Endovascular Stenting of the Ascending Aorta for Type A Aortic Dissections in Patients at High Risk for Open Surgery

Editor's Choice - Outcomes of Endovascular Repair Confined to the Ascending Thoracic Aorta: A Systematic Review and Meta-Analysis

OBJECTIVE

High risk, inoperable patients with ascending aortic disease are increasingly managed with thoracic endovascular aortic repair (TEVAR). The aim of this study was to assess the available literature on TEVAR confined to the ascending aorta (a-TEVAR), describing study and patient characteristics, procedural and stent graft details, and outcomes.

DATA SOURCES

This was a systematic review and meta-analysis. MEDLINE, Web of Science, and Scopus were systematically searched for eligible studies reporting on outcomes after a-TEVAR (PROSPERO ID: CRD42023440826). Eligible studies reported outcomes after a-TEVAR without adjunctive supra-aortic vessel treatment.

REVIEW METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement was followed. The ROBINS-I and Joanna Briggs Institute Critical Appraisal Checklist were used as quality assessment tools. A Grading of Recommendations Assessment, Development, and Evaluation (GRADE) evidence certainty analysis was performed for the main outcomes. The main outcome was death. A proportional meta-analysis was performed with a mean and 95% confidence interval (CI) for the main outcomes. All articles were included up to 1 January 2024.

RESULTS

Ninety four studies were included (19 cohort studies, 75 case reports or series), reporting on 259 patients (57.8% male). The mean age was 69.1 (95% CI 65.0 - 73.1) years and mean follow up 19.6 (95% CI 14.5 - 24.6) months. The most common comorbidity was prior cardiac or thoracic surgery (n = 191). The most frequent indications for a-TEVAR (52.1% urgent a-TEVAR) were type A aortic dissection (43.6%) and pseudoaneurysm (38.6%). The most commonly deployed stent grafts were Gore (44.5%), Cook (23.5%), and Medtronic (17.0%). The in hospital mortality rate was 7.3% (95% CI 4.7 - 11.2%), 30 day mortality rate 7.7% (95% CI 5.1 - 11.6%), and overall mortality rate 17.0% (95% CI 12.9 - 22.0%) during follow up. GRADE showed very low evidence certainty for all outcomes. Eighty eight complications were reported and there was a re-operation rate of 13.1% (95% CI 9.5 - 17.8%). In hospital and 30 day mortality rates for type A dissection were 12.4% (95% CI 7.5 - 19.7%) (n = 14) and 13.3% (95% CI 8.2 - 20.8%) (n = 15), respectively, and for pseudoaneurysm 4.0% (95% CI 1.6 - 9.8%) (n = 4) and 4.0% (95% CI 1.6 - 9.8) (n = 4), respectively.

CONCLUSION

Despite heterogeneous literature and very low GRADE evidence certainty, a-TEVAR seems technically feasible in high risk patients. In addition, there is need for a consensus on when and how to use a-TEVAR and a need for a specific endograft for use in the ascending aorta.

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.

Endovascular stenting of the ascending aorta for visceral malperfusion in a patient with type A aortic dissection

A type A aortic dissection is a challenging condition for both cardiothoracic and vascular surgeons. Although open surgery remains the gold standard, there is considerable interest in the use of endovascular techniques for patients who present with malperfusion. We present the case of an unstable 55-year-old man with visceral malperfusion from a type A dissection who was stabilized using an endovascular technique as a bridge to open surgery. A bare metal thoracic endograft was used in the ascending aorta to rapidly restore perfusion. This hybrid approach to the problem of malperfusion in type A dissection could be useful for these patients with complicated cases.

Endovascular Treatment of Type A Aortic Dissection: A Systematic Review and Meta-Analysis Using Reconstructed Time-to-Event Data

OBJECTIVE

The undisputed gold standard of treatment for type A aortic dissections (TAAD) is open surgery. Anecdotal reports have assessed thoracic endovascular aortic repair (TEVAR) as a last resort for highly selected candidates. The present study aims to evaluate endovascular outcomes in TAAD patients who are unsuitable for open surgery whilst having TEVAR-compatible aortic anatomy.

METHODS

A PRISMA-compliant systematic search of the PubMed, Scopus, and Cochrane databases was performed up to 19 May 2022. Time-to-event data were reconstructed using Kaplan-Meier curves from the source literature.

RESULTS

In 20 eligible studies, 311 patients underwent TEVAR for acute, subacute, or chronic TAAD. Mean age at the time of the operation was 60.70 ± 8.00 years and 75.48% (95% Confidence Interval [CI], 60.33-88.46%) of the included patients were males. Mean operative time was 169.40 ± 30.70 min. Overall, 0.44% (95% CI, 0.00-4.83%) of the cases were converted to salvage open surgery. Technical failure, stroke, and endoleaks occurred in 0.22%, 0.1%, and 8.52% of the cohort, respectively. Thirty-day postoperative complication rate was 7.08% (95% CI, 1.52-14.97%), whereas late complications developed in 16.89% (95% CI, 7.75-27.88%) of the patients. One-, three-, and five-year survival rates were estimated at 87.15%, 82.52% and 82.31%, respectively. Reintervention was required in 8.38% of the cohort over a mean follow-up of 32.40 ± 24.40 months.

CONCLUSIONS

TEVAR seems to be feasible in highly selected patients with TAAD who cannot tolerate open surgery. Overcoming technical limitations and acquiring long-term data are warranted to safely define the place of endovascular treatment in the armamentarium of TAAD repair.

Feasibility and safety of Stanford A aortic dissection complete endovascular repair system in a porcine model

BACKGROUND

Acute type A aortic dissection (ATAAD) is a catastrophic disease with high morbidity and mortality. Although open surgery is still the gold standard for the treatment of ATAAD, some patients, with advanced age and multiple comorbidities, can only receive medical management alone. Nowadays, thoracic aortic endovascular repair (TEVAR) provides a potential treatment option for the patient with ATAAD, but traditional stent grafts (SGs), which are not designed for the ATAAD, are inapplicable to the unique anatomy of the aortic arch. Therefore, we innovatively created the BRIDGE system (Chuangxin Medical, Shenzhen, China), a complete endovascular reconstruction system designed to treat ATAAD. This study aimed to evaluate the feasibility and safety of the novel Stanford A aortic dissection complete endovascular reconstruction system in a porcine model.

METHOD

The BRIDGE system consists of the type A stent system and the type C stent system. Between November 2020 and March 2021, three white swine were utilized in the study. The BRIDGE system was deployed via the transcatheter approach under angiographic guidance. The swine(n = 3) treated with our system were evaluated using angiography before sacrifice 1-month after implantation, which was followed by gross specimen evaluation and histological examination of harvested tissues.

RESULT

The acute procedure success rate was 100% (3/3). The immediate post-procedural angiography showed that both type A SGs and type C SGs were deployed in satisfactory locations, with patency of the supra-aortic trunk and no endoleak. The cumulative mortality of 30-day was 0% without any adverse events. No device migration or leakage was observed angiographically, before sacrifice. The gross observation confirmed a type A SG covered part of the entry of anonyma. Favorable endothelialization, no thrombogenesis, and slight inflammatory infiltration of the tissues around the device were confirmed by microscopic examinations in all pigs.

CONCLUSION

It was feasible and secure to use Stanford A aortic dissection complete endovascular reconstruction system to implement a transcatheter endovascular repair in a porcine model. With this novel system, treating acute type A aortic dissection may be more efficient and secure in human.

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.

Aortic Remodeling After Stepwise External Wrapping for Type A Acute Aortic Dissection

BACKGROUND

The optimal repair technique for type A acute aortic dissection is graft replacement; however, the treatment approach in high-risk patients remains controversial or suboptimal.

METHODS

We have retrospectively analyzed a cohort of high-risk patients who were admitted to our center for type A acute aortic dissection and who were treated by a new surgical approach using artificial grafts (stepwise external wrapping) between January 2016 and January 2020. The primary endpoints included inhospital mortality and survival during follow-up. Secondary endpoints included the assessment of aortic remodeling after ascending aorta wrapping.

RESULTS

Among the 134 patients admitted for type A acute aortic dissection, 43 patients underwent stepwise external wrapping. The mean patient age was 79.1 ± 6.8 years. The new standard European System for Cardiac Operative Risk Evaluation score was 64% ± 12%. There was one hospital death (2.3%). There were two major complications of persistent cerebral disorder (4.6%). Minor complications included temporary neurologic disorder (2.3%) and renal failure (2.3%). The intensive care unit and hospital stays were 2.8 ± 1.0 days and 11.7 ± 2.5 days, respectively. The follow-up survival rate was 95.3% ± 6.2% and 91% ± 10.2% at 1 and 3 years, respectively, after surgery. There was no aortic-related death during follow-up. At 1 year after surgery, complete remodeling of the ascending aorta was obtained in 30 patients (85.7%), and 5 patients (14.3%) showed partial remodeling.

CONCLUSIONS

Our stepwise external wrapping technique was associated with excellent outcomes for high-risk patients with type A acute aortic dissection.

Hybrid Thoracic Aortic Repair and Aortic Valve-In-Valve Replacement for Chronic Type A Dissection

We describe a case of hybrid total thoracic aortic repair and valve-in-valve transcatheter aortic valve replacement in a high-risk patient with complicated chronic type A dissection and severe prosthetic aortic stenosis. The patient underwent a three-stage-procedure including aortic arch debranching, thoracic endovascular aortic repair of the ascending aorta, aortic arch and descending thoracic aorta, and direct aortic valve-in-valve replacement using transcatheter heart valve. The details of the procedures are described with a discussion of the challenges and the decision-making process.

Alternative management of proximal aortic dissection: concept and application

Open surgery remains the mainstay of treatment for acute type A aortic dissection and should be offered to most patients. However, there are elderly patients in which surgical treatment may be deemed extremely high risk or futile. Endovascular treatment approaches have been applied to a small number of these patients and data are limited to case reports and small series. The application of endovascular therapies to ascending aorta is currently limited by anatomical and technical challenges posed by the dynamic motion of the ascending aorta and the proximity of vital structures to intended landing zones (aortic valve, coronary arteries, and supra-aortic branches) and lack of specially designed endografts to address these issues. While thoracic endovascular aortic repair (TEVAR) has replaced open aortic repair for a suitable lesion in distal aortic dissection, some selected patients with type A aortic dissection at high surgical may be candidates. Hence, there is potential because, in proximal (Stanford type A) dissections, 10-30% of patients are not accepted for surgery, and 30-50% are technically amenable for TEVAR. Recent experience has shown that carefully selected patients with favorable anatomical characteristics may be subject to endovascular stent-graft treatment as a last resort with mixed results. Technical improvement is necessary to offer. satisfactory endovascular options in non-surgical candidates.

Towards Endovascular Treatment of Type A Aortic Dissection with Smaller Landing Zones and More Patient Eligibility

OBJECTIVE

Type A or ascending aortic dissection is an acute life-threatening condition with high morbidity and mortality. Open surgery remains standard-of-care. Development of minimally invasive endografts for Type A aortic dissection (TAAD) will require detailed understanding of dissection and aortic root anatomy to determine patient eligibility and optimal device specifications.

METHODS

Computed tomography images of TAAD cases at our institution from 2012-2019 were identified and three-dimensional reconstructions were performed using OsiriX 10.0 (Bernex, Switzerland). Analysis of key anatomic structures including centerline length measurements, ascending aorta/aortic root dimensions, as well as location and extent of dissection were determined in relation to coronary ostia.

RESULTS

A total of 53 patients were identified (mean±SD age 60.4±17.1 years; 36 male, 17 female), 46 of whom underwent surgery for TAAD. Four patients died within 30 days of surgery. In 47 patients (88.7%), the entry tear was distal to the highest coronary ostium. These cases were retrospectively considered for endovascular intervention with a non-branched, single endograft stent. Proximal landing zone (LZ) was defined as distance from the highest coronary ostium to entry tear: 35/53 (66.0%) had a proximal LZ length ≥2.0cm, 38/53 (71.7%) had proximal LZ length ≥1.5cm, and 42/53 (79.2%) had proximal LZ length ≥1.0cm. Proximal and distal LZ diameters of the sinotubular junction (STJ) and distal ascending aorta regions were (median [1^st quartile-3^rd quartile]) 3.29cm [2.73-4.10cm] and 3.49cm [3.09-3.87cm], respectively, with length from STJ to innominate takeoff 8.08cm [6.96-9.40cm]. Ascending aorta radius of curvature was 6.48cm [5.27-8.00cm]. 47.2% (25/53) of patients could be treated with a straight tube graft with ≤20% diameter mismatch between the proximal and distal LZ.

CONCLUSIONS

Almost 80% of patients with TAAD had a proximal LZ ≥1.0cm, and of these, 47.2% had anatomy amenable to endovascular therapy with a non-tapered straight tube graft commercially available devices. To increase patient eligibility for TAAD endovascular intervention, enhanced precision deployment with adequate seal in shorter LZs will be required. Our results serve as a guide for endovascular device specifications designed to treat this devastating condition.

Endovascular Stent-Graft Repair of the Ascending Aorta: Assessment of a Specific Novel Stent-Graft Design in Phantom, Cadaveric, and Clinical Application

Purpose

To test a stent-graft specifically designed for the ascending aorta in phantom, cadaver, and clinical application, and to measure deployment accuracy to overcome limitations of existing devices.

Methods

A stent-graft has been designed with support wires to fixate the apices toward the inner curvature, thereby eliminating the forward movement of the proximal end which can happen with circumferential tip capture systems. The device was deployed in three aortic phantoms, and in four cadavers, deployment precision was measured. Subsequently, the device was implanted in a patient to exclude a pseudoaneurysm originating from the distal anastomosis after ascending aortic replacement.

Results

The stent-grafts were successfully deployed in all phantoms and cadavers. Deployment accuracy of the proximal end of the stent-graft was within 1 mm proximally and 14 mm distally to the intended landing zone on the inner curvature, and 2–8 mm distal to the intended landing zone on the outer curvature. In clinical application, the pseudoaneurysm could be successfully excluded without complications.

Conclusion

The novel stent-graft design promises accurate placement in the ascending aorta. The differential deployment of the apices at the inner and outer curvatures allows deployment perpendicular to the aortic axis.

Level of Evidence

No level of evidence.

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.

Systematic review and meta-analysis of endovascular interventions for Stanford type A aortic dissection

OBJECTIVE

The standard surgical approach to Stanford type A aortic dissection is open repair. However, up to one in four patients will be declined surgery because of prohibitive risk. Patients who are treated nonoperatively have an unacceptably high mortality. Endovascular repair of the ascending aorta is emerging as an alternative treatment for a select group of patients. The reported rates of technical success, mortality, stroke, and reintervention have varied. The objective of the study was to systematically report outcomes for acute type A dissections repaired using an endovascular approach.

METHODS

The systematic review and meta-analysis was conducted in accordance with the PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines. We performed online literature database searches through April 2020. The demographic and procedural characteristics of the individual studies were tabulated. Data on technical success, short-term mortality, stroke, and reintervention were extracted and underwent meta-analysis using a random effects model.

RESULTS

Fourteen studies with 80 cases of aortic dissection (55 acute and 25 subacute) were included in the final analysis. A wide variation was found in technique and device design across the studies. The outcomes rates were estimated at 17% (95% confidence interval [CI], 10%-26%) for mortality, 15% (95% CI, 8%-23%) for technical failure, 11% (95% CI, 6%-19%) for stroke and 18% (95% CI, 9%-31%) for reintervention. The mean Downs and Black quality assessment score was 13.9 ± 3.2.

CONCLUSION

The technique for endovascular repair of type A aortic dissection is feasible and reproducible. The results of our meta-analysis demonstrate an acceptable safety profile for inoperable patients who otherwise would have an extremely poor prognosis. Data from clinical trials are required before the technique can be introduced into routine clinical practice.

Hybrid stepwise external wrapping for type a acute aortic dissection with cerebral Malperfusion

Background

Acute aortic dissection (AAD) is a life-threatening condition which can lead to coronary, brachiocephalic or branch vessel malperfusion, as well as aortic valve insufficiency, or aortic rupture. Mortality of surgical treatment in high-risk or elderly patients with Type A AAD (TAAAD) still remains high, and treatment for such patients remains controversial. We report a successful treatment of TAAAD with a communicating false lumen in a 60-year-old man with acute hemi-cerebral malperfusion.

Case presentation

The ascending aorta was wrapped with stepwise external wrapping (SEW) procedure, and subsequent thoracic endovascular aortic repair (TEVAR) was successfully performed. The patient was discharged in good physical condition without any complications.

Conclusions

Hybrid therapy with SEW and TEVAR with TAAAD associated with major cerebral malperfusion should be considered, especially in patients for whom open surgery is extremely risky.

Endovascular ascending aortic repair in type A dissection: A systematic review

PURPOSE

Up to 10% of acute type A aortic dissection (TAAD) patients are deemed unfit for open surgical repair, exposing these patients to high mortality rates. In recent years, thoracic endovascular aortic repair has proven to be a promising alternative treatment modality in specific cases. This study presents a comprehensive overview of the current state of catheter-based interventions in the setting of primary TAAD.

METHODS

A literature search was conducted, using MEDLINE and PubMed databases according to PRISMA guidelines, updated until January 2020. Articles were selected if they reported on the endovascular repair of DeBakey Type I and II aortic dissections. The exclusion criteria were retrograde type A dissection, hybrid procedures, and combined outcome reporting of mixed aortic pathologies (e.g., pseudoaneurysm and intramural hematoma).

RESULTS

A total of 31 articles, out of which 19 were case reports and 12 case series, describing a total of 92 patients, were included. The median follow-up was 6 months for case reports and the average follow-up was 14 months for case series. Overall technical success was 95.6% and 30-day mortality of 9%. Stroke and early endoleak rates were 6% and 18%, respectively. Reintervention was required in 14 patients (15%).

CONCLUSION

This review not only demonstrates that endovascular repair in the setting of isolated TAAD is feasible with acceptable outcomes at short-term follow-up, but also underlines a lack of mid-late outcomes and reporting consistency. Studies with longer follow-up and careful consideration of patient selection are required before endovascular interventions can be widely introduced.

Catheter-based treatment of the dissected ascending aorta: a systematic review

OBJECTIVES

METHODS

A PubMed search was supplemented by searching through bibliographies and key articles. Demographics, risk score, stent graft detail, access route, mortality, cause of death, complications, reinterventions and follow-up data were extracted and analysed.

RESULTS

Thirty-one articles (7 retrospective reports; 24 case reports/series) were included in the study. In total, 104 patients (mean age 71 ± 14 years) received endovascular treatment for acute (63) or chronic (41) type A dissection. A history of a major cardiac or aortic operation was present in 29 patients. The mean EuroSCORE II was 30 ± 20 in 4 reports. A total of 114 stent grafts were implanted: ‘off-the-shelf’, 65/114; custom made, 12/114; and modified, 7/114. Hospital complications included intraprocedural conversion to open surgery (2/104), stroke (2/104), coronary stenting (2/104), early endoleak (9/104) and repeat aortic endovascular treatment for endoleak (5/104). Hospital mortality was 10% (intraoperative death 2/104). Mean duration of follow-up time was 21 ± 21 months (range 1–81 months); follow-up data were available for 86 patients: 10 patients died of non-aortic-related causes; reintervention for aortic disease (endovascular repair or open surgery) was performed in 8 patients.

CONCLUSIONS

Catheter-based ascending aorta repair for type A aortic dissection with the entry tear in the ascending aorta can be considered in carefully selected high-risk patients. Further analysis and specifically designed devices are required.

Zone 0 Thoracic Endovascular Repair After Aortic Wrapping for Acute Aortic Syndrome

We report a successful treatment of type A acute aortic syndrome (AAS)-associated aortic arch aneurysm in a 71-year-old man with major comorbidities. The ascending aorta was wrapped with artificial graft, and supra-aortic debranching was constructed. Then, Zone 0 thoracic endovascular aneurysm repair (TEVAR) with plug occlusion of the left subclavian artery was successfully performed. The patient was discharged in good physical condition without any complications. To our knowledge, this is the first reported case in the literature of successful Zone 0 TEVAR after ascending aorta wrapping and supra-aortic debranching with type A AAS associated with aortic arch aneurysm.

Repair of Acute Type-A Aortic Dissection in the Present Era: Outcomes and Controversies

Acute Type-A aortic dissection (AAAD) remains a surgical emergency with a relatively high operative mortality despite advances in medical and surgical management over the past three decades. In spite of the severity of disease, there is a paucity of studies reviewing key controversies surrounding AAAD repair and management. A systematic literature search was performed using Cochrane review and PubMed bibliography review. Abstracts were first reviewed for general pertinence and then articles were reviewed in full. Literature review indicates that use of moderate hypothermia and antegrade cerebral perfusion is a safe alternative to deep hypothermia. In hemodynamically stable patients, axillary cannulation may be substituted for femoral cannulation. With regard to the technical aspects of repair, preserving the aortic root whenever possible and performing the distal anastomosis with the open distal technique rather than with the clamp on is the preferred approach. In patients with a patent false lumen, close monitoring is indicated. As demonstrated by the literature, significant improvement of early and late mortality over the past years has occurred in patients presenting with AAAD. Repair of acute Type-A aortic dissection remains a challenge with high operative mortality; however, improvement of surgical techniques and management have resulted in improvement of early and late clinical outcomes.

The future of stenting in patients with type A aortic dissection: a systematic review

Acute type A aortic dissection (ATAAD) carries high morbidity and mortality rates and is a clinical emergency. The reported mortality rate is 50% to 65% within the first 48 hours without surgical intervention. Open surgery therefore remains the gold standard management for ATAAD. However, in patients who are deemed unfit for surgery and where possible, endovascular repair offers a useful alternative to medical treatment alone or high-risk open surgical repair. Several case reports, case series, and retrospective studies have reported good outcomes following endovascular treatment. The endovascular option also has comparable early and late outcomes, favourable aortic remodelling, and satisfactory overall survival despite having a higher-risk patient cohort. However, stenting in patients with ATAAD undoubtedly still has several limitations and technical challenges.

Endovascular Treatment of the Ascending Aorta: is this the Last Frontier in Aortic Surgery?

Regardless the successful treatment of the descending aorta with endovascular prosthesis, for the ascending aorta segment, because of several anatomic and physiologic issues, this technique has been considered an alternative only for high-risk or inoperable patients. Despite restricted indications, hundreds of treatments have been performed worldwide, demonstrating its safety and reproducibility if it is done in high-quality centers. Therefore, understanding patients' selection criteria and technique limitations are critical to its application.

Endovascular Repair of the Ascending Aorta for an Anastomotic Saphenous Vein Graft Aneurysm

The ascending aorta is the final segment of the aorta to be explored with endovascular stent grafts. With a patient population of increasingly advanced age and disease, there are situations where traditional open repair for ascending aneurysms or dissections may be prohibitive. However, the ascending aorta has multiple hostile characteristics that make endovascular treatment challenging. There is also a lack of approved specialized devices in the United States for this aortic territory. We demonstrate the feasibility of adapting an abdominal aortic graft to the ascending aorta for the treatment of a saphenous vein graft aneurysm with a discussion of the technical considerations for the operation.

Back-table Modified Aortic Endograft Deployed via "Innominate Bounce" Technique for Management of a Zone 0 Ascending Aortic Pseudoaneurysm

Ascending aortic pseudoaneurysms pose a difficult therapeutic dilemma. Surgical repair carries high morbidity and mortality risk and may be challenging in patients with unfavorable anatomy or prior aortic surgery. Endovascular repair is difficult due to short landing zones, need for precise delivery, and the lack of adequately sized commercially available devices. This report describes a case of back-table modification of a thoracic aortic stent graft successfully deployed using an "innominate bounce" technique.

Thoracic Endovascular Aortic Repair for Acute Aortic Dissection

Thoracic endovascular aortic repair (TEVAR) for thoracic aortic disease constitutes a paradigm shift in the treatment strategy of aortic dissection, as well as thoracic aortic aneurysms. Conventionally, most patients with Stanford type B acute aortic dissection are treated using conservative medical treatment during the acute phase. However, in patients with complicated type B aortic dissection who present with life-threatening complications, TEVAR has been introduced as a novel and less-invasive alternative and has shown better early results than those observed with conventional therapy. Recently, TEVAR was reported to be effective in not only promoting thrombosis of the false lumen but also in preventing aortic enlargement observed at long-term follow-up. TEVAR has been established as first-line therapy for complicated type B aortic dissection. In contrast, a considerable number of patients who received acute phase medical treatment required surgical intervention for chronic dissecting aortic aneurysms. With the increasing popularity of TEVAR for the treatment of complicated type B aortic dissection, prophylactic and pre-emptive TEVAR has been considered in patients with uncomplicated type B aortic dissection. However, supportive evidence for this strategy is limited, and reassessment is mandatory because it is continuously evolving. Although acute type A aortic dissection is a life-threatening condition, the results of open surgery continue to improve in the modern surgical era. Open surgical treatment is well established and recognized as a gold standard even in the endovascular era. Presently, the application of TEVAR for ascending aortic dissection has undergone a change, and TEVAR is considered a viable rescue option for patients with type A aortic dissection who are not eligible for open surgical repair. However, TEVAR for the descending aorta is well-established treatment for retrograde type A dissection. Several conceptual and technical issues remain unresolved, and technological advances would lead to the development of innovative disease-specific devices and solutions in the future for endovascular treatment of acute aortic dissection. (This is a translation of Jpn J Vasc Surg 2018; 27: 337–345.)

Reverse extra-anatomic aortic arch debranching procedure allowing thoracic endovascular aortic repair of a chronic ascending aortic aneurysm

A 79-year-old woman was admitted with a large chronic dissecting ascending aortic aneurysm starting 5 mm distal to the ostia of the left coronary artery and ending immediately proximal to the innominate artery. A reverse extra-anatomic aortic arch debranching procedure was performed. During the same operative time, through a transapical approach, a thoracic stent graft was deployed with the proximal landing zone just distal to the coronary ostia and the distal landing zone excluding the origin of the left common carotid artery. The postoperative course was uneventful. Computed tomography at 12 months documented patent extra-anatomic aortic arch debranching and no evidence of endoleak.

Endovascular treatment of acute Type A aortic dissection-the Endo Bentall approach

Outcome after classical surgical repair of acute Type A aortic dissection has steadily improved over the years and several modifications in cannulation and perfusion added to this achievement. However, subgroups remain where results of classical surgical repair still have room for improvement, particularly patients with severe preoperative malperfusion as well as elderly patients with a limited physiological reserve. So far, only small case series or case reports have been published on the endovascular treatment of dissected ascending aortas. However, a tube alone is not sufficient to fix the entire complex underlying problem in the vast majority of patients with acute Type A aortic dissection. In addition, these published reports are either due to a favorable anatomy or due to very localized disease processes, which are the exception and not the rule. The concept of an endovascular valve-carrying conduit may significantly increase the number of patients suitable for endovascular therapy and it may soon be common practice.

Right Axillary Artery Cannulation for Endovascular Repair of an Acute type a Aortic Dissection

We present the case of a 48-year-old woman with an acute type A aortic dissection that was treated with thoracic endovascular aortic repair at our institution. The patient was found to have a focal type A dissection with pericardial effusion but no tamponade physiology and no involvement of the aortic valve or root. We elected to treat the patient's type A aortic dissection with an endovascular stent because of the patient's favorable anatomy and no evidence of neurologic deficits or signs of distal malperfusion. The patient was successfully treated with an abdominal aortic cuff deployed through the axillary artery. An axillary approach was necessary because of the short length of the delivery sheath preventing a transfemoral delivery. At 2-year follow-up, the patient remains free of complications with computed tomography scan revealing complete false lumen thrombosis and a stable endovascular repair. This report demonstrates a case of acute type A aortic dissection successfully treated using thoracic endovascular aortic repair and illustrates the utility of axillary cannulation for precise deployment of stent grafts in the ascending aorta.

Thoracic endovascular repair for acute type A aortic dissection: operative technique

Acute type A aortic dissection is a potentially lethal condition which requires immediate diagnostic and therapeutic intervention. Open surgical repair remains the standard of care as survival rates continue to improve in the modern surgical era. Unfortunately, up to twenty percent of patients are denied surgical therapy because they are deemed medically unfit to undergo open repair. The application of thoracic endovascular aortic repair (TEVAR) has changed the treatment paradigm for aortic disease involving the descending thoracic aorta and may be a viable rescue option for patients with type A dissection who are not eligible for open surgical repair. New endovascular devices and advanced image-guided procedures are continually evolving. This article summarizes the pathology of aortic dissection and focuses on currently available endovascular solutions for transapical and transfemoral stent graft deployment for acute aortic dissection involving the ascending aorta for selected patients who are ineligible for open surgical repair.

Challenges of "Reverse" Aortic Arch Debranching for Repair of the Ascending Aorta by Thoracic Endovascular Aortic Repair

INTRODUCTION

Ascending aortic pathology presents a unique challenge for treatment by thoracic endovascular aortic repair (TEVAR), because of lack of adequate endograft landing zones. This report describes a unique "reverse" extra-anatomical aortic arch debranching procedure performed to enable TEVAR of the ascending aorta.

REPORT

A 71-year-old male presented with a large ascending aortic pseudoaneurysm secondary to previous arch repair anastomosis. This pathology was treated by TEVAR of the ascending aorta. To create a sufficient landing zone for the endovascular stent graft, a "reverse" extra-anatomical aortic arch debranching procedure was performed. This involved a left subclavian artery to left carotid artery bypass, left to right carotid-to-carotid bypass, ligation of proximal left common carotid artery, and embolization of the innominate artery origin.

DISCUSSION

TEVAR of the ascending aorta can be made feasible through a novel debranching procedure that creates sufficient landing zones for the endograft. This surgical approach may prove useful in patients who present with aortic arch pathology and comorbidities that prevent open surgical repair.

The imaging assessment and specific endograft design for the endovascular repair of ascending aortic dissection

Background

Endovascular option has been proposed for a very limited and selected number of Stanford type A aortic dissection (TAAD) patients. We have performed a computed tomography (CT)-based TAAD study to explore appropriate endograft configurations for the ascending aortic pathology.

Methods

TAAD patients treated with optimal CT scans were retrospectively reviewed, and their entry tears (ETs) were identified using three-dimensional and multiplanar reconstructions in an EndoSize workstation. After generating a centerline of flow, measurements, including numerous morphologic characteristics of anatomy, were evaluated and a selected subset of patients were determined to be suitable for endovascular treatments. Proximal diameter and distal diameter of endograft were selected based on diameters measured at the ET level and at the innominate artery (IA) level, with 10% oversizing with respect to the true lumen, but not exceeding the original aortic diameter. The length of the endograft was determined by the distance from the sinotubular junction to IA.

Results

This study covered 126 TAAD patients with primary ET in ascending aorta, among which, according to the assumed criteria, 48 (38.1%) patients were deemed to be suitable for endovascular treatment. The diameters of ascending aorta from the sinotubular junction to the IA level presented a downward trend, and the proximal diameters differed significantly from distal diameters of the endograft for TAAD (39.9 versus 36.2 mm, P<0.01), implying that the conical endograft might be compatible with the ascending pathology. In the ascending aorta, lengths of the endograft should be 50, 60, 70, 80, and 90 mm in five (10.4%), 22 (45.9%), 13 (27.1%), six (12.5%), and two (4.2%) patients, respectively.

Conclusion

In this selected number of Chinese patients, the suitability of endovascular repair has been demonstrated based on the CT imaging. Shorter, larger, and bare spring-free conical endografts were preferred in the ascending aortic pathology.