Abstract WP222: Non-invasive Monitoring Of Cortical Activity Post-reperfusion. A Powerful Tool To Improve The Prediction Of Early Clinical Improvement Immediately After Recanalization

Background Although baseline stroke severity is a powerful outcome predictor, in some patients the NIHSS score does not reflect the degree of reperfusion (stunning brain) or it is simply unreliable. Currently the use of BIS(bispectral index) is restricted to monitoring level of consciousness in critical care patients and patients under anaesthesia. Real-time assessment of cortical activity after reperfusion may refine the predictive accuracy of stroke severity on patients outcome and be useful as surrogate of reperfusion success. We aimed to evaluate the impact of BIS monitoring before and shortly after reperfusion on stroke outcome. Methods Consecutive patients with anterior acute ischemic stroke who received reperfusion therapy were monitored with bicortical BIS in the first 6 hours of the admission. We registered the initial and final BIS number on the affected and contralateral side and determined asymmetry and changes in relation with recanalization and other clinical variables. We defined clinical improvement as an decrease of > or = 4 points between NIHSS baseline and the NIHSS at discharge or 5 day. Results 28 patients were monitored by bicortical BIS. The median age was 72 years, baseline NIHSS 16. In all patients, median BIS number in the affected side varied baseline 83 and 85 final (p=0.34). The final BIS number was associated inversely with the NIHSS at discharge or 5 day (p=0,013) and the infarct volume (p= 0.031). Patients with clinical improvement had higher final number BIS (88,4 vs 78,9 p=0,007). A ROC curve identified a Final BIS number of >82 as the better predictor of further clinical improvement with a Sensitivity 88% and Specificity 89% p=0.02. After adjusting for recanalization, post recanalization NIHSS and age, a logistic regression showed that final BIS emerged as the only independent predictive factor of clinical improvement(p=0.024 OR1.41 IC95%: 1.01-1.28) Conclusion Our study demonstrates that some parameters of BIS are related to clinical and radiological variables in acute stroke patients. The final BIS number emerged a powerful independent predictor of further clinical improvements. Larger studies are needed to assessment of post reperfusion cortical activity measured by BIS