Q&A: Reporting type 2 MIs in ICD-10-CM

February 21, 2020
Medicare Web

Q: Our coding department frequently has trouble reporting type 2 myocardial infarctions (MI). Can you share any coding and clinical criteria guidance?

A: A type 2 MI occurs when a disease process causes such a significant decrease in the supply of blood or oxygen to the heart that ischemia (heart muscle cell death) occurs.

Some possible causes of type 2 MI are:

  • Acute hypoxemia
  • Aortic dissection
  • Coronary vasospasm, embolism, vasculitis, dissection
  • Hypertensive emergency
  • Hypertrophic cardiomyopathy
  • Severe anemia
  • Severe aortic valve disease
  • Shock
  • Sustained tachyarrhythmias
  • Sustained bradyarrhythmias requiring intervention

Any one of these conditions may cause MI-type symptoms with no accompanying rise and fall in troponin. This would be demand ischemia without MI and is reported with ICD-10-CM code I24.8 (other forms of acute ischemic heart disease). If the symptoms of ischemia are accompanied by a rise and fall in troponin, it is indicative of a type 2 MI.

A type 2 MI may be documented as an MI due to demand ischemia, an MI due to ischemic imbalance, or a type 2 MI. Regardless of cause, location, or severity, a type 2 MI is coded as I21.A1 (myocardial infarction type 2).

The known or possible precipitating factors for a type 2 MI now need to be documented because the coding conventions and the ICD-10-CM Official Guidelines for Coding and Reporting were updated for fiscal year 2020 to indicate that the cause of the type 2 MI must be sequenced first.

Editor’s note: Sarah Nehring, CCS, CCDS, inpatient lead coder, answered this question.

This answer was provided based on limited information. Be sure to review all documentation specific to your own individual scenario before determining appropriate code assignment.

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