Sympathovagal imbalance in early ischemic stroke is linked to impaired cerebral autoregulation and increased infarct volumes

Autores da FMUP

• Pedro Miguel Araújo Campos De Castro

  Autor

• Elsa Irene Peixoto Azevedo Silva

  Autor

Participantes de fora da FMUP

• Serrador, J
• Sorond, F
• Rocha, I

Unidades de investigação

• Laboratório Associado RISE- Rede de Investigação em Saúde

  

  Investigador

  Fernando Carlos De Landér Schmitt

• Neurociências Clínicas e Saúde Mental

• RISE-Health

  

  Investigador

  Fernando Carlos De Landér Schmitt

Abstract

Background and purpose: Autonomic dysfunction is associated with worse outcome of ischemic stroke patients by mechanisms that are not fully understood. There is evidence of autonomic influence in cerebrovascular control but this has not been studied in acute stroke. Therefore, we examined the relationship between heart rate variability (HRV) and baroreflex sensitivity (BRS) in dynamic cerebral autoregulation in the early hours post ischemia, and its impact in clinical and radiological outcome.Methods: We prospectively enrolled 26 patients with acute ischemic stroke in middle cerebral artery. Arterial blood pressure (Finometer), cerebral blood flow velocity (transcranial Doppler), and electrocardiogram were recorded within 6 h. HRV was assessed by the standard side deviations of normal inter-beat intervals, spectral analysis and non-linear entropy indexes. Spontaneous BRS was assessed by spectral and sequence methods. Dynamic cerebral autoregulation was assessed by transfer function analysis (coherence, phase and gain). Infarct volume was calculated from computed tomography at 24 h. Clinical outcome was assessed by the modified Rankin scale.Results: Increased BRS and HRV high frequencies power, both reflecting increased vagal modulation, were correlated with higher gain values of cerebral autoregulation (p < 0.05). The higher vagal modulation was also associated with later large infarct volumes (p < 0.05) but not with clinical outcome.Conclusions: Increased vagal modulation in early hours of acute ischemic stroke, may interfere with cerebrovascular control and is associated with larger infarcts. Understanding the mechanisms that govern this complex interplay can be useful as novel therapeutic targets to improvement of outcome.

Keywords

• Cerebral autoregulation; Autonomic nervous system; Sympathetic nervous system; Parasympathetic nervous system; Ischemic stroke