Hypothermia and cerebral protection strategies in aortic arch surgery: a comparative effectiveness analysis from the STS Adult Cardiac Surgery Database

OBJECTIVES: Hypothermic circulatory arrest is essential to aortic arch surgery, although consensus regarding optimal cerebral protection strategy remains lacking. We evaluated the current use and comparative effectiveness of hypothermia/cerebral perfusion (CP) strategies in aortic arch surgery. METHODS: Using the Society of Thoracic Surgeons Database, cases of aortic arch surgery with hypothermic circulatory arrest from 2011 to 2014 were categorized by hypothermia strategy-deep/profound (D/P; ≤20°C), low-moderate (L-M; 20.1-24°C), and high-moderate (H-M; 24.1-28°C)-and CP strategy-no CP, antegrade (ACP), retrograde (RCP) or both ACP/RCP. After adjusting for potential confounders, strategies were compared by composite end-point (operative mortality or neurologic complication). RESULTS: Of the 12 521 aortic arch repairs with hypothermic circulatory arrest, the most common combined strategies were straight D/P without CP (25%), D/P + RCP (16%) and D/P + ACP (14%). Overall rates of the primary end-point, operative mortality and stroke were 23%, 12% and 8%, respectively. Among the 7 most common strategies, the 2 not utilizing CP (straight D/P and straight L-M) appeared inferior, associated with significantly higher risk of the composite end-point (odds ratio: 1.6; P < 0.01); there was no significant difference in composite outcome between the remaining strategies (D/P + ACP, D/P + RCP, L-M + ACP, L-M + RCP and H-M + ACP). CONCLUSIONS: In a comparative effectiveness study of cerebral protection strategies for aortic arch repair, strategies without adjunctive CP, including the most commonly utilized strategy of straight D/P hypothermia, appeared inferior to those utilizing CP. There was no clearly superior strategy among remaining techniques, and randomized trials are needed to define best practice.