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I22.2 ICD-10-CM Code: Subsequent non-ST elevation (NSTEMI) myocardial infarction

I22.2 maps to CMS-HCC V28 228. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · free HCC coding tools

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Code lookupI22.2

FY 2026 Apr update / Diseases of the circulatory system (I00-I99) / Ischemic heart diseases (I20-I25)

I22.2

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Subsequent non-ST elevation (NSTEMI) myocardial infarction

A heart attack that occurs after a previous heart attack, where blood flow to part of the heart is blocked but not completely, resulting in damage to the heart muscle. This code is used when the patient has had a prior myocardial infarction and experiences another one.

Buddy the Bee presenting code insight

Buddy Insight

Subsequent NSTEMI represents a recurrent non-ST elevation myocardial infarction within 4 weeks of the initial event.

CMS-HCC V28

HCC 228

Coefficient HCC 228: 0.252 (Community Non-Dual Aged (CNA))

CMS-HCC V24

Historical

Historical

Not used for CY2026 payment

ACA/HHS

HCC 131

Code-level coefficient reference

ESRD/PACE

HCC 86

Code-level coefficient reference

RXHCC

HCC 188

Code-level coefficient reference

Inclusion Terms

Official
  • Subsequent acute subendocardial myocardial infarction
  • Subsequent non-Q wave myocardial infarction NOS
  • Subsequent nontransmural myocardial infarction NOS

Excludes 2

Official
  • certain conditions originating in the perinatal period (P04-P96)Inherited from I00-I99
  • certain infectious and parasitic diseases (A00-B99)Inherited from I00-I99
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)Inherited from I00-I99
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)Inherited from I00-I99
  • endocrine, nutritional and metabolic diseases (E00-E88)Inherited from I00-I99
  • injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from I00-I99
  • neoplasms (C00-D49)Inherited from I00-I99
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)Inherited from I00-I99
  • systemic connective tissue disorders (M30-M36)Inherited from I00-I99
  • transient cerebral ischemic attacks and related syndromes (G45.-)Inherited from I00-I99

Includes

Official
  • acute myocardial infarction occurring within four weeks (28 days) of a previous acute myocardial infarction, regardless of siteInherited from I22
  • cardiac infarctionInherited from I22
  • coronary (artery) embolismInherited from I22
  • coronary (artery) occlusionInherited from I22
  • coronary (artery) ruptureInherited from I22
  • coronary (artery) thrombosisInherited from I22
  • infarction of heart, myocardium, or ventricleInherited from I22
  • recurrent myocardial infarctionInherited from I22
  • reinfarction of myocardiumInherited from I22
  • rupture of heart, myocardium, or ventricleInherited from I22
  • subsequent type 1 myocardial infarctionInherited from I22

Excludes 1

Official
  • subsequent myocardial infarction, type 2 (I21.A1)Inherited from I22
  • subsequent myocardial infarction of other type (type 3) (type 4) (type 5) (I21.A9)Inherited from I22

Code First

Official

No Code First sequencing instructions are included in this display for I22.2. Check the code and parent instructions in the Code Book.

Use Additional

Official
  • code, if applicable, to identify:Inherited from I22
  • exposure to environmental tobacco smoke (Z77.22)Inherited from I22
  • history of tobacco dependence (Z87.891)Inherited from I22
  • occupational exposure to environmental tobacco smoke (Z57.31)Inherited from I22
  • status post administration of tPA (rtPA) in a different facility within the last 24 hours prior to admission to current facility (Z92.82)Inherited from I22
  • tobacco dependence (F17.-)Inherited from I22
  • tobacco use (Z72.0)Inherited from I22

Code Also

Official
  • the presence of hypertension (I10-I1A)Inherited from I20-I25

Buddy Documentation Tip

HCC Buddy guidance
Documentation of a subsequent or recurrent NSTEMI
Timing within 4 weeks of the initial myocardial infarction
Re-elevation of cardiac biomarkers above the declining baseline
Electrocardiogram without persistent ST elevation

MEAT Support

HCC Buddy guidance
Documentation of a subsequent or recurrent NSTEMI
Timing within 4 weeks of the initial myocardial infarction
Re-elevation of cardiac biomarkers above the declining baseline
Electrocardiogram without persistent ST elevation

Audit Caution

HCC Buddy guidance
Using I21.4 for a recurrent NSTEMI within 4 weeks instead of I22.2
Failing to assign both initial and subsequent myocardial infarction codes
Misinterpreting fluctuating troponin levels from the initial event as a new myocardial infarction
Not recognizing a subsequent NSTEMI when the initial event was a STEMI — different event types can occur sequentially

Common Mistakes

HCC Buddy guidance
I21.4 — Initial NSTEMI: for the first NSTEMI event, not recurrence
I22.0 — Subsequent STEMI of anterior wall: requires ST elevation
I22.1 — Subsequent STEMI of inferior wall: requires ST elevation
I20.0 — Unstable angina: no biomarker elevation

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is I22.2 an HCC code?

Yes. I22.2 (Subsequent non-ST elevation (NSTEMI) myocardial infarction) maps to HCC 228, Acute Myocardial Infarction under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.252. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: I22.2 is billable and maps to V28 HCC 228, Acute Myocardial Infarction. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code
I22.2
Description
Subsequent non-ST elevation (NSTEMI) myocardial infarction
HCC (V28)
HCC 228 — Acute Myocardial Infarction
RAF reference coefficient
0.252
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 228, Acute Myocardial Infarction
0.252
ESRDHCC 86, Acute Myocardial Infarction
Not separately weighted
RxHCCHCC 188, Coronary Artery Disease
Not separately weighted

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 I22.2 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for I22.2

For I22.2, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

  • MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
  • EEvaluate: test results, medication response, or physical findings reviewed by the provider
  • AAssess: explicit mention in the assessment or plan with acknowledgment of status
  • TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Coder workflow notes

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What This Code Means

I22.2 is the ICD-10-CM diagnosis code for subsequent non-st elevation (nstemi) myocardial infarction. A heart attack that occurs after a previous heart attack, where blood flow to part of the heart is blocked but not completely, resulting in damage to the heart muscle. This code is used when the patient has had a prior myocardial infarction and experiences another one. I22.2 sits in the ICD-10-CM chapter for diseases of the circulatory system (i00-i99), within the section covering ischemic heart diseases (i20-i25).

Under the CMS-HCC V28 risk adjustment model, I22.2 maps to Acute Myocardial Infarction (HCC 228) with a source-labeled community, non-dual, aged reference coefficient of 0.252. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

Verify the timing - 'subsequent' means this is a second or later MI occurring after the initial MI episode; ensure documentation clearly indicates this is not the initial event. For I22.2, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for I22.2 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • Verify the timing - 'subsequent' means this is a second or later MI occurring after the initial MI episode; ensure documentation clearly indicates this is not the initial event
  • Confirm the location of the current MI (anterior wall, inferior wall, etc.) as this may require an additional 5th character code to specify the anatomical site

Clinical Significance

Subsequent NSTEMI represents a recurrent non-ST elevation myocardial infarction within 4 weeks of the initial event. This indicates persistent coronary instability and high risk of adverse outcomes. Unlike STEMI recurrences, NSTEMI recurrences may be subtler in presentation but carry equally important prognostic and treatment implications.

Documentation Requirements

  • Documentation of a subsequent or recurrent NSTEMI
  • Timing within 4 weeks of the initial myocardial infarction
  • Re-elevation of cardiac biomarkers above the declining baseline
  • Electrocardiogram without persistent ST elevation
  • Clinical symptoms of recurrent ischemia
  • Both initial (I21.x) and subsequent (I22.2) codes must be assigned

Commonly Confused Codes

  • I21.4: Initial NSTEMI: for the first NSTEMI event, not recurrence
  • I22.0: Subsequent STEMI of anterior wall: requires ST elevation
  • I22.1: Subsequent STEMI of inferior wall: requires ST elevation
  • I20.0: Unstable angina: no biomarker elevation
  • I25.2: Old myocardial infarction: for healed events

Child Codes

Code Hierarchy

Also searched as

  • I22 2
  • I222

For I22.2, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

I22.2 maps to CMS-HCC V28 category 228, Acute Myocardial Infarction. See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. The mapping identifies a payment HCC category for I22.2. Review its source-labeled HCC coefficient above, check the RAF Calculator with complete member context for CMS-HCC V28 PY2026, and confirm the documentation the chart needs before the code is submitted. HCC Buddy shows no RAF score unless every required source and calculation check passes.

Work I22.2 in HCC Buddy

Open I22.2 in the Code Book for the full Index-to-Tabular path, MEAT checklist, and V28 HCC mapping, or in the Encoder to code from a keyword search. Pro includes 7 days to try everything, no card required.