Morphological Aortic Remodeling Of Stanford Type B Aortic Dissection After Thoracic Endovascular Aortic Repair

Part I Compare the clinical outcomes after thoracic endovascular aortic repair between acute,subacute and chronic Stanford Type B aortic dissectionobjective:To compare the clinical outcomes and aortic remodeling after thoracic endovascular aortic repair(TEVAR)between acute,subacute and chronic Stanford Type B aortic dissection ·Method:Retrospective analyze 323 patients with Stanford Type B aortic dissections after TEVAR at Nanjing Drum Tower Hospital,The Affiliated Hospital of Nanjing University Medical School(From June 2013 to December 2016)· Evaluate the clinical outcomes(including the incidence of complications and the mortality rate)between the three groups.Select cases with a follow-up period of at least 3 months,and 115 cases meet this requirement(range 3-71 months)-Evaluate the occurrence of complication and aortic remodeling after TEVAR between the three groups ·Results:All 323 patients with Stanford B aortic dissection(129 acute,161 subacute and 33 chronic)underwent TEVAR.Average hospital stay was 20.51±10.23d(range 6-44d).TEVAR technique success rate was 96.3%(311/323).During perioperative period,there were 54(16.7%)cases of complications[including 22(17.1%)in Acute Group,26(16.1%)in Sub-acute Group,and 6(18.2%)in Chronic Group,P>0.05].The 30-day mortality rate was 0.9%(3/323)and all the deaths were in Acute Group.There were 115 cases with a follow-up period>3 months.Dimensional change of aorta,true lumen and false lumen was analyzed based on CTA scans.At thoracic segment,diameter and cross-sectional area of true lumen increased(P<0.05),while the diameter and cross-sectional of false lumen decreased(P<0.05).There was no significant change on diameter and cross-sectional area of thoracic aorta(P>0.05)·Thoracic false lumen thrombosis rate was 92.2%(106/115).There were 52 patients with Type IIIB aortic dissection.At abdominal segment,true lumen re-expanded and false lumen shrank(P<0.05).However,the size of abdominal aorta showed no significant change(P>0.05).False lumen thrombosis rate was only 30.8%(16/52)at abdominal segment.There was no significant difference on aortic remodeling between Acute Group,Subacute Group(P>0.05),but found less effective on aortic remodeling in Chronic Group(P<0.05).Conclusion:Our study shows that TEVAR is a safe,effective and promising treatment for acute,subacute and chronic Stanford Type B aortic dissection.And TEVAR effectively promotes aortic remodeling,especially at thoracic segment,but seems less effective for chronic dissections compared with acute and subacute dissections(P<0.05).However,long-term follow-up is needed to assess the durability of the observed benefits of TEVAR.Part II Aortic remodeling after thoracic endovascular aortic repair for type B aortic dissections using unibody single-branched stent-graftObjective:To summarize experience of thoracic endovascular aortic repair(TEVAR)with single-branched stent-graft for type B aortic dissections involving the left subclavian artery(LSA)and evaluate aortic remodeling after TEVAR.Methods:From June 2013 to February 2014,we retrospectively reviewed 21 patients with Stanford Type B aortic dissections(TBADs)who had insufficient proximal landing zones(<20mm).All patients underwent TEVAR with LSA revascularization using unibody single-branched stent-graft.Follow-up evaluations started at 1 month after TEVAR,computed tomography angiography(CTA)was planned at 6 months and 12 months to assess graft patency,endoleak,the morphology of stent and remodeling of aorta.Results:Technique success was 95.2%(20/21),a type I endoleak occurred in 1 case after TEVAR.The mean operative time was 139.3±49.3min.No serious complications occurred in perioperative period.All patients completed the early follow-up except 2 patients lost contact after discharge.One death occurred 6 months after TEVAR from myocardial infarction,considered unrelated to the stent implantation.During follow-up,there was 1 patient with a slight sidearm graft twist,no endoleak and other complications occurred.At thoracic segment,partial thrombosis of the false lumen was observed in 3 patients and complete thrombosis of the false lumen was noted in 16 cases;significant expansion of the true lumen(P<0.05)and regression of the false lumen(P<0.05)were documented;however,no significant change was revealed in aortic diameter(P>0.05).At abdominal segment,partial thrombosis of the false lumen was observed in 7(63.6%)patients and complete thrombosis of the false lumen was noted in 4(36.4%)cases;true lumen re-expanded(P<0.05)and false lumen shrank(P<0.05);aortic diameter increased a little but the difference was not statistically significant(P>0.05).Conclusion:The side branched stent-graft is a safe and effective choice for LSA revascularization,and effectively promotes aortic remodeling.A larger series of cases with longer follow-up is needed to document sustained efficacy.Part III Chimney technique VS single-branched stent-graft for treating type B aortic dissections with insufficient proximal landing zoneObjective:To compare the short-term efficiency and aortic remodeling of two different endovascular repair for type B aortic dissections(TBADs)with insufficient landing zone.Methods:Forty-three cases of TBADs with insufficient landing zone underwent TEVAR from June 2013 to March 2016,consisting of 22 with chimney grafts and 21 with single-branched stent-graft.Outcomes of the two groups in perioperative period and follow-up were comparatively analyzed,especially on aortic remodeling.Results:The Chimney Group was younger than Single-branched Group(56±12.4 VS 64.3±12.2,P<0.05),and had more acute TBADs(68.2%VS 28.6%,P<0.05).After TEVAR,there was 1 case of graft stenosis in Chimney Group and 1 case of type I endoleak in Single-branched Group.The average postoperative hospital stays were similar in the two groups(8.4±3.7d in Chimney Group VS 8.0±4.0d in Single-branched Group,P>0.05).The median follow-up period was 19 months(range,3-43 months)in Chimney Group and 12 months in Single-branched Group(range,6-32 months).During follow-up,there were 2 cases of chimney graft occlusion,1 case of type I endoleak and 1 death from dissecting aneurysm rupture in Chimney Group;compared with that there was 1 case of sidearm graft twist and 1 death from myocardial infarction in Single-branched Group.In thoracic segment,there was no significant difference on false lumen thrombosis between the two groups[complete thrombosis:83.3%(15/18)in Chimney Group VS 84.2%(16/19)in Single-branched Group,P>0.05;partial thrombosis:16.7%(3/18)in Chimney Group VS 15.8%(3/19)in Single-branched Group,P>0.05)].In abdominal segment,rate of false lumen thrombosis significantly reduced and was higher in Single-branched Group[complete thrombosis:23.1%(3/13)in Chimney Group VS 36.4%(4/11)in Single-branched Group,P<0.05;partial thrombosis:76.9%(10/13)in Chimney Group VS 63.6%(7/11)in Single-branched Group,P<0.05)].Significant true lumen expansion and false lumen shrinkage were revealed in different levels in two groups(P<0.05);however,aortic diameters showed no significant change in both groups(P>0.05).There was no significant difference on aortic remodeling between the two groups(P>0.05).Conclusion:Our study demonstrated that the chimney technique and single-branched stent-graft were both safe and efficient in treating TBADs with insufficient proximal landing zone.A larger series of cases with longer follow-up is needed to substantiate these results.