2026 ICD-10-CM Diagnosis Code I71.012Dissection of descending thoracic aorta

ICD-10-CM Codes›I00–I99›I70-I79›I71

ICD-10-CM I71.012
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

I71.012 is a billable ICD-10-CM diagnosis code for dissection of descending thoracic aorta. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 299 through 301. Coders also document this condition as dissection of descending aorta. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Arterial dissections.

Code Identity

ICD-10-CM Code
I71.012
Billable Status
Yes — Valid for Submission
Code Describes
Dissection of descending thoracic aorta
Short Description
Dissection of descending thoracic aorta
Same as the full description in the CMS dataset.
Parent Code
I71.01
Dissection of thoracic aorta

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI70-I79Diseases of arteries, arterioles and capillaries
CategoryI71Aortic aneurysm and dissection
This CodeI71.012Dissection of descending thoracic aorta

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Dissection of descending aorta
  • Dissection of thoracic aorta
  • Type III dissection of descending aorta
  • Type IIIa dissection of descending thoracic aorta

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Dissection
      • aorta
        • thoracic
          • descending thoracic aorta

Clinical ClassificationClinical

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

CCSR CIR027
Arterial dissections
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Aortic Aneurysm

An aneurysm is a bulge or "ballooning" in the wall of an artery. Arteries are blood vessels that carry oxygen-rich blood from the heart to other parts of the body. If an aneurysm grows large, it can burst and cause dangerous bleeding or even death.

Read the full article at MedlinePlus

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Code History & ChangesHistory

Replacement I71.012 replaces the following previously assigned code(s):

  • I71.01 - Dissection of thoracic aorta
FY 2023AddedAdded to the ICD-10-CM code setEffective October 1, 2022.
FY 2024–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About I71.012Overview

Is I71.012 (Dissection of thoracic aorta) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report dissection of descending thoracic aorta on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does I71.012 group to?

When dissection of descending thoracic aorta is the principal diagnosis on an inpatient stay, it groups to MS-DRG 299, 300, 301, with relative weights from 0.7197 to 1.6327 depending on complications. Higher weights mean higher Medicare reimbursement.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.