When performing aneurysm surgery on the aortic arch, surgeons must interrupt blood flow to have a clear view for the operation. However, this places the entire body at risk, particularly the brain and kidneys. To protect the organs, the body was historically placed under deep hypothermic total circulatory arrest at temperatures of 15-18 °C, a process which requires prolonged exposure to cardiopulmonary bypass, which carries risks of increased inflammation, coagulopathy, renal injury, and infections.

Aortic arch surgery has advanced to enable the procedure to occur at warmer temperatures of 22-28 °C (moderate hypothermia). Recently, mild hypothermia, at temperatures of 28-34 °C (approaching natural body temperature) has also been tested, with positive initial results. However, there has yet to be a randomized trial comparing mild versus moderate hypothermia for non-emergent aortic arch surgery. Therefore, the TITAN: COMMENCE trial seeks to compare the effect of mild versus moderate hypothermia for hemi-arch surgery on clinical outcomes and quality of life. 

This will be the largest RCT in aortic arch surgery and will be the first to test mild versus moderate hypothermia. The results will be practice defining and expected to impact the guidelines for the conduct of aortic arch surgery.

in funding awarded by the Canadian Institutes of Health Research (CIHR)

in funding obtained from multiple academic grants