Hypothermic circulatory arrest time affects neurological outcomes of frozen elephant trunk for acute type A aortic dissection: A systematic review and meta-analysis.

Background: The treatment of complex thoracic aorta pathologies remains a challenge for cardiovascular surgeons. After introducing Frozen Elephant Trunk (FET), a significant evolution of surgical techniques has been achieved. The present meta-analysis aimed to assess the efficacy of FET in acute type A aortic dissection (ATAAD) and the effect of circulatory arrest time on post-operative neurologic outcomes.
Methods: A standard Preferred Reporting Items for Systematic Reviews and Meta-Analyses search was conducted for all observational studies of patients diagnosed with ATAAD undergoing total arch replacement with FET reporting in-hospital mortality, bleeding, and neurological outcomes. A random-effect meta-analysis was performed using STATA software (StataCorp, TX, USA).
Results: Thirty-five studies were eligible for the present meta-analysis, including 3211 patients with ATAAD who underwent total arch replacement with FET. The pooled estimate for in-hospital mortality, postoperative stroke, and spinal cord injury were 7% (95% CI 5 - 9; I ²  = 68.65%), 5% (95% CI 4 - 7; I ²  = 63.93%), and 3% (95% CI 2 - 4; I ²  = 19.56%), respectively. Univariate meta-regression revealed that with increasing the duration of hypothermic circulatory arrest time, the effect sizes for postoperative stroke and SCI enhances.
Conclusions: It seems that employing the FET procedure for acute type A dissection is associated with acceptable neurologic outcomes and a similar mortality rate comparing with other aorta pathologies. Besides, increasing hypothermic circulation arrest time appears to be a significant predictor of adverse neurologic outcomes after FET.
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