Clinically silent circulating microemboli in 20 patients with carotid or vertebral artery dissection

Background and Purpose: Carotid and vertebral artery dissections are freque ntly complicated by cerebral embolism. Detection of clinically silent circu lating microemboli by transcranial Doppler sonography (TCD) is now widely i nvestigated in patients with carotid artery disease in the hope to identify patients at increased risk for stroke. Methods: In 20 patients with caroti d (n = 17) or vertebral (n = 2) artery dissection, or both (n = 1), we perf ormed a 1-hour microembolus detection downstream to the dissection in the m iddle or in the posterior cerebral artery, respectively. Results: Five pati ents with a carotid artery stenosis of greater than or equal to 90% or with carotid artery occlusion showed microembolic signals at a rate Of LIP to 1 5 events/h. In all these patients, the onset of the dissection was within t he last 58 days. Patients with lower degrees of stenosis or onset of sympto ms beyond 58 days did not show microembolic signals at all. Three patients who had presented with recurrent ischaemic events prior to TCD monitoring u nexceptionally had microembolic signals. Conclusion: Microembolic signals o ccur in patients with high-grade stenosis or occlusion due to acute cervica l artery dissection. Patients with microemboli seem to be at increased macr oembolic risk, i.e. stroke recurrence, and may require close-meshed clinica l follow-up and possibly stronger antithrombotic treatment. Copyright (C) 2 001 S.Karger AG, Basel.