Invited Commentary

Abstract

The authors [1Minatoya K. Ogino H. Matsuda H. et al.Evolving selective cerebral perfusion for aortic arch replacement: high flow rate with moderate hypothermic circulatory arrest.Ann Thorac Surg. 2008; 86: 1827-1832Abstract Full Text Full Text PDF PubMed Scopus (71) Google Scholar] present their experience in aortic arch replacement with circulatory arrest (CA) and selective cerebral perfusion (SCP) in three groups of patients using different degrees of hypothermia, namely 20°C, 25°C, and 28°C. In the 28°C cohort, they added a selective perfusion of the left subclavian artery, and SCP flow rate increased to 19 mL/kg/min to maintain a temporal artery pressure of approximately 60 mm Hg. Temperature during CA could be raised to 28°C safely with high SCP flow, without increase of the postoperative neurologic events. As underlined by the authors themselves, this study is neither prospective nor randomized. They have progressively increased the temperature with time; therefore, the patients in group C probably benefited from an increased surgical experience as illustrated by a significantly shorter duration of circulatory arrest (46 vs 64 mins) and of SCP (111 vs 154 mins). This might have protected the group C patients against neurologic deficit. Surprisingly the rewarming times did not significantly differ between the groups, and the operation time was shorter in group C only because of the shorter CA duration. There was also no difference in transfusion volumes, and only the platelets requirement was lower in group C, but what were the criteria for platelets administration? Only the nasopharyngeal temperature was followed, and we know that it reflects more the temperature of the blood in the descending aorta than in the tissues of the patients. Therefore, the difference in temperature of the brain might have been similar for instance between group B and C. Why should the ascending aorta be cannulated in addition to the right axillary artery? The latter can also be used for antegrade reperfusion. The safe duration of circulatory arrest at 28°C for prevention of spinal ischemia has yet to be determined. In spite of the observation by the authors of blood spurting from intercostal arteries inside the descending aorta in group C, it might be good advice to restart lower body perfusion through femoral artery cannulation beyond a circulatory arrest duration of 60 minutes at 28°C. The authors have nicely demonstrated that SCP has a sound physiological basis at predetermined target perfusion pressures rather than fixed flow rates, the target arteries being either the right radial artery or the superficial temporal artery. They have to be commended for their excellent surgical and clinical results in a rather difficult group of patients. In addition, they have paved the way to decrease the impact of profound hypothermia in fragile or elderly patients, or patients who are both fragile and elderly who need this spectacular operation for aortic arch pathology. Evolving Selective Cerebral Perfusion for Aortic Arch Replacement: High Flow Rate With Moderate Hypothermic Circulatory ArrestThe Annals of Thoracic SurgeryVol. 86Issue 6PreviewAlthough hypothermic circulatory arrest (HCA) combined with selective cerebral perfusion (SCP) is a safe strategy for aortic arch surgery, neither the optimal temperature of hypothermia nor the optimal SCP flow rate has been clearly determined. We have since 2002 gradually elevated the temperature of HCA from 20°C to 28°C for aortic arch surgery. This study explored the impact of different temperatures during HCA with SCP on neurologic complications. Full-Text PDF