Brain Protection in Aortic Arch Surgery: Antegrade Cerebral Perfusion and Retrograde Cerebral Perfusion need a Tougher Row to Hoe

Editorial Commentary:

So, although Ganapathi and colleagues1 set out to determine which brain protection technique was more effective, ACP or RCP, it appears that their therapies were insufficiently challenged for detection, because any method of brain protection, including no perfusion at all from either direction, would likely have sufficed for these patients. One might postulate that the exceptionally deep hypothermia was the active modality, and the ACP and RCP were just along for the ride. This perspective is also supported by a recent study by Kaneko and associates7 that compared all 3 of these techniques of cerebral protection (straight DHCA, ACP, and RCP) for noncomplex hemiarch surgery. Kaneko and associates7 showed that DHCA alone is as safe as other adjunct cerebral protection techniques, with no difference in postoperative morbidity and mortality. They concluded that there is no need to complicate the procedure overly with perfusion adjuncts when DHCA is simple, effective, and incurs no additional risks.

Ganapathi and colleagues1 set out to correct the “equipoise” between ACP and RCP. Equipoise is defined as a state of genuine uncertainty regarding the benefits or disadvantages of either therapeutic arm of a clinical trial. This study, by virtue of the short arrest intervals and the very deep levels of hypothermia, did not challenge either modality—ACP or RCP—sufficiently to resolve the equipoise. ACP and RCP need a “tougher row to hoe” to provide evidence of their fullest neuroprotective abilities.

We are indebted to Ganapathi and colleagues1 for demonstrating the adequacy and the equivalence of ACP and RCP for hemiarch operations.