Hemodynamically significant early recurrent carotid stenosis: An often self-limiting and self-reversing condition

Purpose: The natural history of hemodynamically significant (internal carot id systolic velocity more than 125 cm/s) early recurrent carotid stenosis w as studied. Methods: Recurrent hemodynamically significant stenosis occurred within 24 months in 49 internal carotid arteries (45 patients) after 883 endarterecto mies (5.4%). These patients were then examined with serial scans. Subsequen t redo endarterectomy and neurological events were recorded. Results: Patients were observed for 9 to 84 months (mean, 53 months). Arter ies with recurrent stenosis were grouped according to the maximal velocity recorded: group I, systolic velocity more than 125 cm/s and less than 280 c m/s (12); group II, systolic velocity more than 280 cm/s or diastolic veloc ity more than 80 cm/s (21); group III, systolic velocity more than 280 cm/s and diastolic velocity more than 120 cm/s (14); group IV, internal carotid artery occlusion (2). The mean time to a velocity of more than 125 cm/s wa s 11 months. The mean time to peak velocity was 16 months. During the follow-up period, five stenoses remained stable. Nineteen contin ued to increase, with two eventual asymptomatic occlusions (4%). Six recurr ences ultimately had redo endarterectomy, two for symptoms. Three of these developed new secondary recurrent lesions. However, in 25 arteries (53%), t he velocity profile decreased by at least one group classification. The mea n time to the lowest velocity (TTL) was 50 months. Systolic velocity ultima tely fell below 125 cm/s in 13 stenoses (six in group I; five in group II; two in group III). Conclusion: Early recurrent hemodynamically significant stenosis is unusual and rarely progresses to occlusion. Even critical stenosis can regress to within normal limits. Redo endarterectomy is seldom necessary. The challeng e remains to define which patients are at risk for symptoms and occlusion.