Timing of clinically significant microembolism after carotid endarterectomy

A. L. Abbott, C. R. Levi, J. L. Stork, G. A. Donnan, B. R. Chambers

Research output: Contribution to journalArticleResearchpeer-review

21 Citations (Scopus)

Abstract

Purpose: Post-operatively detected transcranial Doppler (TCD) embolic signals (ES) are associated with an increased risk of carotid endarterectomy (CEA) stroke/TIA. The aims here were to quantify this risk and determine the most efficient monitoring protocol. Methods: Sequential patients undergoing CEA (enrolled in a randomised, blinded, placebo-controlled trial of peri-operative dextran therapy) had 30-min TCD monitoring in the first post-operative hour. 30-min monitoring was also performed 2-3, 4-6 and 24-36 h post-operatively. First post-operative hour ES counts were correlated with peri-operative ipsilateral carotid stroke/TIA to determine the size of a clinically significant ES load and the magnitude of the associated risk. The exact Cochran-Armitage test for trend in proportions was used to determine when a clinically significant ES load was first detected. Results: 141 patients (mean age 69.3 years, 72% male) were monitored during the first post-operative hour. An ES count >10 per recording was identified as the best overall predictor of ipsilateral stroke/TIA (sensitivity 72%, specificity 89%). 3/119 (2.5%) patients with 0-10 ES had ipsilateral carotid events compared to 8/22 (36.4%) patients with 11-115 ES (OR = 22.1, 95% CI 4.5, 138.4, p < 0.0001). 13/18 (72%) of subjects with >10 ES were identified in the first post-operative hour with no significant increase in the number of new cases over the subsequent 24-36 post-operative h (p = 0.354). Conclusion: Patients with clinically significant post-operative microembolism had an approximately 15 times higher risk of ipsilateral stroke/TIA and most were identified during a 30-min study in the first post-operative hour.

Original languageEnglish
Pages (from-to)362-367
Number of pages6
JournalCerebrovascular Diseases
Volume23
Issue number5-6
DOIs
Publication statusPublished - 1 May 2007
Externally publishedYes

Keywords

  • Carotid endarterectomy
  • Microembolic signal
  • Stroke
  • Transcranial Doppler

Cite this

Abbott, A. L. ; Levi, C. R. ; Stork, J. L. ; Donnan, G. A. ; Chambers, B. R. / Timing of clinically significant microembolism after carotid endarterectomy. In: Cerebrovascular Diseases. 2007 ; Vol. 23, No. 5-6. pp. 362-367.
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abstract = "Purpose: Post-operatively detected transcranial Doppler (TCD) embolic signals (ES) are associated with an increased risk of carotid endarterectomy (CEA) stroke/TIA. The aims here were to quantify this risk and determine the most efficient monitoring protocol. Methods: Sequential patients undergoing CEA (enrolled in a randomised, blinded, placebo-controlled trial of peri-operative dextran therapy) had 30-min TCD monitoring in the first post-operative hour. 30-min monitoring was also performed 2-3, 4-6 and 24-36 h post-operatively. First post-operative hour ES counts were correlated with peri-operative ipsilateral carotid stroke/TIA to determine the size of a clinically significant ES load and the magnitude of the associated risk. The exact Cochran-Armitage test for trend in proportions was used to determine when a clinically significant ES load was first detected. Results: 141 patients (mean age 69.3 years, 72{\%} male) were monitored during the first post-operative hour. An ES count >10 per recording was identified as the best overall predictor of ipsilateral stroke/TIA (sensitivity 72{\%}, specificity 89{\%}). 3/119 (2.5{\%}) patients with 0-10 ES had ipsilateral carotid events compared to 8/22 (36.4{\%}) patients with 11-115 ES (OR = 22.1, 95{\%} CI 4.5, 138.4, p < 0.0001). 13/18 (72{\%}) of subjects with >10 ES were identified in the first post-operative hour with no significant increase in the number of new cases over the subsequent 24-36 post-operative h (p = 0.354). Conclusion: Patients with clinically significant post-operative microembolism had an approximately 15 times higher risk of ipsilateral stroke/TIA and most were identified during a 30-min study in the first post-operative hour.",
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Timing of clinically significant microembolism after carotid endarterectomy. / Abbott, A. L.; Levi, C. R.; Stork, J. L.; Donnan, G. A.; Chambers, B. R.

In: Cerebrovascular Diseases, Vol. 23, No. 5-6, 01.05.2007, p. 362-367.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Timing of clinically significant microembolism after carotid endarterectomy

AU - Abbott, A. L.

AU - Levi, C. R.

AU - Stork, J. L.

AU - Donnan, G. A.

AU - Chambers, B. R.

PY - 2007/5/1

Y1 - 2007/5/1

N2 - Purpose: Post-operatively detected transcranial Doppler (TCD) embolic signals (ES) are associated with an increased risk of carotid endarterectomy (CEA) stroke/TIA. The aims here were to quantify this risk and determine the most efficient monitoring protocol. Methods: Sequential patients undergoing CEA (enrolled in a randomised, blinded, placebo-controlled trial of peri-operative dextran therapy) had 30-min TCD monitoring in the first post-operative hour. 30-min monitoring was also performed 2-3, 4-6 and 24-36 h post-operatively. First post-operative hour ES counts were correlated with peri-operative ipsilateral carotid stroke/TIA to determine the size of a clinically significant ES load and the magnitude of the associated risk. The exact Cochran-Armitage test for trend in proportions was used to determine when a clinically significant ES load was first detected. Results: 141 patients (mean age 69.3 years, 72% male) were monitored during the first post-operative hour. An ES count >10 per recording was identified as the best overall predictor of ipsilateral stroke/TIA (sensitivity 72%, specificity 89%). 3/119 (2.5%) patients with 0-10 ES had ipsilateral carotid events compared to 8/22 (36.4%) patients with 11-115 ES (OR = 22.1, 95% CI 4.5, 138.4, p < 0.0001). 13/18 (72%) of subjects with >10 ES were identified in the first post-operative hour with no significant increase in the number of new cases over the subsequent 24-36 post-operative h (p = 0.354). Conclusion: Patients with clinically significant post-operative microembolism had an approximately 15 times higher risk of ipsilateral stroke/TIA and most were identified during a 30-min study in the first post-operative hour.

AB - Purpose: Post-operatively detected transcranial Doppler (TCD) embolic signals (ES) are associated with an increased risk of carotid endarterectomy (CEA) stroke/TIA. The aims here were to quantify this risk and determine the most efficient monitoring protocol. Methods: Sequential patients undergoing CEA (enrolled in a randomised, blinded, placebo-controlled trial of peri-operative dextran therapy) had 30-min TCD monitoring in the first post-operative hour. 30-min monitoring was also performed 2-3, 4-6 and 24-36 h post-operatively. First post-operative hour ES counts were correlated with peri-operative ipsilateral carotid stroke/TIA to determine the size of a clinically significant ES load and the magnitude of the associated risk. The exact Cochran-Armitage test for trend in proportions was used to determine when a clinically significant ES load was first detected. Results: 141 patients (mean age 69.3 years, 72% male) were monitored during the first post-operative hour. An ES count >10 per recording was identified as the best overall predictor of ipsilateral stroke/TIA (sensitivity 72%, specificity 89%). 3/119 (2.5%) patients with 0-10 ES had ipsilateral carotid events compared to 8/22 (36.4%) patients with 11-115 ES (OR = 22.1, 95% CI 4.5, 138.4, p < 0.0001). 13/18 (72%) of subjects with >10 ES were identified in the first post-operative hour with no significant increase in the number of new cases over the subsequent 24-36 post-operative h (p = 0.354). Conclusion: Patients with clinically significant post-operative microembolism had an approximately 15 times higher risk of ipsilateral stroke/TIA and most were identified during a 30-min study in the first post-operative hour.

KW - Carotid endarterectomy

KW - Microembolic signal

KW - Stroke

KW - Transcranial Doppler

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DO - 10.1159/000099135

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JF - Cerebrovascular Diseases

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