Preoperative thoracic false lumen branches are predictors of aortic enlargement after stent grafting for DeBakey IIIb aortic dissection

Right thoracotomy approach for the management of uncommon type II endoleak after thoracic endovascular aortic repair

An 80-year-old male with a ruptured pseudoaneurysm after aortic dissection repair underwent thoracic endovascular aneurysm repair. The aneurysm expanded from 43 mm to 89 mm over 4 years because of type II endoleak, with computed tomography angiography revealing a patent right intercostobronchial trunk and left bronchial artery on the lesser curvature of the aortic arch. These arteries were successfully dissected via right thoracotomy. During the 2-year postoperative period, the aneurysm remained stable at 80 mm. Open surgical management of the culprit vessel may be effective for type II endoleaks following thoracic endovascular aneurysm repair when endovascular approaches are challenging.

Complete Endovascular Repair of Entire Aorta for Extensive Pathologies - A Set of China Strategies

BACKGROUND

Endovascular aortic repair was introduced in China in 1997, with domestically produced devices emerging post-2000. Despite progress, treatment of complex aortic pathologies remains limited, necessitating innovative endovascular solutions.

METHODS

Our center developed 8 off-the-shelf endovascular innovations, including 3 inner branch stent graft systems for aortic arch reconstruction, 2 branched/fenestrated stent grafts for thoracoabdominal and juxtarenal aortic aneurysms, 1 iliac branch device for internal iliac artery preservation, and 2 novel devices-EndoPatch and EndoSeal (Endonom Medtech)-designed to seal distal tears and occlude false lumen in aortic dissections. These advancements integrate technologies such as steerable delivery systems, preloaded navigation aids, and mixed or inner branch configurations to accommodate anatomical variations.

RESULTS

Preliminary clinical applications demonstrated promising technical success rates and acceptable complication profiles. Two devices have been approved by China's National Medical Products Administration for clinical use, while others remain under investigation. Key challenges include anatomical variability, branch vessel patency concerns, and the absence of long-term outcomes for most devices.

CONCLUSION

These innovations establish a comprehensive endovascular strategy for extensive aortic pathologies, addressing critical gaps in China's device landscape. Early outcomes demonstrate the feasibility of standardized off-the-shelf solutions for complex anatomies, though multicenter trials and long-term follow-up remain essential to confirm safety and efficacy.

Aortic Remodeling After False Lumen Embolization in Aortic Dissection

Background/Objectives: Retrograde false lumen perfusion after thoracic endovascular aortic repair (TEVAR) can compromise positive remodeling and clinical outcomes. The aim of this study is to describe the feasibility and outcomes of a false lumen thrombosis technique. Methods: A single-center, retrospective analysis of patients between January 2017 and January 2022 who underwent TEVAR in conjunction with false lumen embolization. Results: Twelve patients (83% type A, 17% type B; 33% with frank rupture; mean age 65 years; eleven men) underwent 13 false lumen embolization procedures with a 92% technical success rate and a 100% clinical success rate. Positive aortic remodeling was observed in all the patients. The maximum thoracic aortic diameter remained stable (p = 0.526) but the true lumen increased from 22 to 33 mm (p = 0.009) and the false lumen decreased from 41 to 20 mm (p = 0.076) after a median follow-up of 31 months. Conclusions: False lumen embolization using the candy-plug is safe and promotes positive aortic remodeling.

Exploring hemodynamic mechanisms and re-intervention strategies for partial false lumen thrombosis in Stanford type B aortic dissection after thoracic aortic endovascular repair

OBJECTIVES

False lumen (FL) thrombosis status for Stanford type B aortic dissection (TBAD) after thoracic endovascular aortic repair (TEVAR) is critical for evaluating aortic remodeling and long-term prognosis. This study aimed to monitor the morphology evolution of partial FL thrombosis (PFLT) and its hemodynamic conditions through an innovative approach, providing a re-intervention strategy from both morphologic and hemodynamic perspectives.

METHODS

Three-dimensional geometries are extracted from a five-year follow-up of CTA images for TBAD after TEVAR. The morphology and hemodynamics of PFLT are comprehensively analyzed based on patient-specific reconstructions and computational fluid dynamics (CFD). The impact of various strategies treating risk factors of PFLT, including proximal entry closure, left renal artery stenting, or accessory renal artery embolism on hemodynamics is assessed.

RESULTS

The introduced morphologic approaches appropriately reflected the evolution of PFLT. Gradual dilation of FL (surface area from 82.63cm2 to 98.84cm2, volume from 45.12 mL to 63.40 mL, increase in distal tear (from 3.72 cm to 4.32 cm), and fluctuation of thrombosis-blood lumen boundary are observed. For further surgical preparation in the absence of unanimously recognized re-intervention indicators, velocity and wall shear stress distributions reveal different simulated re-interventions have distinctly suppressive effects on hemodynamic conditions within the PFLT, providing valuable insights for further surgical preparation.

CONCLUSIONS

The present study demonstrates a re-intervention strategy for PFLT in TBAD patients after TEVAR utilizing morphologic and hemodynamic analyses. Acknowledging the deterioration of PFLT may result in adverse long-term outcomes, this strategy might offer an alternative approach for clinical monitoring and management of related patients.

Amplatzer Vascular Plug With Endologix AFX Lining for Visceral Re-Entry Closure in a Patient With Chronic Type B Aortic Dissection

PURPOSE

To demonstrate the efficacy of a combination of Amplatzer vascular plug (AVP2) and Endologix AFX for a visceral entry closure.

CASE REPORT

A 70-year-old woman with treated chronic type B aortic dissection was seen to have sac enlargement. An isolated residual tear was observed at the origin of the celiac artery. A 12 mm AVP2 was successfully deployed for the entry closure. Angiography after the plug deployment still demonstrated residual flow to the false lumen. Hence, an Endologix AFX VELA proximal endograft was deployed, covering the AVP membrane and leaving no endoleak.

CONCLUSION

Deployment of a vascular plug with Endologix AFX lining was efficacious for securing complete closure of an entry tear at the origin of the celiac artery in our patient.

CLINICAL IMPACT

Vascular plugs are reported to be effective for closing small entries, although their effectiveness is limited when the entry site is not located on the flat intima, or in a high-flow situation. In the presented case, an isolated entry tear at the origin of the celiac artery was successfully closed with a vascular plug following Endologix AFX stent-graft lining of the true lumen.

The Influence of Minor Aortic Branches in Patient-Specific Flow Simulations of Type-B Aortic Dissection

Type-B aortic dissection (TBAD) is a disease in which a tear develops in the intimal layer of the descending aorta forming a true lumen and false lumen (FL). Because disease outcomes are thought to be influenced by haemodynamic quantities such as pressure and wall shear stress (WSS), their analysis via numerical simulations may provide valuable clinical insights. Major aortic branches are routinely included in simulations but minor branches are virtually always neglected, despite being implicated in TBAD progression and the development of complications. As minor branches are estimated to carry about 7-21% of cardiac output, neglecting them may affect simulation accuracy. We present the first simulation of TBAD with all pairs of intercostal, subcostal and lumbar arteries, using 4D-flow MRI (4DMR) to inform patient-specific boundary conditions. Compared to an equivalent case without minor branches, their inclusion improved agreement with 4DMR velocities, reduced time-averaged WSS (TAWSS) and transmural pressure and elevated oscillatory shear in regions where FL dilatation and calcification were observed in vivo. Minor branch inclusion resulted in differences of 60-75% in these metrics of potential clinical relevance, indicating a need to account for minor branch flow loss if simulation accuracy is sought.

Fate and Consequences of the False Lumen after TEVAR in Type B Aortic Dissection

BACKGROUND

Type B aortic dissection (TBAD) occurs due to an entry tear in the intimal layer of the aorta distal to the origin of the left subclavian artery where blood enters the newly formed false lumen (FL) and extends distally or proximally to form a dissection over an indeterminate length of the aorta which, over time, may eventually rupture. Thoracic endovascular aortic repair (TEVAR) aims to seal off the entry tear proximally with the stent-graft, occluding the origin of the dissection and excluding the FL. Nevertheless, in some cases, the perfusion to the FL is maintained, hindering the aortic remodelling process and increasing the risk of aneurysmal degeneration and rupture, particularly in the abdominal aorta where evidence suggest that remodelling is slower. This review examines the long-term effects of a patent or partially thrombosed FL on clinical outcomes following TEVAR in TBAD, also highlighting the pathological processes behind negative aortic remodelling. Another aim of this review is to provide an overview and appraisal of the currently available techniques for managing a patent or partially thrombosed FL to prevent long-term morbidity occurring.

METHODS

A comprehensive literature search was performed using several search engines including PubMed, Ovid, Google Scholar, Scopus, and Embase to identify and extract relevant studies.

RESULTS

Evidence in the literature show that a partially thrombosed FL is more dangerous than a patent FL due to the occlusion of the distal re-entry tears, impeding outflow and increasing mean arterial and diastolic pressures, whereas the latter is decompressed via distal re-entry sites. FL thrombosis and satisfactory remodelling is sometimes achieved in as few as 40% of patients after TEVAR due to the maintained perfusion of the FL either at the level of the thoracic or abdominal aorta. However, although the thoracic aorta is predominantly covered by the TEVAR stent-graft, poorer remodelling and more dilation is seen in the abdominal aorta. Several techniques are available to embolize the FL, including the Provisional Extension to Induce Complete Attachment, Stent Assisted Balloon Induced Intimal Disruption and Relamination in Aortic Dissection Repair, candy-plug, and Knickerbocker techniques.

CONCLUSIONS

The management of TBAD is invariably TEVAR to seal off the proximal entry tear while extending the repair distally to completely exclude the FL. A risk of aortic wall dilatation distal to TEVAR stent-graft remains; hence, regular monitoring and accurate imaging are essential. At present, a patent FL can be treated using a range of different endovascular techniques.

The Necessity to Seal the Re-Entry Tears of Aortic Dissection After TEVAR: A Hemodynamic Indicator

Thoracic endovascular aortic repair (TEVAR) is a common treatment for Stanford type B aortic dissection (TBAD). However, re-entry tears might be found distal to the stented region which transports blood between the true and false lumens. Sealing the re-entry tears, especially for the thoracic tears, could further reduce blood perfusion to the false lumen; however, it might also bring risks by re-intervention or surgery. Wise determination of the necessity to seal the re-entry tears is needed. In this study, patient-specific models of TBAD were reconstructed, and the modified models were established by virtually excluding the thoracic re-entries. Computational hemodynamics was investigated, and the variation of the functional index and first balance position (FBP) of the luminal pressure difference, due to the sealing of the re-entries, was reported. The results showed that the direction of the net flow through the unstented thoracic re-entries varied among cases. Excluding the re-entries with the net flow toward the false lumen may induce the FBP moving distally and the relative particle residence time increasing in the false lumen. This study preliminarily demonstrated that the hemodynamic status of the re-entry tears might serve as an indicator to the necessity of sealing. By quantifying the through-tear flow exchange and shift of FBP, one can predict the hemodynamic benefit by sealing the thoracic re-entries and thus wisely determine the necessity of further interventional management.

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.

Spot Stenting Combined With False Lumen Endovascular Occlusive Repair for Post-dissection Abdominal Aortic Aneurysm

PURPOSE

To introduce a new spot stenting, combined with a false lumen endovascular occlusive repair (SS-FLEVOR) technique for treating post-dissection abdominal aortic aneurysms.

TECHNIQUE

This technique is demonstrated in a 74-year-old man who received an initial thoracic endovascular aortic repair 7 years ago and suffered from distal aortic expansion during the follow-up session. All the tears located more than 15 mm away from the orifice of visceral arteries were excluded by spot stenting in the aortic true lumen. Then, a compliant stent-graft was implanted in the false lumen to seal the tears near the visceral arteries orifice from the outside. In addition, coils were deployed to block the potential backflow from the intercostal arteries and to induce false lumen thrombosis. Moreover, visceral arteries originated from false lumen were repaired by covered-stents implanted from the true lumen. The distal iliac arteries were sealed either with iliac extensions or cover-stents. This new technique has been applied in 5 patients, resulting in 100% technical success and encouraging intermediate outcomes.

CONCLUSION

SS-FLEVOR is a feasible and safe technique to promote false lumen thrombosis in selected cases.

The Distance From the Primary Intimal Tear to the Left Subclavian Artery Predicts Thoracic Aortic Enlargement After Thoracic Endovascular Aortic Repair of Type B Aortic Dissection: A Retrospective Cohort Study

PURPOSE

The purpose of this study was to evaluate the association between the distance from the primary intimal tear (PIT) to the left subclavian artery (LSA) (PIT-LSA distance) and the risk of aortic enlargement after thoracic endovascular aortic repair (TEVAR).

METHODS

This is a retrospective cohort study. A total of 228 patients were reviewed from the database of the Registry Of type B aortic dissection with the Utility of STent graft (ROBUST) study performed from January 1, 2011, to December 31, 2016. Of them, 196 patients were eligible for analysis. The PIT-LSA distance was defined as the length from the distal edge of the LSA orifice to the proximal edge of the PIT along the centerline of the true lumen. According to the border between zone 3 and zone 4 of the Ishimaru classification, patients were divided into group A (n = 117, PIT-LSA distance ≤ 2 cm) and group B (n = 79, PIT-LSA distance > 2 cm). Thoracic aortic enlargement (TAE) was defined as a thoracic aortic volume increase of ≥20%. Multivariate Cox regression was used to estimate the association between the PIT-LSA distance and risk of TAE after TEVAR.

RESULTS

The mean age was 52.3 ± 11.6 years, and 88.8% of patients were male. There were no significant differences between groups in demographic and baseline characteristics. The PIT-LSA distance was 1.1 cm (range, -1.6 to 2.0 cm) in group A, and 2.9 cm (range, 2.1-12.6 cm) in group B. TAE occurred in 27 patients in group A, and 6 in group B. The mean follow-up was 12.4 months (range, 0.10-83.1 months) in group A, and 12.63 months (range, 0.10-82.77 months) in group B. The cumulative 12- and 24-month rates of freedom from TAE were 79.0% and 71.3% in group A, versus 92.5% and 92.5% in group B, respectively. Multivariate Cox regression analysis revealed that the PIT-LSA distance was an independent predictor of TAE after TEVAR (adjusted hazard ratio, 0.66; 95% confidence interval, 0.48-0.90; p = 0.009).

CONCLUSION

Patients with a more proximal PIT location have a higher incidence of thoracic aortic enlargement after TEVAR. The location of the PIT in relation to the LSA can be used to identify patients who need closed surveillance after TEVAR or early preemptive intervention.

Endovascular therapies for Type B Aortic Dissection

Aortic dissection is a life-threatening condition resulting from a tear in the intimal layer of the aorta, requiring emergent diagnosis and prompt multi-disciplinary management strategy for best patient outcomes. While type A dissection involving ascending aorta is best managed surgically due to high early mortality, type B aortic dissection (TBAD) involving descending aorta generally has better outcomes with conservative management and medical therapy as primary strategy is favored. However, there has been a recent paradigm shift in management of TBAD due to late aneurysmal degeneration of TBAD increasing morbidity and mortality at longer-term. Late surgical intervention can be prevented by early endovascular intervention when combined with optimal medical therapy. In this narrative review, we explore available literature on different endovascular therapies for TBAD in different populations of patients.

A S-Shaped Association of Distal Oversizing Ratio with Distal Stent-Graft-Induced New Entry Following Thoracic Endovascular Aortic Repair for Stanford B Aortic Dissection

BACKGROUND

This study was performed to evaluate the nonlinear association of the distal oversizing ratio with distal stent-graft-induced new entry (dSINE) following thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD) and to find the optimal value of the distal oversizing ratio for prevention strategy of dSINE.

METHODS

Total of 177 patients who underwent TEVAR for TBAD from the Registry Of type B aortic dissection with the Utility of STent graft were retrospectively investigated. Patients were stratified into two groups on the median distal oversizing ratio: lower group (≤16%, n = 88) and higher group (>16%, n = 89). The Kaplan-Meier method was used to estimate the cumulative incidence of dSINE. The multivariate Cox proportional hazards model was used to identify the association of the distal oversizing ratio with dSINE. Restricted cubic smoothing spline plots and two-piecewise regression were used to analyze the possible nonlinear association.

RESULTS

Eleven patients developed dSINE (6.21%) during the median follow-up time of 12.37 months (interquartile range, 8.07-18.17 months). An S-shaped association of the distal oversizing ratio with dSINE was identified. When the distal oversizing ratio was ≤40%, the risk of dSINE increased with distal oversizing ratio, and the risk of dSINE was highest when the distal oversizing ratio reached 40% (adjusted HR, 1.09; 95% CI, 1.02-1.17; P = 0.011). A larger distal oversizing ratio over 40% did not generate a greater risk of dSINE (adjusted HR, 0.95; 95% CI, 0.87-1.05; P = 0.455).

CONCLUSIONS

This study substantiated previous findings that the dSINE was associated with the increasing distal oversizing ratio. We also found an S-shaped association between the distal oversizing ratio and dSINE after TEVAR for TBAD. The distal oversizing ratio of 40% can be used for stratified management of patients who underwent TEVAR for TBAD.

The 301 Classification: A Proposed Modification to the Stanford Type B Aortic Dissection Classification for Thoracic Endovascular Aortic Repair Prognostication

OBJECTIVE

To assess the usefulness of a modified Stanford classification for risk stratification of complications after thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD).

PATIENTS AND METHODS

This retrospective analysis included 201 patients from an observational multicenter cohort study who underwent TEVAR for TBAD from January 1, 2011, to December 31, 2016. The patients were divided by using a modified Stanford classification, termed 301, into 3 groups: types B1 (n=62) and B3 (n=24), with a true and false lumen, respectively, descending closely along the thoracic vertebral bodies, and type B2 (n=115), a semi-spiral or spiral configuration. The value of the 301 classification in assessing the risk for post-TEVAR thoracic aortic expansion, as main outcome, and other complications was assessed by using the Kaplan-Meier method and multivariable Cox proportional hazards models.

RESULTS

Median follow-up duration was 26.37 months, and the 24-month cumulative rate of freedom from thoracic aortic enlargement was 0.58 (95% CI, 0.25 to 0.81) for type B3, 0.75 (95% CI, 0.64 to 0.83) for type B2, and 0.97 (95% CI, 0.88 to 0.99) for type B1. In the multivariable Cox regression models, types B2 and B3 with type B1 as reference were independently associated with the risk for thoracic aortic expansion (type B2: hazard ratio, 7.81; 95% CI, 1.84 to 33.13; type B3: hazard ratio, 13.91; 95% CI, 2.86 to 67.69).

CONCLUSION

The 301 classification, a modified Stanford classification system in the era of endovascular repair, appears to improve the risk stratification of patients with TBAD undergoing TEVAR.

TRIAL REGISTRATION

Chinese Clinical Trial Registry number: ChiCTR-POC-17011726.

Role of Endoluminal Techniques in the Management of Chronic Type B Aortic Dissection

In recent guidelines of international societies, the most frequent indication for treatment after chronic type B aortic dissection (cTBAD) is aneurysmal dilatation. Endovascular repair is recommended in patients with moderate to high surgical risk or with contraindications to open repair. During the last decade, many advances have been made in the field of endovascular techniques and devices. The aim of this article is to address the current status of endoluminal techniques for the management of cTBAD including standard thoracic endovascular repair, new devices, fenestrated and branched abdominal aortic devices and false lumen occlusion techniques.

Intercostal artery embolization to induce false lumen thrombosis in type B aortic dissection

Persistent false lumen flow is common after thoracic endovascular aortic repair of type B aortic dissection and may contribute to continued aortic aneurysmal degeneration. We report an innovative technique of intercostal artery embolization within the false lumen for a patient who had incomplete false lumen thrombosis and progressive aortic enlargement after thoracic endovascular aortic repair of chronic type B aortic dissection. Technical success was facilitated by use of on-table cone beam computed tomography angiography, virtual vessel marking, and modern endovascular tools. The patient had no complications from the procedure. Postoperative imaging demonstrated complete thoracic false lumen thrombosis and favorable aortic remodeling with reduction in maximal aortic diameter.

Association Between Extent of Stent-Graft Coverage and Thoracic Aortic Remodeling After Endovascular Repair of Type B Aortic Dissection

Purpose: To examine the association between the extent of stent-graft coverage and thoracic aortic expansion after thoracic endovascular aortic repair (TEVAR) for type B aortic dissection. Materials and Methods: A retrospective analysis was conducted of 201 patients (mean age 52.4±11.5 years; 178 men) with acute (135, 67.2%) or chronic (66, 32.8%) type B aortic dissection who underwent TEVAR at 4 medical centers. The mean stent-graft length was 157.1±33.3 mm. The percentage of stented descending aorta (PSDA) represented the extent of stent-graft coverage. After using restricted cubic smoothing spline plots to confirm the roughly linear relationship between PSDA and the risk of thoracic aortic expansion, patients were stratified into 2 groups on the median PSDA: the lower group (≤31.3%) and the higher group (>31.3%). Thoracic aortic expansion was defined as a ≥20% increase in the total thoracic aortic volume on the most recent postoperative computed tomography angiography scan compared with the preoperative measurement. The Kaplan-Meier method was used to estimate the cumulative freedom from thoracic aortic expansion after TEVAR; estimates are given with the 95% confidence interval (CI). A multivariable Cox proportional hazards model was used to analyze any independent association of the PSDA as a continuous or categorical variable with the risk of thoracic aortic expansion; results are presented as the hazard ratio (HR) and 95% CI. Results: No patients developed symptoms of spinal cord ischemia during hospitalization. Over a median 12.4 months of imaging follow-up, 34 (16.9%) patients developed thoracic aortic expansion. The estimate of freedom from thoracic aortic expansion at 12 months for the overall PSDA was 84.0% (95% CI 77.8% to 88.6%); between the groups, the freedom from thoracic aortic expansion estimate for the PSDA ≤31.3% group was significantly lower than in the higher group (p=0.032). Regression analysis showed no significant association between the risk of thoracic aortic expansion and the PSDA as a continuous variable (HR 0.97, 95% CI 0.91 to 1.03, p=0.288); however, analyzing the PSDA as a categorical variable indicated a significantly lower risk of thoracic aortic expansion for the PSDA >31.3% group (HR 0.46, 95% CI 0.22 to 0.95, p=0.036) after adjusting for a variety of demographic and anatomical characteristics. Conclusion: More extensive stent-graft coverage appears to improve thoracic aortic remodeling after TEVAR. However, the clinician should balance the benefit of extensive stent-graft coverage and its related risk of spinal cord ischemia.

Proposed classification of endoleaks after endovascular treatment of Stanford type-B aortic dissections

Objectives

Despite two decades of experience, no dedicated classification system exists to document and prognosticate patterns of endoleak encountered after endovascular therapy of type-B aortic dissection. This nomenclature gap has led to inconsistent management and underreporting of significant findings associated with adverse outcomes after endovascular treatment of type-B aortic dissection. Our goal was to propose a reproducible and prognostically relevant classification.

Methods

A multidisciplinary team of seven experienced open and endovascular aortic surgeons was assembled to provide consensus opinion. Extensive literature review was conducted. Deficiencies in the current classification approach of the various patterns of persistent filling of false lumen after endovascular therapy were identified.

Results

Our focus was to categorize high-risk and low-risk subgroups within endoleaks after endovascular treatment of type-B aortic dissection. In this classification, type-Ia endoleak refers to persistent filling of the false lumen in an antegrade manner. Causes include failure to cover the primary entry tear and sizing or technical related proximal seal failure. False lumen filling via distal entry tears is classified as type Ib endoleak, which is further sub-classified into b1 (major branch-related tears), and b2 (multiple small branches related tears). Retrograde ascending aortic dissection and stent graft-induced new entry were classified as type-I endoleaks (type-Ir and type-Is, respectively). Another focus was reclassification type-II endoleaks, with type-IIa endoleak referring to conventional retroleak from one or more posterior branches and type-IIx referring to retroleak from major branches (visceral or left subclavian arteries).

Conclusions

The majority of endoleaks after endovascular treatment of type-B aortic dissection are related to persistent or new filling of the false lumen. We propose a new false lumen-based classification schema for endoleaks occurring after endovascular therapy of type-B aortic dissection.

[Elimination of late endoleak after endovascular repair of a dissecting thoracoabdominal aortic aneurysm]

Described herein is a clinical case report regarding treatment of a 70-year-old male patient presenting with a late complication following endoprosthetic repair for a Stanford type B dissecting thoracic aortic aneurysm. The man was admitted to our hospital for persistent type IIb endoleak and an increased diameter of the aorta in its thoracic and thoracoabdominal portions. Two years previously, he had endured endoprosthetic repair of the thoracic aorta. The findings of computed tomography revealed negative dynamics manifesting as an increase in the diameter of the false channel of the arch and descending thoracic aorta with persistent type IIb endoleak. He was subjected to elimination of abdominal aortic dissection and type IIb endoleak with partial prosthetic repair of the descending thoracic portion of the aorta by means of prosthetic repair of the lower thoracic portion of the aorta between the stent graft and linear vascular Dacron prosthesis. The postoperative period was complicated by transient acute renal failure and paraparesis of the lower limbs. The patient was discharged on POD 14, with no endoleaks revealed on control computed tomography 3 months thereafter.

Distal landing zone optimization before endovascular repair of aortic dissection

BACKGROUND

The general goals of endovascular management in chronic distal thoracic aortic dissection are optimizing the true lumen, maintaining branch patency, and promoting false lumen (FL) thrombosis. Distal seal can be challenging in chronic distal thoracic aortic dissection due to the well-established secondary fenestrations and fibrotic septum. We describe our approach of distal landing zone optimization (DLZO) to enable full-diameter contact of the distal endoprosthesis.

MATERIALS AND METHODS

Our experience includes 19 procedures in 16 patients (12 male, age 68 ± 8 years) between May 2014 and November 2017. A history of previous ascending repair for type A dissection was present in 8 patients. Treatment indication was enlarging aneurysm in all subjects, and 4 patients had associated chronic visceral or distal ischemia. Point septal fenestrations were expanded by serial balloon dilation and/or wire-pull approaches. Balloon molding was used to ensure complete endograft apposition and FL collapse.

RESULTS

One death occurred due to aortic perforation during wire-pull fenestration in a patient with heavily calcified and angulated aorta. The remaining procedures were accomplished safely and successfully. Balloon fenestration was used in 16 procedures, alone or in combination with a limited wire pull component. Adjunct procedures for distal seal included surgeon-modified fenestrated stent graft (3), iliac branch device (3), parallel superior mesenteric artery stent-graft (1), renal artery or superior mesenteric artery stent-graft (4), iliac stent (3), and plug obliteration of FL (5). Reintervention was required in 3 patients due to delayed loss of seal after the initial procedure (3, 8, and 12 months). Two were managed by repeat DLZO and distal extension. The third had distal extension via a surgeon-modified fenestrated stent-graft component. Follow-up imaging was available in 14 patients (16.0 ± 12.5 months, range: 1-33), with stable or regressed sac diameter with complete or near-complete thrombosis of the FL in all patients.

CONCLUSIONS

DLZO enabled creation of a distal seal zone in all patients. Residual retrograde filling of the FL is a marker of procedure failure, especially when seal segment length or feasible endoprosthesis oversizing are marginal. Insufficient landing segment can be circumvented with the use of a fenestrated or branched device to accomplish seal in the visceral aorta or iliac bifurcation. Adjunct FL ablation is also a valuable technique to promote FL thrombosis.

Techniques and outcomes of false lumen embolization in chronic type B aortic dissection

Endovascular strategies have been increasingly used for the treatment of chronic type B aortic dissection (cTBAD) offering better outcomes in terms of mortality and morbidity compared to open surgical repair. Aortic remodeling after standard TEVAR is less likely in cTBAD due to rigidity of the dissection membrane. Another limitation of endovascular therapy is continued retrograde false lumen perfusion with back-flow from distal entry tears. Treatment strategies in cTBAD should aim at false lumen thrombosis. There are many approaches to achieve this goal of false lumen thrombosis, but concepts as open surgery or fenestrated and branched endovascular repair are limited by either high technical and logistic demands to the surgeon or high rates of mortality and morbidity. False lumen embolization techniques offer less invasive treatment strategies with promising early results. The main strategies for false lumen embolization include the "cork in the bottle neck" technique, the Candy-Plug technique or the Knickerbocker-technique. This article describes technical aspects and early results of these new endovascular techniques of false lumen embolization in chronic aortic dissection.

Protocol for the ROBUST (Registry Of type B aortic dissection with the Utility of STent graft) study: an ambispective, multicentre, open cohort study

INTRODUCTION

Thoracic endovascular aortic repair (TEVAR) is widely used for type B aortic dissection, although with satisfactory outcome in a limited proportion of patients. To better inform patient prognostication, the Registry Of type B aortic dissection with the Utility of STent graft (ROBUST) study aims to identify imaging-based predictors of post-TEVAR adverse outcomes up to 10-year follow-up.

METHODS AND ANALYSIS

ROBUST is designed as an ambispective, multicentre, open cohort study. All patients undergoing TEVAR from 1 January 2008 to 1 July 2027 at participating centres will be invited to join the study. It is conservatively estimated that over 2000 patients will join the study. Data on demographics, disease history, procedural details, imaging features and follow-up will be collected after discharge. Cox proportional-hazards analysis will be used to identify independent predictors of primary outcomes. Stratification analysis will be performed to identify which subgroup of patients would benefit the most from TEVAR.

ETHICS AND DISSEMINATION

The protocol has been approved by the ethics committee of the coordinating centre. Findings will be disseminated in professional peer-reviewed journals to promote understanding of the rehabilitation process.

TRIAL REGISTRATION NUMBER

ChiCTR-POC-17011726; Pre-results.