Abstracts

Rationale: To determine the impact of shunting in EEG or SP (Stump Pressure) monitored patients during CEA in the prevention of perioperative ischemic stroke. To see if EEG monitoring versus SP resulted in a different rate of shunting during CEA. To see if shunt use had higher stroke rate.Methods: Mayo Clinic Arizona CEA and EEG databases were queried and abstracted retrospectively and sequentially for all patients undergoing CEA (last 7 years). Group A uses EEG monitoring; Group B relies on SP to determine the need for shunt placement. Data was analyzed for occurrence of perioperative stroke (<24 hours), frequency of shunt use and other demographic data. Group A patients were shunted if EEG showed major changes (50% suppression/beta frequency loss) with clamping. Group B patients were shunted if the SP was <50 mmHg or if contralateral stenosis was noted. 24 hour post-operative neurological deficits were noted.Results: 313 CEAs were performed from 9/1999 to 2/2006. 101 Group A cases were monitored with EEG and 212 Group B cases with SP. Mean ages were (70.8:71.5 years A:B), male:female ratio was approximately 2:1. All cases were performed under general anesthesia. Of the EEG monitored cases, 10/101 (9.9%) were shunted compared to 75/212 (35.4%) SP cases (p=<0.001). There was trend in Group A for fewer strokes in EEG selected shunted cases, one occurred in the shunted group; Group A, 6/75 shunted had strokes, while 3/137 not shunted sustaining a stroke (p=0.07). Shunt use regardless of monitoring, was associated with a higher rate of stroke: 7/85 shunted (8.2%) versus non-shunted 3/228 (1.3%).Conclusions: EEG may be a superior technique as it is associated with a lower shunt rate, hence a lower stroke rate.