Microembolic Signals Predict Recurrence Of Ischemic Events In Symptomatic Patients With Middle Cerebral Artery Stenosis

Objective: Middle cerebral artery stenosis is a common cause of ischemic stroke in Asian populations.We sought to determine the effect of symptoms on microembolic signals results,and whether microembolic signals can predict the occurrence or recurrence of ischemia in symptomatic and asymptomatic patients with MCA stenosis.Methods: We retrospectively studied 2489 patients from the neurology department of the first hospital of jilin university from June 2011 to April 2015.Among them,a total of 1016 patients underwent transc ranial doppler ultrasound and carotid artery ultrasonography and were diagnosed with MCA stenosis.About 25% of the 1016 patients were unable to complete microemboli monitoring due to the poor penetration of the temporal window.According to the admission criteria,497 patients were followed up,and we lost contact with 229 patients during the follow-up period.We conducted groups of 268 patients with successful follow-up,and studied the relationship between their MES positive rate and symptoms,the occurrence of MES and the occurrence or recurrence of ischemic stroke.Results:The symptomatic group had a significantly higher incidence of MES(30% vs.16.2%,p < 0.05),as well as higher incidences of cerebral infarction and transient ischemic attack(TIA)(infarction,13.0% vs.4.4%,OR 3.123 [95% CI,1.049–9.294],p < 0.05;TIA,21.0% vs.2.9%,OR = 7.108 [95% CI,1.808–27.949],p < 0.001)than the asymptomatic group.After a follow-up period of 0.5–4.5 y,the subgroup of MES-positive(MES+)symptomatic patients had a significantly higher incidence of TIA(36.7% vs.14.3%,OR = 1.623 [95% CI,1.166–2.258];p < 0.001)than the subgroup of MES-negative(MES-)symptomatic patients.The likelihood of the early occurrence of an endpoint event was also higher in the subgroup of MES+ symptomatic patients.In the group of asymptomatic patients with MCA stenosis,no significant differences were identified between the MES+ and MES-subgroups.Conclusions: 1.The occurrence of MES is related to the clinical symptoms,indicating that the thrombus formed in the unstable plaques release the small emboli with the flow of blood,which is the mechanism leading to the occurrence of ischemic stroke.2.The atherosclerotic plaques in patients with symptomatic MCA stenosis were more unst able and were susceptible to microembolization.3.MES has certain predictive value for the future of symptomatic MCA stenosis patients,especially in the early stage of recurrent cerebral ischemia.4.Patients with asymptomatic MCA stenosis had better prognosis.