G45.1Carotid artery syndrome (hemispheric)

G45.1 is the ICD-10-CM diagnosis code for carotid artery syndrome (hemispheric). It belongs to category G45 (transient cerebral ischemic attacks and related syndromes), block G40-G47 (episodic and paroxysmal disorders) and chapter 6 (diseases of the nervous system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within G45 (transient cerebral ischemic attacks and related syndromes), G45.1 is specifically for carotid artery syndrome (hemispheric). Related codes cover Vertebro-basilar artery syndrome (G45.0), multiple and bilateral precerebral artery syndromes (G45.2), Amaurosis fugax (G45.3), transient global amnesia (G45.4), other transient cerebral ischemic attacks and related syndromes (G45.8) and transient cerebral ischemic attack, unspecified (G45.9).

As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 061 (Ischemic Stroke, Precerebral Occlusion or Transient Ischemia with Thrombolytic Agent with MCC, relative weight 2.7211), DRG 062 (Ischemic Stroke, Precerebral Occlusion or Transient Ischemia with Thrombolytic Agent with CC, relative weight 1.7781), DRG 063 (Ischemic Stroke, Precerebral Occlusion or Transient Ischemia with Thrombolytic Agent without CC/MCC, relative weight 1.455) and DRG 069 (Transient Ischemia without Thrombolytic, relative weight 0.7964), in MDC 01 (Diseases and Disorders of the Nervous System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 435.8 (other specified transient cerebral ischemias).