Endovascular repair of type B aortic dissection: long-term results of the randomized investigation of stent grafts in aortic dissection trial

MRI in CFD for chronic type B aortic dissection: Ready for prime time?

OBJECTIVES

Better tools are needed for risk assessment of Type B aortic dissection (TBAD) to determine optimal treatment for patients with uncomplicated disease. Magnetic resonance imaging (MRI) has the potential to inform computational fluid dynamics (CFD) simulations for TBAD by providing individualised quantification of haemodynamic parameters, for assessment of complication risks. This systematic review aims to present an overview of MRI applications for CFD studies of TBAD.

METHODS

Following PRISMA guidelines, a search in Medline, Embase, and the Scopus Library identified 136 potentially relevant articles. Studies were included if they used MRI to inform CFD simulation in TBAD.

RESULTS

There were 20 articles meeting the inclusion criteria. 19 studies used phase contrast MRI (PC-MRI) to provide data for CFD flow boundary conditions. In 12 studies, CFD haemodynamic parameter results were validated against PC-MRI. In eight studies, geometric models were developed from MR angiography. In three studies, aortic wall or intimal flap motion data were derived from PC/cine MRI.

CONCLUSIONS

MRI provides complementary patient-specific information in CFD haemodynamic studies for TBAD that can be used for personalised care. MRI provides structural, dynamic and flow data to inform CFD for pre-treatment planning, potentially advancing its integration into clinical decision-making. The use of MRI to inform CFD in TBAD surgical planning is promising, however further validation and larger cohort studies are required.

Current Understanding of Aortic Dissection

The aorta is the largest artery in the body, delivering oxygenated blood from the left ventricle to all organs. Dissection of the aorta is a lethal condition caused by a tear in the intimal layer of the aorta, followed by blood loss within the aortic wall and separation of the layers to full dissection. The aorta can be affected by a wide range of causes including acute conditions such as trauma and mechanical damage; and genetic conditions such as arterial hypertension, dyslipidaemia, and connective tissue disorders; all increasing the risk of dissection. Both rapid diagnostic recognition and advanced multidisciplinary treatment are critical in managing aortic dissection patients. The treatment depends on the severity and location of the dissection. Open surgical repair is the gold standard of treatment for dissections located to the proximal part of the aorta and the arch, while endovascular interventions are recommended for most distal or type B aortic dissections. In this review article, we examine the epidemiology, pathophysiology, contemporary diagnoses, and management of aortic dissection.

Volume Analysis to Predict the Long-Term Evolution of Residual Aortic Dissection after Type A Repair

Background: The aim of this study was to evaluate the aortic diameter and volume during the first year after a type A repair to predict the long-term prognosis of a residual aortic dissection (RAD). Methods: All patients treated in our center for an acute type A dissection with a RAD and follow-up > 3 years were included. We defined two groups: group 1 with dissection-related events (defined as an aneurysmal evolution, distal reintervention, or aortic-related death) and group 2 without dissection-related events. The aortic diameters and volume analysis were evaluated on three postoperative CT scans: pre-discharge (T1), 3−6 months (T2) and 1 year (T3). Results: Between 2009 and 2016, 54 patients were included. Following a mean follow-up of 75.4 months (SD 31.5), the rate of dissection-related events was 62.9% (34/54). The total aortic diameters of the descending thoracic aorta were greater in group 1 at T1, T2 and T3, with greater diameters in the FL (p < 0.01). The aortic diameter evolution at 3 months was not predictive of long-term dissection-related events. The total thoracic aortic volume was significantly greater in group 1 at T1 (p < 0.01), T2 (p < 0.01), and T3 (p < 0.01). At 3 months, the increase in the FL volume was significantly greater in group 1 (p < 0.01) and was predictive for long-term dissection-related events. Conclusion: This study shows that an initial CT scan volume analysis coupled with another at 3 months is predictive for the long-term evolution in a RAD. Based on this finding, more aggressive treatment could be given at an earlier stage.

Distal aortic replacement followed by endovascular repair for the management of severe intra-pleural adhesions accidentally detected during open surgery for chronic type B aortic dissection: a report of two cases

BACKGROUND

Open repair is the most promising curative treatment option for patients with chronic type B aortic dissection. However, based on our experience, following the accidental detection of intra-pleural adhesions during open surgery for chronic type B aortic dissection, complete replacement of the diseased aorta cannot be accomplished. To overcome this problem, we switched the procedure to create a distal landing zone for subsequent endovascular repair by replacing the distal aorta with a vascular graft.

CASE PRESENTATION

We report two cases in which open repair was attempted; however, the proximal descending thoracic aorta could not be exposed due to the presence of severe adhesion in the pleural cavity. In these patients, we accessed the lower descending thoracic aorta or thoracoabdominal aorta and created a distal landing zone for subsequent endovascular repair by replacing the aorta with a vascular graft. Thereafter, endovascular repair was performed with good outcomes.

CONCLUSIONS

Replacement of the distal aorta, which is typically easy to access despite the presence of intra-pleural adhesions, with a vascular graft serves as a reliable distal landing zone for subsequent endovascular repair. This method may be a viable option for the management of severe adhesions accidentally detected in the pleural cavity during open repair for chronic type B aortic dissection.

MANAGEMENT OF LEFT SUBCLAVIAN ARTERY IN TYPE-B AORTIC DISSECTION TREATED WITH THORACIC ENDOVASCULAR AORTA REPAIR

OBJECTIVE

Thoracic endovascular aortic repair (TEVAR) has been the favored approach for the treatment of type B aortic dissection (TBAD). To obtain an adequate proximal landing zone, coverage of the left subclavian artery (LSA) will often be necessary. The occurrence of possible neurologic complications has continued to be debated. We investigated the management of the LSA in patients with TBAD undergoing endovascular repair.

METHODS

We searched the PubMed and MEDLINE databases to October 2020 for studies of TEVAR for TBAD. Data on the study design, demographics, endograft details, LSA coverage and revascularization, mortality, complications, and follow-up were extracted and analyzed. The effects of LSA coverage and revascularization on neurologic complications and outcomes were investigated.

RESULTS

A total of 26 reports (24 retrospective and 2 prospective) were deemed eligible for our study. A total of 1483 patients (mean age, 56.9 ± 6.2 years) had undergone TEVAR for acute (n = 932; 62.9%), subacute (n = 36; 2.4%), or chronic (n = 515; 34.7%) TBAD, with a success rate of 97.8% and hospital mortality of 4.9%. The LSA origin had been covered for 707 patients (47.7%), and 326 had undergone LSA revascularization (surgical, n = 96; endovascular, n = 170; unspecified or not reported, n = 60). LSA revascularization was concomitant for 68.1% of cases, after TEVAR for 1.8%, and not reported for 30.1%. Of 1146 patients, 10 (0.9%) had experienced left arm claudication, and the overall stroke rate was 3.3% (2.7% for the LSA group and 1% for the uncovered LSA group; P = .0815). Of the patients with stroke and a covered LSA, 1% (2 of 203) had undergone LSA revascularization and 4.8% (5 of 105) had not (P = .0478). Twenty-six patients (1.9%) had developed paraplegia: 0.7% (3 of 433) with a covered LSA, 1.4% (7 of 491) with an uncovered LSA (P = .3508), and not reported for 16 patients. Endoleak was present in 138 patients (13.4%) at a mean follow-up of 32.1 ± 25.6 months.

CONCLUSIONS

Our review has shown that LSA coverage during endovascular repair for complicated TBAD will does not significantly increase the risk of neurologic complications; however, revascularization of the LSA should be always recommended.

Chronic Thoracic Aortic Dissection: How to Treat, When to Intervene

Thoracic aortic dissection (AD) is associated with increased morbidity and mortality. Acute aortic syndrome is the first presentation of the disease in most cases. While acute AD management follows concrete guidelines because of its urgent and life-threatening nature, chronic AD is usually overlooked, although it concerns a wide spectrum of patients surviving an acute event. Acute AD survivors ultimately enter a chronic aortic disease course. Patients with chronic thoracic AD (CTAD) require lifelong surveillance and a proportion of them may present with symptoms and late complications demanding further surgical or endovascular treatment. However, the available data concerning the management of CTAD is sparse in the literature. The management of patients with CTAD is challenging as far as determining the best medical therapy and deciding on intervention are concerned. Until recently, there were no guidelines or recommendations for imaging surveillance in patients with chronic AD. The diagnostic methods for imaging aortic diseases have been improved, while the data on new endovascular and surgical approaches has increased significantly. In this review, we summarize the current evidence in the diagnosis and management of CTAD and the latest recommendations for the surgical/endovascular aortic repair of CTAD.

Procedure and Aortic Remodeling Effects of Entry Closure with Stentgraft for Type B Aortic Dissection: Comparison between the Patients with Narrow True Lumen and Those with Aneurysmal Dilated False Lumen

Objectives: Appropriateness of device selection, procedure protocol and aortic remodeling effects of entry closure (TEVAR) with stent-graft (SG) for patent false lumen type B aortic dissection (TBAD) were compared between the patients with narrow true lumen (narrow group) and those with aneurysmal dilated false lumen (aneurysmal group).

Methods: Twenty-six patients with narrow true lumen (narrow group) and 20 patients with aneurysmal false lumen (aneurysmal group) were included in this study. In narrow group, straight SG was implanted from Zone 3 regardless the distance between the left subclavian artery and entry. In aneurysmal group, straight or taped SG was implanted with proximal landing zone length 20 mm or more. Thoracic aortic anatomy was evaluated by CT and aortic remodeling was defined as true lumen diameter ≥50% of the aortic diameter and occlusion of false lumen. Aorta related death, retrograde type A aortic dissection (RTAD), stentgraft induced new entry (SINE) and aortic maximum diameter enlargement 5 mm or more (aortic expansion) were included in the aortic event.

Results: There was no procedure related complication in narrow group and 1 patient died due to aortic rupture in aneurysmal group, Type Ia endoleak by enhanced CT 7 days after TEVAR was detected in one patient in each group. Achievement of aortic remodeling was significantly better in narrow group. Aortic event occurred in only one patient in narrow group, in whom aortic expansion was observed. In aneurysmal group, aortic event occurred 12 patients (60%) and 2 RTAD, 5 SINE, and 8 aorta expansion were observed. Aortic event free rate was significantly better in narrow group.

Conclusion: TEVAR procedure for the TBAD patients with narrow true lumen seemed to be appropriate, however, different TEVAR procedure or additional procedures would be required for those with aneurysmal dilated false lumen to obtain favorable outcomes. (This is secondary publication from Jpn J Vasc Surg 2021; 30: 347–357.)

False lumen patency status and outcomes after endovascular repair of uncomplicated chronic type B dissection

BACKGROUND

Thoracic endovascular aortic repair (TEVAR) remains a controversial treatment for uncomplicated chronic type B aortic dissection (cTBAD). This study was performed to investigate the postoperative outcomes of TEVAR, such as survival and reintervention, and the risk factors for prognoses.

METHODS

In total, 41 patients with uncomplicated cTBAD who underwent TEVAR from 2014 to 2021 were reviewed. The patients were divided into two groups: those with false lumen complete thrombosis (FLCT) and false lumen partial thrombosis (FLPT) based on computed tomography angiography (CTA) images. Kaplan-Meier analysis was performed to estimate survival and freedom from reintervention. Binary logistic analysis was performed to estimate risk factors for partial thrombosis.

RESULTS

During a mean follow-up of 31 (1-78) months, five deaths and six reinterventions had occurred at 5 years. By 1 week, thoracic FLCT had occurred in 23 (56.1%) patients and thoracic FLPT had occurred in 18 (43.9%). The rate of freedom from reintervention was significantly lower in the FLCT than in the FLPT group (p = 0.04). The 5-year survival rate of the two groups was not statistically significant (p = 0.14). Risk factors for thoracic FLPT were the distance between the re-entry site and the graft (p = 0.02) and the proximal oversizing ratio (p = 0.04).

CONCLUSIONS

TEVAR is an effective and safe treatment for uncomplicated cTBAD and has a low mortality rate. Thoracic FLCT is associated with less reintervention, but overall survival is not impacted by this difference. Patients treated with TEVAR without certain risk factors can have a good prognosis.

Staged Hybrid Repair of a Complex Type B Aortic Dissection

Due to its heterogeneous clinical picture and lengthy evolution, the management of type B aortic dissection represents a clinical challenge, often calling for complex strategies combining medical, endovascular, and open surgical strategies. We present the case of a 45-year-old female who had previously suffered a complicated type B aortic dissection requiring a femoro-femoral crossover bypass and further conservative treatment. Seven years later, due to an aneurysmal development, a staged descending aortic management was strategized, beginning with the implantation of a frozen elephant trunk device due to an insufficient proximal landing zone for endovascular repair. However, the development of a distal stent graft-induced new entry complicated the dissection and led to the formation of a second false lumen, thus prompting an expedited hybrid reconstruction. We describe a hybrid repair strategy tailored to the patient’s particular aortic anatomic conformation, combining ilio-visceral debranching and thoracic endovascular aortic repair. Due to a lack of consensus on the ideal management strategy for type B aortic dissection, an individualized approach conducted by an experienced aortic team may generate the best outcome. The appropriate timing and planning of the intervention are the keys to successful results in complex type B aortic dissection cases with an elaborate anatomic conformation.

Comparative Risks of Initial Aortic Events Associated With Genetic Thoracic Aortic Disease

BACKGROUND

Pathogenic variants in 11 genes predispose individuals to heritable thoracic aortic disease (HTAD), but limited data are available to stratify the risk for aortic events associated with these genes.

OBJECTIVES

This study sought to compare the risk of first aortic event, specifically thoracic aortic aneurysm surgery or an aortic dissection, among 7 HTAD genes and variant types within each gene.

METHODS

A retrospective cohort of probands and relatives with rare variants in 7 genes for HTAD (n = 1,028) was assessed for the risk of first aortic events based on the gene altered, pathogenic variant type, sex, proband status, and location of recruitment.

RESULTS

Significant differences in aortic event risk were identified among the smooth muscle contraction genes (ACTA2, MYLK, and PRKG1; P = 0.002) and among the genes for Loeys-Dietz syndrome, which encode proteins in the transforming growth factor (TGF)-β pathway (SMAD3, TGFB2, TGFBR1, and TGFBR2;P < 0.0001). Cumulative incidence of type A aortic dissection was higher than elective aneurysm surgery in patients with variants in ACTA2, MYLK, PRKG1, and SMAD3; in contrast, patients with TGFBR2 variants had lower cumulative incidence of type A aortic dissection than elective aneurysm surgery. Cumulative incidence of type B aortic dissection was higher for ACTA2, PRKG1, and TGFBR2 than other genes. After adjusting for proband status, sex, and recruitment location, specific variants in ACTA2 and TGFBR2 were associated with substantially higher risk of aortic event with childhood onset.

CONCLUSIONS

Gene- and variant-specific data on aortic events in individuals with HTAD support personalized aortic surveillance and clinical management.

Progressive Aortic Enlargement in Medically Managed Acute SVS/STS Type B Aortic Dissections with Visceral Aortic Involvement

BACKGROUND

Aortic remodeling of the thoracic aorta has been studied in patients treated with medical or endovascular therapy for the treatment of acute aortic dissections; however, particular attention has not yet focused on identifying specific growth patterns and rates across all aortic zones. Additionally, previous studies have not delineated between dissections with and without visceral aortic involvement, and we hypothesize that these two cohorts may exhibit distinct differences. The aim of this study is to investigate aortic behavior over time in medically managed acute SVS/STS Type B dissections with visceral aortic involvement, and identify potential associations of subsequent aortic behavior with clinical outcomes.

METHODS

A single-center retrospective review was performed of all patients between 2010-2020 with acute SVS/STS Type B aortic dissections with visceral aortic involvement that were not surgically managed. Short-axis centerline measurements of the true/false lumen and total aortic diameter (TAD) were taken at standardized locations relative to aortic anatomy within each aortic zone, including non-dissected zones. Measurements were taken at the time of diagnosis and at six subsequent yearly intervals. Diameter changes over time were evaluated using repeated measures mixed models linear growth analysis. Aortic enlargement was classified by growth in TAD≥5mm in either the thoracic (Thoracic Segment Enlargement [TSE], Zone 0-4) or visceral segments (Visceral Segment Enlargement [VSE], Zone 5-9).

RESULTS

A total of 78 patients were identified with a median length of follow-up of 3.3 years (interquartile range [IQR]1.3-6.6 years). Follow-up past 5 years was seen in 31% of the cohort. For the entire cohort, mean thoracic growth in TAD was 2.0±2.0 mm/year and visceral growth in TAD 2.5±2.4 mm/year. TSE was observed in 65% of patients, with a median time until onset of 0.8 years (IQR 0.4-2.3 years). VSE was observed in 57% of the cohort, with a median time until onset of 1.6 years (IQR 0.9-3.3 years). Repeat measures mixed models linear growth analysis identified significant predictable linear growth in all aortic zones except for the non-dissected Zones 0-2. Odds for TSE are significantly increased in patients with known genetically triggered aortic conditions (GenTACs) (OR 2, 95% CI 1.8-4.5, p=0.044) and in cases where the dissection entry tear was in either Zone 1 or 2 (OR 4.8, 95% CI 1.2-8.4, p=0.044). In adjusted regression analysis, odds for intervention in the thoracic aorta were significantly increased in patients with rapid TSE in Zone 3 (OR 3.6 [1.1-8.4], p=0.045). Similarly, odds for intervention targeting the visceral aortic segment were significantly increased in patients with Zone 9 VSE (OR 9.3, 95% CI 1.1-13.3, p=0.014). Odds for 5-year all-cause mortality were significantly increased in cases with large thoracic aneurysms (OR 6.1, 95% CI 1.1-14.9, p=0.042).

CONCLUSIONS

Aortic enlargement was present in the majority of patients with medically managed acute SVS/STS Type B aortic dissections with visceral aortic involvement, with analysis demonstrating predictable linear growth in all dissected zones. Patients with aortic instability demonstrated higher gross changes in diameter in addition to higher yearly rates of change compared to all comers. Odds for enlargement were impacted by both patient demographic and anatomic dissection characteristics. Growth in Zone 3 and Zone 9 significantly increased odds for aortic intervention. Odds for 5-year mortality were significantly increased in the presence of large thoracic aneurysms. Results highlight risk of progressive degeneration beyond acute phase in SVS/STS Type B aortic dissections with visceral aortic involvement, with life-long surveillance remaining crucial in management of dissections.

Aortic Perforation and Ascending Dissection Due to Intra-Aortic Balloon Counterpulsation Implantation in Cardiac Surgery

The intra-aortic balloon pump continues to be a useful ventricular assist device in cardiac surgery. Complications are estimated to be 7% to 40%, significantly high to catastrophic. We describe an aortic injury associated with the use of the device and an interdisciplinary management for the diagnostic and therapeutic approach. (Level of Difficulty: Intermediate.)

Research and clinical translation of trilayer stent-graft of expanded polytetrafluoroethylene for interventional treatment of aortic dissection

The aortic dissection (AD) is a life-threatening disease. The transcatheter endovascular aortic repair (EVAR) affords a minimally invasive technique to save lives of these critical patients, and an appropriate stent-graft gets to be the key medical device during an EVAR procedure. Herein, we report a trilayer stent-graft and corresponding delivery system used for the treatment of the AD disease. The stent-graft is made of nitinol stents with an asymmetric Z-wave design and two expanded polytetrafluoroethylene (ePTFE) membranes. Each of inner and outer surfaces of the stent-graft was covered by an ePTFE membrane, and the two membranes were then sintered together. The biological studies of the sintered ePTFE membranes indicated that the stent-graft had excellent cytocompatibility and hemocompatibility in vitro. Both the stent-graft and the delivery system exhibited satisfactory mechanical properties and operability. The safety and efficacy of this stent-graft and the corresponding delivery system were demonstrated in vivo. In 9 canine experiments, the blood vessels of the animals implanted with the stent-grafts were of good patency, and there were no thrombus and obvious stenosis by angiography after implantation for 6 months. Furthermore, all of the 9 clinical cases experienced successful implantation using the stent-graft and its post-release delivery system, and the one-year follow-ups indicated the preliminary safety and efficacy of the trilayer stent-graft with an asymmetric Z-wave design for interventional treatment.

Usefulness of 18F-FDG PET/computed tomography in differentiating between subacute and chronic aortic dissection: initial investigation

OBJECTIVES

In the selection of thoracic endovascular repair for aortic dissection (AD), it is important to distinguish between the subacute and chronic phases, but there is no reliable way to distinguish between them in patients with unknown onset of AD. The purpose of this study was to assess the diagnostic performance of 2-[18F] fluoro-2-deoxy-d-glucose (18F-FDG)-PET/computed tomography (PET/CT) for discriminating subacute AD from chronic AD.

METHODS

Thirteen patients with AD who were medically treated and followed up for 6 months were studied. 18F-FDG PET/CT images were obtained for each patient in the subacute phase (the first scan) and at 6 months (the second scan) after the onset. Target-to-background ratio (TBR) was measured as the maximum standardized uptake value (SUV) in the dissected aortic wall divided by blood pool SUV.

RESULTS

TBR was significantly higher in the first scan (mean ± SD, 1.97 ± 0.32) than in the second scan (1.69 ± 0.29, P = 0.007). The area under the receiver operating characteristic curve of TBR for discriminating subacute AD from chronic AD was 0.76. With a threshold of 1.74, the TBR showed the sensitivity, specificity, and positive and negative predictive value of 85%, 69%, 73%, and 82%, respectively, for the discrimination of subacute AD from chronic AD.

CONCLUSION

Metabolic assessment of dissected aortic wall by 18F-FDG PET/CT is useful in differentiating between subacute and chronic AD and can provide important information in determining the appropriate indication for treatment for patients with AD of unknown onset.

Contemporary Unplanned Readmission Trends Following Management of Type B Aortic Dissection

Purpose

Methods

Results

Conclusion

False Lumen Flow Assessment by Magnetic Resonance Imaging and Long-Term Outcomes in Uncomplicated Aortic Dissection

BACKGROUND

Despite the absence of clinical complications after an acute aortic dissection (AD) with persistent patent false lumen (FL), a high risk for clinical events may persist.

OBJECTIVES

The aim of this study was to assess the natural evolution of noncomplicated AD and ascertain whether different FL flow patterns by magnetic resonance imaging (MRI) have independent prognostic value for AD-related events beyond established morphologic parameters.

METHODS

One hundred thirty-one consecutive patients, 78 with surgically treated type A dissections and 53 with medically treated type B dissections, were followed up prospectively after acute AD with persistent patent FL in the descending aorta. Maximum aortic diameter, true lumen compression, entry tear, and partial FL thrombosis by computed tomography were assessed. Systolic antegrade true lumen and FL flow volumes and diastolic antegrade and retrograde flows were analyzed by MRI during the first year after AD.

RESULTS

After a median follow-up period of 8.0 years (IQR: 4.6-10.9 years), 43 patients presented aorta-related events (25 died and 18 required endovascular treatment). FL systolic antegrade flow ≥30% with respect to total systolic antegrade flow and retrograde diastolic flow ≥80% with respect to total diastolic FL flow were predictors of aortic events. In multivariate analysis, aortic diameter >45 mm (HR: 2.91), type B dissection (HR: 2.44), and MRI flow pattern (HR: 16.87) were independent predictors of AD-related events.

CONCLUSIONS

High systolic antegrade flow volume in the FL with significant diastolic retrograde flow assessed by MRI and aortic diameter >45 mm identify patients with higher risk for complications in whom more aggressive management would be indicated.

Risk profile analysis of uncomplicated type B aortic dissection patients undergoing thoracic endovascular aortic repair: Laboratory and radiographic predictors

BACKGROUND

There is emerging evidence to support pre-emptive thoracic endovascular aortic repair (TEVAR) intervention for uncomplicated type B aortic dissection (unTBAD). Pre-emptive intervention would be particularly beneficial in patients that have a higher baseline risk of progressing to complicated TBAD (coTBAD). There remain debate on the optimal clinical, laboratory, morphological, and radiological parameters, which would identify the highest-risk patients that would benefit most from pre-emptive TEVAR.

AIM

This review summarizes evidence on the clinical, laboratory, and morphological parameters that increase the risk profiles of unTBAD patients.

METHODS

A comprehensive literature search was carried out on multiple electronic databases including PubMed, EMBASE, Ovid, and Scopus to collate all research evidence on the clinical, laboratory, and morphological parameters that increase the risk profiles of unTBAD patients RESULTS: At present, there are no clear clinical guidelines using risk-stratification to inform the selection of unTBAD patients for TEVAR. However, there are noticeable literature trends that can assist with the identification of the most at-risk unTBAD patients. Patients are at particular risk when they have refractory pain and/or hypertension, elevated C-reactive protein (CRP), larger aortic diameter, and larger entry tears. These risks should be considered alongside factors that increase the procedural risk of TEVAR to create a well-balanced approach. Advances in biomarkers and imaging are likely to identify more pertinent parameters in the future to optimize the development of balanced, risk-stratified treatment protocols.

CONCLUSION

There are a variety of risk profiling parameters that can be used to identify the high-risk unTBAD patient, with novel biomarkers and imaging parameters emerging. Longer-term evidence verifying these parameters would be ideal. Further randomized controlled trials and multicentre registry analyses are also warranted to guide risk-stratified selection protocols.

False lumen being larger than true lumen is associated with late aortic events in uncomplicated type B aortic dissection

OBJECTIVES

In uncomplicated type B aortic dissection, a large false lumen (FL) is reportedly a risk factor for late aortic events. However, it is unclear how the relationship between the false and true lumen (TL) diameters affects the dissected aorta. This study aimed to evaluate the impact on clinical outcomes of the FL being larger than the TL.

METHODS

We retrospectively reviewed 111 consecutive patients with uncomplicated acute type B aortic dissection between 2004 and 2018. We divided the patients into group A (FL > TL; n = 51) and group B (FL ≤ TL; n = 60), and compared the outcomes. The endpoints were aortic events, including surgery for aortic dissection and indication for surgery, and mortality.

RESULTS

The 5-year incidence rates of aortic events were 68.4% in Group A and 33.6% in Group B (P = 0.002). The 5-year all-cause mortality rates were 5.3% in Group A and 21.9% in Group B (P = 0.003). The multivariable analyses revealed that FL > TL was an independent factor associated with aortic events (adjusted hazard ratio 2.482, 95% confidence interval 1.467-4.198, P < 0.001), but had low mortality (adjusted hazard ratio 0.209, 95% confidence interval 0.073-0.597, P = 0.003).

CONCLUSIONS

Patients with uncomplicated type B aortic dissection with FL > TL at admission are at increased risk of aortic events but improve mortality compared to patients with FL ≤ TL.

CLINICAL TRIAL REGISTRATION

UMIN000036997.

Thoracic endovascular aortic repair or best medical therapy for uncomplicated type B aortic dissection? A meta-analysis

INTRODUCTION

The aim of this meta-analysis was to investigate all studies comparing thoracic endovascular aortic repair (TEVAR) and best medical therapy (BMT) for the treatment of uncomplicated type B aortic dissection (TBAD).

EVIDENCE ACQUISITION

PubMed/Medline and Web of Knowledge were searched until September 2014 for relevant studies published in English. Pooled odds ratio (OR) and its corresponding 95% CI were analyzed with Cochrane Review Manager (RevMan v.5.3).

EVIDENCE SYNTHESIS

Our analysis showed that compared with BMT, TEVAR did not significantly affect 30-day (hospital) mortality. A significantly lower 1-year and 2- or 3-year survival rates was observed with TEVAR vs. BMT. Interestingly, a trend just short of statistical significance towards higher 4- or 5-year survival was found with TEVAR treatment (P=0.08). No significant differences were found in false lumen (FL) thrombosis formation with TEVAR vs. BMT treatment. However, a trend toward less incomplete or no FL thrombosis was noted with TEVAR. No significantly impact on the risk of later re-intervention was found with TEVAR vs. BMT.

CONCLUSIONS

TEVAR did not provide obvious early survival advantage for uncomplicated TBAD over BMT, especially in the patients using TEVAR alone. It may remain a treatment option in uncomplicated TBAD patients with high risks for later complications. More randomized, prospective, long-term studies are needed to further clarify whether TEVAR could be a better first-line treatment strategy vs. BMT for uncomplicated TBAD.

Transposition of left subclavian artery with reimplantation of isolated left vertebral artery before thoracic endovascular aneurysm repair for type B aortic dissection

Understanding and recognizing anatomic anomalies of the aortic arch is important when planning extra-anatomic debranching before thoracic endovascular aortic repair. A rare anomaly is the left vertebral artery aberrantly arising from the aortic arch; found in ∼5% of adults. When present, the artery courses through the carotid sheath at a variable length before entering the third or fourth cervical transverse foramen. In the present report, we have described the case of a 49-year-old man with a symptomatic, enlarging type B aortic dissection with an aberrant left vertebral artery and the novel methods used to surgically correct his pathology.

Simple Death Risk Models to Predict In-hospital Outcomes in Acute Aortic Dissection in Emergency Department

Objective

We sought to find a bedside prognosis prediction model based on clinical and image parameters to determine the in-hospital outcomes of acute aortic dissection (AAD) in the emergency department.

Methods

Patients who presented with AAD from January 2010 to December 2019 were retrospectively recruited in our derivation cohort. Then we prospectively collected patients with AAD from January 2020 to December 2021 as the validation cohort. We collected the demographics, medical history, treatment options, and in-hospital outcomes. All enrolled patients underwent computed tomography angiography. The image data were systematically reviewed for anatomic criteria in a retrospective fashion by three professional radiologists. A series of radiological parameters, including the extent of dissection, the site of the intimal tear, entry tear diameter, aortic diameter at each level, maximum false lumen diameter, and presence of pericardial effusion were collected.

Results

Of the 449 patients in the derivation cohort, 345 (76.8%) were male, the mean age was 61 years, and 298 (66.4%) had a history of hypertension. Surgical repair was performed in 327 (72.8%) cases in the derivation cohort, and the overall crude in-hospital mortality of AAD was 10.9%. Multivariate logistic regression analysis showed that predictors of in-hospital mortality in AAD included age, Marfan syndrome, type A aortic dissection, surgical repair, and maximum false lumen diameter. A final prognostic model incorporating these five predictors showed good calibration and discrimination in the derivation and validation cohorts. As for type A aortic dissection, 3-level type A aortic dissection clinical prognosis score (3ADPS) including 5 clinical and image variables scored from −2 to 5 was established: (1) moderate risk of death if 3ADPS is <0; (2) high risk of death if 3ADPS is 1–2; (3) very high risk of death if 3ADPS is more than 3. The area under the receiver operator characteristic curves in the validation cohorts was 0.833 (95% CI, 0.700–0.967).

Conclusion

Age, Marfan syndrome, type A aortic dissection, surgical repair, and maximum false lumen diameter can significantly affect the in-hospital outcomes of AAD. And 3ADPS contributes to the prediction of in-hospital prognosis of type A aortic dissection rapidly and effectively. As multivariable risk prediction tools, the risk models were readily available for emergency doctors to predict in-hospital mortality of patients with AAD in extreme clinical risk.

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.

Thoracic endovascular aortic repair of highly tapered type B aortic dissection with proximal tapered stent grafts and distal restrictive stent grafts

OBJECTIVES

This study evaluated aortic remodeling in highly tapered type B aortic dissection (TBAD) patients who underwent thoracic endovascular aortic repair (TEVAR) with a proximal tapered stent graft plus a distal restrictive stent graft to maximize thoracic coverage while avoiding distal excessive oversizing.

METHODS

Thirty-four patients presenting with highly tapered TABD were randomized to restricted TEVAR (r-TEVAR) and standard TEVAR groups. Highly tapered TBAD was defined as the maximal diameter of the true lumen at proximal and distal thoracic aorta landing zone tapers greater than 8 mm or taper ratio greater than 20%. Patients in the r-TEVAR group underwent proximal tapered stent grafts plus distal restrictive stent grafts to match the taper ratio of the descending thoracic aorta (DTA) and extend the length of stent coverage. Patients in the standard TEVAR group underwent proximal tapered stent grafts implantation without distal restrictive stent grafts. Aortic remodeling was estimated by computed tomography angiography (CTA) during the follow-up.

RESULTS

In total, 16 patients underwent r-TEVAR, and 18 patients underwent standard TEVAR. The taper ratio of the stent graft matched the DTA in the r-TEVAR group (24.7±3.4% vs. 27.3±4.2%, P=0.068) but did not match that in the standard TEVAR group (13.5±3.3% vs. 30.5±9.6%, P<0.001). The length of stent graft coverage in the r-TEVAR group was longer than that in the standard TEVAR group (220.4±21.1 mm vs. 175.3±17.8 mm, P<0.001). Compared with the standard TEVAR group, the r-TEVAR group had better complete remodeling of the DTA at 6 months (40% vs. 5.6%, P=0.03), 12 months (60% vs. 16.7%, P=0.027) and 24 months (78.6% vs. 41.2%, P=0.036) after the operation. There was no difference in the cumulative survival rate between the r-TEVAR and standard TEVAR groups (P=0.166).

CONCLUSIONS

r-TEVAR with overlapping proximal tapered stent grafts and distal restrictive stent grafts can match the taper of highly tapered TABD, extend the length of stent graft coverage, and lead to better remodeling of the DTA than standard TEVAR.

Computational Prediction of Thrombosis in Food and Drug Administration's Benchmark Nozzle

Thrombosis seriously threatens human cardiovascular health and the safe operation of medical devices. The Food and Drug Administration’s (FDA) benchmark nozzle model was designed to include the typical structure of medical devices. However, the thrombosis in the FDA nozzle has yet not been investigated. The objective of this study is to predict the thrombus formation process in the idealized medical device by coupling computational fluid dynamics and a macroscopic hemodynamic-based thrombus model. We developed the hemodynamic-based thrombus model by considering the effect of platelet consumption. The thrombus model was quantitatively validated by referring to the latest thrombosis experiment, which was performed in a backward-facing step with human blood flow. The same setup was applied in the FDA nozzle to simulate the thrombus formation process. The thrombus shaped like a ring was firstly observed in the FDA benchmark nozzle. Subsequently, the accuracy of the shear-stress transport turbulence model was confirmed in different turbulent flow conditions. Five scenarios with different Reynolds numbers were carried out. We found that turbulence could change the shape of centrosymmetric thrombus to axisymmetric and high Reynolds number blood flow would delay or even prevent thrombosis. Overall, the present study reports the thrombosis process in the FDA benchmark nozzle using the numerical simulation method, and the primary findings may shed light on the effect of turbulence on thrombosis.

Acute or Subacute, the Optimal Timing for Uncomplicated Type B Aortic Dissection: A Systematic Review and Meta-Analysis

Objective

To evaluate the optimal timing (acute or subacute) of thoracic endovascular aortic repair (TEVAR) for uncomplicated B aortic dissection (uTBAD) through a systematic review and meta-analysis.

Method

A comprehensive literature search was undertaken across three major databases (EMBASE/Medline, PubMed, and Cochrane Library) and was assessed until November 2021 to identify studies reporting the outcomes of TEVAR utilized to treat patients with uTBAD. The continuous variables were compared between the two groups using t-test and the categorical variables were compared using the χ2-test. A meta-analysis was used to produce pooled odds ratios for early and follow-up outcomes. The random effects models were applied. A statistical analysis was performed using R software v.4.1.

Result

A comprehensive literature search found 490 citations published within the predetermined time span of the analysis. Three studies including 1,193 patients (acute group 718, subacute group 475) were finally included for downstream meta-analysis. An acute uTBAD group presented with higher rates both in 30-day complications (20.5 vs. 13.7%; p = 0.014) and mortality (4.6 vs. 1.3%; p = 0.004) than subacute group. The respiratory complications were significantly higher in the acute group than in the subacute group (10.8 vs. 5.0%; p = 0.015). The procedure success rate (90.8 vs. 93.6%; p = 0.329), the follow-up mortality (7.7 vs. 7.6%; p = 1) and dissection-related late mortality (3.9 vs. 5.3%; p = 0.603) showed no significant difference.

Conclusion

Our meta-analysis suggested that despite significantly higher 30-day complications and 30-day mortality in the acute uTBAD group, there was no significant difference in the follow-up mortality between the two groups.

Systematic Review Registration

PROSPERO, identifier: CRD42021247609.

Time-dependent mechanical behaviour of the aortic chronic dissection flap

OBJECTIVES

The transition of aortic dissection from acute to chronic is poorly understood. We examined time-dependent mechanical behaviour and biochemical properties of chronic dissection tissues.

METHODS

Aorta samples were obtained from 14 patients with mixed aetiology who were undergoing elective surgery for chronic dissected aneurysms, ranging from 3 months to 15 years post-dissection. The tissue elastic modulus and tissue deformation following application of loading for 5 h were measured for the false lumen (FL), true lumen (TL) and flap (FP) tissues with a custom-indentation technique. Collagen, elastin and glycosaminoglycan levels were determined with established biochemical assays. Elastin fragmentation was graded from histological sections. The number of tissues characterized was as follows: FP (n = 10), TL (n = 5 for biomechanical testing, n = 8 for biochemical analysis, n = 8 for histological assessment) and FL (n = 4).

RESULTS

Tissues stiffness was highest in FP [59.8 (14.8) kPa] as compared with TL [50.7 (6.2) kPa] and FL [40.5 (4.7) kPa] (P = 0.023 and P = 0.006, respectively). FP [0.5 (0.08) mm] also exhibited reduced deformation relative to TL [0.7 (0.02) mm] and FL [0.9 (0.08) mm] (P = 0.003 and P = 0.006, respectively), lowest collagen concentration [FP: 40.1 (19.6) µg/mg, TL: 59.9 (19.5) µg/mg, P = 0.008; FL: 79.1 (32.0) µg/mg, P = 0.006] and the lowest collagen: elastin ratio [0.4 (0.1)] relative to the other tissues [TL; 0.6 (0.3), P = 0.006, FL; 1.5 (0.4); P = 0.003]. Significant elastin loss was evident in the FL-stained tissue sections whereas highly aligned, long fibres were visible in the FP and TL. A linear relationship was found between the stiffness, deformation and the time from the dissection event to surgical intervention for the FP. All data are presented as median (interquartile range).

CONCLUSIONS

FP exhibited reduced time-dependent deformation and distinct biochemical properties relative to TL and FL irrespective of connective tissue disorder or the anatomical region of the dissection.

Red Blood Cell Distribution Width: A Prognostic Marker in Patients With Type B Aortic Dissection Undergoing Endovascular Aortic Repair

Background

Red blood cell distribution width (RDW) is associated with cardiovascular mortality. However, the relationship between preoperative RDW and outcomes after thoracic endovascular aortic repair (TEVAR) in type B aortic dissection (TBAD) remains to be determined.

Methods

We review the records of 678 patients with TBAD and treated with TEVAR in three centers. Patients were divided into two groups according to the admission RDW cut-off by receiver operating characteristic curve analysis [≤13.5% (n = 278) and >13.5% (n = 400)]. The association between RDW and long-term mortality was evaluated using Cox survival analysis. Additionally, we used general additive models (GAM) with restricted cubic splines (RCS) to explore non-linear relationships between RDW and outcomes.

Results

Subjects with a high RDW had significantly higher in-hospital mortality rates (1.4 vs. 4.3%, P = 0.038). A total of 70 subjects died after a median follow-up period of 3.3 years. Kaplan–Meier analysis showed that subjects with an RDW >13.5% had worse survival rates than those with lower RDW values (P < 0.001). Multivariate Cox proportional hazard modeling revealed that an RDW >13.5% was an independent predictor of long-term mortality (adjusted HR = 2.27, P = 0.006). Also, we found that there was a non-linear relationship between RDW and mortality from RCS, and RDW of 13.5% might be an inflection point to distinguish the long-term mortality risk of TBAD patients.

Conclusion

As an inexpensive and routinely measured parameter, RDW holds promise as a novel prognostic marker in patients with TBAD receiving TEVAR. We found that an RDW >13.5% on admission was independently associated with increased long-term mortality.

Long-term Thoracic Endovascular Repair follow-up from 1999-2019 - a Single-Center Experience

INTRODUCTION

Thoracic endovascular aortic repair (TEVAR) was introduced in the early 1990's, and long-term follow-up studies are warranted in current guidelines.

METHODS

Patients undergoing TEVAR were consecutively included from 1999-2019. Thoracic aortic disease includes thoracic aortic aneurysms, aortic dissection, traumatic rupture, penetrating aortic ulcer (PAU) and intramural hematoma (IMH). Our prospective database recorded baseline characteristics, endoleak or aneurysm growth and death. Patients were included at time of treatment and censored at death, or first reintervention depending on the analysis. Primary endpoint was all-cause death, secondary endpoint was reintervention. Survival and failure analysis were done using StataIC 16.0® and truncated at 15 years of follow-up.

RESULTS

256 patients were included - 63% were men. Their mean age at intervention was 66.2 ± 14.5 years and they were followed for a mean of 5.2 ± 4.5 years. Indications for TEVAR were acute aortic syndrome 40.6%, chronic aortic disease 44.5%, and traumatic rupture in 14.8 %. Technical success was seen in 94.1 % of the operations, and the left subclavian artery was covered in 27.7%. 30-day mortality rate was 21.2% (22/104) and 1.75% (2/114) (p<0.001) for urgent and elective patients, respectively. Twelve patients (4.7%) died within 24 hours of treatment. Overall, long-term mortality recorded112 (43,8%) deaths, 29 patients had reinterventions (11.3 % (95% confidence interval: 7.7-15.9)), aneurysms accounted for 62.1% of all reinterventions. 24 (82.8%) reinterventions occurred within the first 5 years.

CONCLUSION

This long-term follow-up study shows excess mortality in patients treated for acute aortic syndrome compared to chronic aortic disease, within the first 30 days, this difference diminishes at the end of follow-up. Most endoleak occur within the first five years, though new endoleak continue to develop decades after in previous endoleak-free patients calling for lifelong surveillance.

5-Year Follow-Up of Endovascular Management in a Patient with Chronic Concomitant DeBakey Type II and IIIa Aortic Dissection

The incidence of chronic concomitant DeBakey Type II and IIIa aortic dissection is uncommon and complex. Since the mortality rate is very high, it requires a precise and holistic treatment plan. In some cases, when the patients refuse to undergo open surgery or the patients' condition is not suitable for open surgery, thoracic endovascular aortic repair (TEVAR) is the recommended therapeutic approach. In this case, a patient refused to undergo open surgery and chose TEVAR instead. The patient survived the procedure and lived for years. We present the case of a successful TEVAR procedure in a patient with chronic concomitant DeBakey Type II and IIIa aortic dissection in a 51-year-old man and the 5-year postoperative follow-up of the patient's condition.

False lumen thrombus following aortic dissection diagnosed as the source of repeat lower extremity emboli with angioscopy: a case report

Background

Acute arterial embolization caused by a free-floating thrombus of the false lumen after surgery for acute aortic dissection is a rare complication; hence, determining its cause may be difficult. We report a case in which angioscopy was valuable in diagnosing and treating the unstable thrombus within the false lumen.

Case presentation

The patient was a 71-year-old woman who underwent hemiarch replacement for Stanford type A acute aortic dissection. Two months after the operation, left renal infarction occurred. Eighteen months after the operation, the patient visited the hospital for treatment of intermittent claudication of her left leg. Computed tomography (CT) showed occlusion below the left common femoral artery. Surgical thrombectomy was performed for acute lower extremity arterial occlusion. One month later, thrombectomy was performed again for the same phenomenon and again after 2 months. She had no history of cardiac arrhythmia. No obvious source for the repeat embolization could be found on echocardiography or enhanced CT. Angiography was performed to further identify the cause, revealing a new entry site at the distal anastomosis, which exhibited antegrade flow into the false lumen. Furthermore, selective false lumen angiography via the re-entry revealed a thrombus in the false lumen corresponding to the descending aorta. A non-obstructive angioscopy system in the false lumen revealed a free-floating thrombus. As the patient had undergone multiple surgeries over a short period and desired minimally invasive treatment, coil embolization of the new entry site as well as false lumen was performed. As a result, blood flow from the true to the false lumen resolved. More than 1 year has passed following coil embolization with no signs of embolism.

Conclusions

We experienced a case of repeat embolism caused by unstable thrombus formation in the false lumen resulting from antegrade blood flow in the false lumen secondary to development of a new entry site. Angioscopy revealed that this antegrade flow caused formation of an unstable thrombus which caused recurrent acute lower extremity arterial occlusion. Therefore, angioscopy may be a useful option for the diagnosis of false lumen thrombosis.

Initial Study of the Extended STABILISE Technique for Complete Remodeling in Aortic Dissection

OBJECTIVES

Thoracic endovascular aortic repair (TEVAR) is the standard treatment for acute complicated type B aortic dissection (TBAD). However, long-term results reveal that TEVAR does not achieve a complete aortic remodeling and poses a risk of aneurysmal aortic degeneration. Distal reentry treatment at the abdominal level seems to be necessary to obtain a complete remodeling in TBAD. Moreover, it is necessary to treat the aortoiliac bifurcation in patients with persistent true lumen collapse or limb ischemia.

METHODS

Between January 2018 and October 2019, 11 patients with acute or sub-acute complicated TBAD or non-A non-B aortic dissection were treated in our institution in an endovascular fashion. We performed the stent-assisted balloon-induced intimal disruption and relamination in aortic dissection repair (STABLISE) technique in all cases, but two cases required complementary treatment of the aortoiliac bifurcation with a bifurcated AFX endograft system for limb ischemia due to true lumen collapse.

RESULTS

Technical success was obtained in all patients. No procedural complications occurred. No postoperative deaths, stroke, paraplegia, mesenteric, or renal ischemia were observed, and no secondary intervention was necessary. Satisfactory aortic remodeling was obtained after the follow-up periods with a 57.5% mean true lumen expansion.

CONCLUSION

Our initial experience using the extended STABILISE (e-STABILISE) technique using a bifurcated AFX endograft did not result in any postoperative mortality or complications. Without additional data, this technique should be reserved for specific patients who require revascularization of the aortoiliac bifurcation.

Systematic review and meta-analysis of current evidences in endograft therapy versus medical treatment for uncomplicated type B aortic dissection

OBJECTIVE

Best medical therapy (BMT) should be recommended for treating uncomplicated Stanford type B aortic dissection (uSTBAD), whereas thoracic aortic endovascular repair (TEVAR) has been controversial for uSTBAD.

METHODS

In this paper, a meta-analysis was conducted on all available randomized controlled trials and observational studies that evaluated the relative benefits and harms of TEVAR and BMT for the management of patients suffering from uSTBAD. Primary endpoints consisted of early adverse events, long-term adverse events and aortic remodeling. In addition, Risk difference (RD) or Odds ratios (OR) with 95% confidence intervals (CI) were estimated. The random effects model or the fixed-effects model was used in accordance with the 50% heterogeneity threshold.

RESULTS

Seven observational studies and two RCT studies from 11 articles that contained 15066 patients suffering from uSTBAD (1518 TEVARs) met the inclusion criteria. For early outcomes, no significant differences were found between the TEVAR group and the BMT group in aortic rupture, retrograde dissection, paraplegia/paraparesis, reintervention, aorta-related death and all caused death. In the long run, the TEVAR group was found to have a significantly lower incidence of adverse events, which included aortic rupture (OR:0.26, CI:0.16∼0.42, P<0.05; heterogeneity: P=0.90, I²=0%), reintervention (OR:0.45, CI:0.26∼0.75, P<0.05; heterogeneity: P=0.17, I²=41%), aorta-related death (OR:0.27, CI:0.18∼0.42, P<0.05; heterogeneity: P=0.61, I²=0%) and all caused death (OR:0.52, CI:0.42∼0.66, P<0.05; heterogeneity: P=0.05, I²=53%) as compared with the BMT group. Moreover, in compared with BMT, TEVAR was found to significantly contribute to the complete thrombosis of thoracic false lumen (OR:55.34, CI:34.32∼89.21, P<0.05; heterogeneity: P=0.97, I²=0%) and aortic regression (true lumen expansion and false lumen shrinkage).

CONCLUSIONS

Although early endovascular repair of uSTBAD does not outperform BMT, its implementation is found to be necessary to facilitate the long-term prognosis. Accordingly, if early TEVAR is to be deferred, close follow-up is critical to allow for timely reintervention.

Long-Term Aortic Remodeling After Thoracic Endovascular Aortic Repair of Acute, Subacute, and Chronic Type B Dissections

Objective

This study aimed to investigate the characteristics and predictors of aortic remodeling over a long-term follow-up period after thoracic endovascular aortic repair (TEVAR) for acute, subacute, and chronic type B aortic dissections (TBADs).

Methods

Patients who underwent TEVAR for TBAD from July 2011 to December 2013 were included, and relevant data were retrospectively analyzed.

Results

After TEVAR, the true lumen (TL) dimension increased and the false lumen (FL) dimension decreased or did not change over a 5-year follow-up period in all three temporal groups. Shrinkage proportion of the thoracic aorta was the highest in the subacute group (acute, 28.1%; subacute, 39.1%; and chronic, 17.4%; p = 0.048), while abdominal expansion showed no significant differences among the groups (acute, 29.6%; subacute, 40.5%; and chronic, 44.4%; p = 0.502). The chronic group had a rate of complete FL regression, which is lower than the subacute or acute group at all anatomic sections, with significant differences only in the stented section (chronic, 21.7%; acute, 92.2%; and subacute, 80.4%; p < 0.05) and in the distal thoracic aortic section (chronic, 13.0%; acute, 31.1%; and subacute, 50.0%; p < 0.05). Logistic regression analysis demonstrated that chronic dissection, TL compression, endoleak, the number of branches from FL, and the number of residual tears affected optimal FL remodeling.

Conclusion

The present study provides data on aortic remodeling of TBAD after TEVAR during a long-term follow-up period. The features and risk factors of aortic remodeling in the acute, subacute, and chronic phases are different in different aortic segments. These findings may have implications in the timing of TEVAR.

Zone 2 hybrid thoracic endovascular aortic repair: Is it a good option for all types of thoracic aortic disease?

BACKGROUND

Zone 2 thoracic endovascular aortic repair (TEVAR) is performed for the treatment of various thoracic aortic diseases involving the left subclavian artery. This study aimed to analyze the late clinical outcomes of zone 2 hybrid TEVAR according to the various indications.

METHODS

A total of 48 patients who underwent zone 2 TEVAR at our institution between December, 2010 and July, 2020 were enrolled. The indications were aortic aneurysm (AA, n = 15), acute type B aortic dissection (AD, n = 14), penetrating aortic ulcer (PAU, n = 8), traumatic aortic injury (TAI, n = 8), and others (n = 3). The clinical outcomes including early complications and mid-term aortic measurements were retrospectively reviewed.

RESULTS

The technical success rate was 100% and in-hospital mortality occurred in one patient. The early postoperative complications included stroke (n = 1), transient spinal cord ischemia (n = 1), neck wound hematoma (n = 1), and left phrenic or vagus nerve injury (n = 9). In patients with AD, positive remodeling was observed in ten patients (76.9%) (false lumen regression in the entire or thoracic aorta [n = 9], false lumen thrombosis in the thoracic aorta [n = 1]). However, in patients with AA, increased aneurysm was found in six patients (40%). Persistent aneurysmal growth was found in patients with a maximal aortic diameter of > 60 mm on initial imaging (4/6, 50%). No aortic expansion was observed in those with TAI or PAU. Endoleak was noted in five patients (10.4%), and among them, aortic reintervention was required only in patients with large AAs.

CONCLUSIONS

Zone 2 hybrid TEVAR was associated with an acceptable early complication rate and provided acceptable mid-term aortic results for patients with AD, PAU, and TAI. However, patients with large AAs were at increased risk of aortic reintervention. In cases of large AA, clinicians should carefully consider whether zone 2 hybrid TEVAR or open surgical repair will be more effective for the patient.

The impact of dissection membrane motility on mid-term aortic remodelling after thoracic endovascular repair

OBJECTIVES

The aim of this study was to assess preoperative dissection flap motility and to evaluate its impact on the aortic remodelling and the development of distal stent-induced new entry after thoracic endovascular aneurysm repair (TEVAR)/frozen elephant trunk (FET).

METHODS

Patients with primary or residual type B dissections were included in a retrospective study with transoesophageal echocardiography analysis of the preoperative dissection flap motility assessed by the true lumen (TL) strain. Three-dimensional computing tomography centreline reconstructions before TEVAR/FET and during the follow-up were conducted to measure aortic remodelling: false lumen thrombosis, TL expansion and aortic diameters at 10 and 20 cm downstream the left subclavian artery, at the coeliac trunk and in the infrarenal aorta. All continuous variables are reported as median with first and third quartiles.

RESULTS

Fifty-six consecutive patients were treated with TEVAR (n = 45) or FET (n = 11) in the acute (n = 16), subacute (n = 16) and chronic (n = 24) dissection phase. At a median follow-up of 6 (3-12) months, they showed a favourable TL expansion in the descending aorta, significantly higher in the acute [+9 mm (5-12); P < 0.001] and subacute groups [+5 mm (3-8); P = 0.039] than in the chronic group [+2 mm (0-5)]. The dissection flap motility parameter TL strain was superior in the acute (P = 0.006) and subacute (P = 0.035) groups in comparison to the chronic group. The motile flap [TL strain >22.5% (median)] was associated with a higher TL expansion rate in the thoracic aorta (P = 0.009) and a comparable distal stent-induced new entry incidence (overall: 16%) in comparison to the immobile flap (P = 0.89).

CONCLUSIONS

The intraoperative assessment and the inclusion of the dissection flap motility parameters in the decision-making during TEVAR/FET may refine the distal endograft sizing for an improved remodelling of the TL.

1-Year Outcomes of a Multicenter Randomized Controlled Trial of the Ankura II Thoracic Endoprosthesis for the Endovascular Treatment of Stanford Type B Aortic Dissections

Background

The Ankura II Thoracic Stent Graft System (Lifetech, Shenzhen, China) is an evolution of the Ankura stent graft. This study reports one-year outcomes of the Ankura II Thoracic Stent Graft System for endovascular treatment of Stanford type B aortic dissections.

Methods

The Ankura II Thoracic Aortic Endovascular Trial was a randomized, single-blinded, clinical trial conducted at 12 Chinese institutes. The enrolled patients diagnosed with Stanford type B aortic dissections (TBADs) were randomly assigned to the Ankura group or Ankura II group. Standard follow-up examinations were performed at 1, 6, and 12 months. Safety and efficacy data were analyzed.

Results

132 patients with TBADs were enrolled. The outcomes for the primary safety end points revealed that the Ankura II stent graft was statistically non-inferior compared to the Ankura stent graft. The 1-month device-related major adverse events (1.6 vs. 0%; p = 0.48), 1-month all-cause mortality (1.7 vs. 4.5%; p = 0.621), 12-month survival rate (95.2 ± 2.7% vs. 94.1 ± 2.9%; p = 0.769), and major adverse event (MAE) rate (5.1 vs. 4.7% at 1 month; p = 0.73 and 5.8 vs. 8.9% at 12 months; p = 0.718) of Ankura II group are all comparable to Ankura group. The two groups showed similar primary effectiveness and true lumen expansion effect, and false lumen remodeling was improved in Ankura II group (−100.0 vs. −48.5%; p = 0.08).

Conclusions

The one-year outcomes from this prospective, randomized, multicenter study demonstrate that Ankura II stent graft shows comparable results to Ankura for treating TBADs, resulting in low mortality rates, MAEs and reintervention rates.

Clinical Trial Registration

ChiCTR-TRC-12002844.

Aortic Visceral Segment Instability is evident following Thoracic Endovascular Aortic Repair for Acute and Subacute Type B Aortic Dissection

BACKGROUND

Anatomic remodeling within the thoracic aorta following thoracic endovascular aortic repair (TEVAR) for type B aortic dissections (TBAD) has been well documented, but less is known about the response of the untreated visceral aorta. This study aims to investigate visceral aortic behavior following TEVAR for acute or subacute TBAD and identify associations with clinical outcomes.

METHODS

A multi-center retrospective review was performed of all imaging for all patients treated with TEVAR for acute (0-14 days) and subacute (14-90 days) non-traumatic TBAD between 2006-2020. Cohort was inclusive of uncomplicated, high-risk, and complicated (defined per SVS reporting guidelines) dissections. Centerline aortic measurements of the true and false lumen and total aortic diameter (TAD) were taken at standardized locations relative to aortic anatomy within each aortic zone (zones defined by SVS reporting guidelines). Diameter changes over time were evaluated using repeated measures mixed effects linear growth modeling. Visceral segment instability (VSI) was defined as any growth in TAD ≥ 5mm within aortic zones 5 through 9.

RESULTS

A total of 82 patients were identified. Median length of imaging follow-up was 2.1 years (IQR 3.9 years), with 15% of the cohort having follow-up longer than 5 years. VSI was present in 55% of the cohort, with an average maximal increase in TAD of 10.4±6.3 mm over a median follow-up of 2.1 years (IQR 3.9 years). Roughly a third of the cohort experienced rapid VSI (growth ≥5mm in first year), and 4.8% of the cohort developed a large para-visceral aneurysm aortic (TAD≥5cm) secondary to VSI. Linear growth modeling identified significant predictable growth in TAD across all visceral zones. Zones 7 had the highest rate of TAD dilation, with a fixed effect estimated rate of 1.3 mm per year (95%-CI 0.23-2.1, p=0.022). The preoperative factor most strongly associated with VSI was ≥6 cumulative number of zones dissected (OR 6.4, 95% OR 1.07-8.6, p=0.041). Odds for aortic reintervention were significantly increased in cases where VSI led to development of a para-visceral aortic aneurysm ≥5cm development (OR 3.7, 95%-CI 1.1-13, p=0.038).

CONCLUSION

VSI was identified in the majority of patients treated with TEVAR for management of acute and subacute TBAD. Preoperative anatomic features such as extent of dissection, rather than procedural details of graft coverage, may play a more significant role in VSI occurrence. Importantly, significant TAD growth occurred in all visceral segments. These results highlight the importance of lifelong surveillance following TEVAR, and identify a subset of patients that may be at increased risk for re-intervention.

The Impact of Local vs. General Anesthesia in Patients Undergoing Thoracic Endovascular Aortic Surgery

OBJECTIVE

General anesthesia is associated with inherent risks that can be avoided by the use of lesser invasive anesthetic strategies. We hypothesize that examine and compare the use of local or regional anesthesia (LRA to general anesthesia (GA) in patients undergoing thoracic endovascular aortic repair (TEVAR).

METHODS

Patients undergoing TEVAR between 2010-2020 in the Vascular Quality Initiative were analyzed. Exclusion criteria included receipt of branched or physician modified endografts and devices extending distally beyond Zone 5. Patients were categorized as receiving LRA or GA. Center volume was reported by quartile according to annualized TEVAR volume and operative outcomes were compared using appropriate frequentists tests. Univariable and multivariable regression models for anesthesia type and operative outcomes were created to compare unadjusted and adjusted rates of each outcome. Long-term survival was estimated using a Kaplan-Meier survival estimator, while adjusted survival analysis was performed using a Cox proportional-hazards model.

RESULTS

Of the 17,099 patients who underwent TEVAR, 7,299 met the inclusion and exclusion criteria. Of these, 3.8% received LRA. There were no significant differences in the annual proportion of patients who received LRA from 2011 to 2020 (p = 0.49, Chi-square test for trend). Only 18.8% of patients who received LRA were treated at the highest quartile volume centers. Patients who received LRA were older and more comorbid compared to those who received GA. There were no differences in in-hospital mortality (OR = 0.79, 95% CI 0.42 to 1.38, p = 0.44) or composite of any complication (OR = 0.79, 95% CI 0.54 to 1.14, p = 0.22) between patients who received LRA compared to GA. This also applied to patients presenting with rupture. Receipt of LRA was associated with lower odds of post-operative congestive heart failure (OR = 0.19, 95% CI 0.01 to 0.89, p = 0.01) as well as decreased length of ICU (OR = 0.54, 95% CI 0.40 to 0.72, p < 0.01) and hospital length of stay (OR = 0.64, 95% CI 0.46 to 0.84, p < 0.01). LRA was not associated with decreased long-term survival compared to GA (HR 0.95, 95% CI 0.72 to 1.25, p = 0.72).

CONCLUSION

Despite a greater number of baseline comorbidities, patients undergoing TEVAR with LRA experienced shorter ICU and post-operative lengths of stay, with similar operative outcomes and long-term survival compared to patients who received GA.. Similar findings were found amongst the rupture cohort. LRA should be considered more frequently in select patients undergoing TEVAR.

Utility of 4D Flow MRI in Thoracic Aortic Diseases: A Literature Review of Clinical Applications and Current Evidence

Despite the recent technical developments, surgery on the thoracic aorta remains challenging and is associated with significant mortality and morbidity. Decisions about when and if to operate are based on a balance between surgical risk and the hazard of aortic rupture. These decisions are sometimes difficult in elective cases of thoracic aortic diseases, including aneurysms and dissections. Abnormal wall stress derived from flow alterations influences disease progression. Therefore, a better understanding of the complex hemodynamic environment inside the aortic lumen will facilitate patient-specific risk assessments of complications, which enable clinicians to provide timely prophylactic interventions. Time-resolved 3D phase-contrast (4D flow) MRI has many advantages for the in vivo assessment of flow dynamics. Recent developments in 4D flow imaging techniques has led to significant advances in our understanding of physiological flow dynamics in healthy subjects and patients with thoracic aortic diseases. In this clinically focused review of thoracic aortic diseases, we demonstrate the clinical advances acquired with 4D flow MRI from published studies. We provide a systematic overview of key evidences and considerations regarding normal thoracic aortas, thoracic aortic aneurysms, aortic dissections, and thoracic aortas with prosthetic graft replacement.