The Application Of Fenestration Technique To Reconstruct The Left Subclavian Artery In The Treatment Of Descending Aortic Diseases

Objective: Thoracic endovascular repair TEVAR has become the first-line treatment for descending aortic disease.To ensure sufficient proximal landing zones,the proximal end of the stent often needs to cover the left subclavian artery(Left Subclavian Artery,LSA)opening,and the reconstruction of the covered LSA to restore its blood supply has become a consensus.LSA reconstruction technology is still in the stage of continuous exploration.Fenestration technology is a research hotspot among them.Its safety,effectiveness and feasibility are the focus of clinical attention.The advantages and disadvantages of external fenestration and in-situ fenestration have not been clearly described.The purpose of this study is to understand the operation situation of fenestration technique in TEVAR,evaluate the safety and effectiveness indexes of perioperative and follow-up period,and evaluate the safety,effectiveness and feasibility of fenestration technique.Through statistical analysis,we compared the two kinds of fenestration technology in the operation,perioperative and follow-up indicators,in order to evaluate the advantages and disadvantages of different fenestration technology.In order to understand the influence of learning curve on the therapeutic effect of fenestration technique,the indexes of early and late cases were further compared and analyzed.Methods: Retrospective analysis of clinical data of patients with descending aortic disease diagnosed and treated in our center from January 2016 to December 2020.Patients who were diagnosed and treated for the first time and underwent TEVAR were included in this study after being selected by inclusion and exclusion criteria.Collect and count the clinical data of the enrolled cases,including general conditions(gender,age,comorbidities),preoperative anatomical data(length and diameter of proximal anchoring area,type of aortic arch,diameter of LSA opening,proximal Poor end anchoring area),surgical conditions(vascular stent usage,operation and fluoroscopy duration,radiation dose,contrast agent dose and intraoperative blood loss),perioperative conditions(technical success rate,neurological complications,approach and Fenestration-related complications,ICU and postoperative hospital stay),follow-up conditions(stent internal leakage,stent-related reverse tear,LSA stent occlusion,stent infection,re-intervention).According to the different fenestration techniques,the included cases were divided into two groups:external fenestration group and in-situ fenestration group.Statistics and comparative analysis of the general conditions of the two groups of cases,preoperative lesion anatomy data,surgical conditions,perioperative period Status,various indicators of the follow-up period.According to the different treatment time,the enrolled cases were divided into two groups: early case group(2016.01-2017.12),late-stage case group(2018.01-2020.12),and statistically and comparatively analyzed the technical success rate,surgical complications,and stents of the two groups.Leakage,stent-related reverse tear,left subclavian artery stent occlusion and other indicators.Results: A total of 66 patients were included in this study,including 40 cases of thoracic aortic dissection,accounting for 60.6%;31 cases in the external fenestration group,35 cases in the in-situ fenestration group;21 cases in the early case group and 45 cases in the late case group.Anatomical data of the preoperative lesions of the included patients: the length and diameter of the proximal landing zones were 8.7±4.0mm,34.6±3.6mm,36 cases(54.5%)of type III aortic arch,the diameter of the LSA opening was 10.1±2.2mm,the proximal end A total of 12 cases(18.2%)with poor landing zones;surgical data:operation and fluoroscopy duration 66.2±22.0 min,35.6±16.9 min,radiation dose 2109.7±533.4 m Gy,contrast agent dose 166.6±60.3ml,intraoperative blood loss 68.5±20.8ml.Of the 66 patients,there were no postoperative deaths.61 cases successfully completed the reconstruction of TEVAR and LSA,with a technical success rate of 92.4%;2 cases had neurological complications,with an incidence rate of 3%;5 cases had surgical approach complications.The incidence rate was 7.6%;there were 2 cases of fenestration-related complications,the incidence rate was 3%;the postoperative ICU and hospital stay were 23.6±9.0 hours and 8.1±3.6 days,respectively.During the 1-58 months follow-up,the results showed that there were 7 cases of stent endoleakage,the incidence rate was 10.6%(including 1 case of type Ⅰa endoleak,3 cases of type Ⅱ endoleak,and 3 cases of type Ⅲ endoleak);There were 2 cases of related retrograde tear,with an incidence rate of 3%;4 cases of LSA stent occlusion,with an incidence rate of 6.1%;no cases of stent infection;5 patients underwent re-intervention during the follow-up period,and the re-intervention rate was 7.6%(including 2 Cases,type Ia endoleak in 1 case,LSA stent occlusion in 1 case,and type II endoleak in 1 case).The results of the comparative study between the in vitro fenestration group and the in-situ fenestration group showed that there was no statistical difference in the preoperative general conditions and preoperative anatomical data of the lesions between the two groups(all p>0.05);Indicators: There are statistical differences in the average operation time,fluoroscopy time and radiation dose between the two groups of patients(all P values<0.05),that is,the external fenestration operation time is significantly longer than that of the in-situ fenestration,while the fluoroscopy time and radiation dose are compared with the latter Significantly reduced,but there was no statistical difference in the contrast agent dose and intraoperative blood loss between the two groups of patients(p value>0.05);perioperative indicators: the two groups of patients’ technical success rate,ICU length,postoperative hospital stay,There was no significant difference in the incidence of neurological complications,approach complications and fenestration complications(all p>0.05);follow-up indicators:the incidence of stent-related reverse tear in the external fenestration group was higher than that of in-situ fenestration In the comparative analysis of stent leakage,LSA stent occlusion,and re-intervention rate in the two groups,the difference was statistically significant(p<0.05),and the p values were all >0.05,that is,the difference between the two groups was not statistically significant.The comparative study results of the early case group and the late case group showed that the technical success rate of the late case was significantly higher than that of the early case(p=0.001),and the incidence of surgical complications and stent-related reverse tear was significantly lower than that of the early case(P values,respectively 0.046,0.009),but there was no statistically significant difference in the incidence of stent leakage and LSA stent occlusion between the two groups(both p values> 0.05).Conclusions:1.The fenestration technique can safely and effectively reconstruct the left subclavian artery during TEVAR operation for descending aortic disease.The fenestration technique can expand the anchoring area at the proximal end of the stent and expand the application of TEVAR in the treatment of descending aortic disease.2.Different fenestration techniques have different advantages and disadvantages: in-situ fenestration has more advantages in reducing the operation and anesthesia time,while external fenestration has more advantages in reducing the operation fluoroscopy time and radiation dose,but in external fenestration increases the risk of aortic reverse tear,and the stent related reverse tear rate during follow-up period is higher than in-situ fenestration.3.As the learning curve progresses,the therapeutic effect of the fenestration technique is gradually improved: it may be related to appropriate case selection,accurate preoperative evaluation and stent selection,tacit intraoperative cooperation and skilled surgical operation.4.Regardless of external fenestration or in-situ fenestration,the integrity of the main stent is destroyed,and the branch stent has a certain expansion force on the main stent window.Although the main stent membrane was not damaged or broken in the early and mid-term follow-up,But its long-term durability still needs further follow-up study.