Microembolic signals after 7 days but not within 24 hours of stroke onset should be predictor of stroke recurrence

Background and purposeMicroembolic signals (MES) on transcranial Doppler ultrasonography (TCD) are occasionally detected in acute ischemic stroke patients and gradually decrease over time. If MES is detectable at 7 days after stroke onset, embolic source lesions may still be active. We hypothesized that presence of MES at 7 days after stroke onset is strongly associated with stroke recurrence.MethodsSubjects comprised 143 patients with acute ischemic stroke who were prospectively examined for the presence of MES using TCD both within 24 h and at 7 days after stroke onset. Stroke recurrence was assessed within 3 months of stroke onset. The association between presence of MES and stroke recurrence was investigated.ResultsMES was detected in 70 of 143 patients (49%) within 24 h of stroke onset and in 34 patients (24%) at 7 days. Stroke recurrence was observed in 6 patients after 7 days and in 10 patients between 7 days and 3 months after stroke onset. Presence of MES within 24 h of stroke was not associated with stroke recurrence (10% for MES-positive vs. 12% for MES-negative, p = 0.792). At 7 days after onset, stroke recurrence was more frequent in the MES-positive group at 7 days than in the MES-negative group (24% vs. 7%, p < 0.0001). Cox's proportional hazard analysis demonstrated presence of MES as an independent factor of stroke recurrence (hazard ratio, 6.4; 95% confidence interval, 1.4–28; p = 0.015).ConclusionPresence of MES detected on TCD at 7 days of stroke onset should be a predictor of stroke recurrence.