2027 ICD-10-CM Diagnosis Code I77.812Thoracoabdominal aortic ectasia
ICD-10-CM Codes›I00–I99›I70-I79›I77
- Billable — Valid for Submission
- Chronic Condition
I77.812 is a billable ICD-10-CM diagnosis code for thoracoabdominal aortic ectasia. 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. 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.
I77.812 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
Code Classification
Medicare Risk Adjustment (HCC)Billing
I77.812 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.
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.
- Dilatation of descending aorta
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to I77.812: its own notes plus those printed at I77.81, I77, and 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.
- 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.-)
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
thoracoabdominal I77.812
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Convert I77.812 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About I77.812Overview
What is the ICD-10 code for thoracoabdominal aortic ectasia?
The ICD-10-CM code for thoracoabdominal aortic ectasia is I77.812 (sometimes written as I77812). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
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, 2026 through September 30, 2027.
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 301, 300, 299, with relative weights from 0.7132 to 1.5840 depending on complications. Higher weights mean higher Medicare reimbursement.
Can I77.812 be reported with a code from I71?
Not as a rule. The Excludes1 note at I77.81, which applies to I77.812, lists "aortic aneurysm and dissection (I71.-)". 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).
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.
Does I77.812 risk-adjust for Medicare Advantage payment?
Not for Medicare Advantage. I77.812 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).
