins include saphenous veins.

What are the types of Bypass surgeries?

The types of bypass surgery refer to the number of coronary arteries bypassed in the procedure.

Single bypass: Only one artery is bypassed.

Double bypass: Two coronary arteries are bypassed. (Example: left anterior descending, LAD and right coronary artery (RCA).

Triple bypass: Three coronary arteries are bypassed. (Example: LAD, RCA, left circumflex artery (LCX)

Quadruple bypass: Four arteries are bypassed. (LAD, RCA, LCX, first diagonal artery of the LAD.)

Factors to determine the coronary bypass graft codes:

Type of bypass surgery

This is the foremost step to proceed with the CABG coding. You need to determine the type of bypass surgery whether it is single bypass or double bypass or triple bypass or Quadruple bypass from the operative report. This facilitates an accurate coding without any codes missed in the encounter.

Type of vessel used:

Next step is to proceed with the type of vessel being used in the encounter. You can identify from the operative report whether an artery, vein or both are being used as the bypass graft.

  • If arterial graft is used, then select the code range 33533-33536.
  • If venous graft is used, then select the code range 33510-33516.
  • If both the arterial and venous graft is used, then select the code range 33517 – 33523 and arterial graft codes 33533-33536.

Harvesting codes, if applicable:

As already discussed, harvesting is defined as the process of taking patients healthy vessel from other parts of the body to restore your blood flow. Typically, the services for harvesting grafts are included in the bypass code sets 33533-33536 or 33510-33516. However if the service is not included in the code sets, it is appropriate to bill those services separately.

Vein harvesting:

Per coding guidelines, harvesting of the saphenous vein is bundled into code set 33510 – 33516 and cannot be reported separately. However harvesting of other veins (35500, 33508, 35572 can be billed separately and are modifier -51 exempt.

Artery harvesting:

Per coding guidelines, harvesting of arteries including internal mammary artery, gastroepiploic artery, epigastric artery and arterial conduits are bundled into code sets 33533 – 33536 and cannot be reported separately. However harvesting of upper extremity artery (35600) can be billed separately and is modifier -51 exempt.

CABG with Venous Grafting only:33510-33516

When the CABG surgery involves the use of only vein graft, you need to report the code sets 33510-33516.

Codes for Venous grafting only:

  • CABG with vein only, 1 graft – 33510
  • CABG with vein only, 2 grafts – 33511
  • CABG with vein only, 3 grafts – 33512
  • CABG with vein only, 4 grafts – 33513
  • CABG with vein only, 5 grafts – 33514
  • CABG with vein only, 6 or more grafts – 33516

CABG with Arterial Grafting only: 33533-33536

When the CABG surgery involves the use of only arterial graft, you need to report the code sets 33533-33536.

Codes for Arterial grafting only:

  • CABG with artery only, 1 graft – 33533
  • CABG with artery only, 2 grafts – 33534
  • CABG with artery only, 3 grafts – 33535
  • CABG with artery only, 4 or more grafts – 33536

CABG with Venous and arterial grafting: 33533-33536 AND 33517-33523

When the CABG surgery involves the use of both arterial and vein graft, you need to report two codes as below:

  • Appropriate arterial graft code: 33533 – 33536
  • Appropriate combined arterial-venous graft add-on codes: 33517 – 33523

1. The appropriate arterial graft code: (33533-33536)

CABG with artery only, 1 graft – 33533

CABG with artery only, 2 grafts – 33534

CABG with artery only, 3 grafts – 33535

CABG with artery only, 4 or more grafts – 33536

2. The appropriate combined arterial-venous graft code: (33517-33523)

CABG using venous and arterial grafts using 1 vein graft – 33517

CABG using venous and arterial grafts using 2 vein grafts – 33518

CABG using venous and arterial grafts using 3 vein grafts – 33519

CABG using venous and arterial grafts using 4 vein grafts – 33521

CABG using venous and arterial grafts using 5 vein grafts – 33522

CABG using venous and arterial grafts using 6 or more vein grafts – 33523

Coding tip: Always remember the code series 33517 – 33523 can never be billed alone. These codes are add-on codes and need to be reported with arterial grafting codes 33533-33536.

This article emphasizes only the basic steps of CABG coding. However a more detailed version with relevant example are published into the E-book “Easy coding of coronary artery bypass graft”

Happy learning! Happy coding!

References:

1 Comment

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