Computational Study of Fenestration and Parallel Grafts Used in Aortic Arch Lesion / 医用生物力学

Objective To explore hemodynamics of the aortic arch and supraarch vessels after thoracic endovascular aortic repair with fenestration and parallel grafts techniques, and compare the differences of these techniques. Methods Four patients with aortic arch lesions whose supraarch vessels were reconstructed by different surgical techniques (fenestration, chimney and periscope) were studied, and three-dimensional (3D) geometric models were established based on postoperative image data. The physiological flow obtained from two dimensional (2D) phase contrast magnetic resonance imaging were imposed on the ascending aorta inlet and the supraarch vessels outlets. The pressure waveform of 3-element Windkessel model was imposed on the descending aorta outlet. Through computational fluid dynamics ( CFD ) simulations, the hemodynamic parameters were obtained, including the pressure of supraarch vessels, the velocity vector of the stent inlet, and the relative residence time. Results The pressure change of the periscope stent was the largest, followed by the fenestration stent, and the pressure change of the chimney stent was the smallest. The velocity of the fenestration and periscope stent inlet was uneven, which might form vortex. The velocity of the chimney stent inlet was even. The high relative residence time concentrated in distal end of the fenestration stent outer wall, the ‘gutter’ part, and the place where the chimney and periscope stent adhered to the vessel wall. Conclusions The pressure difference between the inner and outer walls of the fenestration and periscope stent was high, so it was recommended to use the balloon-expandable stent. The pressure difference between the inner and outer walls of the chimney stent was low, so it was recommended to use the self-expanding stent. The predicted location of thrombosis was consistent with the clinical follow-up data, so it may be used for surgical planning and risk assessment of interventional treatment of aortic arch lesions.

Fully protruding into the inferior vena cava deployment of braided stent in the treatment of iliac compression syndrome / 中华普通外科杂志

Objective:To evaluate the clinical efficacy of metal braided stent deployed by fully protruding into the inferior vena cava for the treatment of iliac vein compression syndrome(IVCS).Methods:The clinical data of patients with IVCS treated with interwoven nitinol mesh stent protruding into the inferior vena cava and released from Jan 2018 to May 2021 in our center were retrospectively analyzed.Results:A total of 118 patients were included in this study. Among them, 7 cases were complicated with acute thrombosis, 3 cases were complicated with post thrombotic syndrome (PTS), and 108 cases were no more thrombotic iliac vein compression. The technical success rate was 100%, with an average of 2.03±0.77 stents implanted. Of the 23 ulcer patients, 18 ulcers healed after intervention, and the healing rate was 78.26%. The postoperative CEAP grade was significantly improved ( t=11.54, P<0.01), and the primary patency rate and second patency rate were 97.46% and 98.31% at 1 year after intervention. Conclusion:The fashion of fully protruding into inferior vena cava deployment in the treatment of iliac vein compressive disease has a high patency rate and satisfactory clinical efficacy.

Multidisciplinary team strategy for treatment of diabetic foot / 中华普通外科杂志

Objective:To explore the team construction and treatment strategy of the Diabetic Foot-Multidisciplinary Team.Methods:The clinical data of 19 patients with severe ischemic diabetic foot treated by our Diabetic Foot-Multidisciplinary Team Center from Apr 2021 to Mar 2022 were collected, and the overall amputation rate, above-ankle major amputation rate, minor amputation rate and mortality, Diabetic Foot-Multidisciplinary Team consultation discipline participation rate and treatment participation degree were retrospectively analyzed.Results:Nineteen patients (15 males and 4 females) were enrolled, aged 26 to 94 (68.6±14.2). All were with severe ischemic diabetic foot ulcer:Rutherford grade 5 or up and dysfunction in 2 or more organs. Complications included arteriosclerosis obliterans of the lower extremities in 18 cases, heart diseases in 18, hypertension in 15, and renal insufficiencies in 10. The overall amputation rate was 36.8%, major amputation rate in 21.1%, minor amputation rate in 15.8%, and mortality rate was 15.8%. A total of 16 disciplines participated in Diabetic Foot-Multidisciplinary Team; the main participating disciplines were vascular surgery (19 times), endocrinology (12 times), and cardiology (11 times). The main treatment disciplines were vascular surgery (14 times), plastic surgery (3 times), and cardiology (2 times).Conclusion:For the diagnosis and treatment of diabetic foot, it is necessary to set up a multidisciplinary team as early as possible to control the causes of diabetic foot ulcer, prevent the recurrence of diabetic foot ulcer, reduce the mortality and amputation rate, and improve the quality of life of patients.

The value of three-dimension digital subtraction angiography in diagnosis and treatment of iliac vein compression syndrome / 中华普通外科杂志

Objective:To evaluate the application value of three-dimension digital subtraction angiography (3D-DSA) in the diagnosis and treatment of iliac vein compression syndrome (IVCS).Methods:A retrospective analysis was made on 171 patients with a tentative diagnosis of IVCS based on signs, symptoms, and finding of CTV or MRV, and iliac vein angiography. The diagnostic efficacy of MRV, 2D-DSA and 3D-DSA were analyzed. The imaging advantages of 3D-DSA in the diagnosis and treatment of IVCS were evaluated.Results:Ninty-three patients underwent MRV and 3D-DSA simultaneously, 101 patients had 2D-DSA and 3D-DSA simultaneously. 3D-DSA was taken as gold standard, the diagonotic sensitivity, specificity, Youden index of MRV was 75.61%, 72.73% and 0.48 respectively. The sensitivity, specificity, Youden index of 2D-DSA was 90.22%, 100% and 0.90 respectively. There are significant differences in the diagonotic sensitivity between MRV and 3D-DSA, 2D-DSA and 3D-DSA ( P<0.05). There is no significant difference in the diagonotic specificity between MRV and 3D-DSA, 2D-DSA and 3D-DSA ( P=1.000). In this study, we found that 3D-DSA has greater imaging evaluation advantages in preoperative evaluation, intraoperative guidance and immediate postoperative reexamination in the diagnosis and treatment of iliac vein disease. Conclusions:3D-DSA can improve the detection rate of IVCS, and has its advantage in imaging evaluation.

Clinical outcomes of severe calcified lesions after carotid artery stenting / 中华普通外科杂志

Objective:To evaluate the safety and efficacy of carotid artery stenting (CAS) in the treatment of non-circumferential severe calcification using the distal embolic protection device.Methods:Clinical data of patients with severe calcification lesions in cervical carotid artery treated by CAS from Jan 2018 to Dec 2020 at our center was analyzed retrospectively.Results:226 consecutively admitted patients of cervical carotid artery stenosis and non-circumferential severe calcification (CR>270°) underwent CAS using the distal embolic protection device. The technical success rate was 90.26%. No death or myocardial infarction occurred during the perioperative period. Two patients had ipsilateral hemiparesis ischemic stroke during post-dilatation. The incidence of perioperative bradycardia/hypotension was 25.34%. Patients were followed up for 6-36 months, with median follow-up period of 17.3 months. The incidence of mild or moderate in-stent restenosis (<70%) was 16.59%, and the incidence of severe in-stent restenosis or occlusion (>70%) was 3.22%.Conclusions:For carotid artery stenosis with non-circumferential severe calcification in high risk for CEA patients, carotid artery stenting is safe and effective with the aggressive pre-dilation strategies, strict stent selections and implantation standards. The incidence of perioperative death, myocardial infarction or ipsilateral hemiparesis ischemic stroke was low. The patency rate of the carotid stent in the calcification lesion is satisfactory during the mid-term follow-up.

Comparing plain old balloon and drug-coated balloon supported bare metal stents in the treatment of femoral-popliteal TASC D lesions / 中华普通外科杂志

Objective:To compare the efficacy between drug-coated balloon (DCB) combined with bare metal stenting (BMS) and plain old balloon angioplasty (POBA) with BMS placement in the treatment of femoral-popliteal TASC D lesions.Methods:According to the Trans-Atlantic Inter-Society Consensus (TASC) D grade femoral-popliteal lesions as the standard, we enrolled 115 cases (120 limbs) receiving DCB combined with BMS (group DCB, 37 limbs in 36 cases) and POBA combined with BMS (group POBA, 83 limbs in 79 cases) from Jan 2017 to Mar 2020 to observe patency rate, freedom from clinical-drived target lesion reintervention rate (FCD-TLR) and complications.Results:The mean follow-up time was 18.1 months and the average occlusion length was (29.1±6.5)mm. In group DCB vs group POBA, the primary patency rates at 3-month, 9-month, 1-year and 2-year were 89.2% vs. 86.7%, 86.4% vs. 76.9%, 66.8% vs. 70.9% and 63.1% vs. 56.9%, respectively ( P=0.73); FCD-TLRs were 100.0% vs. 95.1%, 94.3% vs. 82.3% , 78.5% vs. 80.6% and 74.1% vs. 68.9% ( P=0.69), respectively. Conclusion:The benefit of DCB combined with BMS over POBA combined with BMS in improving the early primary patency rate and reducing FCD-TLR was not definite.

Distal embolic filter protection during debulking treatment of peripheral artery disease / 中华普通外科杂志

Objective:To discuss the strategies of distal embolic filter protection(DEFP) during excimer laser ablation (ELA) or percutaneous mechanical thrombectomy (PMT) in treatment of peripheral artery disease.Methods:Clinical data of 29 patients undergoing ELA or PMT under the DEFP from Oct 2019 to Aug 2021 were retrospectively collected to analyze the strategies of DEFP and high-risk factors of capturing clinically significant macrodebris.Results:There were 21 males and 8 females, aged (70.3±11.0) years with 32 lesions (29 limbs) including 5 in-stent restenosis (ISR), 10 thrombosis and 17 chronic total occlusion (CTO). The technical success rate of DEFP device release and recovery was 100%. The overall debris capture rate was 77.3% and the macrodebris capture rate was 36.4%. Even with DEFP the distal embolization (DE) incidence was 3.4%. When ELA for CTO with severe calcification or long-segment ISR lesions, the capture rate of macrodebris was as high as 60.0%, and the former was significantly higher than ELA for CTO without high calcification lesions ( P<0.05). Conclusion:ELA or PMT under the DEFP in treatment of peripheral artery disease appears to be of great significance in preventing DE.

Early and intermediate outcomes of second-grade false-lumen endovascular occlusive repair for aortic dissection / 中华普通外科杂志

Objective:To summarize the early and intermediate outcomes of second-grade false-lumen endovascular occlusive repair (FLEVOR) for aortic dissection.Methods:The clinical data of 12 patients undergoing second-grade FLEVOR after proximal repair of aortic dissection at our center from Aug 2016 to Aug 2019 was retrospectively analyzed.Results:The mean age was (51.3±14.9) years old. Four patients received open repair due to Stanford type A aortic dissection previously, the other 8 patients underwent thoracic endovascular aortic repair for Stanford type B aortic dissection. The time to the proximal repair varied from 3 months to 16 years. The technical success rate was 100%. Visceral ischemia, early spinal cord ischemia and in-hospital death did not occur perioperatively. The mean follow-up time was 16.7 months. Persistent false lumen perfusion was found in 3 patients, complete thrombosis of false lumen was achieved in the other 8 patients. The maximum diameter of abdominal aorta decreased in 8 (72.7%) patients.Conclusions:FLEVOR could block the blood flow from the false lumen and induce the thrombosis of false lumen, which promotes the aortic remodeling. Meanwhile, FLEVOR could protect the blood supply of spinal cord and viscera, and reduce the risk of type Ⅱ endoleaks.

Renal ischemia reduction in TAAA hybrid operation by VORTEC renal artery revascularization / 中华普通外科杂志

Objective:To compare the effect of hybrid open-endovascular repair (HOER) and Viabahn open revascularization technique (VORTEC)+HOER in the treatment of thoracoabdominal aortic aneurysms (TAAA).Methods:From Apr 2005 to Jul 2019, 33 TAAA patients underwent HOER including 21 cases of standard HOER, and 12 of VORTEC+HOER. The intraoperative renal ischemia time (RIT), incidence of postoperative acute kidney injury (AKI), rate of renal artery patency (RAP) and another short-term outcome were observed.Results:RIT was significantly shorter in the VORTEC+HOER group than in the standard treatment group [(9±3) minutes vs. (15±6) minutes, P<0.05]. The increase in serum creatinine (SCr) levels on the 1st postoperative day in the standard treatment group was significantly higher than that in the VORTEC+HOER group [(1.68±0.79) μmol/L vs. (1.05±0.06) μmol/L, P<0.05]. AKI occurred in 5 patients in the standard HOER treatment group (5/21, 24%), while no patient experienced AKI in the VORTEC+HOER group (0/12, 0). Conclusion:VORTEC significantly reduces RIT and postoperative SCr increasing, thereby potentially decreasing the incidence of postoperative AKI.

Treatment strategy of peripheral arterial diseases with Rotarex / 中华普通外科杂志

Objective:To evaluate the effect of Rotarex in peripheral arterial disease (PAD).Methods:The clinical data of 90 PAD patients treated with Rotarex from Aug 2018 to Feb 2020 were retrospectively analyzed.Results:Among the 90 patients, 45 patients had atherosclerotic obliterans complicated with acute thrombosis (ASOCAT), 27 patients had graft restenosis or reocclusion, 16 patients had primary or embolism-induced thrombosis, 2 patients had traumatic or iatrogenic arterial occlusion. Except for 2 patients undergoing hybrid surgery, 88 patients underwent endovascular treatment. Two patients died perioperatively. Within 12 months follow-up, 2 patients died, 4 patients underwent major amputation, target arteries of 10 patients were re-stenosed or re-occluded and 5 patients were lost to follow-up. Compared with the preoperative ankle-branchial index (ABI), significant increase was observed in the 12-month ABI (0.80±0.22 vs. 0.43±0.16, P<0.01). The 12-month restenosis/re-occlusion-free rate was 82.7%, and the 12-month major amputation-free survival (MAFS) was 91.6%. Conclusion:For PAD patients, acceptable outcomes can be achieved with reasonable use of Rotarex for debulking, combined with balloon, stent and other techniques to correct the residual lesions.

Short term result of COOK-ZFEN custom-made endovascular stent graft system for the treatment of short-neck abdominal aortic aneurysm / 中华普通外科杂志

Objective:To evaluate the safety and efficacy of a Zenith fenestrated aortic stent-graft (ZFEN) system in the treatment of short-necked aneurysms.Methods:The clinical data of 5 patients receiving F-EVAR in Zhongshan Hospital, Fudan University from Mar 2018 to Sep 2019 according to the standards of short-necked abdominal aortic aneurysm and COOK ZFEN custom stent were retrospectively analyzed.Results:Patients' average age was (69±11) years old. The time of stent customization was 4-6 weeks. The average maximum diameter of AAA was (60.8±14.0) mm. The average proximal neck diameter was (26.0±2.6) mm and the average length anchoring zone was (6.4±2.2) mm. The rate of technical success was 100%. There was no intraoperative loss of visceral vessels and stent displacement. The meane follow-up time was 6.8 months. The perioperative mortality was 0, and there were no other major complications. There were 3 patients with simple type Ⅱ endoleak and 1 patient with type Ⅲ endoleak. The endoleaks disappeared in 4 patients during follow-up of 3-12 months. 1 patient suffered with type Ⅱ and type Ⅲ endoleak, and the visceral vessels and branching stents were patent in all patients.Conclusion:The short term result of COOK ZFEN stent-graft system was safe and feasible for the treatment of short-necked AAA.

Countermeasures and treatment for aortic acute syndrome with novel coronavirus pneumonia / 中华外科杂志

@#The novel coronavirus pneumonia (NCP) has cost a great loss to the health and economic property of Chines people. Under such a special circumstance, how to deal with such patients with acute aortic syndrome has become a serious challenge. Rapid diagnosis of concomitant NCP, safe and effective transportation, implementation of the interventional procedure, protection of vascular surgical team and postoperative management and follow-up of such patients have become urgent problems for us. Combined with the latest novel government documents, the literature and the experiences from Wuhan, we answered the above questions briefly and plainly. It also hopes to inspire the national vascular surgeons to manage critical emergencies in vascular surgery and even routine vascular diseases with NCP, as a final point to limit the severe epidemic situation, and minimize the damage of NCP.

Treatment for arteriosclerosis obliterans complicated with acute thrombosis of lower extremity / 中华普通外科杂志

Objective:To discuss the clinical treatment for arteriosclerosis obliterans combined with acute thrombosis (ASOCAT) of lower extremities.Methods:The treatment methods and results of 30 patients with ASOCAT admitted to our center from Jan 2009 to May 2019 were retrospectively analyzed.Results:The course of acute thrombosis in 30 patients was (9.5±5.2) days, and the average course of ASO was (2.1±1.4) years. Among 30 patients, 13 patients had aortoiliac occlusion (type Ⅰ), and 17 patients had femoropopliteal lesion (type Ⅱ). Twenty-eight patients underwent endovascular treatment, 1 had hybrid operation, and 1 was given aorto-bilateral femoral bypass. One patient died perioperatively. 24 patients were followed up for (16.3±16.1) months. One died during follow-up.Two patients underwent above-knee amputation within 6 months. Two patients had distal superficial femoral artery reocclusion within 12 months. The restenosis/reocclusion rates within 12 months of type Ⅰ and Ⅱ patients were 12.5% and 21.4%, respectively. The 6/12-month amputation-free survival rates for type Ⅰ and type Ⅱ were 87.5%/87.5% and 92.8%/85.7%, respectively.Conclusion:Reasonable and active use of open surgery, endovascular treatment or hybrid operation could achieve acceptable outcomes in patients with ASOCAT.

Long-term follow up outcomes of surgical resection of Shamblin Ⅱ/Ⅲ carotid body tumor: a single center analysis / 中华普通外科杂志

Objective:To evaluate the correlation between tumor size and surgical outcomes of Shamblin Ⅱ/Ⅲ carotid body tumor (CBT) and the prognosis.Methods:From Apr 2011 to Dec 2017, 88 patients with Shamblin Ⅱ and Ⅲ CBTs undergoing tumor resection were retrospectively analyzed. The long-term prognosis of surgical resection was also evaluated.Results:One patient died of multi-organ failure postoperatively, two patients abandoned surgery. The perioperative mortality was 1%. 85 patients having 87 lesions successfully resected were analyzed. There were 13 Shamblin Ⅱ and 74 Shamblin Ⅲ CBTs resection. Two patients had bilateral CBTs resection. The median of tumor size, procedural blood loss, procedural time, and length of hospital stay was 3.0 (1.2-5.5) cm, 200 (0-2 500) ml, 162 (85-430) min, and 10 (6-28) d, respectively. Seventy-two patients had carotid vascular intervention during the procedure, and thirty-three patients had neurological complications after the procedure. Correlation analysis showed that the tumor size had positive relationship with blood loss (Spearman R=0.35, P<0.01) and procedural time (Spearman R= 0.54, P<0.01). Tumor size was positively associated with the risk of cranial neurological complication ( OR=1.72, 95% CI 1.08-2.73, P=0.02) and carotid vascular intervention ( OR=2.69, 95% CI 1.27-5.69, P=0.01). There were four patients who were diagnosed with malignant CBT due to the metastasis. Three suffered CBT recurrence after 1, 5, and 7 years during the follow up. Conclusions:Shamblin Ⅱ or Ⅲ CBTs should be intervened as early as possible to facilitate the surgical resection, as well as to reduce the risk of carotid vascular and neurological complications.

Countermeasures and treatment for aortic acute syndrome with novel coronavirus pneumonia / 中华外科杂志

The novel coronavirus pneumonia (NCP) has cost a great loss to the health and economic property of Chines people. Under such a special circumstance, how to deal with such patients with acute aortic syndrome has become a serious challenge. Rapid diagnosis of concomitant NCP, safe and effective transportation, implementation of the interventional procedure, protection of vascular surgical team and postoperative management and follow-up of such patients have become urgent problems for us. Combined with the latest novel government documents, the literature and the experiences from Wuhan, we answered the above questions briefly and plainly. It also hopes to inspire the national vascular surgeons to manage critical emergencies in vascular surgery and even routine vascular diseases with NCP, as a final point to limit the severe epidemic situation, and minimize the damage of NCP.

Advances in the fenestrated stent-graft and the stent-graft for the in-situ fenestration technique / 中华外科杂志

The endovascular exclusion is an effective treatment of aortic aneurysm diseases in frail and elderly patients who cannot suffer the open surgery. However, as the key treatment device of this technique, traditional stent-grafts are not suitable to treat complex aortic aneurysm diseases in emergency. The emergence of the fenestrated stent-graft and in-situ fenestration has brought new dawn to the treatment of these patients. This study reviews the advances in complex aortic aneurysms treated by the fenestrated stent-graft and the in-situ fenestration. In addition, the novel concept of the fabric structure designed for "in-situ fenestrated stent-graft" is proposed for the in-situ fenestration technique. It is expected to break through the bottleneck of the present fenestrated stent-grafts. It would be beneficial to the bailout of complex aortic aneurysm diseases and thereby benefitting more patients.

Clinical features and surgical treatment of neurilemmoma versus carotid body tumors at bifurcation of carotid artery / 浙江大学学报·医学版

OBJECTIVE@#To analyze clinical features, surgical treatment and outcomes of neurilemmoma and carotid body tumors in bifurcation of carotid artery.@*METHODS@#The clinical data of 17 patients with neurilemmomas and 76 patients with carotid body tumors at the bifurcation of carotid artery, who were surgically treated in Zhongshan Hospital of Fudan University from March 2012 to November 2016, were retrospectively analyzed. The clinicopathological characteristics, surgical procedures and outcomes were compared between two groups.@*RESULTS@#No difference of preoperative clinical demographic data was found between two groups. Operation time of the neurilemmoma group was significantly shorter than that of the carotid body tumor group[(93.9±30.8) min vs. (159.3±52.9) min, 0.05).@*CONCLUSIONS@#The clinical manifestations of neurilemmoma and carotid body tumors at carotid artery bifurcation are similar. The carotid body tumor group has a longer operating time, larger intra-operative blood loss, higher external carotid resection rate and relative higher incidence of malignancy. More cautions should be given when carotid body tumors at carotid artery bifurcation are treated.

Research progress of acute aortic syndrome / 中华外科杂志

Acute aortic syndrome(AAS) is a lethal disease with acute onset and a high mortality rate as well as a higher incidence rate especially in an aging population. The diagnostic techniques of AAS have been improving in recent years. Many serum biomarkers have been shown to have the potential of further clinical implication. Advancement of imaging techniques has also improved the accuracy of early diagnosis. Although traditional treatment modality involving open surgery is life-saving, it still has a high mortality rate and a high major morbidity rate. The increasing utilization of endovascular techniques has greatly improved the prognosis of AAS, while it still need further optimization to be applied in different subgroups of patients.

Optimal timing of endovascular treatment for uncomplicated Stanford type B aortic dissection / 中华外科杂志

Stanford type B aortic dissection (TBAD) is an acute and life-threatening disease. The treatment of TBAD used to be depended on whether it is complicated. The therapeutic guidelines recommend thoracic endovascular aortic repair (TEVAR) as first-line treatment for patients with acute complicated TBAD, while recommend best medical therapy for patients with acute uncomplicated TBAD (UTBAD). However, the latest studies suggest that patients with UTBAD also should be treated with pre-emptive TEVAR, which can significantly improve aortic remodeling and clinical outcome. Considering improvement of aortic remodeling and prevention of severe complications, the best timing of pre-emptive TEVAR may be 14-90 days after the onset of TBAD (subacute phase). The other main issue is identifying which patients with UTBAD should undergo pre-emptive TEVAR. Several risk factors including imaging, clinical and laboratory parameters have been shown to be associated with aortic-related events in patients with UTBAD. Among imaging finding, the diameters of aortic or false lumen, the status of true or false lumen, the size or number of entry tears have identified to be as predictors of adverse aortic events in patients with UTBAD.

Finite Element Analysis of Aortic Dissection Treated with Stent Graft / 医用生物力学

Objective To study the process of stent graft implantation into the aortic dissection model by finite element simulation, calculate the stress distribution at different locations of the aorta after the implantation, and analyze the biomechanical mechanism of new lesions for implantation of stent grafts. Methods Based on the computed tomography angiography (CTA) image data of the aorta, a three-dimensional geometric model of patient-specific aortic dissection was established with image segmentation and reconstruction. The wall thickness and material properties of the aortic dissection of the computational models were set according to the literature data. Stent grafting rings with different geometric parameters were designed in a computer-aided design (CAD) software, and the procedure of stent graft implantation was simulated by a finite element analysis software. Results When the implanted stent graft reached a steady-state, the maximum Von Mises stress of the aorta was markedly related to the position of the stent graft and located at the bare stent or small nickel-titanium alloy ring. In the long-term, this force might cause a new tear to appear at the treated aorta. Conclusions The position of the stent graft had a weak effect on the distribution of the maximum Von Mises stress of the aorta, but there was an obvious effect on the Von Mises stress of the aorta. These research outcomes may provide significant guidance for selecting the position of the stent graft.