I24.89 ICD-10-CM Code: Other forms of acute ischemic heart disease
HCC Buddy Code Card
Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.
FY 2026 Apr update / Diseases of the circulatory system (I00-I99) / Ischemic heart diseases (I20-I25)
I24.89
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceOther forms of acute ischemic heart disease
Other acute heart conditions caused by reduced blood flow that are not classified elsewhere.
Buddy Insight
Other forms of acute ischemic heart disease captures acute cardiac ischemic conditions that do not fit into specific categories like myocardial infarction, unstable angina, or coronary thrombosis without infarction.
CMS-HCC V28
MappedHCC 229
RAF 0.0
CMS-HCC V24
MappedHCC 87
RAF 0.274
ACA/HHS
00
RAF 0
ESRD/PACE
MappedHCC 87
RAF 0.0
RXHCC
MappedHCC 188
RAF 0.0
Code Trumping
Basket needed
Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for I24.89 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for I24.89 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for I24.89 in this effective period.
Excludes 1
Official- myocardial infarction due to demand ischemia (I21.A1)
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for I24.89 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for I24.89 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for I24.89 in this effective period.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.
Is I24.89 an HCC code?
Yes. I24.89 maps to Unstable Angina and Other Acute Ischemic Heart Disease under the CMS-HCC V28 risk adjustment model (and Unstable Angina and Other Acute Ischemic Heart Disease under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for I24.89
For I24.89to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.
- 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
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed I24.89 during that encounter, not just copy-forwarded from a problem list.
What This Code Means
I24.89 is the ICD-10-CM diagnosis code for other forms of acute ischemic heart disease. Other acute heart conditions caused by reduced blood flow that are not classified elsewhere. I24.89 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, I24.89 maps to Unstable Angina and Other Acute Ischemic Heart Disease (HCC 229) with a community, non-dual, aged base RAF weight of 0.000. Under the older V24 model, I24.89 mapped to the same category but with a base RAF weight of 0.274, V28 recalibrated weights across the entire model. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
Use this code for acute ischemic heart disease presentations that don't fit other specific I24 categories. Because I24.89 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. 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, RAF weights, and MEAT documentation criteria for I24.89 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code for acute ischemic heart disease presentations that don't fit other specific I24 categories
- •Ensure the condition is acute in nature and related to insufficient blood supply to the heart
Clinical Significance
Other forms of acute ischemic heart disease captures acute cardiac ischemic conditions that do not fit into specific categories like myocardial infarction, unstable angina, or coronary thrombosis without infarction. This may include conditions such as acute coronary insufficiency or other documented acute ischemic presentations. It ensures that significant acute ischemic events are captured for risk adjustment even when they do not fit standard diagnostic categories.
Documentation Requirements
- ✓Documentation of an acute ischemic heart condition
- ✓Clinical description of the specific presentation
- ✓Evidence of acute ischemia (electrocardiogram changes, symptoms)
- ✓Confirmation that the condition does not meet criteria for myocardial infarction, unstable angina, or other specific I24 codes
- ✓Treatment plan addressing the acute ischemia
Commonly Confused Codes
- •I24.0: Acute coronary thrombosis not resulting in myocardial infarction: for documented coronary thrombosis
- •I24.1: Dressler's syndrome: specific post-myocardial infarction inflammatory syndrome
- •I24.9: Acute ischemic heart disease, unspecified: even less specific than I24.89
- •I20.0: Unstable angina: specific type of acute ischemic heart disease
- •I21.4: Non-ST elevation myocardial infarction: requires biomarker elevation