Cardiology Coding Alert

Question: The patient suffered from a type 1 ST elevation (STEMI) MI involving the left main coronary artery AMI, then he had a new type 2 AMI within the four-week time frame of the initial type 1 AMI. Which ICD-10 codes should we report in this case?

California Subscriber

Answer: The ICD-10 Official Guidelines for Coding and Reporting specifically address this scenario.

If the patient has a subsequent acute myocardial infarction (AMI) of one type that occurs within four weeks of a different type of AMI, you should report the appropriate codes from category I21- (Acute myocardial infarction) to identify each type, instead of a code from category I22- (Subsequent ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction), according to the Guidelines. So, in this scenario, you should report I21.01 (ST elevation (STEMI) myocardial infarction involving left main coronary artery) for the type 1 AMI and I21.A1 (Myocardial infarction type 2) for the type 2 AMI.

On the other hand, if the patient, who had suffered a type 1 AMI, had a new type 1 AMI within the four-week time frame of the initial AMI, then you should report a code from category I22-, according to the Guidelines.

You must also report a code from category I21- in conjunction with the appropriate code from category I22-. The sequencing of these codes will depend upon the circumstances of the encounter.

Caution: Make sure you report a code from category I22- only if the medical documentation indicates that the AMI is type 1 or unspecified. If the patient has a subsequent type 2 AMI, then you would report I21.A1. And if the patient has a subsequent type 4 or type 5 AMI, then you would report I21.A9 (Other myocardial infarction type).