Contralateral Neurovascular Coupling in Patients with Ischemic Stroke After Endovascular Thrombectomy

Background: Neurovascular coupling (NVC) refers to the process of aligning cerebral blood flow with neuronal metabolic demand. This study explores the potential of contralateral NVC-linking neural electrical activity on the stroke side with cerebral blood flow velocity (CBFV) on the contralesional side-as a marker of physiological function of the brain. Our aim was to examine the association between contralateral NVC and neurological outcomes in patients with ischemic stroke following endovascular thrombectomy.

Methods: We concurrently recorded the CBFVs of the middle cerebral arteries and electroencephalographic (EEG) signals of patients after endovascular thrombectomy. We employed phase-amplitude cross-frequency coupling to quantify the contralateral coupling between EEG activity on the stroke side and CBFV on the contralesional side. Key neurological outcomes were measured, including changes in National Institute of Health Stroke Scale (NIHSS) scores, infarct volume progression over 7 days, and modified Rankin Scale scores at 90 days.

Results: A total of 52 study participants were enrolled in our study (mean age 61.5 ± 10.4 years; 90.4% male; median preprocedural NIHSS score 14 [interquartile range 10-17]). We successfully computed contralateral NVC in 48 study participants. A significant association emerged between contralateral coupling and improvements in NIHSS scores over 7 days (theta band, P = 0.030) and in infarct volume progression (delta band, P = 0.001; theta band, P = 0.013). Stronger contralateral NVC in the delta and theta bands correlated with better outcomes at 90 days (adjusted odds ratio for delta 7.53 [95% confidence interval 1.13-50.30], P = 0.037; adjusted odds ratio for theta 6.36 [95% confidence interval 1.09-37.01], P = 0.039).

Conclusions: A better contralateral coupling between stroke-side EEG and contralesional CBFV is associated with favorable neurological outcomes, suggesting that contralateral NVC analysis may aid in assessing brain function after recanalization. Replication with a deeper understanding of the mechanisms is needed before clinical translation.