Radiology Coding Alert

If you can recognize the prosthesis type used for an endovascular abdominal aortic aneurysm (AAA) repair, choosing the proper code is a piece of cake.

And with Medicare's national reimbursement rates ranging from $1,158 for 34800 (Endovascular repair of infrarenal abdominal aortic aneurysm or dissection; using aortoaortic tube prosthesis) to $1,285 for 34803 (... using modular bifurcated prosthesis [two docking limbs]), you'll want to be sure to put these five answers to work for you.

First, you should determine whether:

• the radiologist places the prosthesis in the abdominal aorta only, or

• a portion of the prosthesis extends into one or more of the iliac (or possibly renal) arteries.

As illustrated (Fig. 1), the abdominal aorta branches into the common iliac arteries below the renal arteries. If the abdominal aorta develops an aneurysm, or bulging due to a weakening of the artery walls, the radiologist may make an incision in the groin and, under fluoroscopic guidance, thread a catheter through the arteries to the aneurysm site. Using guidewires and catheters, the radiologist will then guide the prosthesis into place.

When expanded, the prosthesis reinforces the artery wall, which prevents the aneurysm from further ballooning or bursting.

34800: If the graft remains in the abdominal aorta only (Fig. 2), without extending into either iliac (or renal) artery, you should choose 34800, says Marcella Bucknam, CPC, CCS-P, CPC-H, CCS, CPC-P, CPC-I, CCC, COBGC, manager of compliance education for University of Washington Physicians. This describes placement of a single-piece tube prosthesis without "docking limbs" (discussed later).

If the graft prosthesis extends into one or both iliac arteries (or possibly a renal artery), you must next determine whether the graft is made of:

• one piece (unibody) or

• several pieces that the radiologist places separately and joins together at the aneurysm site (modular).

For unibody grafts, got to Question 3. Otherwise, go to Question 4.

CPT describes two unibody prostheses, which differ according to whether the prosthesis enters one or both iliac arteries.

One artery: Code 34805 (... using aorto-uniiliac or aorto-unifemoral prosthesis) describes a tubular graft, much like that described by 34800, except that for 34805 the graft extends into one iliac artery, Bucknam says. "Codes 34800 and 34805 describe closely related procedures," explains the AMA's CPT Changes 2004: An Insider's View.

The "34800 prosthesis lies only in the aorta and is cylindrical in shape. Alternatively, code 34805 describes a procedure which requires the use of a longer prosthesis that extends into one iliac artery, therefore requiring a tapered cylindrical shape that is smaller in diameter at the distal end" (Fig. 3.1).

Don't miss: You also may report 34805 for a graft that extends upward into a single renal artery (Fig. 3.2).

Two arteries: If the single-piece prosthesis extends from the aorta to both iliac arteries, you'll choose 34804 (... using unibody bifurcated prosthesis). When in place, this prosthesis looks like an upside-down "Y" (Fig. 4).

This prosthesis may be custom-made to match the patient's anatomy. The procedure includes passing a special contralateral iliac limb guidewire into the aorta. The radiologist captures the wire using a snare advanced through the arteries from the opposite groin, and she then pulls the contralateral graft limb downward from the aorta into the opposite iliac artery.

Modular prostheses used for AAA repair extend from the aorta into the iliac arteries. To get the correct CPT code, check how many pieces the graft has.

2 pieces: You should report a two-piece graft (in which the radiologist joins a single docking limb extending up from one iliac artery to the main portion of the prosthesis) using 34802 (... using modular bifurcated prosthesis [one docking limb]). "The prosthesis described by code 34802 is constructed of two separate pieces that are joined inside the patient's body during placement to make the ultimate configuration of an inverted 'Y,'" says CPT Changes 2004 (Fig. 5.1).

3 pieces: A three-piece graft consists of one primary portion in the aorta and two docking limbs extending into each iliac artery, all of which the radiologist separately places and joins inside the patient's body to form  he upside-down "Y" configuration (Fig. 5.2). Again, this graft, as described by 34803, has three pieces, unlike 34804 (single piece) and 34802 (two pieces).

On occasion, the radiologist may choose to place extension prostheses or cuffs at the ends of the main prosthesis, either because the extension is necessary to reach past the aneurysm or because she has detected  an endo-leak at the proximal or distal end(s) of the prosthesis. You should report an extension(s) placement in the initial vessel using 34825 (Placement of proximal or distal extension prosthesis for endovascular repair of infrarenal abdominal aortic or iliac aneurysm, false aneurysm, or dissection; initial vessel).

"Initial vessel" refers to the first vessel the radiologist places the extension prosthesis or cuff in, says Michele Midkiff, CPC-I, PCS, RCC, executive director of Coding Affiliates Inc., an interventional and neuro-interventional radiology coding service in Mountain View, Calif.

Example: If the radiologist places an extension in a single iliac artery, report one unit of 34825 in addition to the primary prosthesis placement code.

But if the radiologist places extensions in more than one vessel, call on a single unit of +34826 (... each additional vessel [List separately in addition to code for primary procedure]) for each additional vessel affected.

Example: If the radiologist places extensions into each iliac artery, report 34825 and +34826 in addition to the code for the primary prosthesis placement.

Stay tuned: Next month, check out Part 2 to get up to speed on coding procedures associated with AAA repair.