Coding Angiography

Vol. 12 •Issue 18 • Page 26
Coding Angiography

Hop in the car and take a road trip

The consensus among coders seems to be that coding angiography is about as fun as the average root canal. So much mystery and uncertainty are packed into coding this growing specialty that it seems difficult just to keep up. But understanding a few key terms and following a few basic principles will take a lot of the mystery out of the process and give coders the tools they need to get to the right code.

The vascular system is in fact a transportation system, so it requires no great leap of the imagination to see it as a network of freeways, highways, secondary roads and streets. Imagine also that the catheters are cars full of tourists, speeding to their various destinations to take photos. Throughout this article, I’ll use this metaphor to explain the complexities of angiography coding.

Driver’s Ed

First, let’s use the transportation metaphor to understand the terms used in angiography:

Nonselective: This means the car took the direct route. The radiologist punctures the destination vessel itself and goes no further, or if he or she goes further it is only to get to the aorta–or the ‘freeway’ as we’ll call it.

A common example of nonselective catheterization is an abdominal aortogram with run-off to the lower extremity, coded as 36200. The car pulls out of the garage and into the femoral artery, merges onto the aorta and parks on the shoulder to take pictures, spewing exhaust (contrast). This is nonselective because the car doesn’t ever leave the freeway again, except to back up and go home. The key here is where the catheter goes, not what images are obtained. Even though the radiologist ends up with information about the lower extremities, the catheterization is only coded to the aorta because that was where the catheter stopped.

Selective: This means the car took the scenic route. Either the vessel is not readily accessible from the outside (intracerebral) or the radiologist wanted to look at some other spots along the way.

One example of selective catheterization is renal angiography, code 36245. The renal arteries cannot be accessed directly from the outside, so the radiologist must get to them via the abdominal aorta. The car pulls out of the garage and into the femoral artery again, merges onto the aorta, but this time exits the freeway at the right main renal artery. This artery has been selected off the aorta.

Vascular family: The metaphor comes in really handy here. Think of the aorta as the freeway, first order vessels as highway exits off the freeway, second order vessels as secondary roads off the highways, and third order vessels as individual streets. All the secondary roads and streets that branch off a given highway belong to a single vascular family. Each exit off the freeway (the aorta, remember) and onto a highway represents a separate vascular family, a separately coded procedure.

Rules of the Road

This brings us to our first principle for coding angiography:

Code separately each vascular family catheterized

Every time the car exits the freeway onto a highway to take photos, that car enters a new vascular family and another procedure can be coded.

Common examples of this are angiography of the head and neck. The radiologist punctures the femoral artery, steers the catheter up the aorta to the arch, exits at the left subclavian and takes a few photos. Then he backs up to the aorta where he first got off, goes forward a bit and makes a second turn, this time at the left common carotid. In this case 36215 is coded twice, because each vessel catheterized is a separate exit off the aorta and so belongs to its own vascular family.

Code to the farthest point within a vascular family

It doesn’t matter how many times the car stops for photos, or even if the radiologist changes catheters (just as our tourists might change from a car to a jeep to negotiate some rough terrain). If there has been only one turn off the freeway to one destination, then code the final destination and forget the stops along the way.

In the previous example there were two separate exits off the aorta, one onto the left subclavian and one onto the common carotid. In this next example, the radiologist will only take the first exit onto the left subclavian. He or she stops for photos as before, but then continues on up the subclavian to the left vertebral artery, which branches off the subclavian. This is classified as a secondary road (second order artery). The radiologist stops and takes photos again, then heads back home.

This procedure would only be coded to the final destination of 36216, for the catheterization of the left vertebral artery, because there was only one exit off the freeway to one final destination. The photo stop at the subclavian was on the way to the final destination. Even if the radiologist had taken the photos in reverse order (not stopping till he/she got to the vertebral artery, and then making a photo stop at the subclavian on the way home) this still would be only one procedure, because the second stop was on the way back from the final destination.

Code 36218 and 36248 where appropriate

There are areas of angiography coding that can be particularly tricky. For example, codes 36218 and 36248 are used for selective arterial catheterization of an additional second or third order branch within the same vascular family. 36218 is used for second or third order branches off the thoracic section of the aorta and 36248 for the abdominal section.

It’s important to remember that the radiologist, after reaching the first secondary road or street and taking photos, backs the car up to an intersection nearby and turns onto the same or smaller type of road. Remember, if he backs all the way to the aorta and then exits onto another highway, then that would be a separate vascular family and coded as such.

Think of it as a side trip. It is not on the way to the first destination, because the radiologist turns off the original route and heads to a new destination.

Here’s an example that supports the assignment of code 36218: Our radiologist heads up the aorta to the thoracic arch again, but this time exits onto the brachiocephalic artery (highway), and takes a quick left onto the right subclavian (secondary road) for some pictures. He gets thinking about ‘the road not taken,’ heads back to the brachiocephalic artery (highway) where he first exited, and turns right at the intersection onto the right common carotid. The view is spectacular, so he takes some pictures for the folks back home. The first turn would be coded to 36216 and the second to 36218, because the radiologist backed up to an intersection and then made another turn going forward.

Code 36218 could also be used if the radiologist had gone farther up the right common carotid (secondary road) all the way to the right internal carotid (street), then backed up to the common carotid and took a left turn onto the right external carotid (street). The first turn would be coded to 36217, because it is a third order artery, and the second turn to 36218, because it is also a third order artery branching off the same highway but catheterized by a separate turn.

•Code each puncture separately

This is a fairly simple principle; it means just what it says. If the radiologist has made a separate entry into the patient’s vascular system, inserted a catheter and taken some pictures from this vantage point, then a separate procedure code can be used.

If, however, the radiologist is unable to catheterize one vessel and so tries another, the first attempt cannot be coded to a separate angiography procedure. For example, say the radiologist plans to do an abdominal aortogram and runoff of the lower extremities starting from the left femoral artery, finds it impassable and instead uses the right. Because no pictures were taken, the first attempt is not considered a separate puncture for angiography; it is just a patient with a sore leg.

Get Yourself a Good Road Map

Having some kind of visual reference handy when you code angiography can make all the difference. Check with your radiology department. They may have charts or other resources you could use.

We in the Nosology department at 3M Health Information Systems find the Interventional Radiology Coding User’s Guide indispensable. It discusses much of what is presented here in more detail, and also contains many color-coded diagrams of the vascular anatomy and corresponding codes. This publication can be ordered online at the Web site of the Society of Cardiovascular & Interventional Radiology, For a great set of reference diagrams only, contact Medical Asset Management Inc. at (404) 346-1900.

Rhonda Butler is a clinical development analyst in the Nosology department at 3M Health Information Systems in Salt Lake City, UT.