A decrease in blood pressure is associated with unfavorable outcome in patients undergoing thrombectomy under general anesthesia

Background Up to two-thirds of patients are either dependent or dead 3months after thrombectomy for acute ischemic stroke (AIS). Loss of cerebral autoregulation may render patients with AIS vulnerable to decreases in mean arterial pressure (MAP). Objective To determine whether a fall in MAP during intervention under general anesthesia (GA) affects functional outcome. Methods This subgroup analysis included patients from the MR CLEAN trial treated with thrombectomy under GA. The investigated variables were the difference between MAP at baseline and average MAP during GA (MAP) as well as the difference between baseline MAP and the lowest MAP during GA (LMAP). Their association with a shift towards better outcome on the modified Rankin Scale (mRS) after 90days was determined using ordinal logistic regression with adjustment for prognostic baseline variables. Results Sixty of the 85 patients treated under GA in MR CLEAN had sufficient anesthetic information available for the analysis. A greater MAP was associated with worse outcome (adjusted common OR (acOR) 0.95 per point mmHg, 95% CI 0.92 to 0.99). An average MAP during GA 10mmHg lower than baseline MAP constituted a 1.67 times lower odds of a shift towards good outcome on the mRS. For LMAP this association was not significant (acOR 0.97 per mmHg, 95% CI 0.94 to 1.00, p=0.09). Conclusions A decrease in MAP during intervention under GA compared with baseline is associated with worse outcome. Trial registration number NTR1804; ISRCTN10888758; post-results.