I22.8 ICD-10-CM Code: Subsequent ST elevation (STEMI) myocardial infarction of other sites

Code

I22.8

Description

Subsequent ST elevation (STEMI) myocardial infarction of other sites

HCC (V28)

HCC 228 — Acute Myocardial Infarction

RAF reference coefficient

0.252

Billable

Yes

Payment year

2026

HCC Category Mapping

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work I22.8 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for I22.8

What This Code Means

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for I22.8 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

• •Use this code for subsequent STEMI of sites such as inferior, lateral, or posterior walls; verify the specific wall location in documentation
• •Confirm the timing is within 4 weeks of the initial MI event

Clinical Significance

Subsequent STEMI of other sites captures recurrent myocardial infarctions within 4 weeks affecting walls other than anterior, such as lateral, posterior, or right ventricular walls. This code is important for documenting multi-territory reinfarction, which suggests diffuse coronary disease and significantly higher patient acuity.

Documentation Requirements

• ✓Documentation of a recurrent STEMI within 4 weeks of the initial event
• ✓Specification of the involved wall (lateral, posterior, right ventricular, or other site)
• ✓New ST elevation on electrocardiogram in territory different from or same as the initial event
• ✓Re-elevation of cardiac biomarkers
• ✓Both initial (I21.x) and subsequent (I22.8) codes must be assigned

Commonly Confused Codes

• •I22.0: Subsequent STEMI of anterior wall: use for anterior wall recurrence
• •I22.1: Subsequent STEMI of inferior wall: use for inferior wall recurrence
• •I22.9: Subsequent STEMI of unspecified site: use only when wall location is unknown
• •I21.29: Initial STEMI of other sites: for the initial event, not recurrence

Child Codes