Frequency of Microemboli in Symptomatic Carotid Stenosis Compared to Carotid Occlusion (P1.234)

Objective: To better understand the frequency of microemboli in recently symptomatic carotid artery occlusions. Background: Patients with symptomatic carotid occlusions are at high risk of progressive or recurrent cerebral ischemia. Proposed mechanisms include cerebral hypoperfusion, embolization from the proximal portion of carotid occlusion through external carotid artery collaterals (the original “stump” emboli), or embolization from flow across thrombus in the distal portion of carotid occlusion. The detection of microembolic signals (MES) on transcranial Doppler ultrasound (TCD) has been associated with increased stroke risk in patients with both asymptomatic and symptomatic cervical or intracranial large vessel stenosis. Methods: This was a prospective single-center observational study. Subjects with recently symptomatic carotid stenosis of ≥50[percnt] or complete occlusion seen on any dedicated vascular imaging modality were enrolled. TCD monitoring was performed for 1 hour and recordings saved for offline review. Manual review of the full duration of TCD recording for detection of MES was performed by an experienced reader. MES were categorized using International Consensus Committee guidelines. Results: TCD recordings were available for 44 subjects of whom 26 (59[percnt]) had carotid stenosis and 18 (41[percnt]) carotid occlusion. Mean age was 65 years, 34[percnt] were female, 86[percnt] presented with stroke and 14[percnt] with TIA. Median time from symptom onset to TCD was 72 hours (IQR 60-120). Overall, ≥1 MES was detected in 17 (39[percnt]) subjects. In those with ≥1 MES, the median number of MES was 2 (IQR 1-3). MES were detected in 12 (46[percnt]) stenosis compared to only 5 (28[percnt]) occlusion subjects, but this difference was not significant (p=0.22). There was no relationship between presence of MES and age, sex, stroke vs. TIA, or onset to TCD time. Conclusions: Microemboli are relatively common in both symptomatic carotid occlusions and stenosis; embolization may play a significant role in recurrent ischemia in both groups. Disclosure: Dr. Zandieh has nothing to disclose. Dr. Liberman has nothing to disclose. Dr. Loomis has nothing to disclose. Dr. Raser-Schramm has nothing to disclose. Dr. Wilson has nothing to disclose. Dr. Torres has nothing to disclose. Dr. Ishida has nothing to disclose. Dr. Gallatti has nothing to disclose. Dr. Gallatti has nothing to disclose. Dr. Yates has nothing to disclose. Dr. Davis has nothing to disclose. Dr. Cucchiara has received personal compensation for activities with Lundbeck and UpToDate.