2027 ICD-10-CM Diagnosis Code I25.85Chronic coronary microvascular dysfunction

ICD-10-CM Codes›I00–I99›I20-I25›I25

ICD-10-CM I25.85
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

I25.85 is a billable ICD-10-CM diagnosis code for chronic coronary microvascular dysfunction. 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. Coders also document this condition as chronic ischemic heart disease. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Coronary atherosclerosis and other heart disease.

I25.85 does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model. It still risk-adjusts in the RxHCC Part D (V08) category 188 for payment year 2027.

Code Identity

ICD-10-CM Code
I25.85
Billable Status
Yes — Valid for Submission
Code Describes
Chronic coronary microvascular dysfunction
Short Description
Chronic coronary microvascular dysfunction
Same as the full description in the CMS dataset.
Parent Code
I25.8
Other forms of chronic ischemic heart disease

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI20-I25Ischemic heart diseases
CategoryI25Chronic ischemic heart disease
This CodeI25.85Chronic coronary microvascular dysfunction

Medicare Risk Adjustment (HCC)Billing

I25.85 does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model, but it maps to payment categories in the other CMS models shown below.

CMS-HCC V28 (Medicare Advantage Payment Model)
Not mapped
no payment category in the model that pays 100% of MA risk scores
Prior Model (CMS-HCC V24)
Not mapped under V24
this diagnosis newly risk-adjusts under the V28 model
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.

  • Chronic ischemic heart disease
  • Chronic microvascular ischemia of myocardium
  • Chronic myocardial ischemia
  • Coronary microvascular dysfunction

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to I25.85: its own notes plus those printed at I25, block I20-I25, and Chapter 9. A note printed at a category, block or chapter applies to every code under it.

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

  • Chronic (presentation of) coronary microvascular disease
  • Coronary microvascular dysfunction NOS

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 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 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 I25.85, its category, or a range that includes it.

Excludes2 2

These codes carry an Excludes2 note naming I25.85: its condition is not part of those codes, and both may be reported when the patient has both.

  • 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

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

Heart Diseases

Heart disease is a general term that includes many types of heart problems. It's a type of cardiovascular disease, which means heart and blood vessel disease.

The full article covers:

  • What is heart disease?
  • What are the types of heart disease?
  • What causes heart diseases?
  • Who is more likely to develop heart diseases?
  • What are the symptoms of heart disease?
  • How are heart diseases diagnosed?
  • What are the treatments for heart disease?
  • Can heart diseases be prevented?

Read the full article at MedlinePlus

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

Code History & ChangesHistory

Replacement I25.85 replaces the following previously assigned code(s):

  • I25.89 - Other forms of chronic ischemic heart disease
FY 2024AddedAdded to the ICD-10-CM code setEffective October 1, 2023.
FY 2025–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About I25.85Overview

What is the ICD-10 code for chronic coronary microvascular dysfunction?

The ICD-10-CM code for chronic coronary microvascular dysfunction is I25.85 (sometimes written as I2585). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is I25.85 (Other forms of chronic ischemic heart disease) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report chronic coronary microvascular dysfunction on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does I25.85 group to?

When chronic coronary microvascular dysfunction 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.

Does I25.85 need an additional code?

When the condition applies, yes. The Use Additional Code note at I25, which applies to I25.85, reads: 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.-); and 1 more listed in the Instructional Notes section. The additional code is reported after I25.85.

Does I25.85 risk-adjust for Medicare Advantage payment?

Not for Medicare Advantage: I25.85 maps to no category in the CMS-HCC V28 model. It still risk-adjusts in the RxHCC Part D (V08) category 188 (Coronary Artery Disease).