Correlation of detecting microembolic signals on transcranial Doppler in patients with large artery atherosclerotic cerebral infarction and ischemic stroke recurrence

Abstract

Objective Microembolic signals (MES) detected by transcranial Doppler (TCD) in patients with large artery atherosclerosis (LAA) ischemic stroke may associate with increased risk of early stroke recurrence because of unstable plague. The purpose of this study was to explore the prevalence of MES, analyze the influencing factors of the MES rate and the relationship between MES and ischemic stroke recurrence. Methods We consecutively included 178 patients with large artery atherosclerotic cerebral infarction in the internal carotid artery cerebral artery regions and detected them for MES. All patients were followed up for ischemic events recurrence. Prevalence of MES, factors related to the MES rate and the association between MES and stroke recurrence factors were analyzed. Results MES were detected in 29 (16.3%) of the 178 patients. Between the MES positive and negative groups, high-density lipoprotein ((0.949±0.204) mmol/L vs (1.066±0.225) mmol/L, t=2.616, P=0.010) and the number of plaelet ((275.1±99.6)×109/L vs (218.4±64.8)×109/L, t=2.948，P=0.006) were significantly different. The presence of MES was more frequent in patients with large severe stenosis artery (23/79, 29.1%) than those with mild-moderate stenosis artery（6/99, 6.1%; χ2=17.122, P=0.000）. During follow-up for a mean of 10.9 months (range, 1 to 21), 9 patients experienced recurrent ipsilateral ischemic events including 2 transient ischemic attack. The rate of recurrence was 17.2% (5/29) vs 2.7% (4/149) between the MES positive and negative groups. The presence of MES predicted ischemic events recurrence (log rank=10.610, P=0.001) by Kaplan-Meier analysis. This remained significant（RR=8.317, 95%CI 1.937—35.717, P=0.004）after Cox regression was used to control for age, hypertension, diabetes，coronary heart disease，smoking, drinking, history of stroke, the regularity of drugs and NIHSS score. Conclusions The presence of MES associates with the number of platelet and the degree of large artery severe stenosis. MES can be a significant independent predictor of ischemic events recurrence in patients with large artery atherosclerotic cerebral infarction. But we need to verify the conclusion with large sample studies. Key words: Brain infarction; Intracranial embolism; Stroke; Recurrence; Ultrasonography, Doppler, transcranial; Platelet count