Thoracic Aortic Stent Graft Research Articles

Preventive Aortic Stent Graft Implantation Prior to Thoracic Surgery: Early and Midterm Results

Background: There is a paucity of data concerning the feasibility and value of thoracic aortic stent graft implantation (TEVAR) applications for removing tumors infiltrating the aortic wall. This analysis aimed to demonstrate the feasibility of TEVAR and monitor the perioperative risks of morbidity and mortality. Additionally, a literature review was performed. Methods: A retrospective data analysis was performed on patients who received TEVAR prior to thoracic malignancy resection between January 2010 and April 2024. The primary endpoint was technical success. Results: A total of 15 patients (median age: 67 years; range: 23–75; 66.7% female) received TEVAR prior to thoracic surgery of different tumor entities. In 80% of cases (n = 12), the proximal landing zone was in aortic zone 3. In three cases, the supra-aortic debranching of LSA and/or LCCA via bypass implantation or in situ laser fenestration was necessary. No postoperative endograft-related complications were observed. In eight patients, aortic wall infiltration was confirmed intraoperatively. In total, R0 resection was achieved in seven patients (46.7%). The 30-day mortality rate was 6.7% (n = 1). Technical success was achieved in all patients (100%), while procedural success was achieved in 80% due to incomplete tumor resection in three patients. Conclusions: To the best of our knowledge, this is the largest analysis to date that confirms the results of previous smaller studies. Aortic stent grafting prior to thoracic tumor resection allows for extensive resection while maintaining low morbidity and a low 30-day mortality risk.

Total Endovascular Repair of a Giant Iliac Vein Aneurysm: A Case Report and Review of Literature.

The iliac veins are the least frequent location for venous aneurysms, with only a few cases described globally. The etiology and clinical presentation of this extremely rare entity is diverse and unclear and no treatment consensus has been reached yet. Our purpose is to present an interesting iliac vein aneurysm (IVA) case that we treated in our department, with a brief review of the literature. We report a case of a 74-year-old male patient with a giant, 55 mm in diameter, asymptomatic, right common IVA, with concurrent aplasia of the left common iliac vein and an extensive network of venous collaterals. The patient was treated, under general anesthesia, with total endovascular iliocaval reconstruction through implantation of a 32 × 100 mm thoracic aortic tubular Ankura stent graft. The computed tomography venography at first-month follow-up showed the complete exclusion of the IVA, without any endoleak and the patient remains up to date free of symptoms and thromboembolic events. Twelve cases of endovascular treatment of IVA have been reported so far, and our case is the first with implantation of a thoracic aortic stent graft. Our results suggest that this technique is safe, effective, and may be considered for appropriately selected patients. This is the first case with total endovascular repair of an iliac vein aneurysm with contralateral iliac vein aplasia through endovenous implantation of a thoracic aortic stent-graft. Our results suggest that this technique is safe and effective and thus, may be considered for appropriately selected cases.

Analysis of Aortic Arch Hemodynamics With Simulated Bird's Beak Effects.

The objective of this study was to investigate the flow effects in different degrees of thoracic aortic stent graft protrusion extension by creating bird beak effect simulations using accurate 3D geometry and a realistic, nonlinear, elastic biomechanical model using computer-aided software SolidWorks. Segmentation in 3D of an aortic arch from a computed tomography (CT) scan of a real-life patient was performed using SolidWorks. A parametric analysis of three models was performed: (A) Aortic arch with no stent, (B) 3mm bird-beak configuration, and (C) 6.5mm bird-beak configuration. Flow velocity, pressure, vorticity, wall shear stress (WSS), and time average WSS were assessed. The flow velocity in Model A remained relatively constant and low in the area of the ostium of the brachiocephalic artery and doubled in the left subclavian artery. On the contrary, Models B and C showed a decrease in velocity of 52.3 % in the left subclavian artery. Furthermore, Model B showed a drop in velocity of 82.7% below the bird-beak area, whereas Model C showed a decline of 80.9% in this area. The pressure inside the supra-aortic branches was higher in Model B and C compared with Model A. In Model A, vorticity only appeared at the level of the descending aorta, with low to non-vorticity in the aortic arch. In contrast, Models B and C had an average vorticity of 241.4Hz within the bird beak area. Regarding WSS, Model A, and Model B shared similar WSS in the peak systolic phase, in the aortic arch, and the bird beak area, whereas Model C had an increased WSS by 5Pa on average at these zones. In the present simulations' lower velocities, higher pressures, vortices, and WSS were observed around the bird beak zone, the aortic arch, and the supra-aortic vessels.

Design and implementation of mechanical property testing equipment for thoracic aortic stent grafts

The mechanical properties of the stent graft are important factors influencing the outcome of TEVAR treatment and the occurrence of postoperative complications. The aim of this study is to improve and design a mechanical performance testing equipment for thoracic aortic stent grafts. The mechanical performance testing equipment consists of a radial force testing equipment of the stent graft designed by the wire compression grip method and a dynamic straightening force testing device with stable and controllable test conditions and continuously variable test angles. By constructing the testing equipment to physically measure the stent specimen, the experimental results reflect the trend of change and the simulation results are basically consistent, i.e. the mechanical properties of the thoracic aortic stent designed in this study is feasible and the measured data are valid. The testing equipment can provide the basis and reference direction for the quality testing of stent graft products, optimisation of mechanical properties of stent grafts and R&D innovation.

Preliminary Outcomes of Zone 2 Thoracic Endovascular Aortic Repair Using Castor Single-Branched Stent Grafts: A Single-Center Experience.

In the context of thoracic endovascular aortic repair (TEVAR), the reconstruction of the left subclavian artery (LSA) has emerged as a crucial component in establishing a sufficient proximal landing zone. However, the technical difficulty of these procedures raises the possibility of endoleaks and neurological consequences. Single-branched stent grafts offer good anchoring and LSA flow for these patients. This study evaluates the feasibility of utilizing novel single-branched stent grafts in the treatment of distal aortic arch disease, identifying good results in the short and medium term. From September 2019 to March 2023, TEVAR and revascularized LSA were performed on ten patients at the Ospedale del Cuore-FTGM in Massa, Italy, using Castor single-branched thoracic aortic stent grafts (Microport Medical, Shanghai, China). The authors' first findings demonstrated that, after an average follow-up of one year, the Castor branching aortic stent graft system was safe and achieving an appropriate proximal landing zone and maintaining sufficient LSA perfusion was possible. With regard to the endovascular treatment of distal aortic arch diseases, this product offers a compelling substitute for surgery. For the purpose of assessing the long-term effectiveness of this approach, the follow-up period should be extended.

Effects of Long Term Fatigue Cycling on In Situ Fenestrations of Polyethylene Terephthalate and Expanded Polytetrafluorethylene Thoracic Aortic Stent grafts: An Experimental Study

In this study, the long term durability of fenestrations after in situ fenestration (ISF) of five commercial thoracic aortic stent grafts was evaluated in an invitro experiment after a simulated 10 year period. Five different thoracic aortic stent grafts (Relay, Valiant, Hercules, TAG, and Ankura, with a diameter of 34 mm) received both needle and laser ISF invitro. A Viabahn (11× 50 mm) was released in each fenestration as a bridging stent graft. Long term fatigue tests (simulating 10 years) of each of the fenestrated stent grafts were then conducted in a flow fatigue test system. The area, shape, margin, and the long and short axis of all the fenestrations were evaluated with light microscopy before and after the fatigue test. The leakage from the fenestration junction before and after the long term fatigue was also measured. The experimental results showed no obvious difference between needle and laser fenestrations. The long axes of all the fenestrations remained unchanged, while the short axes increased after the fatigue test, which was significant in Relay, Valiant, and Hercules polyethylene terephthalate stent grafts. The shape scores of fenestrations improved after the fatigue test in Valiant and Hercules, remained unchanged in Relay and Ankura, and worsened in the TAG. After the fatigue cycling, the average leakage from the fenestration junction decreased in all the stent grafts, and the Ankura had the maximum decline rate. The ISF technique was durable over a simulated 10 year period. The fenestrations were positively remodelled to be more circular, and the leakage from the junction decreased after long term fatigue testing.

Esophageal reconstruction as the first step for treating secondary aortoesophageal fistula due to thoracic endovascular aortic stent infection

BackgroundThe surgical strategy for aortoesophageal fistula (AEF) depends on the experience of each surgeon, and there is no consensus on the strategy to be adopted. We propose our two-stage operation compromising esophagectomy and reconstruction as the first step and in situ aortic graft replacement as the second step after 7 days for treating AEF secondary to thoracic aortic stent graft infection.Case presentationA diagnosis of AEF was made in a 70-year-old man with a history of multiple aortic interventions. The patient underwent esophageal resection and reconstruction with a pedicled stomach roll endoscopically in the right thoracic cavity. Postoperatively, enteral feeding was resumed via a feeding tube placed in the jejunum to maintain adequate nutritional status. There was no evidence of either anastomotic leakage or necrosis. Seven days later, the patient underwent removal of the infected stent graft and in situ graft replacement via a redo left thoracotomy. After the surgery, the patient was able to start oral intake relatively early. Although more than 6 months has passed since the patient was discharged, no recurrence of infection has been observed.ConclusionsThe benefit of our strategy is the radical treatment for secondary AEF and the early resumption of oral intake.

Interim Analysis of an Ongoing Study Evaluating Preventive Aortic Stent Graft Implantation Prior to Major Thoracic Tumor Resection and a Review of the Literature

Abstract Introduction There is limited data in the literature on the use of thoracic aortic stent graft implantation (TEVAR) to facilitate en-bloc resection of tumors that have invaded the aortic wall. After TEVAR, extended resections can be performed, avoiding aortic wall replacement or catastrophic situations such as life-threatening bleeding from aortic injury. Aims The aim of this interim analysis was to demonstrate the feasibility of TEVAR without increased risk of perioperative morbidity and mortality. Methods A retro- and prospective data analysis was performed including all consecutive patients with suspicious aortic wall infiltration on preoperative imaging, who received a TEVAR implantation prior to resection of thoracic malignancy between 1/2008 and 12/2022. In addition, a literature review was conducted. Results Thirteen patients (median age 67 years, range 23-75, 62% female) have been treated at our institution so far. Nine patients received neoadjuvant therapy. In all patients it was possible to implant the stent graft with sufficient overlap at the level of the tumor mass. In 69% the proximal landing zone was located in aortic zone 3 to 4. No postoperative endograft related morbidity, especially no spinal cord ischemia, no stroke, no postoperative bleeding or access site complications, as well as no dissection or aortic rupture was observed. In nine patients, aortic wall infiltration was confirmed intraoperatively, and a partial non-circumferential resection of the aortic wall was necessary. The 30-day mortality rate was 15% (one case) due to respiratory failure and ARDS as well as postoperative empyema. Eight patients died during a median follow up of 11 month (0.7-94). Conclusions In this, to the best of our knowledge, largest analysis to date, the results of previous smaller series were confirmed. Aortic stent grafting prior to thoracic tumor resection allows extensive resections while maintaining low morbidity and a low 30-day mortality risk.

Thoracic Endovascular Aortic RepairAcutely Augments Left Ventricular Biomechanics in An Animal Model: A Mechanism for Postoperative Heart Failure and Hypertension

Thoracic aortic stent grafts are thought to decrease aortic compliance and may contribute to hypertension and heart failure after thoracic endovascular aortic repair (TEVAR). Left ventricular (LV) biomechanics immediately after TEVAR, however, have not been quantified. Pressure-volume (PV) loop analysis provides gold-standard LV functional information. The aim of this study is to use an LV PV loop catheter and analysis to characterize the LV biomechanics before and acutely after TEVAR. Anesthetized Yorkshire swine (N=6) were percutaneously instrumented with an LV PV loop catheter. A 20mm×10cm stent graft was deployed distal to the left subclavian via the femoral artery under fluoroscopy. Cardiac biomechanics were assessed before and after TEVAR. As a sensitivity analysis, inferior vena cava occlusion with PV loop assessment was performed pre and post-TEVAR in 1 animal to obtain preload and afterload-independent end-systolic and end-diastolic PV relationships (ESPVR and EDPVR). All animals underwent successful instrumentation and TEVAR. Post-TEVAR, all 6 animals had higher mean LV ESP (106 vs. 118mm Hg, P=0.04), with no change in the EDPVR. inferior vena cava occlusion also moved the ESPVR curve upward and leftward, indicating increased LV work per unit time. There was no augmentation of EDPVR following TEVAR (P>0.05). Postmortem exams in all animals revealed appropriate stent placement and no technical complications. TEVAR was associated with an acute increase in LV end-systolic pressure and shift in the ESPVR, indicating increased ventricular work. This data provides potential mechanistic insights into the development of post-TEVAR hypertension and heart failure. Future stent graft innovation should focus on minimizing the changes in cardiac physiology.

Comparison of Two Generations Valiant Thoracic Aortic Stent Grafts and Their Impact on Aortic Stiffness in an Ex Vivo Porcine Model

Comparison of Two Generations Valiant Thoracic Aortic Stent Grafts and Their Impact on Aortic Stiffness in an Ex Vivo Porcine Model

Endovascular Management of the Ascending Aorta: State of the Art.

Endovascular stent graft repair (EVAR) has revolutionized the management of aneurysms and dissections of the thoracic and abdominal aorta and is considered the first-line treatment in such pathologies. Initially designed for patients unfit for open repair, EVAR and thoracic endovascular aortic stent graft repair are associated with improved morbidity and mortality and a faster recovery process. The endovascular revolution of the aorta continues moving proximally, with fenestrated and branch stent grafts currently in clinical trials for the management of thoracoabdominal aortic aneurysms, and several branched thoracic devices are either approved or in trial for management of aortic arch pathologies. The final frontier in the endovascular management of the aorta is the aortic root and ascending aorta. The first early feasibility trial for management of type A aortic dissection has recently concluded with a multicenter phase 2 study slated for the spring of 2023. The following article updates the reader on the unique challenges of endovascular management of the ascending aorta and a look at the future technologies that will define this space.

Tevar Acutely Increases Left Ventricular Work In An Animal Model

Thoracic aortic stent-grafts are thought to decrease aortic compliance and may contribute to hypertension and heart failure post-TEVAR. Left ventricular (LV) biomechanics post-TEVAR have not been quantified. The aim of this study is to use LV pressure-volume (PV) loops to characterize the end systolic pressure (ESP)-volume relationship (ESPVR) and end diastolic pressure (EDP)-volume relationship (EDPVR) in a large animal model.

Comparison of Two Generations of Thoracic Aortic Stent Grafts and Their Impact on Aortic Stiffness in an Ex Vivo Porcine Model

Little is known about the cardiovascular changes after TEVAR and regarding the impact on aortic stiffness for different stent graft generations specifically, following changes in device design. The present study evaluated the stent graft induced aortic stiffening of two generations of the Valiant thoracic aortic stent graft. This was an exvivo porcine investigation using an experimental mock circulatory loop. Thoracic aortas of young healthy pigs were harvested and connected to the mock circulatory loop. At a 60 bpm heart rate and stable mean arterial pressure, baseline aortic characteristics were obtained. Pulse wave velocity (PWV) was calculated before and after stent graft deployment. Paired and independent sample t tests or their non-parametric alternatives were performed to test for differences where appropriate. Twenty porcine thoracic aortas were divided into two equal subgroups, in which a Valiant Captivia or a Valiant Navion stent graft was deployed. Both stent grafts were similar in diameter and length. Baseline aortic characteristics did not differ between the subgroups. Mean arterial pressure values did not change after either stent graft, while pulse pressures increased statistically significantly after Captivia (mean 44±10mmHg to 51±13mmHg, p=.002) but not after Navion. Mean baseline PWV increased after both Captivia (4.4±0.6 m/s to 4.8±0.7 m/s, p=.007) and Navion (4.6±0.7 m/s to 4.9±0.7m/s, p=.002). There was no statistically significant difference in the mean percentage increase in PWV for either subgroup (8±4% vs. 6±4%, p=.25). These experimental findings showed no statistically significant difference in the percentage increase of aortic PWV after either stent graft generation and confirm that TEVAR increases aortic PWV. As a surrogate for aortic stiffness, this calls for further improvements in future thoracic aortic stent graft designs regarding device compliance.

Outcomes in the treatment of aberrant subclavian arteries using the hybrid approach.

and keywords OBJECTIVESAberrant subclavian artery (ASCA) occurs rarely but is one of the most frequent anatomical variations of the supra-aortic trunks. No consensus has been established on its best treatment. The goal of this study was to report the outcomes of ASCA treated by the hybrid approach.METHODSThis non-interventional retrospective multicentre analysis included patients treated for ASCA by the hybrid approach in 12 French university hospitals between 2007 and 2019. The hybrid approach was defined as an endovascular procedure combined with open surgery or a hybrid stent graft. Patients were divided in 4 groups (from less to more complex treatment). The primary end point was 30-day mortality. The secondary end points were 30-day complications and late mortality.RESULTSThis study included 43 patients. The mean age was 65 (SD, standard deviation: 16) years. Symptoms were found in 33 patients. Subclavian revascularization combined with aberrant subclavian artery occlusion was undertaken in 13 patients. Unilateral and bilateral subclavian revascularization combined with a thoracic aortic stent graft was undertaken in 11 and 6 patients, respectively. Total aortic arch repair combined with a thoracic aortic stent graft was undertaken in 13 patients. Thirty-day mortality was 2.3% with a technical success rate of 95.3%. The 30-day major postoperative complication rate was 16.3%: 4 strokes, 2 tamponades, 1 acute respiratory distress syndrome. Mean follow-up was 56.3 (SD: 44.7) months. The late mortality was 18.6%.CONCLUSIONSThe ASCA hybrid approach is feasible, safe and effective with low early mortality. Morbidity is rather high. However, it increases with the complexity of the hybrid approach, which should be kept as simple as possible if the anatomical morphology allows.

Treatment of a descending thoracic mycotic aneurysm secondary to disseminated aspergillosis infection with thoracic endovascular aortic repair

Mycotic aortic aneurysms are a rare and potentially fatal aortic pathology. Advancements in vascular technology have allowed endovascular repair to be a durable and less invasive option for the treatment of mycotic aortic aneurysms. We have presented the case of a 51-year-old man with a mycotic aneurysm of the descending thoracic aorta secondary to chronic, disseminated aspergillosis infection after liver transplantation. The aneurysm was successfully treated with thoracic aortic stent graft deployment. No perioperative complications occurred, and follow-up computed tomography angiography showed no signs of an endoleak. The patient will continue with lifelong antifungal therapy and close follow-up with vascular surgery.

A Promising New Method for Cardiac Output Reduction During Thoracic Endovascular Aortic Repair: Is It Time To “Try This At Home”?

Although latest generation thoracic aortic stent grafts allow precise deployments under normal haemodynamic conditions, adjunctive strategies to reduce cardiac output (CO) are still needed in most complex aortic arch and proximal descending thoracic aortic cases.

Radiation-Free Thoracic Endovascular Aneurysm Repair with Fiberoptic and Electromagnetic Guidance: A Phantom Study

PurposeTo evaluate the feasibility and accuracy of a radiation-free implantation of a thoracic aortic stent graft employing fiberoptic and electromagnetic tracking in an anthropomorphic phantom. Materials and MethodsAn anthropomorphic phantom was manufactured based on computed tomography (CT) angiography data from a patient. An aortic stent graft application system was equipped with a fiber Bragg gratings and 3 electromagnetic sensors. The stent graft was navigated in the phantom by 3 interventionalists using the tracking data generated by both technologies. One implantation procedure was performed. The technical success of the procedure was evaluated using digital subtraction angiography and CT angiography (before and after the intervention). Tracking accuracy was determined at various anatomical landmarks based on separately acquired fluoroscopic images. The mean/maximum errors were measured for the stent graft application system and the tip/end of the stent graft. ResultsThe procedure resulted in technical success with a mean error below 3 mm for the entire application system and <2 mm for the position of the tip of the stent graft. Navigation/implantation and handling of the device were rated sufficiently accurate and on par with comparable, routinely used stent graft application systems. ConclusionsThe study demonstrates successful stent graft implantation during a thoracic endovascular aortic repair procedure employing advanced guidance techniques and avoiding fluoroscopic imaging. This is an essential step in facilitating the implantation of stent grafts and reducing the health risks associated with ionizing radiation during endovascular procedures.

Akutna ishemija lijeve ruke nakon TEVAR-a zbog anatomske varijante vertebralne arterije

Aim: In this case we report acute left arm ischemia after thoracic endovascular aortic repair of the saccular thoracic aortic aneurysm due to a rare anatomical variation of the left vertebral artery. Case report: Thoracic aortic stent-graft was deployed to cover the aneurysm, but six hours later acute left arm ischemia occurred due to a rare form of vertebral artery origin from the aortic arch instead of from the left subclavian artery. This hostile anatomy led to an iatrogenic acute ischemia which was the indication for an emergency left-common-carotid-to-subclavian-artery bypass grafting. Conclusion: Multidisciplinary approach and careful pre-procedural planning should always be the standard procedure in complex cases to avoid this complication.

Back-Table Modified Stent-Graft for Endovascular Repair of Ascending Aorta

Objectives To investigate the effectiveness of modified stent-grafts (SGs) for the management of ascending aortic pathologies. Materials and Methods From January 2015 to December 2019, 31 individuals were treated by ascending aortic endovascular repair with a back-table modified SG for acute (n=4) or chronic (n=1) type A aortic dissections, penetrating aortic ulcers (n=18), pseudoaneurysms (n=2), anastomotic fistula (n=1), and endoleaks after thoracic endovascular aortic repair (TEVAR) (n=5). The commercially available thoracic aortic SGs were modified with a fenestration or truncation technique on the back-table according to aortography during the operation. Results The 30-day mortality and aorta-related mortality rates were 12.9% and 6.5%, respectively. There were 2 strokes, 3 respiratory insufficiencies, and 6 endoleaks during hospitalization. During a mean follow-up of 28.8±16.6 months, the overall survival rates at 1 year and 3 years were both 80.6%. Free from adverse event rates at 1 year and 3 years were 88.9% and 84.7%, respectively. There were 2 deaths during follow-up: One patient died of cachexia 1 month after discharge, and the other patient died of acute myocardial infarction 3 months after discharge. One patient with a pseudoaneurysm underwent open ascending aorta replacement 3 months after discharge for a type Ia endoleak. Another patient suffered from cerebellar infarction 17 months after discharge. Conclusion The modified SG for endovascular repair of the ascending aorta is a practicable alternative and presents acceptable outcomes in high-risk patients.

Review of Studies Reporting the Incidence of Acute Type B Aortic Dissection

Aortic dissection (AD) causes more deaths each year in the United Kingdom than road traffic collisions. Yet the incidence of AD is not known. The management of acute type B AD (TBAD) is changing, with the greater use of thoracic aortic stent grafts (TEVAR) in treatment and fewer open surgical procedures performed. The study’s aim is to review the worldwide, English language published, literature on acute TBAD incidence and treatment, to report on its strengths and limitations, and better understand changes in incidence over time and between countries. Thirty-one studies were identified that focus on the epidemiology and treatment of TBAD. Eight of these studies report the incidence of acute TBAD as between of 0.5–6.3 per 100,000 person years. Hospital admissions for aortic dissection are reported to be increasing in six studies and stable in one study. The proportion of patients with TBAD operated on varies between studies (range 13% to 76%). Studies identify patient age (median 51–77 years), gender (range 48%–81% male) and prevalence of cardio-vascular risk factors, specifically hypertension, in the populations studied as independent factors influencing aortic dissection incidence. Treatment of acute TBAD remains largely conservative with analgesia, hypertension control and serial cross-sectional imaging (range 24%–87% TBAD medically treated). The use of TEVAR to treat acute AD is increasing worldwide (range 13%–76% TBAD treated with TEVAR). The incidence of TBAD is under-reported due to out of hospital deaths, variable clinical presentation (miss-diagnosis) and coding errors. Importantly for research, the single International Classification of Diseases (ICD) code for aortic dissection, I17.0, does not distinguish between acute, chronic, type A or type B dissection types. Similarly, the OPCS Classification of Interventions and Procedures version 4 (OPCS-4) codes for TEVAR, L27.4 and L28.4, do not distinguish between acute and chronic AD presentation, unlike the codes for open thoracic aortic replacement. Standardised reporting of aortic dissection type, and the urgency of both the initial presentation (acute or chronic) and treatment (emergency, urgent or planned) in future studies would allow more meaningful comparisons between populations.