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Question:
I code for a large cardiology practice and encounter stent restenosis diagnosis. I have read in different places that the correct code is 996.72, Complication due to cardiac device. Can you give me information on this and does the physician have to state it was a complication due to the stent and not just progression of the disease? I have never seen a physician document a complication of in-stent restenosis.

Theresa Dix, CCS-P, CCP, CPMA
Certified Medical Coder/Auditor
East Tennessee Heart Consultants

Response:
Stents are generally placed in coronary arteries to address areas of stenosis (ie, blockages inside the coronary arterial pathway). These blockages slowly build up over time as sticky, low-density cholesterol molecules hit the arterial wall and accumulate. When a stent is placed at an area of stenosis, it compresses the built-up cholesterol deposits and creates a wider pathway for blood to flow through. A stent is a solid/metal object that acts as scaffolding that keeps the targeted segment of artery open for an extended period of time.

Unfortunately, there is nothing to prevent the same sticky, low-density cholesterol molecules from reaccumulating at the site of a previously placed stent. When new blockages build up at the site of a previously placed stent, it is called in-stent restenosis. In an effort to reduce the likelihood of in-stent restenosis, doctors have employed an array of alternative stent types (drug-coated and drug-eluting stents), a unique form of radiation (brachytherapy), and various medications immediately following stent deployment. However, in-stent restenosis persists as a fairly common occurrence.

While there appears to be some logic behind reporting diagnosis code 996.72 (Other complications due to other cardiac device, implant, and graft) when treating in-stent restenosis, there appears to be more logic behind not classifying this as a complication due to the stent. In reality, if the patient has a high level of low-density cholesterol in his or her bloodstream, blockages will continue to build up throughout the arterial system whether a stent was placed or not. It is not as though the stent malfunctioned in any way; the patient is just predisposed to having these blockages accumulate. If we were to assign blame for the restenosis, it would reside more with the cholesterol levels than with the stent.

Rather than classifying restenosis as a complication due to the stent, it seems more appropriate to report in-stent restenosis as coronary atherosclerosis of the type of vessel in which the stent was placed. For example, if the restenosis took place in a native coronary vessel, code 414.01, Coronary atherosclerosis of native coronary vessel, appears appropriate.

This interpretation is supported by the fact that diagnosis codes exist to report stenosis inside coronary artery bypass grafts: 414.02, Autologous vein bypass graft; 414.03, Nonautologous biological bypass graft; and 414.04, Artery bypass graft. While these blockages are taking place inside the bypass grafts, we would not classify this as a complication due to the bypass graft. There seems to be no precedent for asserting that all in-stent restenosis are complications either.

A quick review of the six published limited coverage determinations places us evenly on the fence between reporting these as complications vs. atherosclerosis. Palmetto GBA, National Government Services, and Wisconsin Physician Services all include 996.72 as a covered indication for coronary interventions. NHIC, Pinnacle, and TrailBlazer do not list 996.72 as a covered indication.

While it certainly would not be the intent of any Medicare carriers/administrative contractors to deprive patients with in-stent restenosis of receiving potentially life-saving interventions, we would have to interpret these coverage policies as further justification for reporting in-stent restenosis as atherosclerosis of the vessel rather than a complication of an implanted device.

— Jim Collins is a certified cardiology coder and the president of CardiologyCoder.com, Inc.