| BackgroundAccording to statistics,aortic dissection(Aortic dissection,AD)is a kind of rare disease.It’s extremely high mortality rate and serious condition make it a difficult problem in clinical treatment.Among them,Stanford type B dissection accounts for about 25～40%of AD patients.The 30-day mortality rate of patients with acute Stanford type B AD is 10%.Thoracic endovascular aortic repair(TEVAR)is the first choice for the treatment of acute complex Stanford type B AD.The proximal landing zone is the key to the successful implementation of TEVAR,so that the stent graft can be firmly landing in the artery.In acute Stanford type B AD with inadequate proximal landing zone,it is a clinical challenge to preserve the left subclavian artery(LSA)and avoid serious complications such as left upper extremity "blood-stealing" syndrome,anterior/posterior cerebral circulation and spinal cord ischemia(SCI).ObjectiveTo investigate the safety and efficacy of the extracorporeal windowing technique versus Castor branch stenting for LSA revascularization in acute Stanford type B AD endovascular repair with inadequate proximal landing zone,and to provide a reference for treatment options.MethodsFrom January 2016 to December 2019,65 patients with acute Stanford type B AD who underwent 2-zone TEVAR with insufficient proximal landing zone were retrospectively analyzed.Chimney stents were used for patients with dissection rupture,and Castor branch stents were used for patients with dissections involving LSA entrance.The treatment plan for patients was determined based on the shared decision-making model(Shared Decision Making,SDM)combined with the characteristics of the lesion.According to the treatment methods,they were divided into two groups,34 cases in the fenestration treatment group(group A),of which 14 cases in group A were treated with internal fenestration with chimney support,and 20 cases were treated with fenestration without chimney support.Castor singlebranched stent graft treatment group of 31 cases(group B).All patients underwent CTA of the thoracoabdominal aorta before operation,and blood pressure and heart rate were strictly controlled during the perioperative period.At 1,3,and 6 months after surgery,CTA of the thoracoabdominal aorta was reviewed once a year thereafter.Type Ⅰ endoleak,retrograde type A dissection(RTAD),stroke,LSA patency rate,30-day mortality rate,aortic remodeling,and aortic diameter change were analyzed in two groups A and B.Data analysis was performed using t-test,chi-square test,Fisher’s exact test,and nonparametric test(Mann-whitney test).Kaplan-Meier curves were used to estimate the difference in the probability of LSA occlusion or reintervention between the two groups during the follow-up period.1.Main research objectives:technical success rate,perioperative and follow-up mortality.2.Secondary research objectives:Type Ⅰ endoleak,RTAD,stroke,LSA patency rate,30-day mortality,aortic remodeling,and aortic diameter.Results1.Baseline dataA total of 276 patients were admitted with suspected acute Stanford type B AD,213 cases were diagnosed with acute Stanford type B AD by CTA,148 patients with sufficient proximal anchoring zone or optimal drug therapy were excluded,and a total of 65 patients were enrolled.According to the characteristics of SDM and patients’ lesions,34 patients underwent dissection repair with fenestration technique,and the other 31 patients underwent dissection repair with Castor single-branched stent graft.There was no significant statistical difference in the baseline data of the two groups of patients.The average ages of groups A and B were 54.65± 11.38 years old and 56.48±10.79 years old,respectively,and the proportion of males was relatively large(73.5%in group A and 77.4%in group B,p=0.716),most of the patients had high blood pressure and smoking habits(85.3%,67.6%in group A,90.3%,77.4%in group B,p=0.812,p=0.379),and the prevalence of other preoperative complications was within the two groups The proportions were small,and there was no statistically significant difference between the two groups.2.Technical success rate,perioperative outcome and complicationsThe technical success rates of groups A and B were 94.12%and 100%,respectively.The operation time was 113.52 ± 27.68 minutes in group A and 149.23 ± 34.69 minutes in group B,which was significantly shorter in group A than in group B(p<0.001);the waiting time before operation in group B(77.85± 49.35 h)was significantly longer than that in group A(23 ± 13.03 h)(p<0.001).The postoperative hospital stays in the two groups were 14.68±2.20 days and 14.95 ± 3.22 days respectively(p=0.687).The incidence of postoperative complications in the two groups:Type Ⅰ endoleak,RTAD,stroke and 30-day mortality in group A were 5.9%,5.9%,2.9%and 2.9%,respectively.The results of subgroup analysis within group A showed that there was no significant difference in the incidence of postoperative complications between external fenestration with or without chimney(p=0.135).No serious complications occurred in group B during the perioperative period.3.Follow-up resultsThe average follow-up time of the two groups of patients was 16.18± 2.08 months and 15.19 ± 2.68 months,respectively.All the patients included in the study successfully preserved the blood perfusion of LSA.In groups A and B,3 patients and 2 patients had LSA occlusion during the follow-up period,and the LSA occlusion rates were 9.1%and 6.5%,respectively(p=0.690).There were 2 patients in group A and 1 patient in group B who underwent re-intervention,and the re-intervention rates of the two groups were 5.9%and 3.2%(p=0.601).No statistical difference.One patient in group A died due to RTAD,and no death was observed in group B.During the follow-up period,pre-operative thrombosis in group A and B during follow-up(group A,zone 5:11.1%,zone 6+7:8.7%;group B,zone 5:8.3%,zone 6+7:12.5%),significant thrombus formation was observed in the aortic false lumen of patients in both groups A and B(group A 5 areas:77.8%,6+7 areas:56.5%;group B 5 areas:83.3%,6+7 areas:62.5%),pre-operative and post-operative thrombosis were statistically different(p<0.001).Most of the changes in aortic diameter were stable contraction(group A 5 zone:75.8%,6+7 zone:69.9%;group B 5 zone:74.6%,6+7 zone:62.5%).Both treatments significantly improved aortic remodeling.Conclusion1.For acute Stanford type B AD with insufficient proximal landing zone,it is feasible and safe to apply fenestration and Castor single-branched stent graft in zone 2 TEVAR,which can effectively reduce the mortality of patients.2.The application of the open-window technique and Castor branch stent implantation technique for LSA reconstruction in Zone 2 TEVAR not only preserves LSA patency,but also has a low rate of postoperative related complications and a low rate of LSA occlusion and reintervention.3.In zone 2 TEVAR,both fenestration technique and Castor single-branched stent graft technique can promote aortic remodeling,have no significant effect on aortic contraction and can improve late prognosis. |
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