Collateral blood vessels in acute ischemic stroke: a physiological window to predict future outcomes

ABSTRACT Collateral circulation is a physiologic pathway that protects the brain against ischemic injury and can potentially bypass the effect of a blocked artery, thereby influencing ischemic lesion size and growth. Several recent stroke trials have provided information about the role of collaterals in stroke pathophysiology, and collateral perfusion has been recognized to influence arterial recanalization, reperfusion, hemorrhagic transformation, and neurological outcomes after stroke. Our current aim is to summarize the anatomy and physiology of the collateral circulation and to present and discuss a comprehensible review of the related knowledge, particularly the effects of collateral circulation on the time course of ischemic injury and stroke severity, as well as imaging findings and therapeutic implications

Early amplitude‐integrated electroencephalography for monitoring neonates at high risk for brain injury

Objective: This study aimed to correlate amplitude‐integrated electroencephalography findings with early outcomes, measured by mortality and neuroimaging findings, in a prospective cohort of infants at high risk for brain injury in this center in Brazil. Methods: This blinded prospective cohort study evaluated 23 preterm infants below 31 weeks of gestational age and 17 infants diagnosed with hypoxic‐ischemic encephalopathy secondary to perinatal asphyxia, with gestational age greater than 36 weeks, monitored with amplitude‐integrated electroencephalography in a public tertiary center from February 2014 to January 2015. Background activity (classified as continuous, discontinuous high‐voltage, discontinuous low‐voltage, burst‐suppression, continuous low‐voltage, or flat trace), presence of sleep‐wake cycling, and presence of seizures were evaluated. Cranial ultrasonography in preterm infants and cranial magnetic resonance imaging in infants with hypoxic‐ischemic encephalopathy were performed. Results: In the preterm group, pathological trace or discontinuous low‐voltage pattern (p = 0.03) and absence of sleep‐wake cycling (p = 0.019) were associated with mortality and brain injury assessed by cranial ultrasonography. In patients with hypoxic‐ischemic encephalopathy, seizure patterns on amplitude‐integrated electroencephalography traces were associated with mortality or brain lesion in cranial magnetic resonance imaging (p = 0.005). Conclusion: This study supports previous results and demonstrates the utility of amplitude‐integrated electroencephalography for monitoring brain function and predicting early outcome in the studied groups of infants at high risk for brain injury

Early amplitude-integrated electroencephalography for monitoring neonates at high risk for brain injury

Abstract Objective: This study aimed to correlate amplitude-integrated electroencephalography findings with early outcomes, measured by mortality and neuroimaging findings, in a prospective cohort of infants at high risk for brain injury in this center in Brazil. Methods: This blinded prospective cohort study evaluated 23 preterm infants below 31 weeks of gestational age and 17 infants diagnosed with hypoxic-ischemic encephalopathy secondary to perinatal asphyxia, with gestational age greater than 36 weeks, monitored with amplitude-integrated electroencephalography in a public tertiary center from February 2014 to January 2015. Background activity (classified as continuous, discontinuous high-voltage, discontinuous low-voltage, burst-suppression, continuous low-voltage, or flat trace), presence of sleep-wake cycling, and presence of seizures were evaluated. Cranial ultrasonography in preterm infants and cranial magnetic resonance imaging in infants with hypoxic-ischemic encephalopathy were performed. Results: In the preterm group, pathological trace or discontinuous low-voltage pattern (p = 0.03) and absence of sleep-wake cycling (p = 0.019) were associated with mortality and brain injury assessed by cranial ultrasonography. In patients with hypoxic-ischemic encephalopathy, seizure patterns on amplitude-integrated electroencephalography traces were associated with mortality or brain lesion in cranial magnetic resonance imaging (p = 0.005). Conclusion: This study supports previous results and demonstrates the utility of amplitude-integrated electroencephalography for monitoring brain function and predicting early outcome in the studied groups of infants at high risk for brain injury