A myocardial infarction (MI) or acute myocardial infarction (AMI), commonly referred to as a heart attack, occurs when one or more coronary arteries that carry blood to the heart are blocked. Symptoms include chest pain, pressure, or tightness, which may move into the jaw, neck, throat, or arm(s). Patients also may experience shortness of breath, excessive sweating, and/or indigestion or burning in the throat and/or chest. MI is a medical emergency. Left untreated, it can cause permanent harm to the heart muscle, brain damage, and death within a short time.
MI is part of the leading cause of death in the United States: Approximately 450,000 people die from coronary disease per year, according to the America Heart Association.
The upcoming ICD-10 implementation will bring significant changes in medical coding for myocardial infarctions. The implementation will have an impact on how medical billing and Coding companies as well as Cardiology Coding in Medical offices approach their coding. The changing definition of “initial” and “subsequent” as well as “duration” is crucial among them. Let’s take a detailed look into ICD-10 coding and documentation for MI.
To code an MI in ICD-10, you will need to know:
- The location of the infarct (anterior, inferior, or other);
- Initial or subsequent episode; and,
- STEMI or NSTEMI.
Codes for the STEMI are also based on the coronary artery involved:
- Anterior MI (I21.0 ST elevation (STEMI) myocardial infarction of anterior wall) is either left main, left anterior descending, or other coronary artery.
- Inferior MI (I21.1 ST elevation (STEMI) myocardial infarction of inferior wall) breaks down to right coronary or other coronary artery.
- STEMI of other sites involve infarct of the left circumflex artery or other sites.
ICD-10 Codes:
Apart from the initial and subsequent episode and MI type, you should also consider the location of the infarct (anterior, inferior or other) while choosing the relevant ICD-10-CM codes. The ICD-10-CM codes for MI are as follows:
I21.01 ST elevation (STEMI) myocardial infarction involving the left main coronary artery
I21.02 ST elevation (STEMI) myocardial infarction involving the left anterior descending coronary artery
I21.09 ST elevation (STEMI) myocardial infarction involving other coronary artery of anterior wall
I21.11 ST elevation (STEMI) myocardial infarction involving right coronary artery
I21.19 ST elevation (STEMI) myocardial infarction involving other coronary artery of inferior wall
I21.21 ST elevation (STEMI) myocardial infarction involving left circumflex coronary artery
I21.29 ST elevation (STEMI) myocardial infarction involving other sites
I21.3 ST elevation (STEMI) myocardial infarction of unspecified site
I21.4 Non-ST elevation (NSTEMI) myocardial infarction
I22.0 Subsequent ST elevation (STEMI) myocardial infarction of anterior wall
I22.1 Subsequent ST elevation (STEMI) myocardial infarction of inferior wall
I22.2 Subsequent non-ST elevation (NSTEMI) myocardial infarction
I22.8 Subsequent ST elevation (STEMI) myocardial infarction of other sites
I22.9 Subsequent ST elevation (STEMI) myocardial infarction of unspecified site
I25.2 Old myocardial infarction
Documentation for MI:
As you know, ICD-10-CM will increase the level of detail required for MI. Here are the details to be included in your documentation.
- Identify and document the number of weeks since the AMI
- Indicate subsequent MI appropriately
- Document when a NSTEMI evolves into a STEMI and when a STEMI converts into a NSTEMI as a result of thrombolytic therapy
- If the patient is still receiving care for the MI, then you should use the term ‘aftercare’ and if the patient no longer receives care for the MI, use the term ‘old’ or ‘healed’ MI
- Document the exact site (for example, left main coronary)