2027 ICD-10-CM Diagnosis Code I25.110Atherosclerotic heart disease of native coronary artery with unstable angina pectoris

ICD-10-CM Codes›I00–I99›I20-I25›I25

ICD-10-CM I25.110
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

I25.110 is a billable ICD-10-CM diagnosis code for atherosclerotic heart disease of native coronary artery with unstable angina pectoris. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 302 through 303. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 65 closely related codes. The code is restricted by the Medicare Code Editor to adult patients (age 15 through 124). Coders also document this condition as preinfarction syndrome. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Coronary atherosclerosis and other heart disease.

For Medicare Advantage risk adjustment, I25.110 maps to CMS-HCC Category 229 (Unstable Angina and Other Acute Ischemic Heart Disease) under the V28 model, adding a risk factor of about 0.240 for a community, non-dual, aged beneficiary in payment year 2027.

This medical diagnosis code is frequently used in Cardiology medical specialties to designate conditions such selected atherosclerosis, ischemia, and infarction.

Code Identity

ICD-10-CM Code
I25.110
Billable Status
Yes — Valid for Submission
Code Describes
Atherosclerotic heart disease of native coronary artery with unstable angina pectoris
Short Description
Athscl heart disease of native cor art w unstable ang pctrs
Parent Code
I25.11
Atherosclerotic heart disease of native coronary artery with angina pectoris

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI20-I25Ischemic heart diseases
CategoryI25Chronic ischemic heart disease
This CodeI25.110Atherosclerotic heart disease of native coronary artery with unstable angina pectoris

Code EditsBilling

Medicare Code Editor checks that affect claim validity for I25.110.

Adult diagnoses
The Medicare Code Editor detects inconsistencies in adult cases by checking a patient's age and any diagnosis on the patient's record. The adult code edits apply to patients age range is 15–124 years inclusive (e.g., senile delirium, mature cataract).

Medicare Risk Adjustment (HCC)Billing

I25.110 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.

CMS-HCC V28 Category (Payment Model)
HCC 229— Unstable Angina and Other Acute Ischemic Heart Disease
Payment HCC · PY 2027 one of 25 ICD-10-CM codes in this category
Risk Adjustment Factor (RAF) Weight
+0.240
community, non-dual, aged · ranges 0.240–0.458 across segments
Hierarchy
Superseded by HCC 228
a more severe related category takes the payment when both are reported
Prior Model (CMS-HCC V24)
HCC 87
V24 retired V28 pays 100% of MA risk scores since PY 2026
Other CMS Models
PACE (CMS-HCC V22): HCC 87 · ESRD (V21): HCC 87 · ESRD (V24): HCC 87
ESRD V21 weights: 0.116 dialysis, 0.258–0.392 functioning graft · ESRD V24 weights: 0.120 dialysis, 0.209–0.463 functioning graft
Part D (RxHCC)
RxHCC 188 — Coronary Artery Disease
also risk-adjusts in the Part D prescription drug model (V08)

Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Preinfarction syndrome
  • Unstable angina co-occurrent and due to coronary arteriosclerosis

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to I25.110: its own notes plus those printed at I25.1, I25, block I20-I25, and Chapter 9. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

  • unstable angina without atherosclerotic heart disease (I20.0)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From I25.1 Atherosclerotic heart disease of native coronary artery applies to 6 codes
  • atheroembolism (I75.-)
  • atherosclerosis of coronary artery bypass graft(s) and transplanted heart (I25.7-)
From I25 Chronic ischemic heart disease applies to 56 codes
  • non-ischemic myocardial injury (I5A)
From Chapter 9 (I00-I99) Diseases of the circulatory system applies to 1,433 codes
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
  • systemic connective tissue disorders (M30-M36)
  • transient cerebral ischemic attacks and related syndromes (G45.-)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From I25.1 Atherosclerotic heart disease of native coronary artery applies to 6 codes
  • code, if applicable, to identify:
  • coronary atherosclerosis due to calcified coronary lesion (I25.84)
  • coronary atherosclerosis due to lipid rich plaque (I25.83)
From I25 Chronic ischemic heart disease applies to 56 codes
  • code to identify:
  • chronic total occlusion of coronary artery (I25.82)
  • exposure to environmental tobacco smoke (Z77.22)
  • history of tobacco dependence (Z87.891)
  • occupational exposure to environmental tobacco smoke (Z57.31)
  • tobacco dependence (F17.-)
  • tobacco use (Z72.0)

Code Also

A second code may be needed to fully describe the condition; the note gives no sequencing direction.

From Block I20-I25 Ischemic heart diseases applies to 94 codes
  • the presence of hypertension (I10-I1A)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name I25.110, its category, or a range that includes it.

Excludes1 2

These codes carry an Excludes1 note naming I25.110: they are not reported together with it, unless the two conditions are unrelated.

  • I20 Angina pectoris
    angina pectoris with atherosclerotic heart disease of native coronary arteries (I25.1-) names I25.1-, which includes this code
  • I24.0 Acute coronary thrombosis not resulting in myocardial infarction
    atherosclerotic heart disease (I25.1-) names I25.1-, which includes this code

Excludes2 6

These codes carry an Excludes2 note naming I25.110: its condition is not part of those codes, and both may be reported when the patient has both.

  • I25.5 Ischemic cardiomyopathy
    coronary atherosclerosis (I25.1-, I25.7-) names I25.1-, which includes this code
  • I70 Atherosclerosis
    arteriosclerotic cardiovascular disease (I25.1-) names I25.1-, which includes this code
  • I70 Atherosclerosis
    arteriosclerotic heart disease (I25.1-) names I25.1-, which includes this code
  • I70 Atherosclerosis
    coronary atherosclerosis (I25.1-) names I25.1-, which includes this code
  • I74 Arterial embolism and thrombosis
    coronary embolism and thrombosis (I21-I25) names I21-I25, which includes this code
  • I82 Other venous embolism and thrombosis
    coronary (I21-I25) names I21-I25, which includes this code

Code First 3

These codes say to code first a condition named in the note, and I25.110 is one of the conditions named.

  • I25.82 Chronic total occlusion of coronary artery
    coronary atherosclerosis (I25.1-, I25.7-, I25.81-) names I25.1-, which includes this code
  • I25.83 Coronary atherosclerosis due to lipid rich plaque
    coronary atherosclerosis (I25.1-, I25.7-, I25.81-) names I25.1-, which includes this code
  • I25.84 Coronary atherosclerosis due to calcified coronary lesion
    coronary atherosclerosis (I25.1-, I25.7-, I25.81-) names I25.1-, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR CIR011
Coronary atherosclerosis and other heart disease
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Atherosclerosis

Atherosclerosis is a condition in which plaque builds up inside your arteries. Plaque is a sticky substance made up of cholesterol, fat, blood cells, calcium, and other substances found in the blood. Over time, plaque hardens and causes your arteries to narrow. That limits the flow of oxygen-rich blood to your body.

The full article covers:

  • What is atherosclerosis?
  • What causes atherosclerosis?
  • Who is more likely to develop atherosclerosis?
  • What are the symptoms of atherosclerosis?
  • What other problems can atherosclerosis cause?
  • How is atherosclerosis diagnosed?
  • What are the treatments for atherosclerosis?
  • Can atherosclerosis be prevented?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert I25.110 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
414.01 Crnry athrscl natve vssl
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.
ICD-9-CM
411.1 Intermed coronary synd
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About I25.110Overview

Is I25.110 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report atherosclerotic heart disease of native coronary artery with unstable angina pectoris on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does I25.110 group to?

When atherosclerotic heart disease of native coronary artery with unstable angina pectoris is the principal diagnosis on an inpatient stay, it groups to MS-DRG 302, 303, with relative weights from 0.6610 to 1.1993 depending on complications. Higher weights mean higher Medicare reimbursement.

Is I25.110 a CC or MCC?

CMS lists I25.110 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 65 closely related codes in its exclusion list.

Who can I25.110 be reported for?

The Medicare Code Editor checks atherosclerotic heart disease of native coronary artery with unstable angina pectoris against patient demographics: this code is intended for adult patients (age 15 through 124). Claims outside these limits are flagged as inconsistent.

Can I25.110 be reported with I20.0?

Not as a rule. The Excludes1 note on I25.110 lists "unstable angina without atherosclerotic heart disease (I20.0)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).

What HCC is I25.110?

I25.110 (atherosclerotic heart disease of native coronary artery with unstable angina pectoris) maps to CMS-HCC Category 229 (Unstable Angina and Other Acute Ischemic Heart Disease), commonly written as HCC 229, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 87 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 188.

Does I25.110 risk-adjust for Medicare Advantage payment?

Yes. When documented and reported on a Medicare Advantage encounter, I25.110 adds a risk adjustment factor of about 0.240 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.240 to 0.458 depending on the payment segment). A more severe related category (HCC 228) supersedes it when both are reported. See the full factor table on the HCC 229 category page.