2027 ICD-10-CM Diagnosis Code G45.8Other transient cerebral ischemic attacks and related syndromes
ICD-10-CM Codes›G00–G99›G40-G47›G45
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Chronic Condition
G45.8 is a billable ICD-10-CM diagnosis code for other transient cerebral ischemic attacks and related syndromes. 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. Coders also document this condition as acute cerebral ischemia. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Transient cerebral ischemia.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Acute cerebral ischemia
- Arterial steal syndrome
- Carotid territory transient ischemic attack
- Cerebral steal syndrome
- Left subclavian steal syndrome
- Right subclavian steal syndrome
- Subclavian steal syndrome
- Vertebrobasilar territory transient ischemic attack
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to G45.8: its own notes plus those printed at G45 and Chapter 6. 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)
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name G45.8, its category, or a range that includes it.
Excludes1 1
These codes carry an Excludes1 note naming G45.8: they are not reported together with it, unless the two conditions are unrelated.
Excludes2 2
These codes carry an Excludes2 note naming G45.8: its condition is not part of those codes, and both may be reported when the patient has both.
- Chapter 9 (I00-I99) Diseases of the circulatory systemtransient cerebral ischemic attacks and related syndromes (G45.-) names G45.-, which includes this code
- I63.9 Cerebral infarction, unspecifiedtransient cerebral ischemic attacks and related syndromes (G45.-) names G45.-, which includes this code
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Syndrome See Also: Disease;
subclavian G45.8
subclavian steal G45.8
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Transient Ischemic Attack
A transient ischemic attack (TIA) is a stroke that lasts only a few minutes. It happens when the blood supply to part of the brain is briefly blocked. Symptoms of a TIA are like other stroke symptoms, but do not last as long. They happen suddenly, and include:
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert G45.8 to ICD-9-CMHistory
Code HistoryHistory
Questions About G45.8Overview
What is the ICD-10 code for other transient cerebral ischemic attacks and related syndromes?
The ICD-10-CM code for other transient cerebral ischemic attacks and related syndromes is G45.8 (sometimes written as G458). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is G45.8 (Transient cerebral ischemic attacks and related syndromes) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report other transient cerebral ischemic attacks and related syndromes on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does G45.8 group to?
When other transient cerebral ischemic attacks and related syndromes 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 G45.8 a CC or MCC?
CMS lists G45.8 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.
Can G45.8 be reported with P91.0?
Not as a rule. The Excludes1 note at G45, which applies to G45.8, lists "neonatal cerebral ischemia (P91.0)". 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).
