Delayed neurological recovery in ischemic stroke patients undergoing endovascular treatment is associated with baseline hyperglycemia: a treatable cause of the stunned brain phenomenon?

Background and aims: In ischemic stroke, there is limited data regarding the impact of baseline hyperglycemia on the treatment effect of recanalization on neurological recovery. This study aimed to directly compare-how short- and long-term serum glucose levels modify the effect of recanalization on functional outcome in patients with ischemic stroke and specifically analyze the occurrence of delayed neurological recovery ("stunned brain phenomenon").

Methods: Observational retrospective analysis including patients with anterior circulation ischemic stroke and large vessel occlusion undergoing mechanical thrombectomy following multimodal-CT upon admission. The primary endpoint was delayed neurological recovery, defined as a lack of early neurological improvement (ENI) at 24 h despite achieving functional independence at day 90. Binary ENI was defined as 24 h-NIHSS ≤ 8 points. The treatment effect of recanalization defined as mTICI 2b-3 was determined for patients with high versus low serum blood glucose (BG, cut-off: 140 mg/dl). Inverse-probability weighting analysis (IPW) was used to assess the treatment effect of recanalization according to glucose profiles.

Results: A total of 348 patients were included in the analysis. The treatment effect of recanalization in patients with low BG on the NIHSS at 24 h and binary ENI was  - 3.5 (95%CI  - 5.3 to  - 1.8, p < 0.001) and 22.4% (95%CI 13.1-31.8, p < 0.001). Furthermore, recanalization in patients with low BG was associated with functional independence at day 90 (26.4%, 95%CI 17.1-35.8, p < 0.001). For patients with high BG, recanalization was not associated with a lower NIHSS at 24 h ( - 1.4, 95%CI  - 3.7-0.9, p = 0.24) although significantly being associated with functional independence at day 90 (+ 14.7%, 95%CI 4.5-24.9, p = 0.005).

Discussion: Successful vessel recanalization was associated with better functional outcome at day 90 independent of BG profiles; however, acute hyperglycemia was significantly linked to delayed neurological recovery. Hence, hyperglycemia might be a major cause of the stunned brain phenomenon and might consequently serve as a promising target for adjunctive therapy in the treatment of ischemic stroke patients.