Understanding the ICD-10-CM Code I21.01: STEMI Involving the Left Main Coronary Artery

Understanding the ICD-10-CM Code I21.01: STEMI Involving the Left Main Coronary Artery

The ICD-10-CM Diagnosis Code I21.01 refers to a ST elevation (STEMI) myocardial infarction involving the left main coronary artery. This is a specific and billable code used in medical documentation for accurate diagnosis and reimbursement.

The 2025 edition of this ICD-10-CM code became effective on October 1, 2024. It represents the American ICD-10-CM version of I21.01, though international adaptations of the code may vary.

Key Details about I21.01

Short Description:
STEMI involving the left main coronary artery.

 

Annotation Back-References:
The code falls under the following categories:

• I00-I99: Diseases of the circulatory system
• I20-I25: Ischemic heart diseases
• I21: Acute myocardial infarction
• I21.0: ST elevation myocardial infarction of the anterior wall

 

Approximate Synonyms

The code covers diagnoses such as:

• Acute heart attack involving the left main coronary artery
• Acute ST segment elevation myocardial infarction of the left main coronary artery
• Myocardial infarction (acute) involving the left main coronary artery

 

Diagnostic Related Group (DRG) Classification

ICD-10-CM I21.01 is grouped under the following MS-DRGs (v42.0):

• 280: Acute myocardial infarction, discharged alive with major complications or comorbidities (MCC)
• 281: Acute myocardial infarction, discharged alive with complications or comorbidities (CC)
• 282: Acute myocardial infarction, discharged alive without CC/MCC
• 283: Acute myocardial infarction, expired with MCC
• 284: Acute myocardial infarction, expired with CC
• 285: Acute myocardial infarction, expired without CC/MCC

 

Code History and Updates

The code I21.01 has been consistently maintained since its introduction in 2016 as a non-draft ICD-10-CM code. Annual updates have not resulted in significant changes. The most recent update, effective October 1, 2024, reflects its continued relevance in clinical and billing practices.

Usage for Reimbursement

For medical claims, the use of ICD-10-CM codes is mandatory for services provided on or after October 1, 2015. Accurate coding ensures proper reimbursement for healthcare providers and supports streamlined healthcare administration.

 

Related Terms in the Diagnosis Index

The following terms are associated with I21.01:

• Infarct/infarction of the myocardium (acute) with a stated duration of four weeks or less (I21.9).
• ST elevation (STEMI) infarction involving the left main coronary artery (I21.01).

Why Accurate Coding Matters

Precise documentation using ICD-10-CM codes like I21.01 is crucial in healthcare. It ensures proper classification of conditions, facilitates effective treatment plans, and supports efficient billing processes.

 

Conclusion

The ICD-10-CM Code I21.01 is an essential tool for identifying and documenting STEMI involving the left main coronary artery. With its clear definition and association with specific DRG groups, it plays a critical role in both clinical practice and medical billing.

For the latest updates, always refer to the ICD-10-CM guidelines applicable to the current year. Proper coding not only aids in compliance but also ensures that patients receive the appropriate level of care and providers are reimbursed accurately.