Neurovascular coupling and functional outcome within 90 days-after ischemic stroke

Abstract

Background and Purpose: The higher metabolic demand during neuronal activity induces an increase in cerebral blood flow. Deterioration of this fundamental healthy brain function was found to be crucial in the development of dementia in animal models. We aimed to determine if neurovascular coupling (NVC) at the acute stage of stroke is predictive of functional recovery at 90 days. Methods: We prospectively included all ischemic strokes with occlusion in the anterior circulation, with Modified Rankin Score (mRS)≤4 and without previous cognitive decline (The Informant Questionnaire on cognitive decline in the elderly score<3.5). Cerebral blood flow (CBFV) was assessed by transcranial Doppler at both P2 segments of the posterior cerebral artery (PCA) secured by a probe-holder. NVC was determined by the peak relative increase in CBFV during a visual stimulus paradigm of each of 5 cycles of increasing length (5-sec, 10-sec and 20-sec ON-OFF phases) of a flickering checkerboard. Functional outcome was determined by mRs at 90 days. Results: We analyzed 135 patients, 91% males, aged 68 (IQR 58-76). A worse functional outcome was observed in 29 patients (21%). The magnitude of CBFV during the stimulus paradigm from short (5-sec) to medium (10-sec) and long (20-sec) lengths did not differ significantly between groups of good and bad functional outcome (p>0.05). Conclusions: The dynamics of NVC from visual stimulation, measured by TCD, in anterior circulation stroke was not predictive of functional impairment within 90 days after stroke. The ongoing prospective study will aim to show if the NVC can be predictor for future subtle cognitive impairment.