Q&A: Coding demand ischemia and MI
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: Your gut is leading you in the right direction. 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 referring to the alphabetic index under ischemia/ischemic instructions will tell you to
- Demand (coronary) see also, Angina I24.8
Also, directly underneath that you will see:
- with myocardial infarction I21.A1
- resulting in myocardial infarction I21.A1
Even though demand ischemia often is the result of another condition there is no additional coding guidance given that requires the reporting of the cause of the demand ischemia or that it would be sequenced first. If demand ischemia occurs with an MI the code I21.A1, Myocardial infarction type 2 would be used. The inclusion terms include Myocardial infarction due to demand ischemia and Myocardial infarction secondary to ischemic imbalance. The code I21.A1, Myocardial infarction type 2, does have guidance on sequencing that tell us to code first the underlying cause such as: anemia (D50.0-D64.9), COPD (J44.-), paroxysmal tachycardia (I47.0-I47.9), and shock (R57.0-R57.9). We are also told to see Guidelines Section I.C.9.e.5 which discusses the codes used for different types of MIs, and that we are not to use code I24.8, Other forms of acute ischemic heart disease.
Here you will also find references to two Coding Clinics from fourth quarter 2017, p. 10, and fourth quarter 2018, p. 44. It would always be to your benefit to look up and read any Coding Clinics that may offer advice regarding the correct code assignment.
Now, 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).
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.
Remember that there are exclusions for CC/MCCs; when certain conditions are coded together the CC/MCC status of a secondary diagnosis could be lost. You can go to https://www.cms.gov/ for a listing of these exclusions.
Editor’s Note: Sharme Brodie, RN, CCDS, CCDS-O, 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. This article originally ran in May 2019 and has been updated according to all new coding and documentation guidelines.