I21.09
BillableST elevation (STEMI) myocardial infarction involving other coronary artery of anterior wall
HCC Category Mapping
V28HCC 228 — Acute Myocardial Infarction
0.000V24HCC 86 — Acute Myocardial Infarction
0.274ESRDHCC 86 — Acute Myocardial Infarction
0.000RxHCCHCC 188 — Coronary Artery Disease and Angina
0.000What This Code Means
A heart attack with ST segment elevation affecting the front wall of the heart caused by blockage of a coronary artery other than the left main or left anterior descending.
Coding Tips
Clinical Significance
This code captures STEMI involving other anterior wall coronary arteries beyond the left main and left anterior descending, such as diagonal branches. It represents a significant acute cardiac event requiring urgent intervention. Proper documentation of the specific culprit vessel is needed to distinguish this from more commonly specified anterior wall STEMI codes.
Documentation Requirements
- ✓Explicit documentation of STEMI with anterior wall involvement
- ✓Identification of the specific coronary artery involved (not left main or left anterior descending)
- ✓Electrocardiogram findings showing anterior ST elevation
- ✓Cardiac biomarker elevation
- ✓Cardiac catheterization or angiography findings identifying the culprit vessel
- ✓Timing of the acute event within 4-week window
Commonly Confused Codes
I21.01 — STEMI involving left main coronary artery: use when left main is the culpritI21.02 — STEMI involving left anterior descending: use when left anterior descending is identifiedI21.3 — STEMI of unspecified site: use only when the site cannot be determined at allI21.29 — STEMI involving other sites: for locations other than anterior and inferior walls
Code Hierarchy
└I21Acute myocardial infarction└I21.0ST elevation (STEMI) myocardial infarction of anterior wall└I21.09ST elevation (STEMI) myocardial infarction involving other coronary artery of anterior wall
└I21.09ST elevation (STEMI) myocardial infarction involving other coronary artery of anterior wall