ObjectiveTo investigate the effect of in vitro fenestration on reconstruction of left subclavian artery in endovascular treatment of aortic dissection.MethodsA total of 89 patients with aortic dissection involving left subclavian artery were treated by endovascular treatment in the Second Affiliated Hospital of Fujian Medical University from February 2017 to January 2020. There were 44 patients in the test group, including 36 males and 8 females, with an average age of 58.02±13.58 years. There were 45 patients in the control group, including 35 males and 10 females, with an average age of 54.10±12.32 years. The left subclavian artery was reconstructed by in vitro fenestration in the test group and by chimney technique in the control group. The clinical data were compared between the two groups.ResultsThe operation time of the test group was longer than that of the control group (126.16±7.53 min vs. 96.49±6.52 min, P<0.01). The median follow-up time was 31 (13-48) months. The incidence of endoleak in the test group (4.7%) was lower than that in the control group (18.6%, P=0.04) during the follow-up. There was no statistical difference in the incidence of stroke, myocardial infarction, false lumen thrombosis, retrograde aortic dissection or left subclavian artery occlusion between the two groups (P>0.05).Conclusion In vitro fenestration for reconstructing left subclavian artery in thoracic endovascular aortic repair of aortic dissection is safe and feasible, which is worthy of further clinical promotion.