2027 ICD-10-CM Diagnosis Code I79.0Aneurysm of aorta in diseases classified elsewhere

ICD-10-CM Codes›I00–I99›I70-I79›I79

ICD-10-CM I79.0
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

I79.0 is a billable ICD-10-CM diagnosis code for aneurysm of aorta in diseases classified elsewhere. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 299 through 301. The code is a manifestation code that cannot be reported as the principal diagnosis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Aortic; peripheral; and visceral artery aneurysms.

I79.0 no longer risk-adjusts for Medicare Advantage: it mapped to HCC 108 under the retired CMS-HCC V24 model through payment year 2025 but maps to no category in the live V28 model. It still risk-adjusts in the PACE (CMS-HCC V22) category 108, ESRD (V21) category 108, and ESRD (V24) category 108 for payment year 2027.

Code Identity

ICD-10-CM Code
I79.0
Billable Status
Yes — Valid for Submission
Code Describes
Aneurysm of aorta in diseases classified elsewhere
Short Description
Aneurysm of aorta in diseases classified elsewhere
Same as the full description in the CMS dataset.
Parent Code
I79
Disorders of arteries, arterioles and capillaries in diseases classified elsewhere

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI70-I79Diseases of arteries, arterioles and capillaries
CategoryI79Disorders of arteries, arterioles and capillaries in diseases classified elsewhere
This CodeI79.0Aneurysm of aorta in diseases classified elsewhere

Code EditsBilling

Medicare Code Editor checks that affect claim validity for I79.0.

Manifestation diagnoses
Manifestation codes describe the manifestation of an underlying disease, not the disease itself, and therefore should not be used as a principal diagnosis.

Medicare Risk Adjustment (HCC)Billing

I79.0 no longer risk-adjusts for Medicare Advantage: it maps to no payment category in the live CMS-HCC V28 model, although it still risk-adjusts in the other CMS models shown below.

CMS-HCC V28 (Medicare Advantage Payment Model)
Not mapped
Dropped in V28 see all codes that no longer risk-adjust
Prior Model (CMS-HCC V24)
HCC 108
V24 retired last contributed to a Medicare Advantage risk score in payment year 2025
Other CMS Models
PACE (CMS-HCC V22): HCC 108 · ESRD (V21): HCC 108 · ESRD (V24): HCC 108
ESRD V21 weights: 0.065 dialysis, 0.086–0.271 functioning graft · ESRD V24 weights: 0.073 dialysis, 0.074–0.287 functioning graft
Part D (RxHCC)
Not mapped
I79.0 does not risk-adjust in the RxHCC prescription drug model

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.

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to I79.0: its own notes plus those printed at 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.

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 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.-)

Code First

The underlying condition named in the note is sequenced before this code.

  • underlying disease

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

Clinical ClassificationClinical

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

CCSR CIR029
Aortic; peripheral; and visceral artery aneurysms
Default principal diagnosis: inpatient No · outpatient No

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

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

Convert I79.0 to ICD-9-CMHistory

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

ICD-9-CM
441.9 Aortic aneurysm NOS
Approximate The match is approximate rather than exact.

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 I79.0Overview

What is the ICD-10 code for aneurysm of aorta in diseases classified elsewhere?

The ICD-10-CM code for aneurysm of aorta in diseases classified elsewhere is I79.0 (sometimes written as I790). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is I79.0 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report aneurysm of aorta in diseases classified elsewhere on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does I79.0 group to?

On inpatient claims, aneurysm of aorta in diseases classified elsewhere maps to MS-DRG 301, 300, 299, with relative weights from 0.7132 to 1.5840 depending on complications. Higher weights mean higher Medicare reimbursement.

Can I79.0 be a principal diagnosis?

No. This is a manifestation code: aneurysm of aorta in diseases classified elsewhere describes the manifestation of an underlying disease rather than the disease itself, so the underlying condition is sequenced first.

Can I79.0 be reported with A52.01?

Not as a rule. The Excludes1 note on I79.0 lists "syphilitic aneurysm (A52.01)". 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).

Does I79.0 risk-adjust for Medicare Advantage payment?

Not for Medicare Advantage. I79.0 mapped to HCC 108 in the retired CMS-HCC V24 model, which last determined payment in 2025, but it maps to no category in the live V28 model; see all codes that no longer risk-adjust. It still risk-adjusts in the PACE (CMS-HCC V22) category 108 (Vascular Disease), ESRD (V21) category 108 (Vascular Disease), and ESRD (V24) category 108 (Vascular Disease).