Endovascular Approaches to Acute Aortic Type A Dissection: A CT-Based Feasibility Study

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.

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.

Endovascular Intervention for Aortic Dissection Is "Ascending"

Ascending aorta diseases represent an important cause of mortality worldwide. Notably, acute and chronic thoracic aorta pathologies have increased during the last years, but medical therapy does not seem to influence their natural history. Currently, although open surgery is the first choice of treatment, many patients are still rejected or have poor outcomes. In this scenario, endovascular treatment is raised as a valuable option. In this review we describe the limitations of conventional surgery and the state-of-art of endovascular ascending aorta repair.

Endovascular surgery for thoracic aortic pathologies involving the aortic arch

Background

Aortic arch pathologies are serious clinical conditions associated with a very dismal prognosis. Traditional open surgery has a high mortality and is not suitable for critically ill patients. Recently years, endovascular treatment of thoracic aorta has made rapid progress and has been gradually applied to the treatment of aortic arch pathologies. However, maintaining cerebral blood flow during endovascular treatment of aortic arch lesions remains a challenge at this time. This study aims to evaluate the feasibility, efficacy, and safety of endovascular treatment of thoracic aortic pathologies involving the aortic arch, and to present initial experience with this technique.

Methods

From October 2016 to December 2020, patients who met the inclusion criteria were enrolled. All patients underwent thoracic endovascular aortic repair with the proximal landing zone of the stent-graft in the aortic arch at Ishimaru zones 0–1, in which cerebral flow needs to be maintained during surgery, and the supra-aortic branches were reconstruction with either in situ fenestration or the chimney technique.

Results

A total of 62 cases with lesions involving the arch were treated with endovascular surgery. Total supra-aortic branches reconstruction was successfully performed in 51 cases, the left carotid artery (LCA) and the innominate artery reconstruction were performed in eight cases, the left subclavian artery (LSA) and the LCA were reconstructed in three patients. Among them, the in situ fenestration or chimney repair technique for the LSA was successful performed in 42 and 12 cases. However, in 20 patients, attempts to reconstruction the LSA using the fenestration technique were unsuccessful due to tortuous and angulated vessels. Early mortality was 6.45%. No neurological complications related to surgery occurred. Computer tomography images at post-operative follow-up (mean 3.51 months) confirmed patency of all branch stents without any signs of endoleaks, migration, conversion to retrograde dissection or receive open-heart surgery.

Conclusion

The endovascular technique is an effective, feasible, safe and repeatable method to reconstruct the aortic arch, which allows for the reconstruction of the supra-aortic branches.

ARISE: First-In-Human Evaluation of a Novel Stent Graft to Treat Ascending Aortic Dissection

BACKGROUND

Operative mortality for type A aortic dissection is still 10-20% at centers of excellence. Additionally, 10-20% are not considered as viable candidates for open surgical repair and not offered life-saving emergency surgery. ARISE is a multicenter investigation evaluating the novel GORE® Ascending Stent Graft (ASG; Flagstaff, AZ).

OBJECTIVE

The purpose of this study is to assess early feasibility of using these investigational devices to treat ascending aortic dissection.

METHODS

This a prospective, multicenter, non-randomized, single-arm study that enrolls patients at high surgical risk with appropriate anatomical requirements based on computed tomography imaging at 7 of 9 US sites. Devices are delivered transfemorally under fluoroscopic guidance. Primary endpoint is all-cause mortality at 30 days. Secondary endpoints include major adverse cardiovascular and cerebrovascular events (MACCE) at 30 days, 6 months, and 12 months.

RESULTS

Nineteen patients were enrolled with a mean age of 75.7 years (range 47-91) and 11 (57.9%) were female. Ten (52.6%) had DeBakey type I disease, and the rest were type II. Sixteen (84.2%) of the patients were acute. Patients were treated with safe access, (7/19 (36.8%) percutaneous, 10/19 (52.6%) transfemoral, 2/19 (10.5%) iliac conduit), delivery, and deployment completed in all cases. Median procedure time was 154 mins (range 52-392) and median contrast used was 111 mL (range 75-200). MACCE at 30 days occurred in 5 patients including mortality 3/19 (15.8%), disabling stroke in 1/19 (5.3%), and myocardial infarction in 1/19 (5.3%).

CONCLUSION

Results from the ARISE early feasibility study of a specific ascending stent graft device to treat ascending aortic dissection are promising.

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.

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.

Transesophageal Ultrasound Guidance for Endovascular Interventions on the Aorta

Aortic pathologies in general require a multidisciplinary approach and decision-making to integrate elements of clinical acuity, vascular pathology, individual comorbidity, and risk assessment; thus, ideally it is a center with access to multiple imaging modalities and expertise in all treatment options. Besides classic open surgical options, endovascular procedures have been accepted for a variety of aortic pathologies. More recently, novel transcatheter interventions even to the proximal aorta have been introduced, particularly for patients unfit for open surgery. Nevertheless, the role of transesophageal echocardiography to guide percutaneous aortic interventions is not well established, notwithstanding the growing potential as an ancillary tool to guide the procedure and document success.

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.

Hybrid repair versus conventional open repair for aortic arch dissection

BACKGROUND

A dissection of the aorta is a separation or tear of the intima from the media. This tear allows blood to flow not only through the original aortic flow channel (known as the true lumen), but also through a second channel between the intima and media (known as the false lumen). Aortic dissection is a life-threatening condition which can be rapidly fatal. There is debate on the optimal surgical approach for aortic arch dissection. People with ascending aortic dissection have poor rates of survival. Currently open surgical repair is regarded as the standard treatment for aortic arch dissection. We intend to review the role of hybrid and open repair in aortic arch dissection.

OBJECTIVES

To assess the effectiveness and safety of a hybrid technique of treatment over conventional open repair in the management of aortic arch dissection.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL and AMED databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 8 February 2021. We also undertook reference checking for additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and clinical controlled trials (CCTs), which compared the effects of hybrid repair techniques versus open surgical repair of aortic arch dissection. Outcomes of interest were dissection-related mortality and all-cause mortality, neurological deficit, cardiac injury, respiratory compromise, renal ischaemia, false lumen thrombosis (defined by partial or complete thrombosis) and mesenteric ischaemia.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened all records identified by the literature searches to identify those that met our inclusion criteria. We planned to undertake data collection and analysis in accordance with recommendations described in the Cochrane Handbook for Systematic Reviews of Interventions. We planned to assess the certainty of the evidence using GRADE.

MAIN RESULTS

We identified one ongoing study and two unpublished studies that met the inclusion criteria for the review. Due to a lack of study data, we could not compare the outcomes of hybrid repair to conventional open repair for aortic arch dissection.

AUTHORS' CONCLUSIONS

This review revealed one ongoing RCT and two unpublished RCTs evaluating hybrid versus conventional open repair for aortic arch surgery. Observational data suggest that hybrid repair for aortic arch dissection could potentially be favourable, but conclusions can not be drawn from these studies, which are highly selective, and are based on the clinical status of the patient, the presence of comorbidities and the skills of the operators. However, a conclusion about its definitive benefit over conventional open surgical repair cannot be made from this review without published RCTs or CCTs. Future RCTs or CCTs need to have adequate sample sizes and follow-up, and assess clinically-relevant outcomes, in order to determine the optimal treatment for people with aortic arch dissection. It must be noted that this may not be feasible, due to the reasons mentioned.

Computed Tomography Imaging of Aortic Dissections with Endovascular Treatment Considerations

PURPOSE OF REVIEW

In the present review, we discuss the role of CT imaging in the management of aortic dissection, with a particular emphasis on endovascular treatment considerations.

RECENT FINDINGS

Computed tomography imaging is a fundamental tool in the diagnosis and management of acute and chronic aortic dissection. Its diagnostic accuracy and high resolution contribute to and guide operative strategy. Persistent high mortality for patients who develop aortic dissections suggests a need for innovative diagnostic and treatment strategies. In the recent era, considerable advances have been made in computed tomography (CT) image acquisition, processing, and analysis as well as endovascular technologies with expanded roles in the treatment of aortic diseases.

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.

Endovascular Bail Out for a Failed Transcatheter Aortic Valve Implantation in High Surgical Risk Patient

The endovascular treatment for acute type A dissection (ATAD) represents an alternative and emerging option in selected high surgical risk patients. We report a successful total endovascular ATAD repair occurred intraoperatively during transcatheter aortic valve implantation (TAVI) placement in 82 years old female, not fit for surgery in emergency setting. The presentation, the diagnostic evaluation, and the technique are discussed. This case would support the feasibility and efficacy of the stent graft technology to treat ATADs after evaluation of clinical, anatomical, and radiological parameters.

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.

Outcomes of urgent aortic wrapping for acute type A aortic dissection

OBJECTIVE

Standard surgical repair of acute type A aortic dissection is associated with high mortality rates, especially in high-risk patients. In an attempt to improve survival in frail patients, we evaluated the outcomes after ascending aorta wrapping in a high-risk patient cohort.

METHODS

This single-center retrospective cohort study included all consecutive patients treated using ascending aorta wrapping for an acute type A aortic dissection from 2008 to 2019. The primary end points included 30-day mortality, survival during follow-up, and dissection-related mortality. Secondary end points included assessment of aortic remodeling after ascending aorta wrapping. Patients with an aortic anatomy suitable for adjunctive endografting of the ascending aorta were also identified.

RESULTS

Thirty-five consecutive patients who underwent ascending aorta wrapping were included. Their median age was 77 years (range, 46-96 years). The 30-day all-cause mortality rate was 9%. Major complications occurred in 7 patients (21%), including early reinterventions in 11 (31%). Median follow-up was 36 months (range, 2.4-106.6; interquartile range, 72). The actuarial survival at 36 months was 82%. The dissection-related mortality was 11.4%. The median aortic growth of the nonwrapped descending thoracic aorta was 3.4 mm. Computed tomography scan analysis depicted that 88% of survivors were theoretical candidates for an additional endovascular procedure to exclude the primary entry tear.

CONCLUSIONS

Aortic wrapping is associated with favorable early outcomes and a low rate of aortic events during follow-up. This therapeutic option should be considered for patients considered too fragile for standard surgical repair.

Anatomic Suitability for Branched Thoracic Endovascular Repair in Patients with Aortic Arch Pathological Features

Background Endovascular repair has become a viable alternative for aortic pathological features, including those located within the aortic arch. We investigated the anatomic suitability for branched thoracic endovascular repair in patients previously treated with conventional open surgery for aortic arch pathological features. Methods and Results Patients who underwent open surgery for aortic arch pathological features at our institution between 2000 and 2018 were included. Anatomic suitability was determined by strict compliance with the anatomic criteria within manufacturers' instructions for use for each of the following branched thoracic stent grafts: Relay Plus Double-Branched (Terumo-Aortic), TAG Thoracic Branch Endoprosthesis (W.L. Gore & Associates), Zenith Arch Branched Device (Cook-Medical), and Nexus Stent Graft System (Endospan Ltd/Jotec GmbH). Computed tomography angiography images were analyzed with outer luminal line measurements. A total of 377 patients (mean age, 64±14 years; 64% men) were identified, 153 of whom had suitable computed tomography angiography images for measurements. In total, 59 patients (15.6% of the total cohort and 38.6% of the measured cohort) were eligible for endovascular repair using at least one of the devices. Device suitability was 30.9% for thoracic aneurysms, 4.6% for type A dissections, 62.5% for type B dissections, and 28.6% for other pathological features. Conclusions The anatomic suitability for endovascular repair of all aortic arch pathological features was modest. The highest suitability rates were observed for thoracic aneurysms and for type B dissections, of which repair included part of the aortic arch. We suggest endovascular repair of arch pathological features should be reserved for high-volume centers with experience in endovascular arch repair.

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.

The IRAD and beyond: what have we unravelled so far?

Acute aortic dissection is a life-threatening condition associated with high morbidity and mortality rates and a long history of challenges to both diagnose and manage this condition successfully. The International Registry of Acute Aortic Dissection (IRAD) was established in 1996 as a global database to understand this old disease better and improve care for dissection. IRAD initially targeted various areas including etiological factors of dissection, modes of presentation, clinical features, physical findings, imaging, management, and outcomes, and is currently branching out in more specific fields such as endovascular intervention, genetic profiling, and functional imaging. Although presenting symptoms and physical findings have not changed significantly over two decades, the widespread use of computed tomography is standard and has improved the diagnostic pathway. Moreover, more patients are managed with appropriate procedures, such as surgery in type A, and endovascular therapy in subsets of type B aortic dissection. With these ongoing improvements in swift diagnostic work-up and therapeutic care, fewer patients are not getting appropriate treatment and more patients survive once they reach hospital.

Comparison of surgical and conservative treatment outcomes for type a aortic dissection in elderly patients

Background

In recent years, surgical outcomes have improved, and positive reports on surgery for type A aortic dissection (AAD) in the elderly are increasing. However, the difference between surgical and conservative treatments in the elderly remains unclear. Therefore, we conducted this study to determine whether surgery should be performed for Stanford (AAD) in elderly patients.

Methods

Data of patients aged 80 years or older who were hospitalized for AAD from April 2014 to March 2016 were extracted from the Japanese national inpatient database. Outcome measures were all-cause in-hospital death, stroke, acute kidney injury and tracheotomy, and composite adverse events (consisting of all-cause in-hospital death, stroke, acute kidney injury, and tracheotomy), and we compared them between surgical and conservative treatments using propensity score matching.

Results

The study cohort included 3258 patients, with 845 matched pairs (1690 patients) in the propensity score matching. All-cause in-hospital death was significantly lower in the surgical treatment group than in the conservative treatment group before and after matching (15.6% vs. 51.1%, p < 0.001; 16.7% vs. 31.6%, p < 0.001, respectively); however, there was no significant difference in composite adverse events after matching (36.0%, conservative vs. 37.2%, surgical; p = 0.65), and adjusted odds ratio was 1.06 and 95% confidence interval was 0.86–1.29 (p = 0.61) with reference to conservative treatment.

Conclusions

All-cause in-hospital death among elderly patients with AAD was significantly lower in patients treated surgically than in those undergoing conservative treatment. However, there was no significant difference between the two groups in the event-free survival, which is important for the elderly. These findings may be used in the consideration of treatment course for elderly patients with AAD.

Electronic supplementary material

The online version of this article (10.1186/s13019-018-0814-6) contains supplementary material, which is available to authorized users.

Combined Ascending Aortic Stent-Graft and Inner Branched Arch Device for Type A Aortic Dissection

Purpose: To report the use of the Zenith Ascend stent-graft in conjunction with the Zenith inner branched arch device to treat type A aortic dissection. Case Report: Five patients (mean age 66 years, range 52–78; 4 men) with type A aortic dissection (2 acute) and insufficient distal landing zones were treated with the Zenith Ascend stent-graft and inner branched arch devices to extend the distal landing zone. Left carotid–subclavian bypass was performed in a staged or simultaneous setting depending on the urgency of the condition. Technical success (no type I or III endoleak and successful revascularization of all supra-aortic vessels) was achieved in all patients. Median intensive care unit stay was 5 days (range 4–23) and the median hospital stay was 16 days (range 8–25). The 2 patients with acute dissection died in hospital and at 5 months, respectively. The 3 elective patients were followed for 7, 13, and 19 months, respectively. All had false lumen thrombosis with either a reduced or stable aneurysm diameter. Conclusion: This limited experience demonstrated the feasibility and safety of the combined use of the Ascend stent-graft and inner branched arch devices. This strategy may sometimes be more beneficial than either stent-graft used alone.

Experimental evaluation of homemade distal stent graft fenestration for thoracic endovascular aortic repair of type A dissection by a transapical approach

OBJECTIVE

The use of off-the-shelf stent grafts for thoracic endovascular aortic repair of type A dissections is limited by variability in both the length of the ascending aorta and the location of the proximal intimal tear. This experimental study aimed to assess the feasibility of using a physician-modified thoracic aortic stent graft to treat acute type A dissection by a transapical cardiac approach.

METHODS

The experiments were performed on six cadaveric human heart, ascending aorta, aortic arch, and descending aorta specimens. Fenestration was fashioned in each standard tubular Valiant thoracic stent graft (Valiant Captivia; Medtronic Vascular, Santa Rosa, Calif) to match the anatomy of each specimen. Stent grafts of sufficient length were selected to cover the entire ascending aorta and aortic arch. Stent graft diameters in proximal sealing zones were oversized by 5% to 10%. The length of the fenestration was the distance between the left subclavian artery and the proximal edge of the origin of the brachiocephalic trunk with an additional 10 mm. The diameter of the scallop was that of the brachiocephalic trunk with an additional 5 mm on all sides. The length of the covered portion of the stent graft was the distance between coronary arteries and the proximal edge of the origin of the brachiocephalic trunk. Two lateral radiopaque markers were positioned to delineate the distal and lateral edge of the scallop. Another 3-cm radiopaque marker was sutured onto the sheath to ensure accurate radiologic positioning of the scallop on the outer curve of the aorta. The left ventricle and the thoracic aorta were connected to a benchtop aortic pulsatile flow model. A 5-mm 30-degree lens was introduced through the left subclavian artery to monitor the procedure. The customized stent graft was deployed by a transapical approach under fluoroscopic control.

RESULTS

Median duration of stent graft modification was 21 minutes (range, 17-40 minutes). All attempts to deploy the homemade proximal scalloped stent graft by a transapical approach were successful. Completion angiography demonstrated patency of the supra-aortic trunks and of the coronary arteries in all cases. Macroscopic evaluation did not identify any deterioration of the customized stent graft.

CONCLUSIONS

The use of physician-modified stent grafts is feasible for thoracic endovascular aortic repair of type A dissection by a transapical approach in this model.

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.

Endovascular creation and validation of acute in vivo animal model for type A aortic dissection

BACKGROUND

Animal modeling is a prerequisite for clinical transfer of new therapies. This study targets an acute in vivo animal model of type A dissection using endovascular approach with a view to test future stent grafts dedicated to this aortic segment.

METHODS

Experiments were conducted on 13 swine. Two arterial accesses, femoral and percutaneous transapical, were required. Entry tear was created by endovascular instrumental means inserted through transapical access with either Outback catheter (group 1, n = 3) or EchoTip Endoscopic Ultrasound Needle (group 2, n = 10). Afterward, dissection extension was obtained in antegrade direction by looped guidewire technique, and, as often as possible, re-entry tear was created with either looped guidewire or Outback catheter. Finally, entry tear, dissected space, and re-entry tear when existing were dilated with 8-mm balloon. In our acute model, animals were euthanized at the end of the experiment day, and aortas were explanted for macroscopic and histologic examination.

RESULTS

The model was successfully created in 10 out of 13 animals. In group 1, dissection was limited to arch with 23 mm average length and no possibility of achieving re-entry tear. One aortic perforation was observed. In group 2, dissection was extended up to descending thoracic or thoracoabdominal aorta, with 110 mm average length (range 40-165 mm), and re-entry tear was created in seven cases. Histologic examination confirmed the presence of intimo-medial flap.

CONCLUSIONS

The present experiment validates a new type A dissection animal model, which morphologically reproduces human aortic dissection features. As such, it provides an advantageous basis for testing future stent grafts.

Hybrid and total endovascular repair of the aortic arch

Background

Recent advances in endovascular technology have enabled minimally invasive repair of the aortic arch, with specifically designed stent-grafts. This article reviews hybrid and total endovascular repair in the management of aortic arch pathology.

Methods

Studies relating to aortic arch management were identified using MEDLINE and Embase, focusing on endovascular repair.

Results

Hybrid arch repair is associated with an early mortality rate of some 12 per cent, and carries significant risk of stroke (up to 15 per cent), paraplegia (up to 6 per cent), retrograde dissection (up to 6·5 per cent) and proximal endoleak (6 per cent). Despite patients being of overall higher perioperative risk, hybrid repair has morbidity and early mortality rates comparable to those of open arch replacement. However, rates of freedom from aortic rupture or reintervention are significantly lower in the longer term, owing to the incidence of endoleak. Total endovascular arch repair may be achieved by the use of parallel stents or in situ fenestration in the emergency setting, or use of custom-made devices (scalloped, fenestrated or branched stent-grafts) in the elective setting. Reports of these relatively novel technologies suggest acceptable short-term outcomes, but long-term data are still awaited.

Conclusion

Repair of aortic arch pathology presents a formidable challenge for endovascular technology. Open aortic arch repair remains the standard in younger, fitter patients, but endovascular technology and experience continue to evolve with encouraging early outcomes and expanding indications.

Anatomic Feasibility of Next-Generation Stent Grafts for the Management of Type A Aortic Dissection in Japanese Patients

BACKGROUND

The aims of the present study were to analyze the anatomical characteristics of type A aortic dissections (TAAD) in Japanese patients and evaluate the feasibility of 3 next-generation stent grafts dedicated to ascending/arch aortic lesions.

METHODS AND RESULTS

We analyzed 172 consecutive patients surgically treated for TAAD at 2 institutions between 2007 and 2015. Computed tomography (CT) images and operative records were used to identify the location of entry tear (ET). The anatomical feasibility of the Zenith Ascend, Zenith A-branch, and TAG Thoracic Branch Endoprosthesis (TBE) was evaluated using the manufacturers' instructions for use (IFU). In total, 131 patients were included in the final analysis. Dissection was present at the sinotubular junction (STJ) in 107 patients (81.7%), and the mean diameter of the STJ was 39.4±6.0 mm. The ET was at the STJ (n=33), ascending aorta (n=47), aortic arch (n=30), and descending aorta (n=21). The mean lengths from STJ to innominate artery and STJ to ET were 79.5±11.4 mm and 57.8±52.1 mm, respectively. When we applied the IFU to each anatomical measurement, we identified 0 patients as candidates for Zenith Ascend, 9 (6.9%) for Zenith A-branch, and 60 (45.8%) for TAG TBE.

CONCLUSIONS

Endovascular treatment for TAAD was not feasible for most of this study population, with risk of stent graft-induced new entry in 81.7% of patients, despite the use of next-generation stent grafts.

CT patterns of acute type A aortic arch dissection: longer, higher, more anterior

OBJECTIVES

This study analysed CT patterns of the acute dissected aortic arch using original biometric features along with comparison with normal aortas.

METHODS

The diagnostic CT scans of 57 patients (42 males, age (mean ± SD: 64.5 ± 13.8 years) admitted with acute Stanford type A dissection involving the aortic arch were analysed by semi-automatic detection protocol of the true lumen of the dissection. We measured the distances from the apex to the ascending and descending aorta, the curvilinear length of the entire arch and of its segments (especially between the brachiocephalic artery trunk and the left subclavian artery), as well as the surface area, angle, height and shift of the arch. These measurements were compared with results previously obtained in a healthy cohort in an analysis adjusted for age, sex and weight. The surface area and rotation of the false lumen were also analysed.

RESULTS

Compared to normal aortic arches (N), dissected aortic arches (D) were longer (D: 155 ± 26  mm, N: 135 ± 25  mm, p = 0.002), higher (D: 51 ± 10  mm, N: 45 ± 9  mm, p = 0.04), and with a more anterior apex (shift: D: 1.19 ± 0.56, N: 1.40 ± 0.62, p = 0.007). False lumen occupied between 47-65% of the aorta, turned preferentially clockwise and its rotation decreased progressively along the arch.

CONCLUSIONS

The morphology of the dissected aortic arch differs from that of the normal arch. Thus, our compilation of aortic arch measurements may help improve existing endovascular devices and/or design of new endoprostheses. Advances in knowledge: In this article, we provide a comprehensive set of measurements of the dissected aortic arch, and show that dissected aortic arches are longer, higher, and with a more anterior apex than normal arches.

Acute Type A Aortic Dissection Treated Using a Tubular Stent-Graft in the Ascending Aorta and a Multibranched Stent-Graft in the Aortic Arch

Purpose: To describe the combined use of a tubular stent-graft for the ascending aorta and an inner-branched arch stent-graft for patients with acute type A aortic dissection. Technique: The technique to deploy these modular, custom-made stent-grafts is demonstrated in 2 patients with acute DeBakey type I aortic dissections and significant comorbidities precluding open surgery. Both emergent procedures were made possible by the availability of suitable devices manufactured for elective repair in other patients. After preliminary carotid-subclavian bypass, a long Lunderquist guidewire was introduced from the right femoral artery to the left ventricle for delivery of the Zenith Ascend and Zenith Branched Arch Endovascular Grafts under inflow occlusion. Bridging stent-grafts were delivered to the innominate and left common carotid arteries to connect to the 2 inner branches; the left subclavian artery was occluded. Both cases were technically successful and resulted in exclusion of the false lumen in the ascending aorta. The operating and fluoroscopy times did not exceed those of comparable elective procedures. The patients were rapidly extubated shortly after the procedure and without serious immediate complications. One patient survived 11 months with a satisfactory repair; the other succumbed to complications of recurrent pneumonia after 23 days. Conclusion: Endovascular treatment of patients with acute type A aortic dissection using a combination of tubular and branched stent-grafts in the ascending aorta is feasible and offers an alternative strategy to open surgery.

Three-Dimensional Visualization and Imaging of the Entry Tear and Intimal Flap of Aortic Dissection Using CT Virtual Intravascular Endoscopy

AIMS

Conventional computed tomography (CT) approaches provides limited visualization of the entire endoluminal changes of aortic dissection (AD), which is essential for its treatment. As an important supplement, three-dimensional CT virtual intravascular endoscopy (VIE) can show relevant details. This study aims to determine the value of VIE in displaying the entry tear and intimal flap of AD.

METHODS AND RESULTS

Among 127 consecutive symptomatic patients with suspected AD who underwent CT angiography (CTA), 84 subjects were confirmed to have AD and were included in the study. Conventional CT and VIE images were observed and evaluated. From the 92 entry tears revealed via conventional CT, 88 (95.7%) tears appeared on VIE with round (n = 26), slit-shaped (n = 9), or irregular (n = 53) shapes, whereas the intimal flaps were sheetlike (n = 34), tubular (n = 34), wavelike (n = 13), or irregular (n = 7) in shape. The VIE also showed the spatial relationship between the torn flap and adjacent structures. Among 58 entry tears with multiple-line type flap shown on conventional CT, 41 (70.7%) appeared with an irregular shape on VIE, whereas among 30 tears with single-line type flap, 17 (56.7%) appeared as round or slit-shaped on VIE. These results demonstrated a significant difference (P < 0.05). The poor display of tears on VIE was related to the low CT attenuation values in lumen or in neighboring artifacts (P < 0.01).

CONCLUSION

CT VIE presents the complete configurations and details of the intimal tears and flaps of AD better than conventional CT approaches. Accordingly, it should be recommended as a necessary assessment tool for endovascular therapy and as part of strategy planning in pre-surgical patients.

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.

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.