Embolism as major cause of neurocognitive complications after heart surgery

We find the article by Miyazaki et al. [1] extremely interesting and would like to take the chance to add some useful, we think, remarks. It is a fact that off-pump surgery does not hinder the occurrence of neurocognitive complications after heart surgery, as various studies have shown [2, 3]. This means that from the three, in total, most possible mechanisms of stroke and delirium genesis (hypoperfusion during extracorporeal circulation, embolic episodes, influence of the anesthetic drugs regimen), the second and third remain as the most important. So, rightfully, in the study of Miyazaki et al., the authors have focused on the role of atheromatic plaques and embolism in the development of postoperative stroke and delirium. As far as the pathophysiological background of neurocognitive–neurosensory complications is concerned, it is believed that ‘major’ complications such as stroke, transient ischemic attack and amaurosis fugax (postoperative blindness) are caused by macroembolism, while ‘minor’ complications, such as postoperative delirium, temporary cognitive decline and blurred vision are caused by microembolism from smaller atheromatic, gas or blood clot particles [4, 5]. As a conclusion, protection against embolism during heart surgery is of cardinal importance for the prevention of neurocognitive and neurosensory complications after heart surgery.