Clinical Risk Factors for Stroke and Associations With Microembolic Signals on Transcranial Doppler

Introduction: Transcranial Doppler (TCD) has been used to identify microembolic signals (MES) in individuals with carotid atherosclerosis (CAS). MES are hypothesized to originate from unstable carotid plaque and have been identified in symptomatic and asymptomatic individuals with CAS. The purpose of this study is to examine the relationship of clinical risk factors for stroke (CRFs) and the presence of MES in patients with advanced CAS. Methods: Participants scheduled for carotid endarterectomy (CEA) (>60% stenosis NASCET and ACAS Criteria) were preoperatively evaluated for CRFs and the presence MES with TCD. Kendall's tau correlation coefficients, Pearson χ2, and logistic regression analysis were used to examine the relationship between MES and CRFs. Results: Participants (n=89) had a median (interquartile range) age of 71(13) years, 30 (33.7%) were female, and 53(59.6%) were symptomatic. MES were detected in 32 (36%) participants. There was significant evidence of association between MES with older age (p =0.026) and male sex (p =0.007). No other clinical variables showed significant association with MES (all p-values>0.05). Logistic regression demonstrated that a model including age(p=0.018), sex(p=0.013) and hyperlipidemia(p=0.083) was significantly associated with the presence of MES (p=0.001). Conclusion: MES were associated with older age and male sex in a cohort with advanced carotid atherosclerosis. Symptomatic status was not a predictor for MES in this cohort, suggesting that plaques in both symptomatic and asymptomatic individuals have the ability to release microemboli, highlighting the need for further work to be done to identify unstable plaques.