MICROEMBOLIC SIGNAL MONITORING IN PATIENTS WITH ACUTE STROKE

Background- There are few data on the occurrence of microembolic signals (MES) in the acute phase of ischemic stroke. The aim of this study was to determine the frequency of MES in patients with middle cerebral artery (MCA) ischemic events and to evaluate the clinical value of MES. Methods- Twenty patients with an ischemic infarction in the MCA territory were investigated by transcranial Doppler technology within 24 hours of the onset of symptom. One-hour recording of MES was performed using an ultrasound device with a 2 MHz probe (Vingmed 800, Oslo, Norway) from the affected MCA. The criteria of MES identification were short duration (100-300 ms), 9 dB above the Doppler background frequency, typical chirp sound, occurring random in cardiac cycle and unilateral visual appearance on the spectral display. Early recurrent stroke was investigated during the observation period. Results- Among the 20 patients completing the study, three (15%) showed MES in their recording and had a definite cardioembolic source. One patient developed a minor ischemic event despite heparinization. In five patients with lacunar stroke and four patients with atherosclerotic carotid artery stenosis, no MES was found. Early recurrent stroke was absent in the patients without MES. Conclusion- There seems to be an association between MES in the acute phase of stroke and a definite cardioembolic sources. Larger studies are needed to confirm these preliminary results.