Hypothermia and Selective Antegrade Cerebral Perfusion Is Safe for Arch Repair in Type A Dissection

Background: Unilateral selective antegrade cerebral perfusion with moderate hypothermic circulatory arrest has been shown to be a safe and effective method of cerebral protection during surgery for acute type A dissection. This study evaluates the impact of this cerebral protection strategy on clinical outcomes after extended aortic arch reconstruction in patients undergoing emergent repair of acute type A dissection.

Methods: A retrospective review from 2004 to 2016 at a US academic center of patients undergoing surgery for acute type A dissections using moderate hypothermic circulatory arrest and selective antegrade cerebral perfusion was performed. Patient data were abstracted from The Society of Thoracic Surgeons (STS) institutional database and patient charts. Cohorts were established based on extent of arch replacement: a hemiarch group and a transverse arch group were created. Owing to a dearth of events, a risk score was estimated using a logistic regression model with 30-day mortality as outcome and preoperative variables as predictors, including non-STS variables such as malperfusion. Postoperative outcomes were then adjusted in subsequent regression analyses for the estimated risk score.

Results: In all, 342 patients met inclusion criteria and were included for analysis (299 hemiarch, 43 transverse arch). The mean age was 55.4 years and not different between groups (p = 0.79). Preoperative comorbidities, including prior stroke, diabetes mellitus, and renal failure, were also similar between groups (p > 0.2). Inhospital mortality was 11.7% for the entire cohort (11.7% hemiarch, 9.3% transverse arch; p = 0.60), and the permanent stroke rate was 7.3% (7.7% hemiarch, 4.3% transverse arch; p = 0.47). Median circulatory arrest time was 38.9 ± 19.2 minutes (35.0 ± 13.2 hemiarch, 65.1 ± 30.1 transverse arch; p < 0.0001). Lowest median circulatory arrest temperature was 25.9° ± 3.1C° and not different between groups (25.9° ± 3.2°C hemiarch, 26.2° ± 2.6°C transverse arch; p = 0.50). In unadjusted analysis, no increase in operative mortality, temporary neurologic dysfunction, stroke, or renal failure was observed in the transverse arch group when compared with the hemiarch group. These results persisted when adjusted analysis was performed.

Conclusions: Unilateral selective antegrade cerebral perfusion with moderate hypothermic circulatory arrest remains a safe strategy for cerebral protection during emergent surgical repair of acute type A dissection and provides equivalent outcomes for both limited and extensive aortic arch reconstruction. Based on these data, unilateral selective antegrade cerebral perfusion and moderate hypothermic circulatory arrest may represent an optimal strategy for cerebral protection in this acute setting.