2027 ICD-10-CM Diagnosis Code G46.1Anterior cerebral artery syndrome

ICD-10-CM Codes›G00–G99›G40-G47›G46

ICD-10-CM G46.1
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

G46.1 is a billable ICD-10-CM diagnosis code for anterior cerebral artery syndrome. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 61 through 63, 69. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 115 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other and ill-defined cerebrovascular disease and Other nervous system disorders (neither hereditary nor degenerative).

Code Identity

ICD-10-CM Code
G46.1
Billable Status
Yes — Valid for Submission
Code Describes
Anterior cerebral artery syndrome
Short Description
Anterior cerebral artery syndrome
Same as the full description in the CMS dataset.
Parent Code
G46
Vascular syndromes of brain in cerebrovascular diseases

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG40-G47Episodic and paroxysmal disorders
CategoryG46Vascular syndromes of brain in cerebrovascular diseases
This CodeG46.1Anterior cerebral artery syndrome

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Anterior cerebral artery syndrome
  • Anterior cerebral circulation infarction
  • Anterior choroidal artery syndrome
  • Central nervous system deficit
  • Neurological deficit

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to G46.1: its own notes plus those printed at G46 and Chapter 6. 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.

From Chapter 6 (G00-G99) Diseases of the nervous system applies to 700 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)

Code First

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

From G46 Vascular syndromes of brain in cerebrovascular diseases applies to 9 codes
  • underlying cerebrovascular disease (I60-I69)

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.

Clinical ClassificationClinical

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

CCSR CIR024
Other and ill-defined cerebrovascular disease
Default principal diagnosis: inpatient No · outpatient No
CCSR NVS020
Other nervous system disorders (neither hereditary nor degenerative)
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Anterior Cerebral Artery Syndrome

    an uncommon stroke syndrome caused by infarction of the cerebral territories supplied by the anterior cerebral artery (aca)and characterized by hemiparesis, dysarthria, aphasia, and limb apraxia.

Patient EducationClinical

Brain Diseases

Your brain is the control center of your body. It controls your thoughts, memory, speech, and movement. It regulates the function of many organs. It's part of your nervous system, which also includes your spinal cord and peripheral nerves. The nervous system sends signals between your brain and the rest of the body.

Read the full article at MedlinePlus

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

Convert G46.1 to ICD-9-CMHistory

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

ICD-9-CM
435.8 Trans cereb ischemia NEC
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 G46.1Overview

What is the ICD-10 code for anterior cerebral artery syndrome?

The ICD-10-CM code for anterior cerebral artery syndrome is G46.1 (sometimes written as G461). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is G46.1 (Vascular syndromes of brain in cerebrovascular diseases) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report anterior cerebral artery syndrome on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does G46.1 group to?

When anterior cerebral artery syndrome is the principal diagnosis on an inpatient stay, it groups to MS-DRG 69, 61, 62, 63, with relative weights from 0.7962 to 2.7211 depending on complications. Higher weights mean higher Medicare reimbursement.

Is G46.1 a CC or MCC?

CMS lists G46.1 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 115 closely related codes in its exclusion list.

What is coded first with G46.1?

The Code First note at G46, which applies to G46.1, reads: underlying cerebrovascular disease (I60-I69). When one of these applies, it is sequenced before G46.1.