ICD-10 code for intracranial arterial thrombosis

The ICD-10-CM code for intracranial arterial thrombosis is I66.9 (Occlusion and stenosis of unspecified cerebral artery). The official index lists 4 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on I66.9.

Within I66, choose I66.9 (unspecified cerebral artery) only when documentation doesn't support a more specific option: middle cerebral artery (I66.0), anterior cerebral artery (I66.1), posterior cerebral artery (I66.2), cerebellar arteries (I66.3) and other cerebral arteries (I66.8).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

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), DRG 067 (Precerebral Occlusion without Infarction with MCC, relative weight 1.4274), DRG 068 (Precerebral Occlusion without Infarction without MCC, relative weight 0.9013), DRG 791 (Prematurity with Major Problems, relative weight 4.1075) and 1 more, in MDC 01 (Diseases and Disorders of the Nervous System) and MDC 15 (Newborns and Other Neonates with Conditions Originating in the Perinatal Period), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.