Carotid endarterectomy was performed in 152 patients during a 27-month period. The first 82 patients had primary closure of the arteriotomy, whereas the subsequent 70 patients underwent closure with Dacron patch angioplasty. Duplex scanning was undertaken postoperatively in 102 of these patients with a mean follow-up period of 17 months. Perioperative thrombosis occurred in two patients (1.3%), late postoperative recurrent stenosis in 14 patients (13.7%), and late postoperative occlusion in three patients (2.9%). Of the various factors investigated for their correlation with late recurrent stenosis or occlusion, only three were significant: the female sex (recurrent stenosis in 29% vs. 8%, p less than 0.05), a small (less than 4 mm) internal carotid artery (37% vs. 12%, p less than 0.05), and failure to close the arteriotomy with a patch (29% vs. 6%, p less than 0.05). The development of recurrent carotid lesions appeared independent of smoking history, antiplatelet therapy, use of a shunt, or extent of carotid plaque. These data suggest that patients with small internal carotid arteries, specifically female patients, are at greater risk for recurrent carotid stenosis. Patch angioplasty may decrease this risk and should be considered in these patients.