Q&A: Coding Type 2 MI and demand ischemia

Q: If Type 2 myocardial infarction (MI) and demand ischemia are both documented, should I code only Type 2 MI based on the Excludes 1 note found in the Tabular List under demand ischemia?

For example, a physician recently documented that a patient had elevated troponin, likely a Type 2 MI/demand ischemia in the setting of a hypertensive emergency. In this case, demand ischemia would be a CC, and Type 2 MI would affect the DRG assignment, but it wouldn’t add a CC/MCC.

My gut tells me that I shouldn’t code I24.8, Other forms of acute ischemic heart disease, in this case. Is that correct?

A: I encourage you to engage with one of your most valuable resources: your coding staff.  I also recommend taking a look at the Fourth Universal Definition of MI, published in 2018, which may help shed some light on the physician’s perspective/thought-process.

When you look up code I24.8, Other forms of acute ischemic heart disease, in the ICD-10-CM Tabular List, there is an Excludes 1 note for MI due to demand ischemia (code 121.41). When you look up the code I24.A1 for a Type 2 MI, the inclusions under the main term include MI due to demand ischemia, and also MI secondary to ischemic imbalance. There’s also a “code first” note for the underlying cause if known, and a direction to read the Official Guidelines for Coding and Reporting, section I.C.9.e5.

I recommend reviewing that section in the Guidelines along with AHA Coding Clinic for ICD-10-CM/PCS, Fourth Quarter 2017, p. 10.

Also, remember that we often need to query providers in situations such as this to clarify what’s exactly going on with the patient. Did the patient have a MI, or was the physician only documenting that an episode of demand ischemia occurred? Anytime you feel that the documentation is unclear, you need to query the provider for clarification of the terms used for correct code assignment.

Editor’s Note: Sharme Brodie, RN, CCDS, CDI education specialist and CDI Boot Camp instructor for HCPro in Middleton, Massachusetts, answered this question. For information, contact her at sbrodie@hcpro.com. For information regarding CDI Boot Camps, click here.