Telestroke networks for area-wide access to endovascular stroke treatment.

BACKGROUND: Endovascular therapy (EVT) offers a highly effective therapy for patients with acute ischemic stroke due to large vessel occlusion. Comprehensive stroke centers (CSC) are required to provide permanent accessibility to EVT. However, when affected patients are not located in the immediate catchment area of a CSC, i.e. in rural or structurally weaker areas, access to EVT is not always ensured. MAIN BODY: Telestroke networks play a crucial role in closing this healthcare coverage gap and thereby support specialized stroke treatment. The aim of this narrative review is to elaborate the concepts for the indication and transfer of EVT candidates via telestroke networks in acute stroke care. The targeted readership includes both comprehensive stroke centers and peripheral hospitals. The review is intended to identify ways to design care beyond those areas with narrow access to stroke unit care to provide the indicated highly effective acute therapies on a region-wide basis. Here, the two different models of care: "mothership" and "drip-and-ship" concerning rates of EVT and its complications as well as outcomes are compared. Decisively, forward-looking new model approaches such as a third model the "flying/driving interentionalists" are introduced and discussed, as far as few clinical trials have investigated these approaches. Diagnostic criteria used by the telestroke networks to enable appropriate patient selection for secondary intrahospital emergency transfers are displayed, which need to meet the criteria in terms of speed, quality and safety. CONCLUSION: The few findings from the studies with telestroke networks are neutral for comparison in the drip-and-ship and mothership models. Supporting spoke centres through telestroke networks currently seems to be the best option for offering EVT to a population in structurally weaker regions without direct access to a CSC. Here, it is essential to map the individual reality of care depending on the regional circumstances.

Dynamical structures in binary media of potassium-driven neurons.

According to the conventional approach neural ensembles are modeled with fixed ionic concentrations in the extracellular environment. However, in some cases the extracellular concentration of potassium ions cannot be regarded as constant. Such cases represent specific chemical pathway for neurons to interact and can influence strongly the behavior of single neurons and of large ensembles. The released chemical agent diffuses in the external medium and lowers thresholds of individual excitable units. We address this problem by studying simplified excitable units given by a modified FitzHugh-Nagumo dynamics. In our model the neurons interact only chemically via the released and diffusing potassium in the surrounding nonactive medium and are permanently affected by noise. First, we study the dynamics of a single excitable unit embedded in the extracellular matter. That leads to a number of noise-induced effects such as self-modulation of firing rate in an individual neuron. After the consideration of two coupled neurons we consider the spatially extended situation. By holding parameters of the neuron fixed, various patterns appear ranging from spirals and traveling waves to oscillons and inverted structures depending on the parameters of the medium.