Distal Stent Graft-Induced New Entry: An Emerging Complication of Endovascular Treatment in Aortic Dissection

Six Years' Experience With a Novel Dissection-Specific Stent-Graft to Prevent Distal Stent-Graft-Induced New Entry

INTRODUCTION

Thoracic endovascular aortic repair (TEVAR) in chronic dissection is associated with a risk for distal stent-graft-induced new entry (dSINE) in up to a quarter of cases. We assess the mid-term outcome of a novel dissection-specific stent-graft (DSSG), which is a custom-made device based on the Cook Alpha platform, with a modified graft design and a distal endovascular elephant trunk without any supporting stent to reduce the radial force on the dissection membrane at the distal landing zone.

METHODS

A retrospective single-center study of chronic dissection patients at high risk of dSINE who received an elective endovascular repair with DSSG from January 2017 to June 2023. The primary outcome is Kaplan-Meier (KM) estimated freedom from dSINE during follow-up. Secondary outcomes included technical success, aortic remodeling, and anatomical evaluation of the distal landing zone in cases with dSINE during follow-up versus those without.

RESULTS

Thirty patients (24 males) with a median age of 66 years [range=31-78] underwent elective TEVAR with the DSSG. The majority, n=27 (90%), had previous aortic repair; 7 (23%) had established connective tissue disease, and 6 (20%) had established dSINE after previous stent-graft implantation as an indication for TEVAR. Technical success was achieved in n=29 (97%). Median follow-up was 38.5 months (4.3-76.4), and KM estimated freedom from dSINE at 1 and 3 years was 95.6% (SE 0.043) and 89% (SE 0.081), respectively Four cases developed dSINE during follow-up. The median distance from the distal stent-graft to the coeliac trunk was 74mm (range=18-123) in the dSINE group versus 26mm (range=0-74) in the non-dSINE group (p=0.049). Median proximal tangential aortic angulation in the distal landing zone was 38.5° (range=26°-50°) in the dSINE group compared to 21° (range=3-61°) in the non-dSINE group (p=0.052).

CONCLUSIONS

The Use of a novel DSSG with low radial force for TEVAR in the setting of chronic dissection is safe and feasible, with remodeling outcomes comparable with standard TEVAR. The reduced distal radial force in the DSSG does not eliminate the risk for dSINE over time, with new entries occurring, particularly in cases where the distal landing zone is in a tortuous aortic segment and not close to the coeliac trunk.

CLINICAL IMPACT

Using the novel dissection-specific stent-graft with reduced radial force is safe and feasible but does not completely eliminate the risk of dSINE occurring over time. The exact positioning of the distal stent-graft in a straight aortic segment, close to the coeliac trunk, may be of importance to further mitigate the risk.

Long-term results of the frozen elephant trunk technique in primary chronic type B aortic dissection

OBJECTIVES

The aim of this study is to analyze long-term results of the total aortic arch replacement with the frozen elephant trunk technique for primary chronic type B aortic dissection.

METHODS

Among 322 patients who had the frozen elephant trunk technique, 43 (13.4%) patients (median age, 64.0 years) with primary chronic type B aortic dissection were analyzed. The patients underwent surgery at a median of 27.0 months after the onset of aortic dissection. The false lumen was patent in 30 (69.8%) patients preoperatively.

RESULTS

Two patients suffered paraplegia and another died of cerebral infarction. Complete thrombosis of the peri-stent false lumen was achieved in 36 (83.7%) patients. Overall survival, freedom from aortic events, and freedom from aortic reintervention were 83.5%, 37.2%, and 42.2% at 5 years, respectively. Survival rates of the patients with or without aortic events were 75.0% and 95.8% at 5 years (Log-rank, p = 0.22). Late aortic events occurred in 19 (44.2%) patients including distal stent graft-induced new entry, type Ib endoleak, and false lumen dilation. The ratio of the stent graft diameter to the preoperative short axis diameter of the true lumen (hazard ratio, 1.90; 95% confidence interval, 1.01-3.59), and the maximal diameter of a postdissection aneurysm (1.07; 1.01-1.12) were the significant multivariate risk predictors of late aortic events.

CONCLUSIONS

Late aortic events occurr fairly frequently, and new strategies need to be explored to enhance the effectiveness of this procedure in the future.

Numerical simulation of the distal stent graft-induced new entry after TEVAR

The study aimed to investigate the mechanical factors for distal stent graft-induced new entry (dSINE) in aortic dissection patients and discussed these factors in conjunction with aortic morphology. Two patients (one dSINE and one non-dSINE), with the same age, gender, and type of implanted stent, were selected, then aortic morphological parameters were calculated. In addition, the stent material parameters used by the patients were also fitted. Simulations were performed based on the patient's aortic model and the stent graft used. The true lumen segment at the distal stent graft was designated as the "dSINE risk zone," and mechanical parameters (maximum principal strain, maximum principal stress) were computed. When approaching the area with higher mechanical parameters in the dSINE risk zone, dSINE patient exhibited higher values and growth rates in mechanical parameters compared to non-dSINE patient. Furthermore, dSINE patient also presented larger aortic taper ratio, stent oversizing ratio, and expansion mismatch ratio of the distal true lumen (EMRDTR). The larger mechanical parameters and growth rates in dSINE patient corresponded to a greater aortic taper ratio, stent oversizing ratio, and EMRDTR. The failure of dSINE prediction by the stent tortuosity index indicated that mechanical parameters were the fundamental reasons for dSINE development.

Prevention of distal stent graft-induced new entry after endovascular repair for type B aortic dissection: A retrospective cohort study

OBJECTIVES

Distal stent graft-induced new entry (dSINE) can occur after thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD). In this study we aimed to compare the effectiveness of restrictive bare stent (RBS), tapered stent graft (TSG), and non-TSG in TEVAR in preventing dSINE after a midterm follow-up.

METHODS

This retrospective cohort study included patients with TBAD who underwent TEVAR (June 2010 to December 2018). The occurrence of dSINE during follow-up was examined. Predictors of dSINE were determined using Fine-Gray regression with death as the competing event. Survival was evaluated using Cox proportional hazards regression.

RESULTS

Finally, 364 patients were included: 111 with non-TSG TEVAR, 125 with TSG TEVAR, and 128 with TEVAR with RBS. After 54.5 months, incidences of dSINE in the 3 groups were 12.61%, 4.80%, and 1.56%, respectively (P = .002). On Fine-Gray regression adjusted for clinically relevant covariates, the expansion mismatch ratio (subdistribution hazard ratio, 1.09; 95% CI, 1.07-1.12; P < .001) and complete false lumen thrombosis (subdistribution hazard ratio, 0.35; 95% CI, 0.13-0.94; P = .037) were identified as predictors of dSINE. The Cox proportional hazards regression analysis revealed that dSINE was not only a risk factor for aortic-related mortality (hazard ratio, 17.90; 95% CI, 3.27-98.12; P = .001), but also a predominant risk factor for all-cause mortality (hazard ratio, 4.91; 95% CI, 1.66-14.52; P = .004).

CONCLUSIONS

dSINE can happen in TBAD patients who undergo TEVAR. Thus, long-term surveillance is crucial. TSG and RBS had lower expansion mismatch ratios, which might help prevent dSINE.

A CT-based predictive model for stent-induced vessel damage: application to type B aortic dissection

OBJECTIVES

The distal stent-induced new entry (distal SINE) is a life-threatening device-related complication after thoracic endovascular aortic repair (TEVAR). However, risk factors for distal SINE are not fully determined, and prediction models are lacking. This study aimed to establish a predictive model for distal SINE based on the preoperative dataset.

METHODS

Two hundred and six patients with Stanford type B aortic dissection (TBAD) that experienced TEVAR were involved in this study. Among them, thirty patients developed distal SINE. Pre-TEVAR morphological parameters were measured based on the CT-reconstructed configurations. Virtual post-TEVAR morphological and mechanical parameters were computed via the virtual stenting algorithm (VSA). Two predictive models (PM-1 and PM-2) were developed and presented as nomograms to help risk evaluation of distal SINE. The performance of the proposed predictive models was evaluated and internal validation was conducted.

RESULTS

Machine-selected variables for PM-1 included key pre-TEVAR parameters, and those for PM-2 included key virtual post-TEVAR parameters. Both models showed good calibration in both development and validation subsamples, while PM-2 outperformed PM-1. The discrimination of PM-2 was better than PM-1 in the development subsample, with an optimism-corrected area under the curve (AUC) of 0.95 and 0.77, respectively. Application of PM-2 in the validation subsample presented good discrimination with an AUC of 0.9727. The decision curve demonstrated that PM-2 was clinically useful.

CONCLUSION

This study proposed a predictive model for distal SINE incorporating the CT-based VSA. This predictive model could efficiently predict the risk of distal SINE and thus might contribute to personalized intervention planning.

CLINICAL RELEVANCE STATEMENT

This study established a predictive model to evaluate the risk of distal SINE based on the pre-stenting CT dataset and planned device information. With an accurate VSA tool, the predictive model could help to improve the safety of the endovascular repair procedure.

KEY POINTS

• Clinically useful prediction models for distal stent-induced new entry are still lacking, and the safety of the stent implantation is hard to guarantee. • Our proposed predictive tool based on a virtual stenting algorithm supports different stenting planning rehearsals and real-time risk evaluation, guiding clinicians to optimize the presurgical plan when necessary. • The established prediction model provides accurate risk evaluation for vessel damage, improving the safety of the intervention procedure.

Distal Stent Graft-Induced New Entry After Frozen Elephant Trunk Procedure for Aortic Dissection

BACKGROUND

The purpose of this study was to evaluate the risk factors of distal stent graft-induced new entry (dSINE) after frozen elephant trunk (FET) procedure for aortic dissection (AD) and to consider strategies to prevent this complication.

METHODS

This retrospective review included 52 patients who had undergone aortic arch repair for AD with the FET procedure using J Graft FROZENIX from 2014 to 2020 at a single center. Baseline characteristics, aortic characteristics and mid-term outcomes were compared between patients with and without dSINE. The extent of unfolding of the device and movement of the distal edge of the device were analyzed by multidetector computed tomography. The primary endpoints were survival and freedom from reintervention.

RESULTS

dSINE was the most prevalent complication after FET procedure, with an incidence of 23%. Eleven of 12 patients with dSINE underwent secondary interventions. dSINE was common in chronic aortic dissection (P = 0.001) and was associated with the residual false lumen area (P < 0.001) and movement distance of the distal edge of the device in the cranial direction (P < 0.001).

CONCLUSIONS

The distal edge of the FET is more likely to move in the cranial direction, and this movement may cause dSINE.

The role of aorta distal to stent in the occurrence of distal stent graft-induced new entry tear: A computational fluid dynamics and morphological study

Distal stent graft-induced new entry tear (dSINE) is an important complication of thoracic endovascular aortic repair (TEVAR) for the treatment of type B aortic dissection (TBAD). This study aims to explore whether the aorta distal to the stent plays an important role in the occurrence of dSINE. Sixty-nine patient-specific geometrical models of twenty-three enrolled patients were reconstructed from preoperative, postoperative, and predSINE computed tomography scans. Computational fluid dynamics (CFD) simulations were performed to calculate the von Mises stress in the CFD group. Meanwhile, morphological measurements were performed in all patients, including measurements of the inverted pyramid index at different follow-up time points and the postoperative true lumen volume change rate. In the CFD study, the time-averaged von Mises stress of the true lumen distal to the stent in dSINE patients was significantly higher than that in the CFD controls (20.42 kPa vs. 15.47 kPa). In the morphological study, a special aortic plane (plane A) with an extremely small area distal to the stent was observed in dSINE patients, which resulted in an inverted pyramid structure in the true lumen distal to the stent. This structure in dSINE patients became increasingly obvious during the follow-up period and finally reached the maximum value before dSINE occurred (mean, 3.91 vs. 1.23). At the same time, enlargement of the true lumen distal to the stent occurs before dSINE, manifesting as a continuous increase in the true lumen volume (mean, 0.70 vs. 013). A new theory of what causes dSINE to occur has been proposed: the inverted pyramid structure of the true lumen distal to the stent caused an increase in the von Mises stress in this region and aortic enlargement, which ultimately led to the occurrence of dSINE.

A systematic review and meta-analysis of retrograde type A aortic dissection after thoracic endovascular aortic repair in patients with type B aortic dissection

BACKGROUND

Retrograde type A dissection (RTAD) is a devastating complication of thoracic endovascular repair (TEVAR) with low incidence but high mortality. The objective of this study is to report the incidence, mortality, potential risk factors, clinical manifestation and diagnostic modalities, and medical and surgical treatments.

METHODS

A systematic review and single-arm and two-arm meta-analyses evaluated all published reports of RTAD post-TEVAR through January 2021. All study types were included, except study protocols and animal studies, without time restrictions. Outcomes of interest were procedural data (implanted stent-grafts type, and proximal stent-graft oversizing), the incidence of RTAD, associated mortality rate, clinical manifestations, diagnostic workouts and therapeutic management.

RESULTS

RTAD occurred in 285 out of 10,600 patients: an estimated RTAD incidence of 2.3% (95% CI: 1.9-2.8); incidence of early RTAD was approximately 1.8 times higher than late. Wilcoxon signed-rank testing showed that the proportion of RTAD patients with acute type B aortic dissection (TBAD) was significantly higher than those with chronic TBAD (P = .008). Pooled meta-analysis showed that the incidence of RTAD with proximal bare stent TEVAR was 2.1-fold higher than with non-bare stents: risk ratio was 1.55 (95% CI: 0.87-2.75; P = .13). Single arm meta-analysis estimated a mortality rate of 42.2% (95% CI: 32.5-51.8), with an I2 heterogeneity of 70.11% (P < .001).

CONCLUSION

RTAD is rare after TEVAR but with high mortality, especially in the first month post-TEVAR with acute TBAD patients at greater risk as well as those treated with proximal bare stent endografts.

Impact of thoracic endovascular aortic repair on aortic biomechanics: Integration of in silico and ex vivo analysis using porcine model

Thoracic endovascular aortic repair (TEVAR) is widespread in clinical practice for treating aortic diseases but it has relevant systemic complications, such as increase of the cardiac workload due to post-TEVAR aortic stiffening, and local issues such as re-entry tears due to the tissue damage caused by endograft interaction. The present study aims to elucidate these aortic biomechanical mechanisms by coupling ex vivo and in silico analysis. By ex vivo tests, the pulse wave velocity before and after TEVAR is measured. Uni-axial tensile tests are performed to measure regional mechanical response of tissue samples, supplied as input data for the in silico analysis. Numerical analysis is finally performed to compute the wall stress induced by the stent-graft deployment and the arterial pressurization. The ex vivo results highlight an increase of baseline PWV by a mean .78 m/s or 12% after TEVAR with a 100 mm stent-graft (p <.013). In the in silico analysis, the average von Mises stress in the landing zone increases of about 15% and 20% using, respectively stent-graft with radial oversizing of 10% and 20%. This work shows the effectiveness of integrated framework to analyze the biomechanical post TEVAR mechanisms. Moreover, the obtained results quantify the effect of prosthesis selection on the stiffening of the aorta after TEVAR and on the local increase of the aortic wall stress that is proportional to the stent-graft oversizing.

Hotspots and development frontiers of postoperative complications of AD: Bibliometric analysis - a review

The research on the postoperative complications of aortic dissection (AD) has received great attention from scholars all over the world, and the number of research articles in this field has consistently increased year after year. However, no bibliometric reports have been published yet to analyze the scientific output and the current situation in this field. The Bibliometrix R-package, VOSviewer, and CiteSpace software were used to conduct a bibliometric analysis of the hotspots and development frontiers of AD. A total of 1242 articles were retrieved. The USA, China, and Japan had the highest number of publications. The five keywords with the highest frequency were "analysis," "incidence," "acute type," "graft," and "risk factor." The results also indicated that the research in related fields had shifted from surgical treatment and utilizing experience to the evidence-based exploration of risk factors and the construction of prediction models to help better manage postoperative complications of AD. This is the first bibliometric analysis of global publications on the postoperative complications of AD. The current research hotspots focus on three areas: common postoperative complications of AD, exploration of the related risk factors, and management of complications. Future research could focus on identifying risk factors through meta-analysis and using a multicenter database for AD as well as building relevant models to predict the development of complications to better facilitate the clinical management of AD patients.

Longitudinal morphological changes of the aorta and the endograft position before and after distal stent graft-induced new entry in aortic dissections

OBJECTIVES

The aim of this study was to assess the endograft position and aortic geometry changes after thoracic endovascular aortic repair (TEVAR) and frozen elephant trunk (FET) in distal stent-induced new entry (dSINE) patients.

METHODS

In this retrospective cohort study, the baseline demographic and the follow-up data were extracted from the hospital records, and computed tomography scans of dSINE patients after TEVAR or FET between 2011 and 2021 were analysed regarding endograft oversizing, length and migration, taper ratio, aortic diameter at the endograft end, aortic elongation (thoracic inner and outer curvature), wedge apposition angle and tortuosity angle in the distal landing zone.

RESULTS

dSINE was found in 22/213 (10%) of TEVAR and 10/31 (32%) of FET patients. The total follow-up time was 45 (27; 59) months. TEVAR was mainly performed with Relay NBS endograft (77%) and FET with Evita open prosthesis (80%). Paraplegia and stroke rates were 3%. dSINE occurred 17 (7; 35) months post-TEVAR and was instantly treated in 18 patients (56%) or followed up for 21 (11; 34) months (n = 14). Migration [+5 mm (1; 11; P < 0.001)], birdbeak angle [+9° (0; 27; P = 0.039)] and aortic diameter +5 mm (1; 11; P < 0.001) increased after dSINE, whereas aortic elongation increased already before [+12 mm (0; 27; P = 0.015)] and peaked after dSINE [+30 mm (9; 38; P < 0.001)]. The aortic elongation was more pronounced in the outer aortic curvature before and after dSINE (before: P = 0.039, after: P = 0.024). Postoperative wedge apposition [17° (12; 20)] increased before dSINE [21° (16; 35; P < 0.001)] and peaked thereafter [31° (21; 40; P < 0.001)].

CONCLUSIONS

Aortic elongation may influence the endograft position and provoke TEVAR failure in the distal and proximal landing zones.

Aortic remodeling, reintervention, and survival after zone 0 arch repair with frozen elephant trunks for acute type A aortic dissection: Midterm results

Objectives

To investigate the midterm results after zone 0 arch repair with frozen elephant trunks for acute type A aortic dissection.

Methods

Between October 2014 and April 2021, 196 patients underwent zone 0 arch repair with frozen elephant trunks for acute type A aortic dissection. The true lumen area, aortic lumen area, and false lumen status were assessed at four aortic levels, the proximal and distal descending thoracic aorta (level A and level B, respectively), celiac artery branching (level C), and terminal aorta (level D). Aortic remodeling (postoperative area as a percentage of the preoperative area) was classified into 3 groups, positive (true lumen area ≥120% with aortic lumen <120% or true lumen area ≥80% with aortic lumen <80%), minimal (80% ≤ true lumen area and aortic lumen area <120%), and negative remodeling (all other changes).

Results

In-hospital mortality was 13 (6.6%) patients. The overall survival rate was 85.1% at 5 years. The freedom from distal aortic reintervention was 89.9% at 5 years. The prevalence of completely thrombosed or obliterated false lumen at 2 years was 96.8% at level A, 88.4% at level B, 47.2% at level C, and 27.6% at level D. The prevalence of positive aortic remodeling at 2 years was 84.7% at level A, 75.0% at level B, 29.2% at level C, and 16.7% at level D.

Conclusions

Zone 0 arch repair with frozen elephant trunks for acute type A aortic dissection can avoid invasive aortic arch resection and facilitate aortic remodeling of the descending thoracic aorta. The FET effect on aortic remodeling is limited at the aortic level below the FET stent end.

Early and midterm results of frozen elephant trunk operation with Evita open stent-graft in patients with Marfan syndrome: results of a multicentre study

BACKGROUND

Endovascular treatment of patients with Marfan syndrome (MFS) is not recommended. Hybrid procedures such as frozen elephant trunk (FET), which combines stent-graft deployment with an integrated non-stented fabric graft for proximal grafting and suturing, have not been previously evaluated. The aim of this study was to assess the safety and feasibility of FET operation in patients with MFS.

METHODS

Patients enrolled in the International E-vita Open Registry (IEOR) who underwent FET procedure between January 2001 and February 2020 meeting Ghent criteria for MFS were included in the study. Early and midterm results were retrospectively analyzed. Preoperative, postoperative and follow-up computed tomography angiography scans were analysed.

RESULTS

We analyzed 37 patients [mean age 38 ± 11 years, 65% men]. Acute or chronic aortic dissection was present in 35 (95%) patients (14 and 21 patients respectively). Two (5%) patients had an aneurysm without dissection. Malperfusion syndrome was present in 4 patients. Twenty-nine (78%) patients had history of aortic surgical interventions. The 30-day and in-hospital mortality amounted to 8 and 14% respectively. False lumen exclusion was present in 73% in stented segment in last postoperative CT. The overall 5-year survival was 71% and freedom from reintervention downstream was 58% at 5 years. Of the nine patients who required reintervention for distal aortic disease, one patient died.

CONCLUSIONS

FET operation for patients with MFS can be performed with acceptable mortality and morbidity. In long-term follow-up no reinterventions on the aortic arch were required. FET allows for easier second stage operations providing platform for surgical and endovascular reinterventions.

Endovascular and Hybrid Repair in Patients with Heritable Thoracic Aortic Disease

OBJECTIVE

In individuals with heritable thoracic aortic disease (HTAD), endovascular repair for treatment of aortic aneurysm and dissection may be lifesaving but is associated with increased risk of failure of endovascular repair and adverse outcomes. This study reports our experience with early and late outcomes of endovascular aortic and branch vessel repair in patients with HTAD.

METHODS

A retrospective case series was performed by chart review of individuals with HTAD followed at Washington University School of Medicine/Barnes-Jewish Hospital who underwent endovascular aortic and/or branch vessel repair. Clinical features, imaging characteristics, and short- and long-term outcomes were collected.

RESULTS

Twenty-nine patients with HTAD (20 male; mean age 45 ± 13 years) underwent thirty-seven endovascular procedures between 2006 and 2020 with mean follow up of 54 ± 41 months. Seven patients underwent two or more separate endovascular procedures. Each procedure was considered separate for data collection and analysis. Underlying conditions included Marfan syndrome (n=16 procedures), Loeys-Dietz syndrome (n=14 procedures), vascular Ehlers-Danlos syndrome (n=3 procedures), and nonsyndromic HTAD (n=4 procedures). Twenty patients (69%) had prior open surgical aortic repair. Indications for endovascular aortic repair (n=31) included urgent repairs of acute complications of aortic dissection (n=10) or aneurysm rupture (n=3), and elective aortic repair (n=18; 10 chronic dissections and 8 chronic aneurysms). Six patients underwent elective endovascular repair of six branch vessel aneurysms or dissections. Six patients underwent hybrid open surgical and endovascular repair. Of the 37 procedures, twenty-five (68%) proximal landing zones were in the native aorta or branch vessel, eleven (30%) were in a surgical graft or elephant trunk and one was in a previously placed endograft. Thirty-six (97%) procedures were technically successful, and none required emergency surgical conversion. Two patients died: one from sepsis and one from presumed late pseudoaneurysm rupture, for a 5% per-procedure mortality rate. Two procedures were complicated by stroke and one patient developed paraparesis. Of the 31 aortic procedures, seven aortic endografts (23%) developed a stent-induced new entry (SINE) discovered with imaging at 20 ± 15 days post-procedure. Seven endografts (23%) developed a Type I endoleak and eight (26%) developed a Type II endoleak. No Type III endoleaks were seen. Within 30 days, two endografts (of 37, 5%) required reintervention. After 30 days, fifteen additional endografts (of 37, 41%) required reintervention. Two patients (of 6, 33%) who underwent hybrid repair required reintervention.

CONCLUSIONS

This study is the largest single-center case series examining outcomes of HTAD patients following endovascular repair. Urgent and elective endovascular repairs in patients with HTAD can manage acute and chronic complications of aortic aneurysm and dissection with relatively low risk. However, risk of early and late endoleaks and SINE is high. Close post-procedural surveillance is required, and many individuals will require additional interventions. Hybrid repair shows promise and requires further investigation.

Predictive factors of distal stent graft-induced new entry after frozen elephant trunk procedure for aortic dissection

OBJECTIVES

The incidence rate of distal stent graft-induced new entry after frozen elephant trunk technique for aortic dissection remains controversial. The aim of this study was to investigate the incidence and seek the clinical and anatomical predictive factors.

METHODS

This study is a retrospective multicenter evaluation of complications including distal stent graft-induced new entry, aortic events, and re-intervention after the frozen elephant trunk procedure for aortic dissection.

RESULTS

Our cohort included total 177 consecutive patients who underwent the frozen elephant trunk procedure for acute and chronic aortic dissection at five centers in Japan from May 2014 to March 2021. The incidence rate of distal stent graft-induced new entry was 14.1% (25/177 patients). The cumulative incidence of d-SINE was 7.1%, 12.4%, 21.4% after 12, 36, and 60 months, respectively. Distal stent graft-induced new entry was not associated with mid-term survival rate. After competing risk regression analysis, onset time > 48 hours (subdistribution hazard ratio, 3.80; 95% confidence interval, 1.13-12.79; P=0.031) was detected as an independent predictor.

CONCLUSIONS

Awareness that there is a relatively higher incidence of distal stent graft-induced new entry after frozen elephant trunk procedures is important. Non-hyperacute phase was detected as an independent risk factor. Preemptive endovascular repair may be appropriate to protect new entry in high-risk patients.

Functional Evaluation of Embedded Modular Single-Branched Stent Graft: Application to Type B Aortic Dissection With Aberrant Right Subclavian Artery

Background

Endovascular repair of type B aortic dissection (TBAD) with aberrant right subclavian artery (ARSA) is challenging due to anatomical complexity. The embedded modular single-branched stent graft (EMSBSG) could solve this problem. However, the hemodynamic efficacy of this innovative technique has not been fully assessed. This study aimed to propose morphometric and functional indicators to quantify the outcomes of EMSBSG in treating TBAD with ARSA.

Material and Methods

A patient who had TBAD with ARSA underwent EMSBSG implantation was admitted. Computational fluid dynamics (CFD) and three-dimensional structural analyses were conducted based on CTA datasets before the operation (Pre-1) and at 4 and 25 days after EMSBSG implantation (Post-1 and Post-2). Quantitative and qualitative functional analyses were conducted via pressure-, velocity- and wall shear stress (WSS) -based parameters, such as the luminal pressure difference (LPD), total energy loss, and flow distribution ratio. By precisely registering the aortas at the three time points, parameter variations in the EMSBSG region were also computed to investigate the prognostic improvement after EMSBSG implantation.

Results

The first balance point of LPD distally shifted to the abdominal aorta in Post-1 by a distance of 20.172 cm, and shifted out of the dissected region in Post-2, indicating positive pressure recovery post EMSBSG. The flow distribution ratios of all aortic arch branches increased after EMSBSG implantation. A positive normal deformation index in the EMSBSG region confirmed true lumen expansion; dominant AR_N (area ratio of negative value) of pressure and WSS-based parameters indicated an improved prognosis from Post-1 to Post-2.

Conclusions

The short-term results of EMSBSG in treating TBAD with ARSA proved to be promising, especially in EMSBSG region. Comprehensive evaluation could provide new insight into the therapy of TBAD with ARSA. Thus, it might guide the further management of complex aortic arch lesions.

The PETTICOAT-snowshoe technique prevents distal stent graft-induced new entry in patients with aortic dissection

PURPOSE

Distal stent graft-induced new entry (SINE) is a serious complication of thoracic endovascular aortic repair (TEVAR) for Stanford type B aortic dissection (TBAD). The PETTICOAT-snowshoe technique was developed to prevent distal SINE for double-barrel TBAD. Initially, a proximal stent-graft (SG) is deployed, followed by the extension of a bare stent above the celiac artery and deployment of a second SG within the bare stent. This study examined whether the PETTICOAT-snowshoe technique prevents distal SINE.

MATERIALS AND METHODS

This was a single-center, retrospective study comparing two groups that underwent conventional standard TEVAR between January 2013 and September 2018 and TEVAR using the PETTICOAT-snowshoe technique after October 2018 for double-barrel TBAD.

RESULTS

Twenty-seven patients (74% male) underwent standard TEVAR (group A), while another 27 (78% male) underwent the PETTICOAT-snowshoe technique (group B). TEVAR was performed in the chronic phase on 15 patients (55.6%) in group A and on 16 (59.2%) in group B. Aorta-related mortality occurred in one patient in group A (3.7%). Oversizing ratios at the distal edge of the SG diameter to the major axis of the true lumen were 25% ± 26% and 25% ± 21% in groups A and B, respectively. During the follow-up period, five patients (18.5%) in group A and none in group B (p = 0.02) developed distal SINE. Three out of the five patients with distal SINE in group A were treated with additional TEVAR, one with thoracoabdominal aortic replacement, and one with conservative observation. The freedom from distal SINE rate was significantly higher in group B than in group A (p = 0.04).

CONCLUSIONS

The PETTICOAT-snowshoe technique significantly prevented distal SINE during the mid-term period even with the same distal SG oversizing as conventional standard TEVAR.

NEO E-vita—NEO era!

In this review article, the history of the first commercially available thoracic aortic hybrid graft, the E-vita Open, later modified to the blood-impermeable E-vita Open Plus, is reported from its beginning in 2005 until its newest variation, the E-vita Open NEO, European conformity (CE) marked in 2020. Besides the background of its design and clinical experience in Essen, concomitant evolutionary steps in surgery as well as in strategic approaches like the hybrid operating room concept are displayed, finally leading to a well-rounded surgical package with a device that can be applied in all elective as well as emergency situations with complex arch involving aortic pathologies. With the E-vita Open NEO, now, surgery has been facilitated to convenient anastomosing in any of the arch zones, with the opportunity to use the island technique with a straight graft variation as well as individual head vessel anastomosing with either a trifurcated graft for zone 0 or the branched graft for zone 2 or 3 implantation. With its proven long-term stability, the surgical armamentarium to cope with complex multisegmental thoracic aortic pathologies has been significantly improved.

Aortic-related Readmission after Thoracic Endovascular Aortic Repair for Type B Aortic Dissection Patients: A Single-center Retrospective Study

OBJECTIVES

This study aimed to investigate the characteristics of and risk factors for aortic-related readmission after thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD).

METHODS

Data from TBAD patients who underwent TEVAR from 2009-2018 at a Chinese tertiary center were retrospectively collected and analyzed. Enrolled patients were categorized into two groups according to whether aortic-related readmission occurred during follow-up, which was defined as hospitalization at least once after the initial procedure due to events that were related to or caused by aortic dissection or the initial procedure.

RESULTS

A total of 1 288 TBAD patients were enrolled, and 99 patients experienced aortic-related readmissions (7.7%), among whom chronic patients had the highest readmission rate (9.8%). The yearly proportion of readmission during the first year after initial procedure revealed a decreasing trend with a -9.7% annual percentage change. Seventy-one patients underwent reintervention (71.7%). Distal aneurysmal degeneration (43.7%) and distal stent graft-induced new entries (32.4%) were two major causes for reintervention. Fourteen patients in the reintervention subgroup underwent a second reintervention (19.7%). In-hospital mortality was 1.0% during the readmission and 14.3% during the second readmission. The overall survival was comparable between two groups (p=.93).

CONCLUSIONS

This study highlighted the importance of surveillance after initial procedure for TBAD patients with potential risk factors for aortic-related readmission, and the predisposition of patients with reintervention to multiple readmissions deserves attention.

Early experience with a novel dissection-specific stent-graft to prevent distal stent-graft-induced new entry tears after thoracic endovascular repair of chronic type B aortic dissections

PURPOSE

The aim was to report short and mid-term outcomes of a novel, investigational, dissection-specific stent-graft (DSSG), specifically designed to address the features of chronic type B aortic dissection (CTBAD) and reduce the risk of distal stent-graft-induced new entry tears (dSINE).

MATERIALS AND METHODS

A retrospective single center cohort study of all patients undergoing TEVAR with the DSSG for CTBAD from January 1, 2017 to January 31, 2020. The DSSG, which is a modified stent-graft based on the Cook Zenith Alpha Thoracic platform, has no proximal barbs and a customized longer body length with substantial taper. The second and third distal Z-stents are sited internally to avoid any contact of the metal skeleton with the dissection membrane and have reduced radial force, while the most distal stent was removed creating a distal 30 mm unsupported Dacron graft.

RESULTS

Sixteen patients (13 males, 3 females) with a median age of 66 years (range 31-79 years) underwent elective TEVAR of CTBAD using the DSSG. Six patients (38%) had an underlying connective tissue disorder. The median tapering was 10mm (range 4mm-21mm) and median length 270mm (range 210-380 mm). Technical success was achieved in all but one case (96%). One patient died within 30 days, due to retrograde type A dissection with cardiac tamponade. The 30-day rate of stroke, spinal cord ischemia and re-interventions was 0%. After median imaging follow-up time of 17 months (range 1 - 31 months), one patient developed a dSINE four months after the index procedure. After median survival follow-up of 23 months (range 2 - 35 months), one late death occurred due to traumatic brain injury, while no aortic-related death occurred during follow-up. Complete false lumen (FL) thrombosis was achieved in nine patients while the remaining six showed partial FL thrombosis. No instances of diameter increase at the level of treated aortic segment were noted with serial measurements showing either stable (n=7) or decreased (n=8) maximal transverse diameter.

CONCLUSIONS

Use of a novel DSSG with low radial force for TEVAR in the setting of CTBAD is safe and feasible. This early real-world experience shows promising mid-term effectiveness with low rates of dSINE or unplanned re-interventions and satisfactory aortic remodelling during follow-up. Longer follow-up is needed, however, before any firm conclusions can be drawn.

Influence of measurement and sizing techniques in thoracic endovascular aortic repair on outcome in acute complicated type B aortic dissections

OBJECTIVES

Thoracic endovascular aortic repair (TEVAR) is the first-line therapy in acute complicated type B aortic dissections (cTBAD). Nevertheless, no evidence-based consensus on the optimal measurement technique and sizing for TEVAR in cTBAD exists. The aim was to evaluate how different measurement and sizing techniques for TEVAR affect long-term outcomes.

METHODS

Retrospective analysis investigating the association between sizing and postoperative results after TEVAR in patients with cTBAD, treated between January 2003 and December 2020. Diameter measurements were performed perpendicular to a centreline in pre-interventional Computed tomography angiographies. Oversizing was determined by measuring aortic diameter in zone 2 of the aortic arch in relation to the implanted stent graft, and categorized into 2 sizing groups (≤10% and >10%). The primary outcome was freedom from aortic-related events. Secondary outcomes included mortality and a comparison of 3 alternative measurement techniques considering the estimated pre-dissection diameter.

RESULTS

Fifty-seven patients (median age 69, interquartile range 59.6-78.2 years) were included. Stent graft oversizing by ≤10% showed a trend towards fewer aortic-related events hazard ratio 0.455 (95% confidence interval 0.128-1.624, P = 0.225).The 3 measurement techniques using the pre-dissection aortic diameter differed by a mean of 1.7-4.0 mm with a variability of up to 8.4 mm. In none of the 57 patients, the same stent graft would have been chosen based on the different measurement techniques using an oversizing ≤10%.

CONCLUSIONS

TEVAR oversizing of ≤10% in patients with cTBAD might reduce aortic-related events up to 50%. Consensus on measurement techniques of the pre-dissection aortic diameter and stent graft sizing is of paramount importance.

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.

Secondary Interventions After TEVAR for Aortic Dissection

The goal of thoracic endograft placement in type B aortic dissection is to prevent aneurysmal degeneration and other complications. Although TEVAR is a highly effective tool for managing type B aortic dissection, many patients will require additional interventions. In this article, we present a case-based review of techniques for the management of persistent false lumen perfusion and stent-graft induced new entry tears after TEVAR for aortic dissection.

Patient-specific simulation of stent-graft deployment in type B aortic dissection: model development and validation

Thoracic endovascular aortic repair (TEVAR) has been accepted as the mainstream treatment for type B aortic dissection, but post-TEVAR biomechanical-related complications are still a major drawback. Unfortunately, the stent-graft (SG) configuration after implantation and biomechanical interactions between the SG and local aorta are usually unknown prior to a TEVAR procedure. The ability to obtain such information via personalised computational simulation would greatly assist clinicians in pre-surgical planning. In this study, a virtual SG deployment simulation framework was developed for the treatment for a complicated aortic dissection case. It incorporates patient-specific anatomical information based on pre-TEVAR CT angiographic images, details of the SG design and the mechanical properties of the stent wire, graft and dissected aorta. Hyperelastic material parameters for the aortic wall were determined based on uniaxial tensile testing performed on aortic tissue samples taken from type B aortic dissection patients. Pre-stress conditions of the aortic wall and the action of blood pressure were also accounted for. The simulated post-TEVAR configuration was compared with follow-up CT scans, demonstrating good agreement with mean deviations of 5.8% in local open area and 4.6 mm in stent strut position. Deployment of the SG increased the maximum principal stress by 24.30 kPa in the narrowed true lumen but reduced the stress by 31.38 kPa in the entry tear region where there was an aneurysmal expansion. Comparisons of simulation results with different levels of model complexity suggested that pre-stress of the aortic wall and blood pressure inside the SG should be included in order to accurately predict the deformation of the deployed SG.

Effect of Vessel Tortuosity on Stress Concentration at the Distal Stent-Vessel Interface: Possible Link With New Entry Formation Through Biomechanical Simulation

A computational approach is used to investigate potential risk factors for distal stent graft-induced new entry (dSINE) in aortic dissection (AD) patients. Patient-specific simulations were performed based on computed tomography images acquired from six AD patients (three dSINE and three non-dSINE) to analyze the correlation between anatomical characteristics and stress/strain distributions. Sensitivity analysis was carried out using idealized models to independently assess the effect of stent graft length, stent tortuosity and wedge apposition angle at the landing zone on key biomechanical variables. Mismatch of biomechanical properties between the stented and nonstented regions led to high stress at the distal stent graft-vessel interface in all patients, as well as shear strain in the neighboring region, which coincides with the location of tear formation. Stress was observed to increase with the increase of stent tortuosity (from 263 kPa at a tortuosity angle of 50 deg to 313 kPa at 30 deg). It was further amplified by stent graft landing at the inflection point of a curve. Malapposition of the stent graft led to an asymmetrical segment within the aorta, therefore changing the location and magnitude of the maximum von Mises stress substantially (up to +25.9% with a +25 deg change in the distal wedge apposition angle). In conclusion, stent tortuosity and wedge apposition angle serve as important risk predictors for dSINE formation in AD patients.

Changes of stent-graft orientation after frozen elephant trunk treatment in aortic dissection

OBJECTIVES

Our goal was to evaluate the extent of stent-graft (SG) elastic recoil in the descending aorta after the frozen elephant trunk procedure in acute (AAD) and chronic (CAD) aortic dissection as well as the impact of SG movement on distal stent graft-induced new entry (d-SINE).

METHODS

We retrospectively analysed 149 (105 AAD, 44 CAD) of 259 aortic dissection patients after the frozen elephant trunk procedure between January 2005 and April 2019. Inclusion criteria were at least 1-year computed tomography angiography (CTA) aortic examinations during a follow-up time of 3.8 ± 2.7 years and absence of open or endovascular reintervention. Multiplanar reconstruction of CTA scans was used to define the SG vector position and movement in a virtual Cartesian coordinate system. The angle φ of vector movement and changes of aortic areas at the distal landing zone were analysed.

RESULTS

The distal SG position changed over time in the cranial (10.06 ± 11.12 mm), dorsal (8.45 ± 11.12 mm) and lateral (4.96 ± 9.89 mm) directions (P < 0.001). The total change of φ (4.08 ± 7.03°) was greater in AAD than in CAD (P = 0.026). d-SINE was more common in CAD (P < 0.001) and was associated with the size of the aortic area, aortic area enlargement and continuous SG unfolding (P < 0.001).

CONCLUSIONS

With the frozen elephant trunk technique, movement and change of SG orientation in the descending aorta were observed over time. Elastic recoil was greater in AAD than in CAD. The incidence of d-SINE was particularly dependent on the size of the aortic lumen and SG radial expansion and less on elastic recoil.

Computed Tomography Imaging of Aortic Dissections with Endovascular Treatment Considerations

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

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.

Diameter change in completely remodelled proximal descending aorta after acute type I dissection repair: implications for estimating the pre-dissection size

 

OBJECTIVES

Pre-dissection diameter of the proximal descending thoracic aorta (p-DTA), if available, would be the reference for determining the size of the stent graft or elephant trunk. Acute type B dissection is known to increase p-DTA diameter by 23% (Rylski factor). This study aimed to investigate the accuracy of estimating post-remodelling diameter of the p-DTA based on the Rylski factor and other post-dissection morphological parameters in acute type I dissection, based on the assumption that the post-remodelling diameter is similar to the pre-dissection diameter.

METHODS

In 60 patients with acute type I dissection showing complete remodelling of the p-DTA false lumen after surgical repair, preoperative and post-remodelling computed tomography scans were reviewed. Parameters, including maximal true lumen diameter (TLDmax) and aortic area-derived diameter divided by the Rylski factor (AoDRylski), were measured at the p-DTA.

RESULTS

After complete remodelling, p-DTA diameter decreased by 4.1 mm (P < 0.001). The equivalent to the Rylski factor was 15%. Both TLDmax and AoDRylski frequently showed ≥2 mm discrepancy from post-remodelling aortic diameter (36.7% and 48.3%, respectively, P = 0.30). When 2 parameters coincided within 2 mm, two-third of their estimations were accurate. AoDRylski was more accurate than TLDmax in patients with a large extent of circumferential dissection, and vice versa with less circumferential dissection (P = 0.027).

CONCLUSIONS

Prediction of post-remodelling aortic diameter relying on a single morphologic parameter carries a substantial risk of overestimation and underestimation. Evaluation based on the extent of circumferential dissection together with the 2 parameters may provide a more reliable estimation.

An unusual case of Thoraflex displacement after blunt thoracic trauma during skiing

We present a case of a patient, who had previously undergone a frozen elephant trunk procedure for acute non-A-non-B aortic dissection, and developed a traumatic new entry tear due to the displacement of the hybrid prosthesis while skiing. An emergency thoracic endovascular aortic repair was performed without postoperative complications.

Relevance of Aortic Dissection Chronicity to the Development of Stent Graft-induced New Entry

BACKGROUND

The relevance of aortic dissection chronicity to the development of stent graft-induced new entry (SINE) is unknown.

METHODS

This study enrolled 69 patients who underwent thoracic endovascular aortic repair (TEVAR) for chronic aortic dissection from January 2006 to December 2017 and were followed up for ≥6 months. Their medical records were reviewed retrospectively. Patients were stratified according to TEVAR timing into an early group (≤6 months from the onset of aortic dissection) and a late group (>6 months after the onset). The incidence of SINE as well as the interval between TEVAR and the development of SINE was compared between these groups.

RESULTS

During the follow-up period, SINE occurred in 12% (3/26) and 35% (15/43) of patients in the early and late groups, respectively (P = .029). The interval between TEVAR and SINE development was significantly longer in the late group than the early group (median, 92 days vs 1144 days, respectively; P = .002). According to the multivariate analysis results, the late group (hazard ratio, 3.667; 95% confidence interval, 1.037-12.968; P = .044) and the distal oversizing ratio (hazard ratio, 1.492; 95% confidence interval, 1.071-2.080; P = .018) were the independent predictors for SINE development.

CONCLUSIONS

TEVAR should be performed in the early period of the chronic phase to prevent SINE. Close and lifelong follow-up is mandatory for patients who undergo TEVAR >6 months after onset because SINE can develop several years after TEVAR in those patients.

Comparative Outcome Analysis of N-Butyl Cyanoacrylate Embolization of the False Lumen Versus Thoracic Endovascular Aortic Repair in Aortic Dissection

PURPOSE

To evaluate the feasibility, safety, and effectiveness of N-butyl cyanoacrylate (NBCA) embolization for the treatment of aortic dissection.

MATERIALS AND METHODS

In this single-center retrospective study conducted from February 2003 to June 2019, NBCA embolization of an aortic false lumen was attempted in 12 patients (median age, 59 y; range, 41-68 y) and thoracic endovascular aortic repair (TEVAR) was performed in 53 patients (median age, 59 y; range, 37-70 y) for aortic dissection with one or more indications of persisting pain, malperfusion, rupture or impending rupture, maximal aortic diameter ≥ 55 mm, and/or rapid aortic enlargement. The main exclusion criterion for embolization was the presence of fast blood flow in the aortic false lumen on aortography. The efficacy of NBCA embolization and TEVAR was compared by evaluating technical and clinical outcomes, repeat intervention-free survival (RFS), and overall survival (OS).

RESULTS

Technical success was achieved in 11 of the 12 patients treated with NBCA embolization (91.7%), and clinical success was achieved in 9 of these 11 (81.8%). No significant difference was found between embolization and TEVAR in clinical success rates (embolization, 81.8%; TEVAR, 84.9%; P = .409) or procedure-related complications (embolization, 1 patient [8.3%]; TEVAR, 4 patients [7.5%]; P = .701). In addition, embolization showed comparable 5-y RFS (embolization, 82.5% ± 9.3; TEVAR, 85.5% ± 4.8; P = .641) and 5-y OS (embolization, 100%; TEVAR, 95.4% ± 3.2; P = .744) rates to TEVAR.

CONCLUSIONS

NBCA embolization of the false lumen in aortic dissection seems to be a safe and effective treatment modality for the closure of false lumen in selected patients.

Endograft exclusion of the false lumen restores local hemodynamics in a model of type B aortic dissection

OBJECTIVE

Endovascular intervention in uncomplicated type B dissection has not been shown conclusively to confer benefit on patients. The hemodynamic effect of primary entry tear coverage is not known. Endovascular stent grafts were deployed in a model of aortic dissection with multiple fenestrations to study these effects. It is hypothesized that endograft deployment will lead to restoration of parabolic true lumen flow as well as elimination of false lumen flow and transluminal jets and vortices locally while maintaining distal false lumen canalization.

METHODS

Thoracic stent grafts were placed in silicone models of aortic dissection with a compliant and mobile intimal flap and installed in a flow loop. Pulsatile fluid flow was established with a custom positive displacement pump, and the models were imaged by four-dimensional flow magnetic resonance imaging. Full flow fields were acquired in the models, and velocities were extracted to calculate flow rates, reverse flow indices, and oscillatory shear index, the last two of which are measures of stagnant and disturbed flows.

RESULTS

Complete obliteration of the false lumen was achieved in grafted aorta, with normal parabolic flow profiles in the true lumen (maximal velocity, 30.4 ± 8.4 cm/s). A blind false lumen pouch was created distal to this with low-velocity (5.8 ± 2.7 cm/s) and highly reversed (27.9% ± 13.9% reverse flow index) flows. In distal free false lumen segments, flows were comparable to ungrafted conditions with maximal velocities on the order of 7.0 ± 2.1 cm/s. Visualization studies revealed forward flow in these regions with left-handed vortices from true to false lumen. Shear calculations in free false lumen regions demonstrated reduced oscillatory shear index.

CONCLUSIONS

Per the initial hypothesis, endovascular grafting improved true lumen hemodynamics in the grafted region. Just distally, a prothrombotic flow regimen was noted in the false lumen, yet free false lumen distal to this remained canalized. Clinically, this suggests a need for advancing endovascular intervention beyond sole entry tear coverage to prevent further false lumen canalization through uncovered fenestrations.

Re-TEVAR in treatment of stent graft-induced new entry between two non-overlapping stent-grafts: a case report

Background

Progress of the aortic disease after the stent graft treatment of aortic dissection implicates the potential risks of stent graft-induced new entry (SINE). Although rarely reported, it should be vigilant in patients who might incur serious complication in early period after the thoracic endovascular aortic repair (TEVAR). Thus, the development of aortic disease-specific stent grafts would assist in achieving positive patient outcomes when suffering SINE. However, it is an extremely rare for SINE between two non-overlapping stent-grafts.

Case presentation

We here reported a 59-year-old male patient with sudden onset of chest pain for 4 h. Multi-detector computed tomography (MDCT) revealed a huge SINE formed between two non-overlapping stent-grafts. The re-TEVAR surgery was performed and the patient experienced a good recovery.

Conclusion

The SINE between two non-overlapping stent-grafts treated by re-TEVAR operation was alternative and feasible. The short-term and medium-term follow-up results were satisfactory.

Dissected thoracoabdominal aortic aneurysm repair with modified parallel endografting

A 67-year-old woman with a prior history of aortic dissection was admitted for enlarging the thoracoabdominal aortic aneurysm (TAAA). She has received multiple treatments including Bentall procedure, hemiarch replacement, and subsequent endovascular procedures for the closure of re-entry. Preoperative computed tomography revealed previously implanted thoracic endograft from distal arch to superior mesenteric artery with dissected TAAA measuring up to 70 mm in diameter. Re-entry was observed at bilateral common iliac arteries. The patient was successfully treated by endovascular treatment using a fenestrated stent graft to obtain a landing zone for parallel endograft technique to the iliac arteries for the closure of re-entry.

Important issues regarding planning and sizing for emergent TEVAR

In the past decades, treatment of acute thoracic aortic syndrome underwent drastic changes with a central role for thoracic endovascular aortic repair (TEVAR). One of the essential factors in the success of TEVAR is accurate sizing of the endograft, as both under- and oversizing can lead to suboptimal results and disastrous complications. The aim of this review was to give an overview of issues regarding endograft sizing in emergent TEVAR. Sizing of the endograft can be complicated by specific factors related to the underlying disease. For instance, different types of the acute thoracic aortic syndrome, i.e. blunt thoracic injury, thoracic aortic aneurysm or dissection with concomitant rupture are associated with hemorrhagic shock and the need for resuscitation, which leads to profound changes in diameter of the thoracic aorta. These diameter changes should be taken into account during endograft sizing. Measuring the thoracic aorta based on the admission CTA can lead to inaccurate sizing, even if proper centerline-based measurements are performed. The use of real-time imaging, in particular intravascular ultrasound (IVUS), has been shown to provide more accurate endograft sizing in acute thoracic aortic syndromes, especially if associated with hypovolemia. Future research should provide additional data on the exact role of different intra-operative imaging modalities (e.g. IVUS, transesophageal echocardiography [TEE], three dimensional CTA) on endograft sizing and long-term outcomes to ultimately improve patient outcome.

Use of Fenestrated Stent-Grafts for Preservation of Spinal Artery Flow During Endovascular Repair of Thoracoabdominal Aortic Disease

We illustrate the safety and feasibility of the application of fenestrated stent-grafts for the preservation of spinal artery flow during endovascular repair of thoracoabdominal aortic aneurysms (TAAA) in 2 patients deemed high-risk for spinal cord ischemia (SCI). In one case, an unstented fenestration was used in a 78-year-old male treated for distal stent-graft induced new entry tear. In the other case, a fenestration with a bridging stent-graft was used to revascularize a spinal artery in a 66-year-old female with Marfan disease and island patch aneurysm following open TAAA reconstruction. Both procedures were successful without any postoperative neurologic complication. The unstented fenestration led to a type III endoleak that required the relining of the aortic stent-graft 2 years later. The stented spinal fenestration was patent at a 5-year imaging follow-up.

Landing Zone Remodelling after Endovascular Repair of Dissected Descending Aorta

OBJECTIVE

The aim of this study was to determine geometric changes in the proximal and distal aortic landing zones after thoracic endovascular aortic repair (TEVAR) for acute descending aortic dissection.

METHODS

This was a retrospective analysis of clinical and radiological data. Included are patients who underwent TEVAR for acute descending aortic dissection between 2004 and 2018. Analysed are the proximal and distal landing zones' initial geometries and their change at follow up. Median follow up time was 2.3 (first quartile 0.9, third quartile 4.5) years.

RESULTS

One hundred and one patients were included (93 type B and 8 non-A non-B dissections, aged 65 (57, 74) years old, and 29% female). Dissection extended down to the abdominal aorta in 69% patients. The proximal landing zone was non-dissected in 92 patients. The diameters of non-dissected proximal landing zones increased by 3 (-1, 5; p < .001) mm at follow up. The distal landing zone was dissected in 84% of patients. The diameters of dissected distal landing zones had increased at follow up by 7 (3, 12) mm and 4 (1, 10; both p < .001) mm measured in true lumen and total aorta, respectively, observed one year after TEVAR. Stent grafts reached their nominal diameter at follow up in 22% and 17% of proximal and distal landing zones, respectively. There were seven proximal and 10 distal stent graft induced new entries at follow up. Aortic re-intervention was necessary in 23 patients entailing 19 TEVAR extensions and four open aortic repairs.

CONCLUSION

The distal landing zone in patients undergoing TEVAR for descending aortic dissection is frequently dissected and is associated with the risk of d-SINE at follow up and the need for re-interventions after TEVAR - factors that emphasise the importance of long term follow up.

Parametric Hemodynamic 4D Flow MRI Maps for the Characterization of Chronic Thoracic Descending Aortic Dissection

BACKGROUND

Systematic evaluation of complex flow in the true lumen and false lumen (TL, FL) is needed to better understand which patients with chronic descending aortic dissection (DAD) are predisposed to complications.

PURPOSE

To develop quantitative hemodynamic maps from 4D flow MRI for evaluating TL and FL flow characteristics.

STUDY TYPE

Retrospective.

POPULATION

In all, 20 DAD patients (age = 60 ± 11 years; 12 male) (six medically managed type B AD [TBAD], 14 repaired type A AD [rTAAD] now with ascending aortic graft [AAo] or elephant trunk [ET1] repair) and 21 age-matched controls (age = 59 ± 10 years; 13 male) were included.

FIELD STRENGTH/SEQUENCE

1.5T, 3T, 4D flow MRI.

ASSESSMENT

4D flow MRI was acquired in all subjects. Data analysis included 3D segmentation of TL and FL and voxelwise calculation of forward flow, reverse flow, flow stasis, and kinetic energy as quantitative hemodynamics maps.

STATISTICAL TESTS

Analysis of variance (ANOVA) or Kruskal-Wallis tests were performed for comparing subject groups. Correlation and Bland-Altman analysis was performed for the interobserver study.

RESULTS

Patients with rTAAD presented with elevated TL reverse flow (AAo repair: P = 0.004, ET1: P = 0.018) and increased TL kinetic energy (AAo repair: P = 0.0002, ET1: P = 0.011) compared to controls. In addition, TL kinetic energy was increased vs. patients with TBAD (AAo repair: P = 0.021, ET1: P = 0.048). rTAAD was associated with higher FL kinetic energy and lower FL stasis compared to patients with TBAD (AAo repair: P = 0.002, ET1: P = 0.024 and AAo repair: P = 0.003, ET1: P = 0.048, respectively).

DATA CONCLUSION

Quantitative maps from 4D flow MRI demonstrated global and regional hemodynamic differences between DAD patients and controls. Patients with rTAAD vs. TBAD had significantly altered regional TL and FL hemodynamics. These findings indicate the potential of 4D flow MRI-derived hemodynamic maps to help better evaluate patients with DAD.

LEVEL OF EVIDENCE

3 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2020;51:1357-1368.

Surgical Outcomes And Postoperative Descending Aorta Morphologic Remodeling After Thoracic Endovascular Aortic Repair For Acute And Chronic Type B Aortic Dissection

Background

This study aims to investigate the descending aortic morphological alterations caused by pathological changes in acute and chronic Type B aortic dissection (TBAD) and morphological remodeling after thoracic endovascular aortic repair (TEVAR).

Patients and methods

From February 2012 to January 2016, 86 TBAD patients undergoing TEVAR were divided into an acute group (n=63) and a chronic group (n=23). The areas of the true, false and maximal lumen and descending aorta morphological parameters, including the taper ratio (TR), oversizing ratio (OR), mismatch ratio (MR), radius of curvature (RoC) and tortuosity index (TI), were evaluated. Follow-ups were performed postoperatively before discharge, at 1 and 6 months, and yearly thereafter.

Results

Before TEVAR, the TR (0.57 (0.49) vs 0.74 (0.60); P < 0.05), OR (2.75 ± 1.89 vs 3.96 ± 2.27; P < 0.05) and TI (1.22 (1.19) vs 1.41 ± 0.17; P < 0.05) were significantly higher in the chronic group than in the acute group. The TEVAR technical success rate was 100%. No differences were found in 30-day and >30-day mortality between the two groups. Pathology-specific devices, such as tapered stent grafts and distal bare stents, were used more frequently in the chronic group than in the acute group (47.8% vs 23.8%, P = 0.03; 43.5% vs 12.7%, P = 0.002, respectively). The OR and TI changes that occurred after TEVAR were significantly higher in the chronic group than in the acute group (1.80 ± 0.86 vs 2.98 ± 1.85, P = 0.028; 0.00 ± 0.09 vs 0.09 ± 0.10, P < 0.001, respectively).

Conclusion

TEVAR is a safe and effective therapy for acute and chronic TBAD. Compared to acute TBAD, chronic TBAD resulted in an adverse preoperative descending aorta morphology. Pathology-specific devices may be a feasible treatment option for endovascular repair of chronic TBAD. A larger series of cases with longer follow-up are needed to draw definitive conclusions.