Anatomic feasibility of an endovascular valve–carrying conduit for the treatment of type A aortic dissection

Anatomic feasibility of a modular Endo-Bentall stent graft system for type A aortic dissection

OBJECTIVE

The implementation of thoracic endovascular aortic repair in patients with type A aortic dissection has been strictly constrained due to the pulsatile movement and distensibility and the insufficient length of landing zones on ascending aorta. The most prevalent anatomical limitation is the insufficient length of proximal and distal landing zones. We propose a modularly designed Endo-Bentall stent graft system to broaden the scope of thoracic endovascular aortic repair in the ascending aorta by covering intimal tears in the aortic root and ascending aorta and reconstructing coronary arteries. This study was conducted to assess the anatomical feasibility of a novel stent graft design.

METHODS

In this study, we included 152 patients with type A aortic dissection for image measurement and analysis. All computed tomography angiography images were assessed on a 3mensio Workstation version 10.2 (3mensio Medical Imaging B.V.) utilizing the centerline method. We compared the diameters and lengths at various planes in relation to the proposed anatomical criteria for the modular Endo-Bentall stent graft system.

RESULTS

The patients were predominantly male (67.1%), with a median age of 56.5 years (interquartile range, 50.0-65.0 years). Among all aortic dissections, 91.5% extended proximally to the sinotubular junction, whereas only 8.6% were restricted to the tubular ascending aorta. The median perimeter-derived diameter of the aortic annulus was 24.1 mm. The median maximum aortic diameter at the sinotubular junction and brachiocephalic trunk were 44.6 mm and 43.5 mm, respectively. The median height of the left coronary artery, right coronary artery, and sinus of Valsalva were 12.7 mm, 16.7 mm, and 28.4 mm, respectively. After applying exclusion criteria, 66.4% of all patients were anatomically eligible for the modular Endo-Bentall stent graft system. A total of 85.1% of patients were suitable for stent grafts with lengths of 70 mm, 80 mm, or 90 mm. Both antegradely and retrogradely tapered stent grafts were required, according to the diameter differences between the STJ and brachiocephalic trunk.

CONCLUSIONS

Utilizing the modular Endo-Bentall stent-graft design, approximately two-thirds of patients with type A aortic dissection are anatomically eligible for endovascular repair. Further animal studies are required to optimize the device design.

Feasibility of Total Endovascular Repair of the Aorta in Patients with Acute Type A Aortic Dissection: Morphological Analysis of 119 Patients

(1) Background: This study aimed to morphologically analyze acute type A aortic dissection (aTAAD) patients for potential endovascular treatment candidates. The objective was to specify requirements for aTAAD endovascular devices. (2) Methods: A single-center retrospective analysis included aTAAD patients who underwent open surgical repair between November 2005 and December 2020. Preoperative CTA scans were used for morphological analysis, assessing endovascular repair eligibility. Statistical tests were performed. (3) Results: A total of 129 patients with aTAAD were studied, with 119 included. Entry tear (ET) locations were identified, mainly in the aortic root, 20 mm above the sinotubular junction (STJ) and within the ascending aorta (20 mm above STJ to -20 mm before the brachiocephalic trunk). Endovascular treatment was deemed feasible for 36 patients, with suggested solutions for the aortic arch and descending aorta. Significant differences were observed between eligible and noneligible groups for aortic diameter, false lumen diameter, distance between STJ and entry tear, and more. Dissection extension showed no significant difference. (4) Conclusions: Morphological analysis identified potential aTAAD candidates for endovascular treatment, highlighting differences between eligible and noneligible morphologies. This study offers insights for implementing endovascular approaches in aTAAD treatment and emphasizes the need for research and standardized protocols.

Acute aortic dissection: evidence, uncertainties, and future therapies

Remarkable progress has become especially apparent in aortic medicine in the last few decades, leading to essential changes in how thoracic aortic dissection is understood and treated. This state-of-the-art review article addresses the mechanisms of acute aortic dissection, explaining the role of its primary entry location, proximal, and distal dissection extension in their clinical presentation and impact on the decision-making process towards the best treatment approach. The latest evidence on novel treatment methods for acute aortic syndromes is presented, and the diverse dissection classification systems that remain uncertain are discussed, which reveals the need for shared terminology and more clarity. Finally, future aspects are discussed in treating acute aortic dissection, such as the endovascular treatment of aortic dissection Type A and biomarkers for acute aortic syndromes.

Intervention rates and outcomes in medically managed uncomplicated descending thoracic aortic dissections

OBJECTIVE

To evaluate the long-term incidence and outcome of aortic interventions for medically managed uncomplicated thoracic aortic dissections.

METHODS

Between January 2012 and December 2018, 91 patients were discharged home with an uncomplicated, medically treated aortic dissection (involving the descending aorta with or without aortic arch involvement, no ascending involvement). After a median period of 4 (first quartile: 2, third quartile: 11) months, 30 patients (33%) required an aortic intervention. Patient characteristics, radiographic, treatment, and follow-up data were compared for patients with and without aortic interventions. A competing risk regression model was analyzed to identify independent predictors of aortic intervention and to predict the risk for intervention.

RESULTS

Patients who underwent aortic interventions had significantly larger thoracic (P = .041) and abdominal (P = .015) aortic diameters, the dissection was significantly longer (P = .035), there were more communications between both lumina (P = .040), and the first communication was significantly closer to the left subclavian artery (P = .049). A descending thoracic aortic diameter exceeding 45 mm was predictive for an aortic intervention (P = .001; subdistribution hazard ratio: 3.51). The risk for aortic intervention was 27% ± 10% and 36% ± 11% after 1 and 3 years, respectively. Fourteen patients (47%) underwent thoracic endovascular aortic repair, 11 patients (37%) thoracic endovascular aortic repair and left carotid to subclavian bypass, 3 patients (10%) total arch replacement with the frozen elephant trunk technique, and 2 patients (7%) thoracoabdominal aortic replacement. We observed no in-hospital mortality.

CONCLUSIONS

The need for secondary aortic interventions in patients with initially medically managed, uncomplicated descending aortic dissections is substantial. The full spectrum of aortic treatment options (endovascular, hybrid, conventional open surgical) is required in these patients.

Anatomical Feasibility Study on Novel Ascending Aortic Endograft With More Proximal Landing Zone for Treatment of Type A Aortic Dissection

Objective

Type A aortic dissection (TAAD) is associated with high morbidity and mortality, and open surgery is the best treatment option. Development of endovascular repair devices for TAAD will benefit patients deemed unfit for open surgery. In this study, we performed a thorough investigation of anatomical features in Asian patients with TAAD to learn about the patient eligibility of a novel ascending aortic endograft technique.

Methods

Computed tomography angiography (CTA) images of TAAD cases in our institution from January 2015 to November 2021 were reviewed, and three-dimensional reconstructions were performed with the Endosize software (Therenva, Rennes, France). Anatomic structures including length measured along centerline and greater/lesser curvature, ascending aorta/aortic root dimensions, as well as location of entry tear and extent of dissection were analyzed.

Results

A total of 158 patients were included [median age 58 years, interquartile range (IQR), 30–76 years; 115 males, 72.8%]. In 99 (62.7%) of the cases, entry tear was distal to the sinotubular junction (STJ). In 106 (67.1%) of the cases, the pathology proximally extended into the aortic root, which was intramural hematoma in 37 (23.4%) of the cases, and the aortic root was free from the pathology in 52 (32.9%) of the cases. The median distance from the STJ to the proximal edge of the ostium of the innominate artery (IA) measured along the centerline was 65 mm (IQR 58–74 mm). The median distance from the distal edge of the higher coronary ostium to the STJ was 7.95 mm (IQR 5.625–10.9 mm). The bare metal stent part was set between the edge of the higher coronary ostium and the STJ. In our series, 63 (39.9%) of the cases had this distance >10 mm. The relative difference was <20% between the STJ and the proximal edge of the ostium of the IA in 92 (58.2%) of the cases. Ascending aorta radius of curvature was 52.2 mm (IQR 43.7–63.7 mm).

Conclusions

Our study demonstrates that 56.3% of the TAAD cases would be amenable to endovascular repair by the novel ascending aortic endograft, with sufficient landing zone free of the dissected aorta.

Modular Endo-Bentall Procedure Using a "Rendez-Vous Access"

PURPOSE

The concept of a single endovascular valve-carrying conduit device was designated endo-Bentall, but published experience is limited to a single case. This technical note describes an alternative modular endo-Bentall technique and a novel access technique to implant it.

TECHNIQUE

A 82-year-old woman with chest pain referred for a 10 cm symptomatic aneurysm of the distal arch and descending aorta. An ascending aortic aneurysm of 5.5 cm prevented endovascular aortic arch repair due to lack of a proximal landing zone. The technique is a modular approach combining a physician-modified endograft (PMEG) with 3 large fenestrations for coronary artery perfusion and a transcatheter aortic valve implantation (TAVI). A "rendez-vous access" with a transapical and transfemoral through-and-through wire offered rapid sequential deployment in a modular fashion of both components. The PMEG was deployed first, landing 5 mm deep in the left ventricular outflow tract (LVOT) and the transcatheter aortic valve was implanted few millimeters below. The endo-Bentall procedure was combined with endovascular aortic arch repair.

CONCLUSION

A modular endo-Bentall procedure combining a PMEG and TAVI is feasible and adaptable to emergent setting using the "rendez-vous access."

Endovascular repair of ascending aortic diseases with custom-made endografts

OBJECTIVES

The aim of this article is to report the mid-term results of ascending thoracic endovascular aortic repair using a custom-made device (CMD).

METHODS

This was a retrospective study performed at tertiary centres. Nine patients considered unfit for open surgery received elective total endovascular repair of the ascending aorta with a Relay® (Terumo Aortic, Sunrise; FL, USA) CMD: pseudoaneurysn (n = 5), localized dissection (n =3) and contained rupture (n = 1).

RESULTS

Primary clinical success was achieved in all patients with no major complications and no early conversion to open surgery. All patients were discharged home and independent: median length of stay was 7 days (interquartile range, 6-18). No patient was lost to follow-up at a median 26 months (interquartile range, 12-36). Three patients died 2, 6 and 24 months after intervention; 1 was aorta related (late aorto-atrial fistula due to infection that required open surgery). At the last follow-up available, no endoleaks, migrations, fractures or ruptures were observed in the remaining 6 patients.

CONCLUSIONS

Ascending thoracic endovascular aortic repair with Terumo Aortic CMDs was technically feasible, effective and safe in very selected lesions. CMDs showed good ascending aorta conformability with different configurations and diameters, and satisfactory mid-term durability as shown by both structural integrity and aortic lesion exclusion.

Anesthetic Considerations in Endovascular Repair of the Ascending Aorta

Since the first endovascular aortic repair in 1990, endovascular devices and the indications for their use have significantly grown. Considerable progress has been made in endovascular devices and techniques, such that endovascular repair is now considered first-line treatment for patients with descending aortic disease. However, for patients with ascending aortic disease, open surgical repair with cardiopulmonary bypass and hypothermic cardiac arrest was the only option until recently. Although the outcomes for open surgical repair of the ascending aorta have improved over the years, approximately 30% of patients with an emergent surgical indication, such as type A aortic dissection, are considered to be too high risk for open repair. For these patients, endovascular repair of the ascending aorta offers a life-saving procedure. The ascending aorta is regarded as the final frontier for endovascular therapy. Endovascular repair of it has posed a formidable challenge thus far, due to its unique anatomy, hemodynamic forces, and lack of an appropriate stent-graft designed specifically for the ascending aorta. Although currently there are no comprehensive data from randomized clinical trials, there are several case series and case reports that have shown favorable outcomes. Improvements in available devices soon will drive an exponential increase in the number of patients undergoing endovascular ascending aortic repair. In this review, the authors discuss multiple aspects of endovascular ascending aortic repair including the unique surgical and anesthetic considerations, the devices used, and the available outcomes data, and future directions are also explored.

Finite element modeling to predict procedural success of thoracic endovascular aortic repair in type A aortic dissection

Objective

Thoracic endovascular aortic repair (TEVAR) is recommended for type B aortic dissection and recently has even been used in selected cases of proximal (Stanford type A) aortic dissections in scenarios of prohibitive surgical risk. However, mechanical interactions between the native aorta and stent-graft are poorly understood, as some cases ended in failure. The aim of this study is to explore and better understand biomechanical changes after TEVAR and predict the result via virtual stenting.

Methods

A case of type A aortic dissection was considered inoperable and selected for TEVAR. The procedure failed due to stent-graft migration even with precise deployment. A novel patient-specific virtual stent-graft deployment model based on finite element method was employed to analyze TEVAR-induced changes under such conditions. Two landing positions were simulated to investigate the reason for stent-graft migration immediately after TEVAR and explore options for optimization.

Results

Simulation of the actual procedure revealed that the proximal bare metal stent pushed the lamella into the false lumen and led to further stent-graft migration during the launch phase. An alternative landing position has reduced the local deformation of the dissection lamella and avoided stent-graft migration. Higher maximum principal stress (>20 KPa) was found on the lamella with deployment at the actual position, while the alternative strategy would have reduced the stress to <5 KPa.

Conclusions

Virtual stent-graft deployment simulation based on finite element model could be helpful to both predict outcomes of TEVAR and better plan future endovascular procedures.

One-stage off pump combined transapical aortic valve replacement and ascending aorta endografting

An 84-year-old patient was referred for severe symptomatic aortic valve stenosis and focal chronic dissection of the ascending aorta. After multidisciplinary discussion, the patient was scheduled for combined transapical transcatheter aortic valve replacement and ascending aorta stent-grafting. The procedure was performed with a balloon aortic valvuloplasty followed by a custom-made stent graft implantation into the ascending aorta and then by balloon-expandable transapical transcatheter aortic valve replacement. The patient had an uneventful hospital stay. In conclusion, in selected high-risk patients, transapical combined ascending aorta stent-grafting and transcatheter aortic valve replacement are feasible and safe.

Endo-Bentall for proximal aortic dissection: from conception to application

The endovascular treatment of pathologies of the ascending aorta has not been incorporated into routine clinical practice. The aim of this article is to provide an overview of the endovascular treatment of pathologies of the ascending aorta, particularly type A aortic dissection. A thorough analysis and discussion of anatomical, physiological, clinical and technical challenges, and obstacles is performed. Conventional straight stent-grafts alone are not capable of fixing the entire complex underlying problem in the vast majority of patients with acute type A aortic dissection. An endovascular valve-carrying conduit consisting of a proximal transcatheter aortic valve connected to a covered stent-graft would be able to close a primary entry tear in the ascending aorta, ensure coronary perfusion, initiate true lumen expansion, treat malperfusion, treat aortic regurgitation, drain any pericardial effusion through a transapical approach, and possibly stabilize the distal aorta. Two thirds of all patients with acute aortic dissection are potential candidates for endovascular treatment, and the concept may help to significantly improve survival in patients with acute aortic dissection.

Endovascular treatment of acute type A aortic dissection in a nonagenarian: stabilization of a short covered stent using a bare-metal stent

Endovascular treatment is a viable alternative therapy in high-risk patients with acute type A aortic dissection. However, the optimal endovascular treatment strategy is still evolving. Herein, we present a case of a 91-year-old man who successfully underwent repair of an ascending aortic dissection using a stent-in-stent technique. At 1-year follow-up, the stent demonstrated repair durability.