Is routine carotid ultrasound surveillance after carotid endarterectomy worthwhile?

BACKGROUND: Periodic ultrasound studies are routinely performed after carotid endarterectomy with the aim of detecting recurrent stenosis or progression of contralateral disease. The frequency with which these studies should be performed and their clinical utility is at present unclear. Our experience with ultrasound surveillance after carotid endarterectomy was reviewed.

METHODS: We performed a retrospective analysis of our carotid registry as a follow-up on patients who had undergone primary endarterectomy between 1982 and 1995. The database was searched for events referable to the contralateral carotid artery including incidence of contralateral endarterectomy, progression of contralateral stenosis, and development of new neurologic symptoms. Data was analyzed by life-table methodology.

RESULTS: A total of 562 patients underwent 660 endarterectomies during the study interval with a postoperative stroke rate of 3.6% and a mortality of 1.1%. Of these, 496 patients had data available on the contralateral artery. There were 384 patent, nonoperated contralateral arteries available for long-term clinical follow-up, of which 276 had serial Doppler examinations. At the time of initial presentation, 30% of patients (141 cases) had greater than 50% diameter stenosis in the contralateral artery including 45 occlusions. There were 67 contralateral endarterectomies performed within 6 months of the original surgery. An additional 15 endarterectomies were performed within 24 months of the original surgery and only 16 subsequent endarterectomies were performed up to the 8-year follow-up. Progression of contralateral stenosis from less than to greater than 50% occurred in 10.1% of the patient population. The rate of disease progression was 5.1% at 3 years, 17.8% at 5 years, and 30% at 7 years. Stroke-free survival in patients without progression was 94.7% at 3 years and 93.3% at 5 years.

CONCLUSIONS: Significant contralateral disease occurs in about one third of patients, most of whom are candidates for early contralateral endarterectomy. In patients who present with minimal contralateral disease, the incidence of progression is low over time. Follow-up duplex examinations on a biennial schedule is sufficient to detect clinically significant disease progression in these patients.