2026 ICD-10-CM Diagnosis Code I25.42Coronary artery dissection
ICD-10-CM Codes›I00–I99›I20-I25›I25
- Billable — Valid for Submission
- MCC — Major Complication or Comorbidity
- Chronic Condition
I25.42 is a billable ICD-10-CM diagnosis code for coronary artery dissection. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 314 through 316. As a secondary diagnosis, it counts as a major complication or comorbidity (MCC) and places an inpatient stay in the highest severity level of its MS-DRG family. It does not count, however, when the principal diagnosis is one of 16 closely related codes. Coders also document this condition as acute dissection of coronary artery. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Arterial dissections.
I25.42 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 2026.
This medical diagnosis code is frequently used in Cardiology medical specialties to designate conditions such selected atherosclerosis, ischemia, and infarction.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
I25.42 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.
Source: CMS Payment Year 2026 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.
- Acute dissection of coronary artery
- Chronic dissection of coronary artery
- Dissection of anterior descending branch of left coronary artery
- Dissection of coronary artery
- Idiopathic spontaneous coronary artery dissection
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.
Patient EducationClinical
Coronary Artery Disease
Coronary artery disease (CAD) is the most common type of heart disease. It is the leading cause of death in the United States in both men and women.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert I25.42 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About I25.42Overview
What is the ICD-10 code for coronary artery dissection?
The ICD-10-CM code for coronary artery dissection is I25.42 (sometimes written as I2542). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is I25.42 (Coronary artery aneurysm and dissection) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report coronary artery dissection on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does I25.42 group to?
When coronary artery dissection is the principal diagnosis on an inpatient stay, it groups to MS-DRG 314, 315, 316, with relative weights from 0.6821 to 2.0852 depending on complications. Higher weights mean higher Medicare reimbursement.
Is I25.42 a CC or MCC?
CMS lists I25.42 as an MCC (major complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it places the inpatient stay in the highest-weighted DRG of its severity family. It does not count when the principal diagnosis is one of the 16 closely related codes in its exclusion list.
What is the ICD-9 equivalent of I25.42?
Under the General Equivalence Mappings, coronary artery dissection converts to ICD-9-CM 414.12 (dissection cor artery). The mapping is a direct match.
Does I25.42 risk-adjust for Medicare Advantage payment?
Not for Medicare Advantage: I25.42 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).
