Advanced Search

Radiology Coding Alert

Coding Tactics for Interventionalists Performing Emergency Stroke Thrombolysis

Published on Wed Aug 01, 2001

More interventional radiologists are treating stroke patients with thrombolysis, a technique that may minimize damage to the brain and allow for a more complete clinical recovery.

"Catheter-directed thrombolysis is an aggressive therapy that interventionalists provide under emergent conditions," noted Richard Duszak Jr., MD, an interventional radiologist with West Reading Radiology Associates in Reading, Pa., during a presentation at the spring meeting of the Radiology Business Managers Association meeting in Scottsdale, Ariz. "It's an exciting area of practice because it is an emergency procedure and the radiologist is on the front lines of treatment."

Describing a stroke as a "brain attack" similar to a heart attack, he explains that thrombolysis must usually be performed within six hours of the event to be most effective. During the multistep procedure, a catheter is advanced to the site of obstruction or occlusion, and a thrombolytic agent is injected or infused to restore blood flow.

Step One: Locating the Occlusion

Interventional radiologists pinpoint the precise site of an obstruction by inserting a catheter, advancing it through the arterial system and performing angiography, explains Jeff Fulkerson, supervisor of radiology billing at the Emory Clinic in Atlanta. "When a patient presents with symptoms of a stroke, interventionalists won't know precisely where the occlusion has occurred within the brain. Cerebral angiography provides information about what is going on throughout the entire vascular structure."

This process is described by two sets of codes -- one for reporting the catheterization and one for reporting the angiography.
 
Catheter Access

Most often, catheter access is gained through the femoral artery and, depending on the final position of the catheter in the head or neck, one of the following catheterization codes is assigned:

  CPT 36215  -- selective catheter placement, arterial system; each first order thoracic or brachiocephalic branch, within a vascular family;

  CPT 36216  -- ... initial second order thoracic or brachiocephalic branch, within a vascular family;

  CPT 36217  -- ... initial third order or more selective thoracic or brachiocephalic branch, within a vascular family.

A fourth arterial access code, CPT 36218 (... additional second order, third order and beyond, thoracic or brachiocephalic branch, within a vascular family [list in addition to code for initial second or third order vessel as appropriate]), is an add-on code that may be assigned if additional second- or higher-order branches within a vascular family are accessed.

When reporting catheterization, coders must avoid two common errors, according to Lisa Grimes, RT [R], radiology special procedures technologist and reim-bursement specialist for the University of Texas/Houston Health Science Center. "First, practices cannot report more than one first-, second- or third-order code within the same vascular family during a single procedure," she says. "Each code includes advancing the catheter through the previous branches. For instance, 36217 includes both the first- and second-order vessels that are traversed to reach the third."

Second, coders should take care not to assign a code describing lower-level access when the more-advanced codes are justified. "Reimbursement reflects the amount of work required to access each order," she points out. "For instance, the interventionalist is paid more for accessing a second-order branch than for a first-order branch because it takes greater skill and effort to advance the catheter farther into the system. Therefore, it's important that coders can identify which vessel was accessed to ensure the highest-level code is assigned."

Because interventionalists need a complete picture to locate an occlusion, they may advance catheters into multiple vascular families to perform angiography of the entire brain. When this occurs, multiple catheterization codes may be reported.

"For instance, the interventionalist may advance the catheter into both the internal and external carotid on the right side," Fulkerson explains. "The coder would assign 36217 for the internal carotid. However, because both of the vessels selected are in the same family, the coder wouldn't be allowed to assign 36217 for the external carotid, too. Instead, 36218 would be reported."

If the physician then repeated the catheterization on the left side, the coder would report two additional codes because those vessels represent a separate family. "Because the vascular structures are different on the left side than they are on the right, however, coders would assign 36216 for the internal carotid and 36218 for the external carotid," he says.

Angiography

Once the catheter has been positioned, the interventional radiologist will perform angiography to evaluate the vessels and pinpoint the occlusion, Duszak says. Codes are selected from the 75660-75685 angiography series, depending on the vessels imaged. Coders should note that 75660 and 75662 are "selective" codes, requiring that the radiologist insert the catheter directly into the external carotid to perform the angiography. The remaining codes are nonselective, which means the catheter does not have to be directly placed into those vessels. Instead, the images may be obtained as a result of contrast injected into lower-order vessels, which then flows in an antegrade manner into the deeper vessels. When performing angiography prior to a potential lysis of thrombus, it is highly unlikely that nonselective angiography will be performed. Selective catheterizations are usually necessary.

"Coders would assign the appropriate codes to describe vessels where angiography was done," Fulkerson explains. "In the example above, if the interventionalist had taken a selective angiogram of the bilateral internal carotid and the bilateral external carotids, both 75671 (angiography, carotid, cerebral, bilateral, radiological supervision and interpretation) and 75662 (angiography, external carotid, bilateral, selective, radiological supervision and interpretation) would be assigned because of the selective catheter placement." However, even if multiple views or projections of each vessel must be obtained to locate the cause of the stroke, each angiography code may be billed only once per session.

On occasion, coders may also assign add-on code 75774 (angiography, selective, each additional vessel studied after basic examination, radiological supervision and interpretation [list separately in addition to code for primary procedure]). Many vessels originating from main branches extend deep into the brain. Because many of these are not explicitly defined in 75660-75685, coders may report 75774 in addition to other angiography codes when one of these branch vessels is selectively catheterized, injected and imaged.

Step Two: Conducting Thrombolysis
 
Once the area of concern has been identified and evaluated, the interventionalist will inject or infuse the thrombolytic agent. Duszak notes that this procedure is reported with 37201 (transcatheter therapy, infusion for thrombolysis other than coronary). Also, 75896 (transcatheter therapy, infusion, any method [e.g., thrombolysis other than coronary], radiological supervision and interpretation) would be assigned for the imaging guidance. These codes are usually reported only once per operative session.

The thrombolytic agent may also be delivered intravenously, but this is a service usually provided by neurologists and not interventional radiologists and is reported with 37195 (thrombolysis, cerebral, by intravenous infusion).

Step Three: Follow-Up Angiography

After stroke thrombolysis, the interventionalist will once again perform angiography to determine the success of the therapeutic intervention. Unlike preprocedural angiography, clinically distinct follow-up images may be reported as often as they are obtained and medically necessary, Duszak points out. If only one angiogram is required to determine that the occlusion has been dissolved, 75898 (angiogram through existing catheter for follow-up study for transcatheter therapy, embolization or infusion) should be billed once. If angiography is repeated after additional thrombolytic therapy, the code may be reported each time.

If angiography is medically necessary, the interventionalists may repeat it as many times as required. "The coder must realize, however, that the physician must clearly document each time the follow-up is performed," Fulkerson says.

Other Articles in this issue of

Radiology Coding Alert

View All