A Policy of Quality Control Assessment Helps to Reduce the Risk of Intraoperative Stroke During Carotid Endarterectomy

Lennard, N.; Smith, Julia; Gaunt, Michael E.; Abbott, Richard J.; London, N. J. M.; Bell, P. R. F.; Naylor, A. Ross

doi:10.1053/ejvs.1998.0723

Cited by 45 publications

(35 citation statements)

References 17 publications

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“…12 Our data have suggested that approximately 50% of patients will have Ն1 emboli detected during the 3-hour period of postoperative TCD monitoring. 13 Of these, Ͻ5% will undergo high-grade embolization, 4 defined as Ն25 emboli in a given 10-minute period. 9 It has been shown independently and conclusively by 5 different research centers worldwide that in the postoperative period, increasing rates of embolization are seen before manifestation of a neurological deficit.…”

Section: Discussionmentioning

confidence: 99%

“…Intraoperative stroke, apparent on recovery from anesthesia, was reduced in the last 1200 patients from 4% to 0.25% by introducing a policy of intraoperative transcranial Doppler (TCD) monitoring and completion angioscopy. 3,4 However, this failed to prevent postoperative stroke due to thrombosis of the endarterectomy zone, which continued to complicate 2.7% of CEAs. 4 …”

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confidence: 99%

“…3,4 However, this failed to prevent postoperative stroke due to thrombosis of the endarterectomy zone, which continued to complicate 2.7% of CEAs. 4 …”

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confidence: 99%

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Beneficial Effects of Clopidogrel Combined With Aspirin in Reducing Cerebral Emboli in Patients Undergoing Carotid Endarterectomy

et al. 2004

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Background-Postoperative thromboembolic stroke affects 2% to 3% of patients undergoing carotid endarterectomy (CEA) and is preceded by 1 to 2 hours of increasing cerebral embolization. Previous work has demonstrated that high rates of postoperative embolization are associated with increased platelet reactivity to adenosine 5Ј-diphosphate (ADP). Our hypothesis was that preoperative administration of the platelet ADP antagonist clopidogrel could reduce postoperative embolization. Methods and Results-One hundred CEA patients on routine aspirin therapy (150 mg) were randomized to 75 mg clopidogrel (nϭ46) or placebo (nϭ54) the night before surgery. Platelet response to ADP was assessed by whole-blood flow cytometry. The number of emboli detected by transcranial Doppler within 3 hours of CEA was independently quantified. Time taken from flow restoration to skin closure was used as an indirect measure of the time to secure hemostasis. In comparison with placebo, clopidogrel produced a small (8.8%) but significant reduction in the platelet response to ADP (PϽ0.05) while conferring a 10-fold reduction in the relative risk of those patients having Ͼ20 emboli in the postoperative period (odds ratio, 10.23; 95% CI, 1.3 to 83.3; Pϭ0.01, Fisher's exact test). However, in the clopidogrel-treated patients, the time from flow restoration to skin closure (an indirect marker of hemostasis) was significantly increased (Pϭ0.04, Fisher's exact test), although there was no increase in bleeding complications or blood transfusions. Conclusions-This is the first study to show that a CEA patient's postoperative thromboembolic potential can be significantly reduced by targeted preoperative antiplatelet therapy without increasing the risk of bleeding complications.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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Beneficial Effects of Clopidogrel Combined With Aspirin in Reducing Cerebral Emboli in Patients Undergoing Carotid Endarterectomy

et al. 2004

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“…40,57,58 Microembolic signals most commonly occur during the dissection phase intraoperatively, during shunting and unclamping, during wound closure, and in the first few hours postoperatively. [59][60][61][62][63][64][65][66] The number of microembolic signals during dissection correlates best with new ischemic lesions seen on MRI 62 and postoperative cognitive deterioration. 59 The presence of Ͼ50 microembolic signals/hour during the early postoperative phase is reported to predict the development of ipsilateral focal cerebral ischemia.…”

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confidence: 96%

Assessment: Transcranial Doppler ultrasonography: [RETIRED]

et al. 2004

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Abstract-Objective:To review the use of transcranial Doppler ultrasonography (TCD) and transcranial color-coded sonography (TCCS) for diagnosis. Methods: The authors searched the literature for evidence of 1) if TCD provides useful information in specific clinical settings; 2) if using this information improves clinical decision making, as reflected by improved patient outcomes; and 3) if TCD is preferable to other diagnostic tests in these clinical situations. Results: TCD is of established value in the screening of children aged 2 to 16 years with sickle cell disease for stroke risk (Type A, Class I) and the detection and monitoring of angiographic vasospasm after spontaneous subarachnoid hemorrhage (Type A,

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“…1 Postoperative carotid thrombosis is preceded by increasing embolization, which can be detected by transcranial Doppler, and there is increasingly convincing evidence that the postoperative transcranial Doppler signals represent platelet microemboli. 2 We have previously shown that the rate of postoperative embolization is related to the inherent responsiveness of the patients' platelets to adenosine diphosphate (ADP).…”

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confidence: 99%

Therapeutic Benefit of Low-Dose Clopidogrel in Patients Undergoing Carotid Surgery Is Linked to Variability in the Platelet Adenosine Diphosphate Response and Patients’ Weight

Payne

Jones

Hayes

et al. 2007

Stroke

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Background and Purpose-We have previously shown that a single 75-mg tablet of clopidogrel, taken before carotid endarterectomy, significantly reduces postoperative embolization, a marker of thromboembolic stroke. This study explores the antiplatelet effect of this submaximal dose. Methods-Fifty-six patients on long-term aspirin (150 mg) were randomized to 75 mg clopidogrel or placebo before carotid endarterectomy. Blood samples were taken pre-and postdrug administration and at the end of surgery to measure platelet activation and adenosine diphosphate (ADP) response by flow cytometry and aggregometry. Results-Surgery produced a significant rise in platelet activation in vivo as evidenced by a rise in the percentage of monocyte-platelet aggregates in patients given placebo, but this was not seen in patients receiving clopidogrel. Before surgery, clopidogrel produced a significant reduction in the platelet response to ADP; for example, with 10 Ϫ6 M ADP, 77.32Ϯ2.3% bound fibrinogen in placebo group compared with 67.16Ϯ3.1% after clopidogrel (Pϭ0.01). This was accentuated after surgery when the percentage of platelets binding fibrinogen in response to ADP was 76.53Ϯ2.2% in patients given placebo and 62.84Ϯ3.3% in the clopidogrel group (Pϭ0.002). Similar differences were seen over a range of ADP concentrations and by aggregometry. Platelet responsiveness before treatment was highly variable and was positively correlated with the inhibitory effect of clopidogrel; patients with the highest baseline response to ADP showed the greatest response to clopidogrel. A negative correlation was seen between the effect of clopidogrel and patients' weight (rϭ0.57; Pϭ0.002). Conclusions-These results explain how a single 75-mg dose of clopidogrel produces a significant clinical impact on embolization.

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A Policy of Quality Control Assessment Helps to Reduce the Risk of Intraoperative Stroke During Carotid Endarterectomy

Cited by 45 publications

References 17 publications

Beneficial Effects of Clopidogrel Combined With Aspirin in Reducing Cerebral Emboli in Patients Undergoing Carotid Endarterectomy

Beneficial Effects of Clopidogrel Combined With Aspirin in Reducing Cerebral Emboli in Patients Undergoing Carotid Endarterectomy

Assessment: Transcranial Doppler ultrasonography: [RETIRED]

Therapeutic Benefit of Low-Dose Clopidogrel in Patients Undergoing Carotid Surgery Is Linked to Variability in the Platelet Adenosine Diphosphate Response and Patients’ Weight

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