I66.02 Occlusion and stenosis of left middle cerebral artery

Billable ICD-10-CM code, FY2026.

Applies from I66 Occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction

Includes

• embolism of cerebral artery
• narrowing of cerebral artery
• obstruction (complete) (partial) of cerebral artery
• thrombosis of cerebral artery

Excludes1 (never code together)

• Occlusion and stenosis of cerebral artery causing cerebral infarction (I63.3-I63.5)

MS-DRG index

Defines the logic of DRG(s) 061-063 in MDC 01.

Approximate ICD-9-CM (GEMs)

• 434.00 Cerebral thrombosis without mention of cerebral infarction (approximate)
• 434.10 Cerebral embolism without mention of cerebral infarction (approximate)
• 434.90 Cerebral artery occlusion, unspecified without mention of cerebral infarction (approximate)

Code annotations containing back-references to I66.02

Back-references to I66

• Type 1 Excludes: G31.84 Mild cognitive impairment of uncertain or unknown etiology ("cerebrovascular diseases (I60-I69)")
• Code First: G46 Vascular syndromes of brain in cerebrovascular diseases ("underlying cerebrovascular disease (I60-I69)")
• Type 2 Excludes: I10 Essential (primary) hypertension ("essential (primary) hypertension involving vessels of brain (I60-I69)")
• Type 2 Excludes: I15 Secondary hypertension ("secondary hypertension involving vessels of brain (I60-I69)")
• Type 2 Excludes: I74 Arterial embolism and thrombosis ("cerebral embolism and thrombosis (I63.3-I63.5, I66.-)")

Nearby codes

• 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 (this code)
• 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