Cerebral protection and canulation techniques during aortic arch surgery

The necessity for cerebral protection during open aortic arch surgery is due to the interruption of the blood flow in the afferent cephalic vessels and in the brain perfusion. Irreversible cell damage can occur in the brain depending on the ischemia time. To avoid this, various techniques have been developed for cerebral protection. Hypothermic circulatory arrest (HCA) plays a central role in the avoidance of neurological deficits (ND) and is a safe technique for short periods of circulatory arrest. Due to the high incidence of cerebral complications during prolonged circulatory arrest, additional techniques of cerebral perfusion were developed, with the aim of increasing the safety even in complex interventions. Knowledge of the underlying anatomical situation and the pathological alterations to the aorta is important for the planning of the procedure and for estimation of the surgical risk and NDs. During the preoperative diagnostics, imaging examinations of the complete aorta, including the visualization of the supra-aortic vessels are carried out in addition to the routine preoperative investigations. Computed tomography (CT) or CT angiography with 3-D reconstruction is particularly suited for this. Moderate HCA in combination with selective antegrade cerebral perfusion (SACP) has become established as the gold standard for the technique of cerebral protection. Nearly two thirds of all cases of perioperative stroke in aortic surgery can be attributed to embolisms. The selection of the cerebral protection and the cannulation technique should take the different cerebral risks of patients into account. Neuromonitoring using near infrared spectroscopy (NIRS) is helpful, but NIRS only measures the oxygen saturation in a small area of the frontal brain. Nevertheless, NIRS can provide indications of cerebral ischemia due to reduced perfusion. Despite cerebral protection by HCA and SACP, the time factor represents a risk for the outcome of the patient in aortic arch surgery. A reduction of the HCA and SACP times can be achieved by a simplification of the surgical techniques and anastomoses.