doi: 10.1161/01.STR.0000204060.73207.c5
(Stroke. 2006;37:767.)
© 2006 American Heart Association, Inc.
Letters to the Editor |
Potential Role for TCD-Directed Antiplatelet Agents in Symptomatic Carotid Artery Dissection
Coventry and Warwickshire County Vascular Unit, Coventry and Warwickshire University Hospitals, Coventry, UK
Nuffield Department of Anaesthetics, University of Oxford, The John Radcliffe Hospital, Oxford, UK
To the Editor:
We read with interest the debate regarding the role of anticoagulation in extracranial arterial dissection.1–3 We agree with Norris1 that artery to artery embolism is the most likely cause of stroke, and also agree with Lyrer2 that there is no evidence supporting anticoagulation for extracranial internal carotid artery dissection (CAD). Donnan and Davis3 make a most important contribution when they differentiate between the use of antithrombotic agents and antiplatelet agents in CAD.
The commonest mechanism of stroke in carotid artery dissection is hypothesized to be artery to artery embolism.1 If this hypothesis is correct, then the situation would appear to be analogous to transient ischemic attacks arising from a critical internal carotid artery stenosis. Transcranial Doppler (TCD)-directed intravenous antiplatelet agents have been successful in treating these patients4,5,6 both before and after elective surgery. In further support of this hypothesis, we have recently reported a 45-year-old patient who was successfully treated with TCD-directed antiplatelet agents7 for recurrent focal deficits associated with an embolizing subintimal CAD.
Converging lines of evidence suggest that embolization from large arteries can cause focal cerebral symptoms and can be treated in the short-term with TCD-directed antiplatelet agents.4 TCD can rapidly and noninvasively assist both in identifying those patients at higher risk of a subsequent neurological event,8 and in assessing the efficacy of interventions.5 TCD emboli detection appears to offer an important advance, enabling the optimal integration of both medical therapy and the timing of any surgical intervention, in patients with symptomatic large-vessel disease. We advocate TCD interrogation of the middle cerebral artery for microemboli in symptomatic CAD, particularly where there are fluctuating neurological signs. TCD-directed antiplatelet agents could then be used to control cerebral microemboli and symptoms.7 Elective surgical or endovascular intervention can then be considered where appropriate.
References
1. Norris JW. Extracranial arterial dissection: anticoagulation is the treatment of choice: For. Stroke. 2005; 36: 2041–2042.
2. Lyrer PA. Extracranial arterial dissection: anticoagulation is the treatment of choice: Against. Stroke. 2005; 36: 2042–2043.
3. Donnan GA, Davis SM. Extracranial arterial dissection: anticoagulation is the treatment of choice. Stroke. 2005; 36: 2043–2044.
4. Lennard NS, Vijayasekar C, Tiivas C, Chan CWM, Higman DJ, Imray CHE. Control of emboli in patients with recurrent or crescendo transient ischaemic attacks using preoperative transcranial Doppler-directed Dextran therapy. Br J Surg. 2003; 90: 166–170.[CrossRef][Medline] [Order article via Infotrieve]
5. Imray CHE, Tiivas CAS. Are some strokes preventable? The potential role of transcranial Doppler in transient ischaemic attacks of carotid origin. Lancet Neurol. 2005; 4: 580–586.[CrossRef][Medline] [Order article via Infotrieve]
6. Naylor AR, Hayes PD, Allroggen H, Lennard N, Gaunt ME, Thompson MM, London NJ, Bell PR. Reducing the risk of carotid surgery: a 7-year audit of the role of monitoring and quality control assessment. J Vasc Surg. 2000; 32: 750–759.[CrossRef][Medline] [Order article via Infotrieve]
7. Joseph T, Kandiyil N, Beale D, Tiivas C, Imray CHE. A novel treatment for symptomatic carotid dissection. Postgraduate Med J. 2005; 81: e6.
8. Markus HS, MacKinnon A. Asymptomatic embolization detected by Doppler ultrasound predicts stroke risk in symptomatic carotid artery stenosis. Stroke. 2005; 36: 971–975.
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