Transcranial Doppler–Detected Microemboli in Patients With Acute Stroke

Background and Purpose Transcranial Doppler sonography (TCD) has been used to detect microembolic signals in a variety of clinical situations. We studied the prevalence of TCD-detected microemboli in 38 acute stroke patients. Methods Consecutive patients with acute anterior circulation stroke were stratified into high-risk (group 1), medium-risk (group 2), and low-risk (group 3) groups based on their risk factors for cerebral embolism. Results Microemboli were detected in 11% of patients. They were present in 17% of group 1, 10% of group 2, and 0% of group 3 patients. Emboli were present in patients with mechanical prosthetic valves, carotid stenosis (>70%), and mitral valve strands with a patent foramen ovale. Patients with microemboli more frequently had a history of cerebral ischemia compared with patients without microemboli ( P <.05). They also more frequently had recent (<3 months) symptoms compared with patients without microemboli ( P <.05). In patients with a cardiac source of embolization, the number of microemboli detected was directly proportional to the acuity of previous symptoms. Conclusions These data suggest that TCD-detected microemboli are associated with an increased prevalence of prior cerebrovascular ischemia. The presence of TCD-detected microemboli could be a risk factor for cerebrovascular ischemia.