Objective To calculate the pre-stretching of the microscopic components of the aortic wall under physiological homeostasis by considering a three-dimensional(3D)residual stress field.Methods The aortic wall was simplified into a double-layer ideal circular tube,and the 3D residual stress field of the vascular wall was calculated based on a 3D expansion angle experiment.Then,the in vivo stress distribution characteristics under mean blood pressure and the pre-stretching of each microscopic constituent of the vascular wall under a physiologically steady state were obtained.The inverse problem was constructed according to the internal pressure-radius relationship measured in vivo.Physiological homeostasis of the aorta was considered the reference state,and inversion identification of the material parameters of the aorta in vivo was realized while integrating the three residual stress fields.Results When residual stress was not considered,the mean stress of the middle membrane was greater than that of the outer membrane.When residual stress was considered,the outer membrane bore more stress than the middle membrane,and the outer membrane protected the middle membrane.The pre-stretching of the middle film with residual stress was lower than that without residual stress,whereas the pre-stretching of the outer film was higher than that without residual stress.Moreover,the pre-stretching of the outer membrane collagen fibers was greater than that of the middle membrane collagen fibers.The in vivo calculations of the material parameters of the aorta were performed using physiological homeostasis as the reference configuration,and the proportion of each component was consistent with the experimental results.However,the proportion of elastin in the outer membrane was significantly overestimated when the non-stress configuration was used as the initial configuration,which was inconsistent with the experimental results.Conclusions Residual stress significantly influences the pre-stretching and physiologically steady mechanical states of the microscopic components of the aortic wall.Therefore,it is necessary to fully consider the influence of residual stress to establish the physiologically steady state of the aortic wall accurately.Furthermore,it is also necessary to fully consider the 3D characteristics and layer specificity of residual stress in the in vivo identification of material parameters.

Objective:To compare the aortic remodeling of the Fabulous stent system and standard thoracic aortic endovascular repair (TEVAR) on distal aorta type B aortic dissection (TBAD). Methods:The prospective data collected between Dec 2017 and Oct 2019 from 134 patients with type B aortic dissection (TBAD) who underwent treatment with the "Fabulous" stent system, and retrospective data from 159 TBAD patients receiving standard TEVAR from corresponding multicenter. By using propensity score matching analysis, we compared the prognosis and aortic remodeling outcomes in patients undergoing Fabulous and standard TEVAR treatments during a 1-year postoperative follow-up.Results:In this study, 62 patients in Fabulous group and 62 patients in standard TEVAR were included.There were no significant statistical differences in baseline characteristics between the two groups. In terms of aortic remodeling in bare stent region, Fabulous group had better change trends of diameter of true lumen [10.6 (4.4, 14.5) mm vs. 4.7 (0.9, 10.7) mm, P=0.001] and false lumen [-24.2 (-30.5, -4.9) mm vs. 0.7 (-11.8, 2.3) mm, P<0.001] than those in the standard TEVAR group. The rate of complete false lumen thrombosis was also higher in the Fabulous group (62.9% vs. 37.1%, P=0.042). Conclusion:The Fabulous stent system, when compared to standard TEVAR surgery, demonstrates good aortic remodeling outcomes in the distal aorta.

Objective:To evaluate the medium-term efficacy and safety of the controlled supra-aortic pre-fenestration technique in the management of aortic arch lesions.Methods:The clinical and follow-up data of 167 patients with aortic arch lesions located in the Z1 and Z2 zones and undergoing endovascular treatment at the Department of Vascular Surgery, Tianjin Medical University General Hospital from Jul 2015 to Dec 2022 were retroactively analyzed.Results:The surgical success rate was 100% in both the pre-fenestration and non-pre-fenestration groups. Regarding technical success, the pre-fenestration group exhibited a rate of 97.26%, while the non-pre-fenestration group showed a rate of 95.74% ( P>0.05). Cost in the pre-fenestration group was lower compared to the non-pre-fenestration group ( P<0.05). The mean follow-up period were (63.92±25.23) months for the pre-fenestration group and (37.63±21.48) months for the non-pre-fenestration group. During the follow-up period, no significant differences were found in complications, reinterventions, and survival rates between the two groups ( P>0.05). Conclusion:Controlled supra-aortic pre-fenestration technique exhibits excellent medium-term efficacy and safety in the treatment of aortic arch diseases located in the Z1 and Z2 zones with lower total hospitalization costs.

Humans ; Endovascular Aneurysm Repair ; Stents ; Blood Vessel Prosthesis ; Aortic Dissection/surgery* ; Endovascular Procedures ; Aortic Aneurysm, Thoracic/surgery* ; Treatment Outcome ; Blood Vessel Prosthesis Implantation ; Retrospective Studies

Fenestrated thoracic aortic endovascular repair (TEVAR), as the most advantageous technique for total endovascular repair of aortic arch lesions, has been widely carried out in China, but the technical level is different, the operation process lacks standardization, and the quality control is insufficient. This article discusses the technical details include how to ensure the controllability of TEVAR in physician-modified fenestration, how to choose indications, select fenestration positions, make fenestration, install preset guide wires, unwind guide wires, accurately position fenestration of the hole, delivery and release of the bridging stent combined with author′s experience.

Objective:To compare the efficacy and safety of different treatment methods for thoracoabdominal aortic aneurysm(TAAA).Methods:The clinical data of 39 TAAA patients admitted to our department from Jan 2010 to Feb 2018 were retrospectively analyzed.Results:There were 25 patients in endovascular group, 11 in open group and 3 in hybrid group. The mean age in the endovascular group was significantly higher than that in the open group ( P<0.05). The blood loss and operation time in the endovascular group were significantly lower than those in the open group and the hybrid group ( P<0.05). There was no significant difference in the operation success rate, the complication rate in post-operative 30 days and the rate of re-intervention ( P>0.05) among the three groups. The post-operative 30 days mortality was significantly higher in the hybrid group than that in the endovascular group and open group ( P<0.05). During the follow-up period, the complication rate in the endovascular group was significantly higher than that in the open group ( P<0.05). Conclusion:Endovascular surgery is more suitable for elderly patients because of shorter operation time, less trauma and bleeding.

Objective To simulate the interaction between the stent graft (SG) and the aortic wall with finite element (FE) analysis by considering the influence of residual stress field, so as to study the stent influence on stress distributions of the aortic wall. Methods The three-dimensional (3D) residual stress field was generated in an idealized bi-layered thick-wall aortic model via a stress-driven anisotropic growth model by reducing the transmural stress gradient. Upon virtually deploying the SG, the stress on the aortic wall was calculated. Results The 3D residual stress field, corresponding to an opening angle of 117.5°, was shown to reduce the transmural stress gradient in both the circumferential and axial directions. The maximum stress was found at the contact area between aortic wall and wave peak of the stent. At 20% oversize ratio of the stent, the maximum stresses on the aortic wall in circumferential and axial direction were 412 and 132 kPa, respectively, while the in-plane shear stresses σrθ and σrz were both 78 kPa. Under residual stress, the maximum radial, circumferential and axial stresses were decreased by 14.9%, 40.5% and 33.8%, respectively, while the maximum shear stresses σrθ ，σrz，σθz were reduced by 2.5%, 7.1% and 27%, respectively. With the increase of oversize ratio from 10% to 20%, the maximum radial, circumferential and axial stresses were increased by 316%, 129% and 41%, respectively, while the maximum shear stresses σrθ ，σrz，σθz were increased by 661%, 450% and 466%, respectively. Conclusions The residual stress can effectively reduce the transmural stress gradient. Both the residual stress and the oversize ratio of the stent play an important role in modulating the wall stress distribution and the maximum stress.

Objective To propose a one-way fluid-structure interaction (FSI) method based on an idealized aortic dissection model, so as to analyze the hemodynamics and wall stress in the false lumen (FL) under the influence of multiple overlapping uncovered stents (MOUS). Methods Upon establishment of the numerical model, the models were divided into two categories according to whether the model involved FL perfused branch artery. The characteristics of hemodynamics and wall stress state in the post-operative scenarios were simulated under different surgical strategies. The wall stress state of the FL before and after thrombosis formation was also compared and analyzed. ResultsThe release process of the stents had little influence on wall stress of the FL. The high velocity and high wall shear stress (WSS) area in the FL could not be reduced by using the MOUS alone. If only the proximal entry tear was blocked with a covered stent-graft, the distal end would maintain a region of high flow rate and high WSS. The combination of covered stent-graft and MOUS would result in a region of low flow rate and low WSS, as well as reduced wall pressure and wall stress in the FL. Compared with the model with FL perfused branch arteries, the model without it was more likely to form a region of low flow rate and low WSS after surgery. However, blood pressure in the FL was relatively higher. The formation of thrombus in the FL could greatly reduce wall stress in the area covered by the thrombus. Conclusions The method proposed in this study can simultaneously investigate hemodynamics and wall stress characteristics of the FL, and provide support for studying mechanical mechanism of FL thrombolysis induced by MOUS and the post-operative aortic expansion.

Objective:To evaluate the efficacy and safety of physician-modified fenestration TEVAR for treating type B aortic dissection with unhealthy or short anchoring zone.Methods:Clinical data of patients with type B aortic dissection who received TEVAR for left subclavian artery fenesration from May 2016 to Dec 2018 were analyzed prospectively.Results:The technical success rate was 93.2%. One case was converted into chimney stenting. One case suffered type Ⅰendoleak. One case had type Ⅲ endoleak. There were no deaths or neurological complications during the perioperative period, and the mean hospital stay was 9.2 (5-26) days. The median follow-up time was 30 (12-42) months. One case developed type Ⅰ endoleak during follow-up. No retrograde dissection occurred and all LSA stents remained patent.Conclusion:Physician-modified fenestration TEVAR is safe and effective for the treatment of type B aortic dissection with unhealthy or short anchoring zone.

To assess the efficacy and outcome of endovascular aortic repair (EVAR for the treatment of primary infected aortic aneurysms (PIAAs).Methods The clinical data of 15 consecutive patients presenting with PIAA from Apr 2010 to Apr 2018 were retrospectively reviewed.Results 10 were male out of 15 patients ranging from 55 to 80 years old.The aneurysms were located in thoracoabdominal aorta in 1 case,abdominal aorta in 10 cases and left common iliac artery in 4 cases.Positive microbial cultures were reported in 13 patients,including Salmonella species in 12 and Streptococcus in 1.Eleven patients received preoperative antibiotics therapy before elective EVAR for more than 1 week.Four patients underwent emergency EVAR due to ruptured aneurysms.Postoperative antibiotic therapy was given for at least six months.There was no death within 30 days.Mean follow-up time was 44.6 months.Infection relapsed in 6 patients during follow-up.Infection-related death occurred in 3 cases.3 of them were healed.Conclusions EVAR combined with aggressive antibiotic strategy is feasible for the treatment of PIAAs,particularly in high-risk surgical patients or in the acute setting of rupture.