2026 ICD-10-CM Diagnosis Code I77.812Thoracoabdominal aortic ectasia

ICD-10-CM Codes›I00–I99›I70-I79›I77

ICD-10-CM I77.812
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

I77.812 is a billable ICD-10-CM diagnosis code for thoracoabdominal aortic ectasia. 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 dilatation of descending aorta. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified circulatory disease.

Code Identity

ICD-10-CM Code
I77.812
Billable Status
Yes — Valid for Submission
Code Describes
Thoracoabdominal aortic ectasia
Short Description
Thoracoabdominal aortic ectasia
Same as the full description in the CMS dataset.
Parent Code
I77.81
Aortic ectasia

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI70-I79Diseases of arteries, arterioles and capillaries
CategoryI77Other disorders of arteries and arterioles
This CodeI77.812Thoracoabdominal aortic ectasia

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Dilatation of descending 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.

    • Ectasia, ectasis
      • aorta
        • thoracoabdominal

Clinical ClassificationClinical

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

CCSR CIR032
Other specified and unspecified circulatory disease
Default principal diagnosis: inpatient Yes · outpatient Yes

Convert I77.812 to ICD-9-CMHistory

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

ICD-9-CM
447.73 Thoracoabd aortc ectasia
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About I77.812Overview

Is I77.812 (Aortic ectasia) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report thoracoabdominal aortic ectasia on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does I77.812 group to?

When thoracoabdominal aortic ectasia 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.

What is the ICD-9 equivalent of I77.812?

Under the General Equivalence Mappings, thoracoabdominal aortic ectasia converts to ICD-9-CM 447.73 (thoracoabd aortc ectasia). The mapping is a direct match.

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.