NSTEMI ICD-10-CM Codes

What ICD-10 codes are used for NSTEMI?

Non-ST elevation myocardial infarction (NSTEMI) is a type of heart attack characterized by specific electrocardiogram (EKG) changes without ST-segment elevation.

As part of the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM), NSTEMI is classified under multiple diagnostic codes depending on the episode, location, and related conditions.

• I21.4 - Non-ST elevation (NSTEMI) myocardial infarction: This is the primary code for acute myocardial infarction without ST elevation.
• I21.A1 - Myocardial infarction type 2: This can include NSTEMI when caused by an imbalance between oxygen supply and demand rather than coronary thrombosis.
• I22.1 - Subsequent ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction of the inferior wall: This is used when a subsequent myocardial infarction occurs within four weeks of a previous MI.
• I22.2 - Subsequent non-ST elevation (NSTEMI) myocardial infarction: For recurrent MI impacting areas other than the anterior wall or inferior wall.
• I22.8 - Subsequent non-ST elevation (NSTEMI) myocardial infarction of other sites: For recurrent NSTEMI affecting different regions of the myocardium.
• I22.9 - Subsequent myocardial infarction of unspecified site: When the location of a subsequent MI is not documented.

Which NSTEMI ICD codes are billable?

Specific criteria and insurance company guidelines govern the billability of codes.

• I21.4: Yes, this specific code for NSTEMI is billable for patients with an initial acute coronary syndrome without ST elevation.
• I21.A1: Yes, as it represents a Type 2 myocardial infarction caused by conditions other than coronary artery disease.
• I22.1: Yes, billable when representing a subsequent MI of the inferior wall within four weeks of the initial event.
• I22.2: Yes, billable for subsequent MI impacting other sites of the heart.
• I22.8: Yes, for subsequent NSTEMI affecting other documented cardiac regions.
• I22.9: Yes, when a subsequent MI occurs with an unspecified site.

When coding MI cases, it's important to identify whether the patient is receiving care at the current facility or a different facility than where the initial MI was treated, as this affects code selection.

Clinical information

NSTEMI is a serious condition within the spectrum of diseases of the circulatory system where blood supply to part of the heart is decreased or interrupted, causing ischemia and potentially cell death in the myocardium. The underlying cause is typically:

• Partial occlusion coronary artery, thrombosis infarction, or ventricle myocardial infarction
• Embolism coronary vessel
• Rarely, rupture coronary artery

NSTEMI differs from STEMI in that it usually doesn't present with Q wave changes or persistent ST elevation on EKG, but does show elevated cardiac enzymes indicating cardiac infarction.

Symptoms include chest pain, discomfort, shortness of breath, nausea, and fatigue, which typically begin within a few hours of presentation.

Treatment includes medications, percutaneous coronary intervention, and possible revascularization to restore blood supply to the heart. After initial treatment, an appropriate aftercare code should be assigned for patients receiving recovery care.

Synonyms include

• Non-ST segment elevation heart attack
• Partial heart attack
• Minor heart attack
• Non-ST elevation acute coronary syndrome
• Subendocardial myocardial infarction