Tip: Making sense of myocardial infarction sequencing rules

One of the most confusing diagnoses to code and sequence is the acute myocardial infarction (AMI). It is the elephant in the room of circulatory diagnoses—it takes up the most space and can never be ignored. I’m going to try to make some sense out of the AMI rules so that you can easily determine how the MI fits in your CDI/coding picture.

 

As a reminder, here are the MI DRGs:

One situation you may encounter is a patient admitted with a diagnosis of AMI, who undergoes cardiac catheterization without percutaneous intervention. It is an odd quirk of the DRG guidelines that coding and billing for cardiac catheterization excludes a diagnosis of MI. 

 

So the patient with coronary artery disease, but not a MI, who undergoes cardiac catheterization without angioplasty or stent, will go to DRG 287, but the MI patient having the same procedure will stay in DRG 282, acute myocardial infarction. DRG 287 only accepts circulatory disorders except acute MI, with cardiac cath. This is true regardless of whether the MI is the principal diagnosis or a co-morbidity. This leads me into the really bewildering sequencing rules regarding the MI.

 

A MI is considered such a major diagnosis that it trumps every other medical diagnosis within the circulatory group. But—and remember this—that doesn’t automatically make it the principal diagnosis.  The principal diagnosis still has to meet the Uniform Hospital Discharge Data Set (UHDDS) definition of a principal diagnosis. An AMI as principal diagnosis goes to DRG 282.  But you could have a patient admitted with a principal diagnosis of peripheral vascular disease (PVD) who then experiences a MI.  Without the MI, the DRG would be 301, PVD. Because of the MI, the DRG is 282.  And because the MI was used to trump the PVD and get it into a “better” hierarchy, it can’t then be “double-dipped” and used as the MCC.

 

Editor’s Note: This article was originally published on ACDIS Blog. Brown is a clinical documentation specialist at Banner Good Samaritan Medical Center in Phoenix, AZ. Contact her at catladyrn@gmail.com.