Efficacy of cerebral autoregulation in early ischemic stroke predicts smaller infarcts and better outcome

© 2017 Castro, Serrador, Rocha, Sorond and Azevedo. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.Background and purpose: Effective cerebral autoregulation (CA) may protect the vulnerable ischemic penumbra from blood pressure fluctuations and minimize neurological injury. We aimed to measure dynamic CA within 6 h of ischemic stroke (IS) symptoms onset and to evaluate the relationship between CA, stroke volume, and neurological outcome. Methods: We enrolled 30 patients with acute middle cerebral artery IS. Within 6 h of IS, we measured for 10 min arterial blood pressure (Finometer), cerebral blood flow velocity (transcranial Doppler), and end-tidal-CO2. Transfer function analysis (coherence, phase, and gain) assessed dynamic CA, and receiver-operating curves calculated relevant cut-off values. National Institute of Health Stroke Scale was measured at baseline. Computed tomography at 24 h evaluated infarct volume. Modified Rankin Scale (MRS) at 3 months evaluated the outcome. Results: The odds of being independent at 3 months (MRS 0–2) was 14-fold higher when 6 h CA was intact (Phase > 37°) (adjusted OR = 14.0 (IC 95% 1.7–74.0), p = 0.013). Similarly, infarct volume was significantly smaller with intact CA [median (range) 1.1 (0.2–7.0) vs 13.1 (1.3–110.5) ml, p = 0.002]. Conclusion: In this pilot study, early effective CA was associated with better neurological outcome in patients with IS. Dynamic CA may carry significant prognostic implications.This study was part of Ph.D. thesis of PC and received publiC national grant from Fundação para a Ciência e a Tecnologia (FCT), Portugal, PTDC/SAU-ORG/113329/2009. FS is supported by R01 NS085002 (NINDS).