The etiology of symptoms in patients with recurrent carotid stenosis.

We performed 33 carotid endarterectomies in 29 patients for recurrent carotid stenosis. The interval between the initial and second operations ranged from six weeks to 11 years with a mean of 56 months. Three types of pathologic lesions were identified: (1) recurrent atherosclerosis (RA), (2) neointimal fibromuscular hyperplasia (NFH), and (3) lesions with elements of both RA and NFH (complex lesions). Histologic examination of early-recurring lesions (less than three years) revealed NFH in 17 patients and one complex lesion. Late-recurring lesions (three years or later) were due to atherosclerosis in eight vessels, NFH in four, and both RA and NFH in three. Focal neurologic symptoms occurred in 25 (76%) of 33 vessels, and an embolic source could be identified in 16 (64%) of 25 patients. Embolic events rather than reduced blood flow due to progressive stenosis are more frequent causes of symptoms in patients with recurrent carotid stenosis than was formerly believed.