Analysis Of The Related Factors Of Aortic Dilation After TEVAR Of Type B Aortic Dissection

Objective:To investigate the incidence of aortic dilatation in patients with Type B aortic dissection after TEVAR and to analyze its risk factors.Methods:Between Sep 2014 to Dec 2020,We retrospectively analyzed 86 patients with type B aortic dissection who received TEVAR and were followed up in our hospital.Scan the CTA images of each patient before operation and at the end time.After curved surface reconstruction,measured the maximum diameter of thoracic aorta and abdominal aorta,true and false lumen.According to the time of onset,the patients were divided into hyperacute stage(<24 hours),acute stage(2-7 days),subacute stage(8-30days),chronic stage(>30 days),analyzed the aortic dilatation at different stages and segments after TEVAR.The patients were divided into dilated group and non dilated group according to the maximum diameter of aorta increased more than 5mm after operation.Analyzed the clinical and imaging data of the two groups,and logistic regression analysis was used to analyze the risk factors of aortic dilatation after TEVAR.Results:In acute stage,the maximum diameter of thoracic aorta had no difference before and after operation(P>0.05),the diameter of TL increased significantly(P<0.001),the diameter of FL decreased significantly(P<0.001);the maximum diameter of abdominal aorta had no difference before and after operation(P>0.05),the diameter of TL increased after operation(P<0.01),and the diameter of FL did not change significantly(P>0.05);In subacute stage,the maximum diameter of thoracic aorta was slightly enlarged(P<0.01),the diameter of TL was enlarged(P<0.01),and the diameter of FL had no difference(P>0.05);In chronic stage,there was no significant difference in the maximum diameter of thoracic aorta(P>0.05),the diameter of TL was significantly enlarged,and the diameter of FL was significantly reduced,but the differences were not statistically significant(P>0.05);the maximum diameter of abdominal aorta was enlarged,the diameter of TL was slightly enlarged,and the diameter of FL was slightly expanded(P>0.05).The maximum diameter of aorta:thoracic dilation in 3 cases(10.7%)and abdominal dilation in 4 cases(14.3%)in acute stage;thoracic dilation in 7 cases(15.2%)and abdominal dilation in 10 cases(21.7%)in subacute stage;There were 7 cases(58.3%)with thoracic dilation and 6 cases(50%)with abdominal dilation in chronic stage.The incidence of dilation of maximum diameter of thoracic aorta and abdominal aorta in chronic stage was higher than that in acute stage and subacute stage(P<0.05).False lumen diameter:1 case(3.6%)of thoracic false lumen diameter dilation and 3 cases(10.7%)of abdominal false lumen diameter dilation in acute stage;4 cases(8.7%)of thoracic false lumen diameter dilation and 12 cases(26.1%)of abdominal false lumen diameter dilation in subacute stage;1 case(8.3%)of thoracic false lumen diameter dilation and 6 cases(50%)of abdominal false lumen diameter dilation in chronic stage;the dilation rate of abdominal false lumen diameter in chronic stage was higher than that in acute stage and subacute stage(P<0.05).In acute stage,the maximum diameter of FL decreased slightly after TEVAR.In subacute stage,the maximum diameter of FL decreased from 22.2±6.8mm to 12.8±3.6mm.In chronic stage,the maximum diameter of FL also decreased.There were significant differences in the maximum diameter of FL before and after operation among the three groups(P<0.05),especially in subacute stage(P<0.01).The thrombotic rate of FL in subacute phase was higher(78.3%),and there was significant difference among the three groups(P<0.05).Preoperative maximum diameter of thoracic aorta(OR=1.152;95%CI:1.006-1.320;P=0.041)and chronic stage(OR=10.303;95%CI:1.636-64.876;P=0.013)were risk factors for thoracic aortic dilatation after TEVAR.Incomplete thrombosis(OR=8.491;95%CI:1.251-57.612;P=0.029),chronic stage(OR=5.848;95%CI:1.071-31.924;P=0.041),stent diameter(OR=0.836;95%CI:0.700-0.998;P=0.048)were risk factors for abdominal aortic dilatation after TEVAR.Conclusions:TEVAR is beneficial to aortic remodeling,especially in subacute stage;In chronic stage,the rate of aortic dilatation is higher,and more often occurs in the abdominal aorta;The risk factors of thoracic aorta after TEVAR are chronic stage and preoperative thoracic aorta diameter;Chronic stage incomplete thrombosis of false lumen and stent diameter are the risk factors of abdominal aorta dilatation after TEVAR.