Abstract 34: A Decrease in Blood Pressure is Associated with Unfavorable Outcome in Patients Undergoing Thrombectomy Under General Anesthesia in the Mr Clean Study

Background: Patients treated with thrombectomy for acute ischemic stroke (AIS) under general anesthesia (GA) appear to have less favorable outcomes than patients treated under local anesthesia. Anesthetics used for the induction of GA are known to be associated with decreases in blood pressure. The aim of this study was to determine whether a fall in blood pressure during treatment under GA affects functional outcome. Methods: This subgroup analysis included Patients from the MR CLEAN trial treated with endovascular therapy under GA. The investigated variables were the difference between baseline mean arterial pressure (MAP) and mean MAP during intervention as well as the difference between baseline MAP and the lowest MAP during intervention. Their association with a shift in the outcome on the score on the modified Rankin Scale (mRS) at 90 days from onset was determined using ordinal logistic regression with adjustment for prognostic baseline variables. Results: Sixty of the 85 patients treated with GA in MRCLEAN had sufficient anesthetic information available and were included in this analysis. The difference between baseline MAP and mean MAP during intervention was associated with decreased likelihood of favorable outcome on the mRS (adjusted common odds ratio (acOR) 0.95 per point mmHg, 95%CI 0.92-0.99 ) . For a mean MAP during intervention 10 mmHg lower than baseline MAP this would constitute an odds of favorable outcome ( 1/(0.95^10)= ) 1.67 times lower than patients without this decrease. The association with outcome of the difference between baseline MAP and the lowest MAP during intervention was not significant (acOR 0.97 per point mmHg, 95%CI 0.94-1.00, p=0.09). Conclusion: A decreased MAP during thrombectomy under GA as compared to baseline MAP is associated with a lower likelihood of favorable outcome. This finding underlines the importance of blood pressure management during mechanical thrombectomy under GA.