Clinical Study Of Endovascular Graft Exclusion For Stanford Type B Aortic Dissection

BackgroundAortic dissection is a serious disease in the aorta.It refers to a physical change of blood flow from the tear opening of tunic intima to the tunica media,resulting in the stratification of aortic wall and the formation of two cavity in the aorta.The original aortic cavity is called the true cavity,and the other is false cavity.The is from the middle layer between The true and false cavity are separated by the tunic intima and partial tunic intima,and can be interlinked each other through one or several fragments.Aortic dissection is the most common catastrophic disease in aortic disease.It has a rapid onset,high mortality and poor natural prognosis.The mortality rate of aortic dissection increases 1% per hour,and up to 50 % within 48 h after onset in the untreated patients.The treatment of aortic dissection is closely related with the classification of disease.Stanford type B aortic dissection refers to the disease involving the descending aorta distal to left subclavian artery.In 1994,the Dake et al were the first team who successfully treated the thoracic descending aortic aneurysm with endovascular graft implantation.In 1999,Nienaber and Dake reported the successful treatment of Stanford B aortic dissection with stent implantation in the aorta,which initiated the era of minimally invasive endovascular exclusion for the treatment this disease.In 1999,the treatment experience of aortic endovascular graft implantation for type B aortic dissection was reported independently by Zhonghao Wang and Jing King in China.Since then,with the continuous progress and constantly updated stent endovascular techniques,endovascular graft exclusion has been increasingly developed.It has become an important means for the treatment of type B aortic dissection because of its improvedeffect.However,with the increasing number of operations,the complications associated with endovascular graft exclusion were more common.There was no large sample randomized controlled study on the long-term survival rate and the quality of life.Therefore,the treatment of Stanford B aortic dissection is still controversial.Objective1.To evaluate the safety and long-term therapeutic effect of endovascular repair for Stanford type B aortic dissection and to summarize relevant surgical experience of endovascular repair.2.To summarize the causes and treatments of various complications of aortic endovascular repair in the course of Stanford type B aortic dissection treatment.3.To explore the relationship between the different branches of aortic arch and the occurrence of aortic dissection.MethodsThe data of 80 cases of Stanford B type aortic dissection from January 2017 to December 2017 in Anhui Provincial Hospital were retrospectively analyzed.Among them,there were 60 males and 20 females,from 28 years old to 86 years old,with an average of 60±13 years.All patients underwent computed tomography angiography(CTA)examination to evaluate the thoracic and abdominal aorta before operation.The blood pressure and heart rate were strictly controlled during perioperative period.The1 st,6th,12 th months and every after operation,the thoracic and abdominal aorta was also evaluated by CTA.The main follow-up contents included the survival rate,the incidence of complications,the morphology of the aorta,and the control of blood pressure.The patients who were excluded from aortic dissection were selected as the control group.The data of the two groups were treated with three dimensional reconstruction of the post processing workstation.The related data of the branches ofthe aortic arch were measured and compared.ResultsThe operation in all patients were completed successfully.There was no misplacement and displacement of stents,no rupture of the aneurysm and no transfer to thoracotomy.The average time for surgery was 1 h and the average amount of bleeding was 50 ml.The average time of free movement after surgery was 2 d and the postoperative hospital stay was 7 d.The double stents were placed in 7 cases intraoperatively.Angiography showed complete elimination of the false lumen of dissection and no significant proximal leakage formation during intraoperative and postoperative.The left subclavian artery was completely closed in 4 patients and the vagus right subclavian artery was completely closed in 1 patient.All 5 patients showed no obvious complications.There were 4 patients with dissection rupture before admission and a large number of pleural hemorrhage.After admission,emergency endovascular exclusion was performed.Unfortunately,3 patients were died and the death rate was as high as 75%.Another 4 cases got serious mental symptoms after operation,all of whom were female.One male patient had peripheral facial paralysis with mild symptoms and no required of special treatment.The remaining perioperative complications included upper limb numbness in 2 cases(2.5%),paraplegia in 1 case(1.25%)and intestinal ischemia in 1 case(1.25%).The follow-up time was 1-12 months.4 patients were died within 30 days after surgery and the mortality rate was 5%,of which 3 patients died of rupture of aortic dissection aneurysm and another patient,with a large area of cerebral infarction history,died of respiratory failure eventually.During the follow-up time,5 patients were lost and the other 71 patients were followed up.None of them died and no obvious complications were found.Compared with control group,the diameters of brachiocephalic trunk(BCT),leftcommon carotid artery(LCA)and left subclavian artery(LSA)in aortic dissection patients were 16%,25% and 20% higher.The straight distances from LCA and LSA to the aortic root were 17% and 21% longer.The angles between BCT,LCA,LSA and the long axis of aortic arch were 6%,7% and 11% larger.There was no significant difference of adjacent distance branches of the aortic arch.Conclusions1.The operation of aortic endovascular isolation is relatively simple,with small trauma,low complications and mortality.The long term results are good.Now it has become the first choice for Stanford B aortic dissection.2.In the acute stage of aortic dissection,the mortality rate was high.For those patients with Stanford type B aortic dissection who did not have life-threatening complications,they were treated by conservative medicine for 2 weeks.For patients who have signs of lamination rupture,emergency surgery should be considered even if the perioperative mortality is high.3.After careful evaluation of the superior side of the vertebral artery,most patients were able to tolerate complete closure of the left subclavian artery.For patients who requires long-term transplantation,the left subclavian artery should be completely closed to reduce the incidence of paraplegia.4.The oversize of the graft should not be too large.In the case of large proximal anchoring area,small caliber stent or short mulch stent can be placed in the distal end to limit the diameter of the distal stent and reduce the compression of the distal stent wall.5.The anatomic variation of aortic arch morphology is related to the occurrence of Stanford B aortic dissection.In addition,the data obtained in this study can provide data reference for the scaffolding design of patients with later surgical treatment.