Are all myocardial infarctions (MIs) created equal? Let’s take a look at demand ischemia, non-ischemic myocardial injury, and type 2 myocardial infarctions.
According to ACDIS, demand ischemia is a specific type of ischemia wherein oxygen requirements of the myocardium are not being met due to some increased need. The code for demand ischemia is I24.8.
According to the Coding Clinic for the Fourth Quarter of 2021, pgs. 14-15, non-ischemic myocardial injury is characterized by the rise and/or fall of cardiac troponin levels, with at least one value above the 99th-percentile upper limit. The case presented is a patient who becomes increasingly somnolent.
The diagnostic workup reveals elevated troponin level and intermittent atrial fibrillation. The patient did not have chest pain or EKG changes, and troponin levels stabilized. The provider documented non-ischemic myocardial injury. The question associated with the case was how the diagnosis was coded. The response was I5A.
The Coding Clinic for the Fourth Quarter of 2017, pgs. 12-14, lists the types of myocardial infarction. There are various types that range from type 1 through type 5. Type 2 myocardial infarction is a myocardial infarction secondary to ischemic imbalance, as in coronary vasospasm, anemia, or hypotension.
There is a question in this issue of Coding Clinic regarding how to code a type 2 NSTEMI due to demand ischemia. The answer is I21.A1 – myocardial infarction, type 2. Do not assign I24.8. According to the ICD-10-CM guidelines, codes I21.01-I21.4 should only be assigned to type 1 acute myocardial infarctions.
The Fourth Universal Definition of Myocardial Infarction provides detailed definitions of various types of MIs. This document was published by the Journal of American College of Cardiology, on Nov. 13, 2018. It is important that the cardiologists are clear regarding the type of myocardial infarction or injury that is being treated.
When I am auditing, I frequently see I21.A1 assigned for demand ischemia, but there is no documentation of a myocardial infarction. If the documentation is unclear, a query should be written to determine if the patient has a type 1 myocardial infarction, a type 2 myocardial infarction with demand ischemia, a non-ischemic myocardial injury, or just plain-old demand ischemia.
Even if a query is written, the diagnosis must be supported by clinical information. If the documentation states “myocardial infarction,” then there should be support found in the electrocardiograms and cardiac enzymes. This query could avoid denials that occur after the payor processes the claim and reviews medical records.
While the query may slow down reimbursement, it will ensure that you are paid correctly for the patient’s presentation.
Programming note: Listen to live coding reports by Laurie Johnson every Tuesday on Talk Ten Tuesdays with Chuck Buck and Dr. Erica Remer.