Microembolic signals detected by transcranial Doppler sonography during carotid endarterectomy and correlation with serial diffusion-weighted imaging.
OBJECTIVE
Embolic events are a major cause for procedure-related strokes after carotid endarterectomy (CEA). Transcranial Doppler sonography can reveal embolic events as microembolic signals (MES) during CEA. MES during declamping and shunting are frequently detected. MES during shunting are rare and known to be correlated with the neurological outcome of the patient. In the present study, we analyzed the occurrence of MES within different stages of CEA and whether MES within those stages were correlated with cerebral ischemia, as detected by diffusion-weighted imaging (DWI), and brain infarction, as detected by contrast-enhanced MRI.


METHODS
Thirty-three patients were monitored intraoperatively for MES using transcranial Doppler sonography. DWI was performed within 24 hours before and after surgery. Positive postoperative DWI led to reexamination with contrast-enhanced T1-MRI 7 to 10 days after CEA for detection of cerebral infarction.


RESULTS
MES were detected in 32 of 33 patients. The highest number of MES was found during shunting and declamping. A significant correlation was found between MES and DWI-lesions during dissection. A significant correlation was found between MES during dissection and shunting, and nonsignificant correlation was found between MES and the occurrence of cerebral infarction.


CONCLUSIONS
MES could be regularly detected during CEA. Dissection and shunting seem to be the most vulnerable stages of the procedure.
Wolf
Oliver
O
Department of Vascular Surgery, Technical University of Munich, Rechts der Isar Medical Center, Ismaninger Strasse 22, 81675 München, Germany. wolfdr2@hotmail.com
Heider
Peter
P
Heinz
Marco
M
Poppert
Holger
H
Sander
Dirk
D
Greil
Oliver
O
Weiss
Wolfgang
W
Hanke
Marc
M
Eckstein
Hans-Henning
HH
D000368:Aged; D020520:Brain Infarction / Q000175:diagnosis / Q000209:etiology; D002545:Brain Ischemia / Q000175:diagnosis / Q000209:etiology; D038524:Diffusion Magnetic Resonance Imaging; D016894:Endarterectomy, Carotid / Q000009:adverse effects*; D005260:Female; D006801:Humans; D020766:Intracranial Embolism / Q000175:diagnosis* / Q000209:etiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D017585:Ultrasonography, Doppler, Transcranial