We conservatively estimate that about 41,000 strokes may be attributed to extracranial ICA stenosis annually in the United States.

The annual rate of first-ever and recurrent stroke attributed to extracranial ICA was 13.4 (11.4-15.4) per 100,000 persons.

Conclusions: Large-vessel atherosclerosis is an important cause of stroke, with extracranial ICA stenosis being significantly more common than extracranial ICA occlusion or intracranial atherosclerotic disease.