Background: The advent of Frozen elephant trunk (FET) for reconstruction of elective and non-elective aortic arch surgery has augmented the treatment of complex aortic pathologies in a single-stage operation. To date, no studies have been focused on the prevalence and predictors of coagulopathy potentiated by FET procedure. Methods: In a systematic review, we searched databases up to June 2020 for studies reporting coagulopathy complications after FET procedure. A proportional meta-analysis was carried out using STATA software (StataCorp, TX, USA). Results: In total, 46 studies including 6313 patients were eligible. The pooled estimation of reoperation for postoperative bleeding was 7% (95% confidence interval [CI] 5 to 8; I2 = 84.73%; reported by 39 studies including 4796 patients). The mean volume of transfused packed blood cells and fresh frozen plasma was 1677 ml (95% CI 1066.4-2287.6) and 1016.5 ml (95% CI 450.7-1582.3). The subgroup by stent type showed a decrease in the heterogeneity (I2 = 0.01%, I2 = 53.95%, I2 = 0.01%, and I2 = 54.41% for Thoraflex® Hybrid, E-vita®, Frozenix®, and Cronus®, respectively). The subgroup by chronicity of operation resulted in less heterogeneity among patients undergoing elective compared to non-elective operation (I2 = 29.22% versus I2 = 80.56% in non-elective). Meta-regression analysis showed that age and male gender significantly impacted on the reoperation for postoperative bleeding. Conclusions: The FET procedure for arch replacement is associated with coagulopathy and the transfusion of blood products. Male, age, and selective choice of FET use were identified as heterogeneity sources of reoperation for postoperative bleeding.

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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; I2 = 68.65%), 5% (95% CI 4 – 7; I2 = 63.93%), and 3% (95% CI 2 – 4; I2 = 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.