2027 ICD-10-CM Diagnosis Code I71.019Dissection of thoracic aorta, unspecified
ICD-10-CM Codes›I00–I99›I70-I79›I71
- Billable — Valid for Submission
- MCC — Major Complication or Comorbidity
- Risk Adjusts — HCC 264
- Chronic Condition
I71.019 is a billable ICD-10-CM diagnosis code for dissection of thoracic aorta, unspecified. 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. 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 54 closely related codes. Coders also document this condition as chronic dissection of thoracic aorta. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Arterial dissections.
For Medicare Advantage risk adjustment, I71.019 maps to CMS-HCC Category 264 (Vascular Disease with Complications) under the V28 model, adding a risk factor of about 0.455 for a community, non-dual, aged beneficiary in payment year 2027.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
I71.019 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.
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.
- Chronic dissection of thoracic aorta
- Chronic nontraumatic dissection of thoracic aorta
- Congenital dilatation of aorta
- Dissection of thoracic aorta
- Dissection of thoracic aorta due to trauma
- Familial thoracic aortic aneurysm and aortic dissection
- Intramural hematoma of aorta
- Intramural hematoma of thoracic aorta
- Nontraumatic dissection of thoracic aorta
- X-linked severe syndromic thoracic aortic aneurysm and dissection
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to I71.019: its own notes plus those printed at I71 and Chapter 9. A note printed at a category, block or chapter applies to every code under it.
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.-)
Code First
The underlying condition named in the note is sequenced before this code.
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name I71.019, its category, or a range that includes it.
Excludes1 1
These codes carry an Excludes1 note naming I71.019: they are not reported together with it, unless the two conditions are unrelated.
Excludes2 2
These codes carry an Excludes2 note naming I71.019: its condition is not part of those codes, and both may be reported when the patient has both.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Hematoma (traumatic) (skin surface intact) See Also: Contusion;
thoracic See Also: Dissection, aorta, thoracic; I71.019
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Dissection of Thoracic Aorta
a tear within the wall of the thoracic aorta.
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.
Code History & ChangesHistory
Replacement I71.019 replaces the following previously assigned code(s):
- I71.01 - Dissection of thoracic aorta
Questions About I71.019Overview
What is the ICD-10 code for dissection of thoracic aorta, unspecified?
The ICD-10-CM code for dissection of thoracic aorta, unspecified is I71.019 (sometimes written as I71019). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is I71.019 (Dissection of thoracic aorta) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report dissection of thoracic aorta, unspecified on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does I71.019 group to?
When dissection of thoracic aorta, unspecified 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.
Is I71.019 a CC or MCC?
CMS lists I71.019 as an MCC (major complication or comorbidity) for FY 2027. 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 54 closely related codes in its exclusion list.
What is coded first with I71.019?
The Code First note at I71, which applies to I71.019, reads: , if applicable: syphilitic aortic aneurysm (A52.01); traumatic aortic aneurysm (S25.09, S35.09). When one of these applies, it is sequenced before I71.019.
What HCC is I71.019?
I71.019 (dissection of thoracic aorta, unspecified) maps to CMS-HCC Category 264 (Vascular Disease with Complications), commonly written as HCC 264, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 107 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. It does not map to any RxHCC in the Part D prescription drug model.
Does I71.019 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, I71.019 adds a risk adjustment factor of about 0.455 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.338 to 0.622 depending on the payment segment). A more severe related category (HCC 263) supersedes it when both are reported. See the full factor table on the HCC 264 category page.
