All ICD10 Codes
Chapter 9

I00–I99: Diseases of the Circulatory System

Diseases of the Circulatory System diagnostic classification updated for 2026.

Chapter Instructions

Excludes2(Not included here. Code separately if applicable.)
  • 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.-)
All CodesBillable Only
Internal Codes
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  • I63.539—

    Cerebral infarction due to unspecified occlusion or stenosis of unspecified posterior cerebral artery

  • I63.54—

    Cerebral infarction due to unspecified occlusion or stenosis of cerebellar artery

  • I63.541—

    Cerebral infarction due to unspecified occlusion or stenosis of right cerebellar artery

  • I63.542—

    Cerebral infarction due to unspecified occlusion or stenosis of left cerebellar artery

  • I63.543—

    Cerebral infarction due to unspecified occlusion or stenosis of bilateral cerebellar arteries

  • I63.549—

    Cerebral infarction due to unspecified occlusion or stenosis of unspecified cerebellar artery

  • I63.59—

    Cerebral infarction due to unspecified occlusion or stenosis of other cerebral artery

  • I63.6—

    Cerebral infarction due to cerebral venous thrombosis, nonpyogenic

  • I63.8—

    Other cerebral infarction

  • I63.81—

    Other cerebral infarction due to occlusion or stenosis of small artery

  • I63.89—

    Other cerebral infarction

  • I63.9—

    Cerebral infarction, unspecified

  • I65—

    Occlusion and stenosis of precerebral arteries, not resulting in cerebral infarction

  • I65.0—

    Occlusion and stenosis of vertebral artery

  • I65.01—

    Occlusion and stenosis of right vertebral artery

  • I65.02—

    Occlusion and stenosis of left vertebral artery

  • I65.03—

    Occlusion and stenosis of bilateral vertebral arteries

  • I65.09—

    Occlusion and stenosis of unspecified vertebral artery

  • I65.1—

    Occlusion and stenosis of basilar artery

  • I65.2—

    Occlusion and stenosis of carotid artery

  • I65.21—

    Occlusion and stenosis of right carotid artery

  • I65.22—

    Occlusion and stenosis of left carotid artery

  • I65.23—

    Occlusion and stenosis of bilateral carotid arteries

  • I65.29—

    Occlusion and stenosis of unspecified carotid artery

  • I65.8—

    Occlusion and stenosis of other precerebral arteries

  • I65.9—

    Occlusion and stenosis of unspecified precerebral artery

  • I66—

    Occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction

  • I66.0—

    Occlusion and stenosis of middle cerebral artery

  • I66.01—

    Occlusion and stenosis of right middle cerebral artery

  • I66.02—

    Occlusion and stenosis of left middle cerebral artery

  • I66.03—

    Occlusion and stenosis of bilateral middle cerebral arteries

  • I66.09—

    Occlusion and stenosis of unspecified middle cerebral artery

  • I66.1—

    Occlusion and stenosis of anterior cerebral artery

  • I66.11—

    Occlusion and stenosis of right anterior cerebral artery

  • I66.12—

    Occlusion and stenosis of left anterior cerebral artery

  • I66.13—

    Occlusion and stenosis of bilateral anterior cerebral arteries

  • I66.19—

    Occlusion and stenosis of unspecified anterior cerebral artery

  • I66.2—

    Occlusion and stenosis of posterior cerebral artery

  • I66.21—

    Occlusion and stenosis of right posterior cerebral artery

  • I66.22—

    Occlusion and stenosis of left posterior cerebral artery

  • I66.23—

    Occlusion and stenosis of bilateral posterior cerebral arteries

  • I66.29—

    Occlusion and stenosis of unspecified posterior cerebral artery

  • I66.3—

    Occlusion and stenosis of cerebellar arteries

  • I66.8—

    Occlusion and stenosis of other cerebral arteries

  • I66.9—

    Occlusion and stenosis of unspecified cerebral artery

  • I67—

    Other cerebrovascular diseases

  • I67.0—

    Dissection of cerebral arteries, nonruptured

  • I67.1—

    Cerebral aneurysm, nonruptured

  • I67.2—

    Cerebral atherosclerosis

  • I67.3—

    Progressive vascular leukoencephalopathy

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