Transcranial Doppler monitoring after carotid endarterectomy.

The objectives of this study were to evaluate the feasibility of transcranial Doppler (TCD) monitoring after carotid endarterectomy (CEA) and to investigate whether 1 hr of monitoring is sufficient to detect a clinically relevant change in the number of postoperative microemboli. We also evaluated the association of patient characteristics and procedure-related variables with the number of postoperative microemboli. One hundred and two patients were monitored during the second hour after CEA. The main outcome measure was the number of TCD-detected microemboli. The secondary outcome measure was a procedure-related cerebral complication graded according to the modified Rankin scale. The median number of microemboli during the second postoperative hour was two (interquartile ranges, 0.75-11) and decreased in most the patients during this time. Two patients had a relatively high and increasing number of microemboli and developed a minor stroke after a symptom-free interval. One patient developed a TIA intraoperatively. There was no significant association between patient characteristics and the use of a venous patch and the number of postoperative microemboli. Conversely, a statistically significant negative association was found between shunt use and the number of microemboli (p = 0.02). The majority of patients had no or a small and decreasing number of microemboli. One hour of monitoring appeared to be effective to select those patients in whom the number of microemboli did not spontaneously decrease and who may need additional medical treatment or surgical reexploration. The role of TCD-detected microemboli as a surrogate measure for the risk of stroke after CEA remains to be validated.