Impact of Carotid Endarterectomy upon Cognitive Functioning

Abstract

Background and Purpose: The extent to which carotid endarterectomy (CEA) influences cognitive functioning has been the subject of a number of studies often with conflicting conclusions. This paper systematically reviews the literature in an attempt to clarify this issue. Results: Although the majority of studies (16/28) reported an improvement in cognition after surgery, a substantial minority (12/28) found no change. Studies before 1984 tended to report an improvement, while later studies tended to report no change in cognition. Cognitive improvement was also more likely the longer the time interval between CEA and assessment. The studies were found to differ on many methodological factors, e.g. sample size, type of patient and control group, severity and side of carotid stenosis, the range of cognitive tests and timing of postoperative assessment. Conclusion: Given the conflicting findings, and the methodological issues, it is not possible to draw a clear conclusion regarding the impact of carotid endarterectomy upon cognition. Future research which pays attention to these methodological factors is needed in order to adequately resolve the current debate.

Comparison of Microembolism Detected by Transcranial Doppler and Neuropsychological Sequelae of Carotid Surgery and Percutaneous Transluminal Angioplasty

“…We have recently reviewed these. 5 Just over 50% of the studies reported an improvement in cognition after CEA. The remainder found no change.…”

Changes in Cognitive Function After Carotid Endarterectomy in Older Patients: Comparison With Younger Patients

“…12,17) A recent study has reported that the practice effect occurs even during the neuropsychological testing of healthy elderly subjects, and that there was no correlation between the magnitude of the practice effect and age in such subjects. 15) While neuropsychological test scores reportedly increase after CEA in patients aged º76 years when analyzed as a group, 22) test scores did not change after surgery in those aged AE76 years in the present group-rate analysis.…”

“…4) Numerous studies have investigated changes in cognitive function following CEA using objective neuropsychological testing and found that, while CEA may improve cognitive function, 9,17) cognitive impairment occurs in 10% to 30% of patients following CEA. 7,12,13,20) However, reports defined no clear criteria for determining significant cognitive improvement or impairment after surgery on neuropsychological test scores, because such postoperative changes may, in part, reflect the``practice effect'' (an improvement in scores when patients are repeatedly tested).…”

“…7,12,13,20) However, reports defined no clear criteria for determining significant cognitive improvement or impairment after surgery on neuropsychological test scores, because such postoperative changes may, in part, reflect the``practice effect'' (an improvement in scores when patients are repeatedly tested). 12,17) In contrast, physicians and/or patients' families often report subjective postoperative improvements or impairments in cognition for patients undergoing CEA; indeed, patients º76 years old who underwent CEA experienced subjective improvement in 11% and impairment of cognition in 11% of cases after surgery. 22) Further, neuropsychological testing can detect subjective improvement and impairment in cognition after surgery if the optimal cut-off points for changes of the test scores are defined.…”

The impact of carotid revascularization on cognitive function

“…The combined impact of these competing factors has not yet been fully investigated. 54,55 They found that 16 out of 28 studies analyzed demonstrated improved CF after CEA, but that the remaining 12 either did not detect improvements or even found evidence of a decline in CF.…”