Cardiology Coding Alert

Question: We are experiencing some confusion with the ICD-10 guidelines for myocardial infarctions (MIs). What ICD-10 code should we report if the patient has an old MI?

California Subscriber

Answer: You should report I25.2 (Old myocardial infarction) for old or healed MIs not requiring further care, according to the 2018 ICD-10-CM Official Guidelines for Coding and Reporting.

Per ICD-10, included conditions for I25.2 are the following:

• A healed myocardial infarction
• A past myocardial infarction diagnosed by electrocardiogram (ECG) or other investigation, but currently presenting no symptoms.

You can also look to the "four-week rule" in Chapter 9 of the guidelines for further clarification.

MI is four weeks old or less: For any encounters that happen while the patient's MI is four weeks old or less, which includes transfer to another acute or post-acute setting, and if the MI meets the requirements of "other diagnoses" from Section III, Reporting Additional Diagnoses of the guidelines, then you should report the appropriate code from category I21- (Acute myocardial infarction).

After four-week time frame, patient still receiving care: On the other hand, for any encounters occurring after the four-week time frame, and if the patient is still receiving care related to the MI, you should report the appropriate aftercare code, not a code from I21-.

Old or healed MI: For old or healed MIs that do not require further care, report I25.2.

Don't miss: When reporting a code from I25- (Chronic ischemic heart disease), ICD-10 instructs you to use an additional code to identify:

• I25.82 (Chronic total occlusion of coronary artery)
• Z77.22 (Contact with and (suspected) exposure to environmental tobacco smoke (acute) (chronic))
• Z87.891 (Personal history of nicotine dependence)
• Z57.31 (Occupational exposure to environmental tobacco smoke)
• Z72.0 (Tobacco use).