Various Endoluminal Approaches Available for Treating Pathologies of the Aortic Arch

Mechanisms of aortic dissection: From pathological changes to experimental and in silico models

Aortic dissection continues to be responsible for significant morbidity and mortality, although recent advances in medical data assimilation and in experimental and in silico models have improved our understanding of the initiation and progression of the accumulation of blood within the aortic wall. Hence, there remains a pressing necessity for innovative and enhanced models to more accurately characterize the associated pathological changes. Early on, experimental models were employed to uncover mechanisms in aortic dissection, such as hemodynamic changes and alterations in wall microstructure, and to assess the efficacy of medical implants. While experimental models were once the only option available, more recently they are also being used to validate in silico models. Based on an improved understanding of the deteriorated microstructure of the aortic wall, numerous multiscale material models have been proposed in recent decades to study the state of stress in dissected aortas, including the changes associated with damage and failure. Furthermore, when integrated with accessible patient-derived medical data, in silico models prove to be an invaluable tool for identifying correlations between hemodynamics, wall stresses, or thrombus formation in the deteriorated aortic wall. They are also advantageous for model-guided design of medical implants with the aim of evaluating the deployment and migration of implants in patients. Nonetheless, the utility of in silico models depends largely on patient-derived medical data, such as chosen boundary conditions or tissue properties. In this review article, our objective is to provide a thorough summary of medical data elucidating the pathological alterations associated with this disease. Concurrently, we aim to assess experimental models, as well as multiscale material and patient data-informed in silico models, that investigate various aspects of aortic dissection. In conclusion, we present a discourse on future perspectives, encompassing aspects of disease modeling, numerical challenges, and clinical applications, with a particular focus on aortic dissection. The aspiration is to inspire future studies, deepen our comprehension of the disease, and ultimately shape clinical care and treatment decisions.

Safety and validity of extracorporeal fenestration and in situ fenestration in patients with aortic disease involving the left subclavian artery: a prospective, single-center, randomized controlled study

BACKGROUND

Thoracic aortic pathologies involving the aortic arch are a great challenge for vascular surgeons. Maintaining the patency of supra-aortic branches while excluding the aortic lesion remains difficult. Thoracic EndoVascular Aortic Repair (TEVAR) with fenestrations provides a feasible and effective approach for this type of disease. The main purpose of this trial is to assess the safety and validity of extracorporeal fenestration and in situ fenestration in patients with aortic disease involving the left subclavian artery.

METHODS

This is a prospective, single-center, randomized controlled study. A total of 170 eligible patients will be recruited from The Fourth Affiliated Hospital, Zhejiang University School of Medicine in China and randomized on a 1:1 basis either to the group A (extracorporeal fenestration) or the group B (in situ fenestration). The primary outcome will be the all-cause mortality (30 days). The secondary outcomes will include incidence of secondary intervention (30 days, 6 months, 1 year), incidence of endoleak (30 days, 6 months, 1 year), incidence of major adverse events (MAE) (i.e., immediate procedural success and complications) (30 days, 6 months, 1 year), immediate technical success rate, and all-cause mortality (6 months, 1 year).

DISCUSSION

Suppose extracorporeal fenestration non-inferior to in situ fenestration in patients with aortic disease involving the left subclavian artery. This trial aims to demonstrate the safety and validity of extracorporeal fenestration and in situ fenestration in patients with aortic disease involving the left subclavian artery, which is expected to provide a reference for Thoracic EndoVascular Aortic Repair (TEVAR) with fenestrations.

TRIAL REGISTRATION

ClinicalTrials.gov NCT06256757. Registered on February 5, 2024. https://clinicaltrials.gov/study/NCT06256757 .

Endovascular Repair of Penetrating Thoracic Aortic Ulcers Using Tubular Stent Grafts Versus Stent Grafts With a Proximal Scallop

PURPOSE

In penetrating aortic ulcers (PAUs), limited data support tubular thoracic endovascular aortic repair (TEVAR) as a viable treatment option. For treatment of more proximal PAUs, hybrid approaches and-more recently-scalloped TEVAR (scTEVAR) have been advocated. Outcomes of scTEVAR specifically for PAUs have not yet been reported. This study reports long-term outcomes for tubular and scTEVAR in PAUs and compares the safety profile in both cohorts regarding the significantly more proximal landing zone (LZ) for scTEVAR.

MATERIALS AND METHODS

This single-center retrospective cohort study includes all nonacute patients treated for complicated PAU with scTEVAR and tubular TEVAR. Patient and PAU characteristics as well as procedural success, complication and reintervention rates, and all-cause and aortic mortality were analyzed.

RESULTS

Of 212 TEVAR procedures reviewed, 21 patients with tubular TEVAR and 19 patients with scTEVAR were included. Patient and PAU characteristics were similar, and LZ was significantly more proximal in the scTEVAR cohort (p=0.0001), with similar number and types of supra-aortic revascularization procedures. Clinical success was reached in all 40 patients (100%), and reintervention rate was 2/21 (9.5%) and 1/19 (5.3%), respectively. Over the mean follow-up of 63 (TEVAR) and 53 (scTEVAR) months, clinical success was stable in all patients with one (abdominal) aortic-related mortality in the scTEVAR cohort.

CONCLUSION

Treatment of complicated PAUs with TEVAR as well as scTEVAR provides excellent and similar clinical success, stability of clinical success, and aortic survival with acceptable complication and reintervention rates. Scalloped TEVAR safely lengthens the proximal sealing zone to address more proximal pathologies.

CLINICAL IMPACT

Treatment of asymptomatic complicated penetrating aortic ulcers (PAUs) with thoracic endovascular aortic repair (TEVAR) provides excellent clinical success and acceptable complication and reintervention rates. More patients become amenable to endovascular treatment by including scalloped TEVAR (scTEVAR) as a means to safely lengthen the proximal sealing zone to address more proximal pathologies.

Stent Graft-Induced High Wall Stress Promoted Aortic Wall Failure and Aortic Wall Injurious Complications After TEVAR: A Study of Numerical Simulation and Bioinformatics Analysis Based on Pig Models

OBJECTIVES

Stent graft-related aortic injury is a major complication after thoracic endovascular aortic repair (TEVAR) and seriously affects patient prognosis. However, the distribution characteristics of aortic wall stress under the action of stent grafts and the mechanism of abnormal wall stress leading to aortic wall injury and adverse remodeling were unclear. The aim of this study was to explore the potential mechanisms of high wall stress on the structural and functional alterations of the aortic wall by combining animal experiments, numerical simulations, and bioinformatics.

METHODS

We observed stent graft-induced aortic injury by performing fenestrated TEVAR in 6 pigs, and quantitatively analyzed and visualized the stress distribution of the aortic wall under the stent graft through numerical simulation. Hematoxylin and eosin (HE) staining, Masson's trichrome staining, Verhoeff's Van Gieson (EVG) staining, and immunostaining were used to evaluate pathological changes in the aorta. Based on the numerical simulation results, the corresponding high-stress and low-stress regions of the aortic wall were subjected to bulk-RNA sequencing, and hub genes were identified by bioinformatics analysis.

RESULTS

Stent grafts were successfully implanted in 5 pigs. In all computational models, we found that obvious deformation and characteristic maximum stress concentration occurred on the side of the greater curve of the aortic arch in contact with the stent graft tip, and the high wall stress concentration areas were highly consistent with the obvious pathological injury area. Subsequent pathological analysis revealed that high wall stress-induced confusion and fragmentation of elastic fibers, collagen deposition, loss and phenotypic switching of vascular smooth muscle cells, and increased inflammatory responses. Gene expression profiles of the aortic wall under different wall stress conditions were described for the first time, and the hub genes (TGFB1, CDH5, DCN, ITGA5, ITGB3, and WT1) that may be involved in regulating the aortic injury and remodeling process in response to high wall stress stimulation were identified.

CONCLUSIONS

This study revealed a panoramic view of stent graft-associated high wall stress-induced aortic wall injury through technical approaches of multiple dimensions. Understanding these biomechanical features and hub genes is pivotal for advancing our comprehension of the complications associated with aortic injury after TEVAR and facilitating the development of future therapeutic interventions.

CLINICAL IMPACT

This study revealed a panoramic view of stent graft-associated high wall stress-induced aortic wall injury through technical approaches of multiple dimensions. The biomechanical distribution characteristics of the aortic wall, the secondary pathological injury and the alteration of gene expression profile under the action of stent graft were comprehensively revealed by animal experiments for the first time. This will advance clinicians' comprehension of complications associated with aortic injury after TEVAR, provide a new biomechanical perspective for the rational preoperative planning of TEVAR and the management of postoperative complications, and facilitate the development of future therapeutic interventions and stent graft device designs.

Endovascular repair of ascending aortic pathologies in patients unfit for open surgery: case series and literature review

The number of vascular centers performing endovascular repair of ascending aortic disease is constantly increasing. Accordingly to the guidelines, open surgical repair remains the gold standard for these pathologies. However, approximately one quarter of patients are deemed unfit for open surgery. In this study, we describe three cases of ascending thoracic endovascular aortic repair (TEVAR) performed at our center. All the patients were deemed unfit for open surgery by the aortic team. Two patients had an ascending aortic pseudoaneurysm, and the third had a focal type A aortic dissection. In two cases, we used two abdominal aortic cuffs deployed from zone 0B to zone 0C, with no need for supra-aortic trunk debranching. In one case, we performed a "reverse" extrathoracic debranching, and we deployed a thoracic endograft from zone 0B to zone 2. Complications included one minor stroke and one inguinal hematoma. In one patient with an infected pseudoaneurysm, we performed ascending TEVAR as a bridge strategy for open repair. This patient developed a type Ia endoleak; however, clinical stabilization and infection control were obtained, and he was able to undergo heart surgery successfully. He underwent a second reintervention to treat superior mesenteric embolic occlusion. At 2 years of follow-up, all three patients were alive. Our preliminary experience demonstrates the technical feasibility and clinical appropriateness of ascending TEVAR using standard, commercially available endografts. However, no consensus has been reached regarding some critical aspects, such as the development of a standardized technique or the efficacy of the currently available devices. The improvements in graft design and the adoption of the "aortic team" approach could help in the near future to standardize the procedure, establish appropriate indications, and ensure good clinical outcomes.

Outcomes of thoracic endovascular aortic repair with physician-manufactured partial micropore stent grafts for aortic arch pathologies

OBJECTIVE

Thoracic endovascular aortic repair (TEVAR) has been used extensively in the management of thoracic aortic diseases. Numerous efforts have been made to enhance clinical outcomes through the use of stent grafts. This study aimed to investigate the effectiveness and safety of physician-manufactured partial micropore stent grafts (PSMGs) in TEVAR.

METHODS

Between December 2017 and June 2022, data were collected from 56 patients who underwent TEVAR using physician-manufactured PSMGs. The evaluation encompassed technical success, perioperative and follow-up morbidity and mortality, stroke incidence, and branch artery patency.

RESULTS

In this investigation, 56 patients received treatment with physician-manufactured PSMGs. Of these patients, 46 were male, with a mean age of 62.1 ± 11.2 years. Aortic pathologies comprised aortic dissection (n = 31 [55.4%]), aortic aneurysms (n = 10 [17.9%]), penetrating aortic ulcer (n = 8 [14.3%]), and intramural hematoma (n = 7 [12.5%]). During a median follow-up of 18 months (interquartile range, 13-25 months), the stroke rate, supra-aortic branch patency rate, and endoleak rate were 0%, 100%, and 7.1%, respectively. There were no occurrences of all-cause mortality, stroke, or the necessity for open conversion.

CONCLUSIONS

TEVAR with physician-manufactured PSMGs is a viable alternative for addressing aortic arch pathologies in proficient medical centers. The approach demonstrates favorable branch patency, a low complication rate, and minimal postoperative mortality.

The creation and validation of predictive models to assess the risk of unfavorable outcomes following hybrid total arch repair for Stanford type A aortic dissection

BACKGROUND

The objective of this study was to develop and validate a nomogram for the individualized prediction of adverse events in patients with Stanford type A aortic dissection (TAAD) undergoing hybrid total aortic arch repair.

METHODS

From April 2019 to April 2022, we conducted a comprehensive review of the medical records of Stanford type A aortic dissection patients who underwent hybrid total aortic arch repair surgery at our hospital. Patients were separated into two groups based on whether or not a composite adverse event occurred following surgery. Using univariate and multivariate analyses of logistic regression, the prediction model was created. Construct risk prediction models utilizing nomograms and evaluate their precision, discrimination, and clinical utility.

RESULTS

Age, platelets, serum blood urea nitrogen, and ascending aortic diameter were the variables included in the nomogram by univariate and multivariate analysis. The risk model performed well in internal validation, with an area under the curve (AUC) of 0.829. The calibration curve demonstrated good agreement between predicted and actual probabilities (Hosmer-Lemeshow test, P = 0.22). Clinical decision analysis curves demonstrate predictive nomograms' clinical utility.

CONCLUSION

This study created and validated a nomogram for predicting the risk of composite endpoint events in TAAD patients undergoing hybrid total aortic arch repair. The nomogram can help determine the severity of a patient's condition and provide a more personalized diagnosis and treatment.

NEXUS Arch: A Multicenter Study Evaluating the Initial Experience With a Novel Aortic Arch Stent Graft System

OBJECTIVE

To assess the initial clinical experience with a novel endograft system (NEXUS Aortic Arch Stent Graft System) designed to treat aortic arch pathologies and address the morphology and hemodynamic challenges of the aortic arch.

SUMMARY BACKGROUND DATA

The aortic arch remains the most challenging part of the aorta for both open and endovascular repair. Transcatheter aortic arch repair has the potential to significantly reduce surgical risks.

METHODS

Patients underwent transcatheter aortic arch repair with a single branch, 2 stent graft system, implanted over a through-and-through guidewire from the brachiocephalic trunk, to the descending aorta with an ascending aorta stent graft. The ascending aorta stent graft is deployed into a designated docking sleeve to connect the 2 stent grafts and isolate the aortic arch pathology. Proximal landing zone in all cases was in Zone 0. Anatomical inclusion criteria included adequate landing zone in the ascending aorta, brachiocephalic trunk, and descending thoracic aorta. Preparatory debranching procedure was performed in all patients with carotid-carotid crossover bypass and left carotid to left subclavian bypass, or parallel graft from descending aorta to left subclavian artery. Safety and performance were evaluated through 1 year. Survival analysis used the Kaplan-Meier method.

RESULTS

Twenty-eight patients, 79% males, with a mean age of 72.2 ± 6.2 years were treated with 100% procedural success. Isolated aortic arch aneurysm was the principle pathology in 17 (60.7%) of patients, while chronic aortic dissection was the principle pathology in 6 (21.4%) of patients. The remaining 5 (17.8%) had combined or other pathologies. At 1 month, the vascular pathology was excluded in 25 of 26 alive patients (96.1%). The 30 days mortality rate was 7.1%, stroke rate was 3.6% (all nondisabling), and combined mortality/stroke rate was 10.7%. One-year mortality was 10.7%, without device or aneurysm-related death. Two patients (7.1%) reported stroke or transient ischemic attack at 1 year that recovered completely. One year combined mortality/stroke rate was 17.8%. There were 3 patients (10.7%) that had device-related unplanned reinterventions through 1 year.

CONCLUSIONS

The NEXUS Aortic Arch Stent Graft System, a novel single branch, 2 stent graft system used for endovascular aortic arch repair that requires landing in the ascending aorta, demonstrates a high success rate with excellent 1 year safety and performance.

Technical details of thoracic endovascular aortic repair with fenestrations for thoracic aortic pathologies involving the aortic arch: A Chinese expert consensus

Thoracic aortic pathologies involving the aortic arch are a great challenge for vascular surgeons. Maintaining the patency of supra-aortic branches while excluding the aortic lesion remains difficult. Thoracic EndoVascular Aortic Repair (TEVAR) with fenestrations provides a feasible and effective approach for this type of disease. The devices needed in the procedure are off-the-shelf, with promising results reported in many medical centers. Up until now, there have been no guidelines focusing exclusively on the details of the TEVAR technique with fenestrations. Experts from China have discussed the technical parts of both in situ fenestrations (needle and laser) and fenestrations in vitro (direction inversion strategy and guidewire-assisted strategy), providing a technical reference to standardize the procedure and improve its results.

Hemodynamic numerical simulation of aortic arch modular inner branched stent-graft in eight early patients from the first-in-human case series

Background

The modular inner branched stent-graft (MIBSG) (WeFlow-Arch™) is an emerging device for challenging aortic arch pathologies. Hemodynamic numerical simulation is conducive to predicting long-term outcomes as well as optimizing the stent-graft design.

Objective

This study aims to analyze the hemodynamic characteristics of the MIBSG devices based on numerical simulation analyses.

Methods

From June 2019 to June 2021, MIBSGs were utilized in eight cases. Numerical simulation analyses of branch perfusion and indicators including the time-averaged wall shear stress, oscillatory shear index, and relative residence time were performed.

Results

Lesions involved Zone 1 (n = 2), Zone 2 (n = 4), and Zone 3 (n = 2). Branched stent-grafts were deployed in the innominate artery and left common carotid artery (n = 5) or in the innominate artery and left subclavian artery (n = 3). The hemodynamic change in common was increased perfusion in the descending aorta and left common carotid artery. Half of the patients had increased cerebral perfusion of 8.7% at most, and the other half of the patients showed a reduction of 5.3% or less. Case 3 was considered to have acquired the greatest improvement in hemodynamic features.

Conclusion

The MIBSG showed improved hemodynamic features in most cases. The design of the MIBSG could be partly modified to acquire better hemodynamic performance.

Outcomes of thoracic endovascular aortic repair with chimney technique for aortic arch diseases

Objective

This study aimed to summarize the long-term experience of using the chimney technique in thoracic endovascular aortic repair (TEVAR) for aortic arch diseases.

Methods

From November 2007 to June 2021, a total of 345 consecutive patients (mean age 56 ± 11.3 years, range 28–83, 302 men) with aortic arch pathologies underwent TEVAR combined with chimney technique (cTEVAR). Their medical data and follow-up results were retrospectively reviewed and analyzed.

Results

Among the 345 patients, 278 (80.6%) received single chimneys, 53 (15.4%) received double chimneys, 7 (2%) received triple chimneys, and 7 (2%) underwent cTEVAR accompanied by other techniques (two with extra-anatomical bypass, two with in situ fenestration, and three with physician modified fenestration). A total of 412 chimney stents were used, including 27 in the innominate artery (IA), 113 in the left common carotid artery, 270 in the left subclavian artery, and two in the aberrant right subclavian artery. Early type IA endoleaks were found in 38 (11%) patients, including 12 with the double or triple chimney technique. Early type II endoleak was found in nine (2.6%) patients. Early re-intervention occurred in two patients with double chimney technique, one for chimney stent migration and the other for compression of chimney stent. The 30-day mortality was 1.2% (4 in 345). During a mean follow-up of 42 ± 22 months (range 1–108 months), major stroke occurred in nine (2.6%) patients, chimney occlusion or stenosis occurred in six (1.7%), and retrograde type A aortic dissection occurred in four (1.2%). Fourteen (4.1%) patients received the secondary intervention. The all-cause mortality was 6.7% (23 in 345). Additionally, the total adverse event rate after cTEVAR was 13.9% (48 in 345).

Conclusion

TEVAR with chimney technique provides a minimally invasive alternative with good chimney graft patency and low postoperative mortality during follow-up. However, the double and triple chimney techniques should be used cautiously as they seem to have a higher risk for type IA endoleak and adverse events after the operation.

Total Percutaneous Access for Deployment of a Custom Made Fenestrated Stent Graft in a 90 Year Old with a Large Symptomatic Thoracic Aortic Aneurysm

Introduction

Open surgical cut down has been the standard for gaining carotid access in most thoracic endovascular repairs of aortic aneurysm (TEVAR) cases; however, when suitable, total percutaneous repair can be beneficial.

Report

A relatively fit 90 year old man with few medical comorbidities presented with six months of worsening upper back pain and an Ishimaru zone 2 fusiform thoracic aortic aneurysm of 7.2 cm diagnosed on CT aortography. A total percutaneously inserted custom made device (CMD) with innominate artery (IA) scallop, left common carotid artery (LCCA) fenestration combined with left subclavian artery (LSA) occlusion provided an effective repair. Haemostasis was obtained with Abbott Perclose ProGlide suture-mediated devices. The patient was discharged on post-operative day two. Follow up CT at one month was unremarkable without any endoleak, and an improvement in symptoms.

Discussion

There are risks of cerebral ischaemia and other complications with open carotid cut down, hence it is worth considering avoiding if possible, especially for select patients. Retrograde carotid access and subsequent closure device deployment is not new, but in conjunction with CMD, TEVAR allowing for carotid stenting is feasible and less often described in the literature.