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Natural history of recurrent and residual stenosis after carotid endarterectomy: implications for postoperative surveillance and surgical management.

BACKGROUND
Noninvasive surveillance of patients after carotid endarterectomy is practiced routinely to detect recurrent stenoses. Many authors advocate repair of asymptomatic severe stenoses so detected. The likelihood of these lesions causing neurologic symptoms is unknown. Our aims were to (1) define the incidence of lesions, (2) determine the frequency of associated neurologic symptoms, and (3) identify patient-dependent factors that might predict restenosis.


METHODS
Data on the status of 449 carotid arteries after endarterectomy were reviewed. The number of recurrent and residual severe (greater than or equal to 80%) stenoses was identified. Interval to development of symptoms was determined by life-table analysis. Patient-dependent factors (age, gender, smoking, diabetes, and patch closure) were evaluated by univariate and multivariate analysis to identify possible associations with severe lesions.


RESULTS
Severe (greater than or equal to 80%) stenoses were seen in 35 patients (7.9%). Residual lesions were seen in 17 cases (eight occlusions and nine stenoses); recurrent lesions were identified in 18 patients (3.9%). Symptoms developed in five cases (14%) (one residual and four recurrent) 35, 48, 68, 98, and 103 months after surgery. The likelihood of developing symptoms associated with stenosis at 5 years was 6%. No factors correlated with residual stenosis. Age less than 60 years, female gender, primary closure, and absence of diabetes were more common in patients with recurrent lesions.


CONCLUSIONS
Severe lesions can be found after carotid endarterectomy in at least 8% of patients and consist of residual defects, as well as recurrent stenoses. Recurrent lesions are more common in specific patient subgroups. These lesions are stable for long periods and the majority remain asymptomatic. Operation is not indicated unless symptoms develop in these patients. Intraoperative completion evaluation may be indicated to reduce the incidence of residual disease. Early noninvasive evaluation is useful as a quality-control measure. Repeated surveillance may provide data on the course of restenosis or contralateral disease progression but is of limited clinical benefit.