FY2027 ICD-10-CM reference
I22.9: Subsequent ST elevation (STEMI) myocardial infarction of unspecified site
By the HCC Buddy Coding Team
The official ICD-10-CM descriptor is Subsequent ST elevation (STEMI) myocardial infarction of unspecified site. The FY2027 annual edition starts October 1, 2026. Check the edition that applies to the encounter or inpatient discharge, including any April update.
Billable code. Verified against the official FY2027 order file.
CMS-HCC V28
- HCC 228: Acute Myocardial Infarction · RAF 0.252, Community Non-Dual Aged (CNA)
Payment year 2027, 2026 dates of service. HCC from the CMS 2027 Initial ICD-10-CM Mappings; RAF from the CMS-HCC V28 relative factors. For 2027 dates of service, CMS has not yet published the payment year 2028 mappings.
CMS-HCC V24
Not used for payment year 2027 Medicare Advantage payment
ESRD
- HCC 86: Acute Myocardial Infarction
Coefficient pending: payment year 2027 coefficients for this model are not yet verified, so no RAF is shown. Mapping: PY2026 CMS mapping; CMS 2027 initial file unchanged.
PACE
Source verification pending
RxHCC
- HCC 188: Coronary Artery Disease
Coefficient pending: payment year 2027 coefficients for this model are not yet verified, so no RAF is shown. Mapping: PY2026 CMS mapping; CMS 2027 initial file unchanged.
HHS-HCC
- HCC 131: Acute Myocardial Infarction
RAF not applicable: HHS-HCC weights vary by metal level. Mapping: HHS-HCC 2026 benefit year.
FY2027 Tabular instructions
Instructions below include applicable chapter, section and parent-code notes. Each note identifies where it appears in the official source.
Excludes2
certain conditions originating in the perinatal period (P04-P96)
Source: I00-I99 (chapter, inherited).
Excludes2
certain infectious and parasitic diseases (A00-B99)
Source: I00-I99 (chapter, inherited).
Excludes2
complications of pregnancy, childbirth and the puerperium (O00-O9A)
Source: I00-I99 (chapter, inherited).
Excludes2
congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
Source: I00-I99 (chapter, inherited).
Excludes2
endocrine, nutritional and metabolic diseases (E00-E88)
Source: I00-I99 (chapter, inherited).
Excludes2
injury, poisoning and certain other consequences of external causes (S00-T88)
Source: I00-I99 (chapter, inherited).
Excludes2
neoplasms (C00-D49)
Source: I00-I99 (chapter, inherited).
Excludes2
symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Source: I00-I99 (chapter, inherited).
Excludes2
systemic connective tissue disorders (M30-M36)
Source: I00-I99 (chapter, inherited).
Excludes2
transient cerebral ischemic attacks and related syndromes (G45.-)
Source: I00-I99 (chapter, inherited).
Code also
the presence of hypertension (I10-I1A)
Source: I20-I25 (section, inherited).
Includes
acute myocardial infarction occurring within four weeks (28 days) of a previous acute myocardial infarction, regardless of site
Source: I22 (category, inherited).
Includes
cardiac infarction
Source: I22 (category, inherited).
Includes
coronary (artery) embolism
Source: I22 (category, inherited).
Includes
coronary (artery) occlusion
Source: I22 (category, inherited).
Includes
coronary (artery) rupture
Source: I22 (category, inherited).
Includes
coronary (artery) thrombosis
Source: I22 (category, inherited).
Includes
infarction of heart, myocardium, or ventricle
Source: I22 (category, inherited).
Includes
recurrent myocardial infarction
Source: I22 (category, inherited).
Includes
reinfarction of myocardium
Source: I22 (category, inherited).
Includes
rupture of heart, myocardium, or ventricle
Source: I22 (category, inherited).
Includes
subsequent type 1 myocardial infarction
Source: I22 (category, inherited).
Instructional note
code, if applicable, to identify:
Source: I22 (category, inherited).
Instructional note
exposure to environmental tobacco smoke (Z77.22)
Source: I22 (category, inherited).
Instructional note
history of tobacco dependence (Z87.891)
Source: I22 (category, inherited).
Instructional note
occupational exposure to environmental tobacco smoke (Z57.31)
Source: I22 (category, inherited).
Instructional note
status post administration of tPA (rtPA) in a different facility within the last 24 hours prior to admission to current facility (Z92.82)
Source: I22 (category, inherited).
Instructional note
tobacco dependence (F17.-)
Source: I22 (category, inherited).
Instructional note
tobacco use (Z72.0)
Source: I22 (category, inherited).
Excludes1
subsequent myocardial infarction, type 2 (I21.A1)
Source: I22 (category, inherited).
Excludes1
subsequent myocardial infarction of other type (type 3) (type 4) (type 5) (I21.A9)
Source: I22 (category, inherited).
Instructional note
Subsequent acute myocardial infarction of unspecified site
Source: I22.9 (self, direct).
Instructional note
Subsequent myocardial infarction (acute) NOS
Source: I22.9 (self, direct).
Compare the FY2027 additions, removals and billable-status changes
What does I22.9 mean in FY2027?
The official ICD-10-CM descriptor is Subsequent ST elevation (STEMI) myocardial infarction of unspecified site. The FY2027 annual edition starts October 1, 2026. Check the edition that applies to the encounter or inpatient discharge, including any April update.
Is I22.9 billable in FY2027?
The FY2027 order file marks I22.9 as billable. Check the complete Tabular instructions and documentation before assigning it.
Does I22.9 map to an HCC?
In the CMS 2027 Initial ICD-10-CM Mappings (payment year 2027, 2026 dates of service), I22.9 maps to CMS-HCC V28 HCC 228 (Acute Myocardial Infarction). For 2027 dates of service, CMS has not yet published the payment year 2028 mappings. Under the PY2026 CMS mapping; CMS 2027 initial file unchanged: ESRD HCC 86; RxHCC HCC 188. Coefficients for these models are pending verification for payment year 2027. HHS-HCC: HCC 131 under the HHS-HCC 2026 benefit year mapping (no RAF; HHS-HCC weights vary by metal level). CMS-HCC V24: not used for payment year 2027 Medicare Advantage payment (CMS CY 2027 Rate Announcement). The PACE mapping is still pending verification for FY2027.
Source: CMS FY2027 ICD-10-CM order file. Payment model: CMS CY 2027 Rate Announcement. Read the FY2027 Official Guidelines.
Review the FY2026 April edition