Transcranial Doppler-detected microemboli in patients with acute stroke.
OBJECTIVE
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.
Tong
D C
DC
Stanford Stroke Center, Department of Neurology and Neurologic Sciences, Stanford University Medical Center, Palo Alto, Calif, USA.
Albers
G W
GW
D000208:Acute Disease; D000368:Aged; D001281:Atrial Fibrillation / Q000150:complications; D002545:Brain Ischemia / Q000150:complications; D016893:Carotid Stenosis / Q000150:complications; D002561:Cerebrovascular Disorders / Q000000981:diagnostic imaging*; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D006331:Heart Diseases / Q000150:complications; D006333:Heart Failure / Q000150:complications; D006344:Heart Septal Defects, Atrial / Q000150:complications; D006349:Heart Valve Diseases / Q000150:complications; D006350:Heart Valve Prosthesis / Q000009:adverse effects; D006493:Heparin / Q000627:therapeutic use; D006801:Humans; D002542:Intracranial Embolism and Thrombosis / Q000000981:diagnostic imaging*; D002546:Ischemic Attack, Transient / Q000150:complications; D008297:Male; D008943:Mitral Valve / Q000473:pathology; D009203:Myocardial Infarction / Q000150:complications; D012307:Risk Factors; D013927:Thrombosis / Q000150:complications; D017585:Ultrasonography, Doppler, Transcranial; D014859:Warfarin / Q000627:therapeutic use
D005343:Fibrinolytic Agents; D014859:Warfarin; D006493:Heparin