Tepid hypothermic (32 C) circulatory arrest for total aortic arch replacement: a paradigm shift from profound hypothermic surgery

In total aortic arch replacement (TARCH) using hypothermic circulatory arrest (HCA) and selective cerebral perfusion (SCP), postoperative cerebral complications, including metabolic abnormalities, are by no means rare. Furthermore, there is a lack of international guidelines for the optimal perfusion temperature and flow for SCP. Starting in 2008, TARCH was performed using tepid HCA at 32 °C. In the present study, 27 patients (group C) who underwent TARCH with deep hypothermia at the lowest rectal temperatures of 20-25 °C were retrospectively reviewed and compared with 23 patients (group W) who underwent TARCH with 32 °C tepid hypothermia. Preoperative patient characteristics and intraoperative and postoperative parameters were compared. Preoperative patient characteristics did not differ significantly between the two groups. Circulatory arrest time, cardiopulmonary bypass time, operating time, amount of blood transfused and postoperative neurological complications were significantly reduced in group W compared with group C. Our procedure of TARCH using tepid hypothermia at 32 °C was safe, and it significantly reduced all parameters of extracorporeal circulation time. However, this study has several limitations. To indicate the safety and usefulness of tepid HCA for TARCH, a further multifaceted study should be performed with a greater number of patients.