ABSTRACT
Although “clamp and sew” techniques for aortic reconstruction may be feasible for distal segments, the unique anatomy of the aortic arch and direct perfusion of the brain from the great vessels, with its poor tolerance to ischemia, makes operations involving arch reconstruction nearly impossible without circulatory arrest. The vascular pathologies that result in a need for proximal aorta replacement also affect the great vessels; in the setting of acute dissection or aneurysmal disease, fragile innominate and carotid arteries are at risk of further irreparable damage with extensive manipulation and clamping, so HCA allows for meticulous
field. As a protective adjunct to cerebral ischemia, hypothermia is a relatively intuitive concept as decreased temperature results in reduction of metabolic demand. The brain is highly metabolically active and sensitive to ischemic insult, so hypothermia effectively reduces this metabolic need, attenuates the ischemia-reperfusion injury, and helps to limit cerebral edema. More recently, increased use of SACP has further refined the protective strategies for brain protection by initiating circulatory arrest at more moderate levels of hypothermia and avoiding deep hypothermia. Due to the fact that end-organ systems outside the brain can tolerate ischemia at warmer temperatures, moderate hypothermia has been shown to be safe and effective when utilized in conjunction with SACP.
