Strategies of cerebral protection and neurologic dysfunctions after circulatory arrest: back to the future?

The introduction of deep hypothermic circulatory arrest (CA) was the factor that contributed to the diffusion of aortic arch surgery in the surgical world. The progressive quest to improve the outcome of such a complex surgery included the introduction of different tools to better protect the brain, such as retrograde or antegrade cerebral perfusion. The increased experience not only resulted in a continuous improvement of the results, but also facilitated the widespread adoption of arch surgery across most of the cardiac Centers. The trend moved towards a gradual rise in the temperature (from ≤ 20 to 30 °C), coupled with a preference for selective/unilateral antegrade cerebral perfusion for brain protection. Nevertheless, results are not perfect and neurologic dysfunctions, temporary or permanent, remain a frequent complication. The spinal cord is not completely protected by cerebral perfusion and ischemia of the lower body can cause organ malfunctions with severe consequences. After decades, the field is still open for new strategies to minimize the damages intrinsic to the procedure. This review will briefly describe the energetics of the brain, the mechanisms of neurologic dysfunctions, and the advantages and disadvantages of the strategies of cerebral protection commonly used during CA for aortic arch surgery.