Stent graft–induced new entry tear (SINE): Intentional and NOT

Efficacy of intentional undersized thoracic endovascular repair for Stanford type B aortic dissection

OBJECTIVE

Thoracic endovascular aneurysm repair (TEVAR) is widely used for the treatment of aortic dissection. Endograft oversizing is a risk factor for stent graft-induced new entry tears and retrograde type A aortic dissection. However, there is no clear consensus on the optimal graft size selection for Stanford type B acute or subacute aortic dissection (TBAD). Herein, we examined the safety and efficacy of TEVAR using an intentionally undersized endograft to treat TBAD.

METHODS

This retrospective chart review study included 82 patients who underwent TEVAR for acute or subacute Stanford TBAD between 2015 and 2022. We measured the true lumen diameter just distal to the subclavian artery and opted for a stent graft of the same diameter. In instances where deformation resulting from false lumen pressure displacement was pronounced, we measured the diameter at the site just proximal to the subclavian artery. Patients' characteristics, procedural, in-hospital, and follow-up data, and aortic remodeling were analyzed. The aortic diameter was analyzed using one-way analysis of variance followed by Dunnett's test. Survival and freedom from reintervention were estimated using Kaplan-Meier curves.

RESULTS

The follow-up rate was 98.4%. The mean age was 58.3 ± 12.3 years, and 76 were men (92.7%). The mean diameters of the stent graft and native proximal landing zone were 30.9 ± 3.2 mm and 30.8 ± 3.0 mm, respectively. The oversize rate of the stent graft in relation to the native proximal aortic diameter was 0.3% ± 4.7%. In-hospital mortality was observed in one patient, retrograde type A aortic dissection in one patient, distal stent graft-induced new entry tear in zero patients, and type 1a endoleak in 22 patients (26.8%). Type 1a endoleaks, characterized by antegrade false lumen blood flow originating from the primary entry, in 12 patients spontaneously disappeared within 1 year of follow-up. According to aortic remodeling, 59 patients (86.8%) achieved complete aortic remodeling at the aortic arch level and 51 (75.0%) at the eighth thoracic vertebral level. The diameters of the aortic arch and descending aorta were significantly reduced compared with the postoperative measurements (P <.001). Survival rates were 97.5% and 93.6% at 1 and 3 years, respectively. Freedom from reintervention was 84.7% and 84.7% at 1 and 3 years, respectively.

CONCLUSIONS

Intentionally undersized TEVAR was safe and achieved acceptable aortic remodeling despite a high rate of type 1a endoleaks. A type 1a endoleak was acceptable as it primarily diminished during the mid-term follow-up.

A Case of Aortic Strain due to Spring Back Force by Stent Graft 3 Years after Thoracic Endovascular Aortic Repair

A 79-year-old man underwent 1-debranched thoracic endovascular aortic repair (TEVAR) for a saccular aneurysm of the distal arch of the aorta. Computed tomography performed 3 years after surgery revealed a significant displacement of the distal side of the stent graft and severe deformity due to displacement of the aorta. There were no obvious findings after aortic dissection. Endovascular treatment was selected, and surgery was performed semiemergency. Additional TEVAR was performed to restore the aortic shape and displacement to its normal position.

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.

Transcatheter electrosurgical septotomy technique for chronic postdissection aortic aneurysms

Aortic dissection often results in chronic aneurysmal degeneration due to progressive false lumen expansion. Thoracic endovascular aortic repair and other techniques of vessel incorporation such as fenestrated-branched or parallel grafts have been increasingly used to treat chronic postdissection aneurysms. True lumen compression or a vessel origin from the false lumen can present considerable technical challenges. In these cases, the limited true lumen space can result in inadequate stent graft expansion or restrict the ability to reposition the device or manipulate catheters. Reentrance techniques can be used selectively to assist with target vessel catheterization. Transcatheter electrosurgical septotomy is a novel technique that has evolved from the cardiology experience with transseptal or transcatheter aortic valve procedures. This technique has been applied in select patients with chronic dissection to create a proximal or distal landing zone, disrupt the septum in patients with an excessively compressed true lumen, or connect the true and false lumen in patients with vessels that have separate origins. In the present report, we summarize the indications and technical pitfalls of transcatheter electrosurgical septotomy in patients treated by endovascular repair for chronic postdissection aortic aneurysms.

Long-term outcomes for hybrid aortic arch repair

OBJECTIVE

Since its inception in the early 2000s, hybrid arch repair (HAR) has evolved from novel approach to well-established treatment modality for aortic arch pathology in appropriately selected patients. Despite this nearly 20-year history of use, long-term results of HAR remain to be determined. As such, objectives of this study are to detail the long-term outcomes for HAR within an expanded classification scheme.

METHODS

From August 2005 to August 2022, 163 consecutive patients underwent HAR at a single referral institution. Operative approach was selected according to an institutional algorithm and included zone 0/1 HAR in 25% (n = 40), type I HAR in 34% (n = 56), and type II/III HAR in 41% (n = 67). Specific zone 0/1 technique was zone 1 HAR in 31 (78%), zone 0 with innominate snorkel (zone 0S HAR) in 7 (18%), and zone 0 with single side-branch endograft (zone 0B HAR) in 2 (5%). The 30-day and long-term outcomes, including overall and aortic-specific survival, as well as freedom from reintervention, were assessed.

RESULTS

The mean age was 63 ± 13 years and almost one-half of patients (47% [n = 77]) had prior sternotomy. Presenting pathology included degenerative aneurysm in 44% (n = 71), residual dissection after prior type A repair in 38% (n = 62), chronic type B dissection in 12% (n = 20), and other indications in 6% (n = 10). Operative outcomes included 9% mortality (n = 14) at 30 days, 5% mortality (n = 8) in hospital, 4% stroke (n = 7), 2% new dialysis (n = 3), and 2% permanent paraparesis/plegia (n = 3). The median follow-up was 44 month (interquartile range, 12-84 months). Overall survival was 59% and 47% at 5 and 10 years, respectively, whereas aorta-specific survival was 86% and 84% at the same time points. At 5 and 10 years, freedom from major reintervention was 92% and 91%, respectively. Institutional experience had a significant impact on both early and late outcomes: comparing the first (2005-2012) and second (2013-2022) halves of the series, 30-day mortality decreased from 14% to 1% (P = .01) and stroke from 6% to 3% (P = .62). Improved operative outcomes were accompanied by improved late survival, with 78% of patients in the later era vs 45% in the earlier era surviving to 5 years.

CONCLUSIONS

HAR is associated with excellent operative outcomes, as well as sustained protection from adverse aortic events as evidenced by high long-term aorta-specific survival and freedom from reintervention. However, surgeon and institutional experience appear to play a major role in achieving these superior outcomes, with a five-fold decrease in operative mortality and a two-fold decrease in stroke rate in the latter half of the series. These long-term results expand on prior midterm data and continue to support use of HAR for properly selected patients with arch disease.

Hostile Hemodynamics in Distal Stent Graft-Induced New Entry Prior to Aortic Rupture: A Comparison of Transient versus Steady-State CFD Simulations

BACKGROUND

 Computational fluid dynamics (CFD) simulations model blood flow in aortic pathologies. The aim of our study was to understand the local hemodynamic environment at the site of rupture in distal stent graft-induced new entry (dSINE) after frozen elephant trunk with a clinically time efficient steady-flow simulation versus transient simulations.

METHODS

 Steady-state simulations were performed for dSINE, prior and after its development and prior to aortic rupture. To account for potential turbulences due geometric changes at the dSINE location, Reynolds-averaged Navier-Stokes equations with the realizable k-ε model for turbulences were applied. Transient simulations were performed for comparison. Hemodynamic parameters were assessed at various locations of the aorta.

RESULTS

 Post-dSINE, jet-like flow due to luminal narrowing was observed which increased prior to rupture and resulted in focal neighbored regions of high and low wall shear stress (WSS). Prior to rupture, aortic diameter at the rupture site increased lowering WSS at the entire aortic circumference. Concurrently, WSS and turbulence increased locally above the entry tear at the inner aortic curvature. Turbulent kinetic energy and WSS elevation in the downstream aorta demonstrated enhanced stress on the native aorta. Results of steady-state simulations were in good qualitative agreement with transient simulations.

CONCLUSION

 Steady-flow CFD simulations feasible at clinical time scales prior to aortic rupture reveal a hostile hemodynamic environment at the dSINE rupture site in agreement with lengthy transient simulations. Consequently, our developed approach may be of value in treatment planning where a fast assessment of the local hemodynamic environment is essential.

Implantation of ascyrus medical dissection stent, our first-hand experience

BACKGROUND

Acute type A aortic dissection is associated with high perioperative morbidity and mortality. Ascyrus Medical Dissection Stent (Cryolife, Kennesaw, USA) is a novel uncovered hybrid stent graft developed to be used as an adjunct to standard surgical approach to promote true lumen expansion and enhance aortic remodeling.

METHODS

From March 2021 to March 2022, four consecutive patients presented with acute Debakey type I aortic dissection and underwent emergent surgical repair with Tirone David procedure and implantation of Ascyrus Medical Dissection Stent. We reviewed patient's files retrospectively and described the perioperative outcomes.

RESULTS

All four device implantations were successful. Overall 30-day mortality was 0%. Malperfusion that was present in two patients pre-operatively improved after Ascyrus Medical Dissection Stent implantation. No aortic reinterventions were needed. No aortic injury related to the device was noted. Favourable changes in aortic true lumen and false lumen dimensions were found in most of our patients but the stent was compressed at the isthmus in one patient.

CONCLUSION

Ascyrus Medical Dissection Stent is a reliable and secure device. However, its benefits remain unclear when it comes to a positive remodeling and seems less likelihood comparable to a frozen elephant trunk. The main reason seems to be an insufficient radial force of the stent.

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.

Partial arch replacement of type A aortic dissection after thoracic endovascular aortic repair for type B dissection

BACKGROUND

Stent graft-induced new entry (SINE), defined as the stent graft-induced formation of a new entry point for blood to enter an area, is increasingly being observed after thoracic endovascular aortic repair (TEVAR) for Stanford type B aortic dissection worldwide. We herein describe a case of Stanford type A aortic dissection due to proximal SINE after TEVAR for Stanford type B dissection.

CASE PRESENTATION

This case involved a 58-year-old man with type A aortic dissection due to SINE. Six years previously, he had developed severe back pain and was diagnosed with type B aortic dissection after computed tomography examination. Because the primary entry was positioned at the descending aorta, we conducted TEVAR for exclusion of the entry with a GORE TAG conformable thoracic aortic graft. He was thereafter followed by our hospital. Six years later, he developed jaw pain and was examined at another hospital. He was transferred to our hospital because of the possibility of type A dissection. Computed tomography revealed type A aortic dissection with proximal site SINE. Emergency partial arch replacement was conducted, and he was discharged on postoperative day 27. Because the entry was at the lesser curve of the arch, we excluded the entry and conducted partial arch replacement.

CONCLUSIONS

In this case, proximal SINE occurred 6 years after TEVAR. Because SINE may occur even in the long term after TEVAR, careful follow-up is necessary.

Tailored approach and outcomes of aortic arch reconstruction after acute type A dissection repair

OBJECTIVE

After limited root/ascending with or without hemiarch repair for acute type A aortic dissection (ATAAD), 20% to 30% of patients require distal reintervention, frequently for arch pathology. In this report, we describe an institutional algorithm for arch management after previous limited ATAAD repair and detail operative and long-term outcomes.

METHODS

From August 2005 to April 2021, 71 patients status post previous limited ATAAD repair underwent reoperative arch repair involving zones 1 to 3 for aneurysmal degeneration of residual arch dissection including complete cervical debranching with zone 0/1 thoracic endovascular aortic repair in 6 (8%), open total arch in 13 (18%), type I hybrid arch repair in 23 (32%), and type II/III hybrid arch repair in 29 (41%).

RESULTS

Mean age was 59 ± 12 years; time from index ATAAD repair to reoperation was 4 (interquartile range, 2-9) years. There were 2 (2.8%) in-hospital deaths and 2 (2.8%) postdischarge deaths within 30 days of surgery. Three patients suffered stroke (4.2%) and 2 (2.8%) had acute renal failure requiring dialysis. Overall Kaplan-Meier survival was 78%, 70%, and 58% at 1, 3, and 5 years, respectively. Institutional experience appeared to play a significant role in early and late outcomes, because there have been no operative mortalities in the past 9 years and improved survival of 87% versus 66%, 79% versus 58%, and 79% versus 40% at 1, 3, and 5 years in comparisons of the past 9 years with the previous era (P = .01).

CONCLUSIONS

Aneurysmal degeneration of residual arch dissection after limited ATAAD repair presents a complex reoperative challenge. An algorithmic operative approach tailored to patient anatomy and comorbidities yields excellent early and late outcomes, which continue to improve with increasing institutional experience.

How to treat type 1b endoleakage-extension, fEVAR, bEVAR, or open repair

Thoracic endovascular aneurysm repair has been well described in the literature as a treatment for a wide range of thoracic aortic pathologies. As with any intervention, there remains a risk of an unfavorable outcome, including endoleak, a term used to describe unexpected blood flow between the stent-graft and the wall of the excluded aneurysm. Endoleaks cause pressurized enlargement of the aneurysmal sac and may lead to catastrophic outcomes such as rupture and death. Type 1b endoleak represents a distal landing zone that is compromised by retrograde blood flow. Moreover, there is a lack of data on type 1b endoleaks and its management options. With the increase in emerging endovascular techniques and technologies, endoleaks are more frequent. However, the management of endoleaks is not standardized among different centers. The purpose of this article is to provide an overview of type 1b endoleaks after thoracic endovascular aneurysm repair, current management options, and our experience.

Hemodynamic parameters impact the stability of distal stent graft-induced new entry

Stent graft-induced new entry tear (SINE) is a serious complication in aortic dissection patients caused by the stent-graft itself after thoracic endovascular aortic repair (TEVAR). The stability of SINE is a key indicator for the need and timing of reinterventions. This study aimed to understand the role of hemodynamics in SINE stability by means of computational fluid dynamics (CFD) analysis based on patient-specific anatomical information. Four patients treated with TEVAR who developed a distal SINE (dSINE) were included; two patients had a stable dSINE and two patients experienced expansion of the dSINE upon follow-up examinations. CFD simulations were performed on geometries reconstructed from computed tomography scans acquired upon early detection of dSINE in these patients. Computational results showed that stable dSINEs presented larger regions with low time-averaged wall shear stress (TAWSS) and high relative residence time (RRT), and partial thrombosis was observed at subsequent follow-ups. Furthermore, significant systolic antegrade flow was observed in the unstable dSINE which also had a larger retrograde flow fraction (RFF) on the SINE plane. In conclusion, this pilot study suggested that high RRT and low TAWSS may indicate stable dSINE by promoting thrombosis, whereas larger RFF and antegrade flows inside dSINE might be associated with its expansion.

Imaging Challenges in Chronic Dissection

Chronic aortic dissection comprises a heterogeneous group of unrepaired and repaired disease requiring lifelong clinical and imaging surveillance. CT and MRI are the main imaging modalities for longitudinal surveillance, with growing interest in emerging imaging techniques for prognostic potential. Imaging difficulties span technical and diagnostic challenges, some of which are unique to the repaired aorta, with specific complications depending on the type of repair. This review describes existing and emerging imaging techniques, outlines the technical and diagnostic challenges encountered at CT and MRI, and highlights the diagnostic pitfalls of chronic aortic dissection.

Thoracic Endovascular Aortic Repair for Chronic Type B Aortic Dissection: Pre- and Postprocedural Imaging

Aortic dissection is a chronic disease that requires lifelong clinical and imaging surveillance, long after the acute event. Imaging has an important role in prognosis, timing of repair, device sizing, and monitoring for complications, especially in the endovascular therapy era. Important anatomic features at preprocedural imaging include the location of the primary intimal tear and aortic zonal and branch vessel involvement, which influence the treatment strategy. Challenges of repair in the chronic phase include a small true lumen in conjunction with a stiff intimal flap, complex anatomy, and retrograde perfusion from distal reentry tears. The role of thoracic endovascular aortic repair (TEVAR) remains controversial for treatment of chronic aortic dissection. Standard TEVAR is aimed at excluding the primary intimal tear to decrease false lumen perfusion, induce false lumen thrombosis, promote aortic remodeling, and prevent aortic growth. In addition to covering the primary intimal tear with an endograft, several adjunctive techniques have been developed to mitigate retrograde false lumen perfusion. These techniques are broadly categorized into false lumen obliteration and landing zone optimization strategies, such as the provisional extension to induce complete attachment (PETTICOAT), false lumen embolization, cheese-wire fenestration, and knickerbocker techniques. Familiarity with these techniques is important to recognize expected changes and complications at postintervention imaging. The authors detail imaging options, provide examples of simple and complex endovascular repairs of aortic dissections, and highlight complications that can be associated with various techniques. Online supplemental material is available for this article. ^©RSNA, 2022.

Endovascular reintervention after frozen elephant trunk: where is the evidence?

The introduction of the single-step hybrid frozen elephant trunk (FET) procedure for total arch replacement has revolutionized the field of aortovascular surgery. FET has proven to achieve excellent results in the repair of complex thoracic aorta pathologies. However, there remains a risk of reintervention post-FET for a variety of causes. This secondary intervention can either be performed endovascular, with thoracic endovascular aortic repair (TEVAR), or via open surgery. Multiple FET hybrid prosthesis are commercially available, each requiring different rates of endovascular reintervention. The current review will focus on providing an overview of the reintervention rates for main causes in relation to the FET grafts on the market. In addition, strategies to prevent reintervention will be highlighted. A comprehensive literature search was conducted on multiple electronic databases including PubMed, Ovid, Scopus and Embase to highlight the evidence in the literature on endovascular reintervention after FET. The main causes for secondary intervention are distal stent graft-induced new entry (dSINE), endoleak and negative aortic remodeling, and to a much lesser extent, graft kinking and aorto-esophageal fistulae. In addition, it is clear that the Thoraflex Hybrid (Terumo Aortic, Inchinnan, UK) is the superior FET device, showing excellent reintervention rates for all the above causes. Interestingly, the choice of FET device as well as its size and length can help prevent the need for reintervention. The FET procedure is indeed associated with excellent clinical outcomes, however, the need for reintervention may still arise. Importantly, the Thoraflex Hybrid prosthesis has shown excellent results when it comes to endovascular reintervention. Finally, several strategies exist that can prevent reintervention.

[Chronic type B aortic dissection-what to do?]

BACKGROUND

Chronic type B aortic dissection requires optimal medical therapy. However, secondary complications like organ or extremity malperfusion or development of aneurysmal dilatation require interventional therapy.

OBJECTIVES

Presentation of different endovascular treatment options for complications of chronic type B aortic dissection.

MATERIALS AND METHODS

Analysis of current literature with regard to indications, techniques, results, and differential indications of interventional techniques for the treatment of chronic type B aortic dissection complications.

RESULTS

Endovascular implantation of an aortic stent graft is interventional standard therapy for treatment of aneurysmal dilatation of the aorta following type B dissection. Technical problems are the proximal and distal landing zones and the treatment of persistent flow in the false lumen.

CONCLUSION

Endovascular treatment of chronic complicated type B aortic dissection is increasingly used compared to open surgical treatment because not only are more complex stent grafts (fenestrated and branched devices) available but also because of newly developed techniques for effective occlusion of flow in the false lumen (e.g., candy plug).

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Stent Graft-Induced Aortic Wall Injury (SAWI) - Incidence, Risk Factors, and Outcomes

BACKGROUND

Stent graft-induced new entry (SINE) has been described in thoracic endovascular aortic repair (TEVAR) for aortic dissection. The incidence of stent graft-induced aortic wall injury (SAWI) related to iatrogenic injury in non-dissections is incompletely described. We describe incidence, risk factors, and outcomes of SAWI.

METHODS

All post-TEVAR CT angiograms (1/2005-12/2018) were reviewed for radiographic evidence of SAWI. Endograft-induced aortic dissections were likewise considered SAWI. Patient characteristics, time to SAWI, and need for re-intervention were noted. Cox proportional hazards modeling was used to identify risk factors for SAWI.

RESULTS

Within the study cohort (n=430), 38 (9%) patients developed SAWI during a median follow-up of 2.3 years (IQR 4.8 years). 42% (n=16) of SAWI were proximal, 53% (n=20) distal and 5% (n=2) both proximal and distal. Nine (23%) were distal intimal flap injuries in dissection cases, thus sub-classifying them as SINE. 29% (n=11) of SAWI required re-intervention. Of these, 45% (n=5) were open and 55% (n=6) endovascular. TEVAR for acute dissection had a higher incidence of SAWI development (HR 4.6, 95% CI: [2.4, 9.0]; p<0.001) as compared to other indications. Use of devices with proximal bare springs or barbs was also associated with increased SAWI incidence (HR 5.3, 95% CI: [2.6, 11.0]; p<0.001).

CONCLUSIONS

The rate of SAWI following TEVAR is low (9%), but nearly one-third will require re-intervention. TEVAR in the setting of acute dissection and use of devices with proximal bare springs or barbs were associated with an increased incidence of SAWI.

Unexpected Bare Metal Stent Migration Associated With Aortic Remodeling After PETTICOAT Technique for Aortic Dissection

PURPOSE

To report a unique case of bare metal stent migration in the overlapping zone and subsequent distal stent graft-induced new entry (SINE) after the Provisional Extension to Induce a Complete Attachment (PETTICOAT) technique for aortic dissection.

CASE REPORT

A 67-year-old man underwent thoracic endovascular aortic repair (TEVAR) using the PETTICOAT technique for acute complicated type B aortic dissection. The postoperative course was uneventful, and follow-up computed tomography (CT) showed not only favorable aortic remodeling but also progressive bare metal stent migration in the overlapping zone between the stent graft and the bare metal stent. A 6-month postoperative CT revealed a distal SINE, and the patient underwent re-TEVAR to cover the new entry. Postoperative CT demonstrated successful repair of the distal SINE. The patient is currently in good health 2 years after the reintervention.

CONCLUSION

Surgeons should consider the potential risk of device migration due to favorable aortic remodeling after TEVAR for aortic dissection, especially with the use of additional bare metal stents.

Distal Stent Graft-Induced New Entry after Total Arch Replacement with Frozen Elephant Trunk for Aortic Dissection

Objectives: Distal stent graft-induced new entry (dSINE), defined as a new tear caused by a stent graft, has been increasingly observed following total arch replacement using frozen elephant trunk (FET) for aortic dissection. We aimed to investigate the incidence and treatment of dSINE after the use of FET. Methods: This retrospective study evaluated 70 patients who underwent total arch replacement using FET for aortic dissection between August 2014 and March 2020. They were followed up for at least 6 months postoperatively. Between-group comparisons were performed between those who did and did not develop dSINE. The risk factors for the development of dSINE and the treatment of dSINE were analyzed. Results: dSINE occurred postoperatively in nine patients (12.9%) with a median time frame of 17.7±11.7 months. The incidence of dSINE did not differ significantly according to classification, phase of dissection, or oversizing. All patients in the dSINE group developed enlargement of the false lumen. dSINE closure was successfully achieved without complications via thoracic endovascular aortic repair (TEVAR) in all patients. Conclusion: No independent factors predicting the development of dSINE were noted in this study. Additional TEVAR for dSINE provides good results and achieves false lumen thrombosis in the thoracic aorta, with no complications.

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.

Aortic septotomy to optimize landing zones during thoracic endovascular aortic repair for chronic type B aortic dissection

OBJECTIVE

The role of thoracic endovascular aortic repair for chronic type B aortic dissection remains controversial. Clinical outcomes of thoracic endovascular aortic repair with recently implemented aortic septotomy strategy were compared with stand-alone thoracic endovascular aortic repair.

METHODS

Between 2008 and 2020, 88 patients with chronic type B aortic dissection and degenerative aortic aneurysm underwent a thoracic endovascular aortic repair with or without adjunctive aortic septotomy, consisting of 36 (41%) with de novo chronic type B aortic dissection and 52 (59%) with residual chronic type B aortic dissection after type A aortic dissection repair.

RESULTS

Aortic septotomy was performed in 31 patients (35%) to optimize the proximal (3/31;10%) and distal (31/31;100%) landing zones. The aortic septotomy techniques comprised laser aortic septotomy in 16 patients (52%) and cheese wire septotomy in 15 patients (48%) with a 97% overall technical success rate. The median time interval between aortic dissection occurrence and thoracic endovascular aortic repair was 1.2 years. During follow-up, there were 12 (21%) sudden deaths and 17 (30%) combined aorta-related and sudden deaths in the nonaortic septotomy group, whereas there were no deaths in the septotomy group (P < .001). Patients without aortic septotomy required aortic reinterventions more frequently than those with aortic septotomy (30% vs 7%; P = .014), and 77% of these procedures were related to residual retrograde false lumen flow. Positive aortic remodeling was confirmed in 90% and 37% in the aortic septotomy and nonseptotomy groups, respectively (P < .001).

CONCLUSIONS

Stand-alone thoracic endovascular aortic repair outcomes without adjunctive procedures for chronic type B aortic dissection remain unfavorable. In contrast, landing zone optimization using aortic septotomy resulted in a remarkably higher positive aortic remodeling rate. Routine aortic septotomy strategy may positively affect long-term chronic type B aortic dissection survival and expand thoracic endovascular aortic repair candidacy.

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.

Surgical strategies in the management of chronic dissection of the thoracoabdominal aorta

Most operations for dissection of the thoracoabdominal aorta take place in the chronic phase of the disease, because the acutely dissected distal aorta is almost always initially treated non-surgically with aggressive pharmacological anti-impulse therapy. Identifying patients who are no longer responding to medical treatment is the first step in preventing further disease progression and rupture. Symptomatic aneurysms should be promptly repaired. Asymptomatic patients are followed until significant aortic dilation occurs and reaches a threshold of intervention: current guidelines endorse repair once a diameter of 5.5 cm is reached. In patients with heritable thoracic aortic disease (such as Marfan Syndrome), the threshold of intervention is often lowered. Aortic replacement typically centers on the dilatated segment. For all extents of repair, we use passive mild hypothermia, sequential aortic cross-clamping, aggressive reimplantation of intercostal and lumbar arteries, and cold renal perfusion whenever possible. For Crawford extents I and II thoracoabdominal aneurysm repair, we routinely use cerebrospinal fluid drainage, left heart bypass, and selective visceral perfusion. A four-branched graft approach to thoracoabdominal aortic aneurysm repair is frequently used in patients with chronic aortic dissection; this approach facilitates visceral artery perfusion during repair, expedites the distal anastomosis, and prevents subsequent visceral patch aneurysms. Lifelong imaging surveillance is necessary, because the distal aorta often continues to expand; residual aortic dissection commonly remains after repair and may necessitate further repair.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

The provisional extension to induce complete attachment technique is associated with abdominal aortic remodeling and reduces aorta-related adverse events after aortic dissection

OBJECTIVE

This study evaluated the efficacy of the provisional extension to induce complete attachment (PETTICOAT) technique for type B and postoperative residual type B aortic dissections compared with the conventional thoracic endovascular aortic repair (TEVAR) technique.

METHODS

In this retrospective study, we compared sequential aortic morphologic changes in consecutive patients with type B and postoperative residual type B aortic dissections treated with the PETTICOAT technique between January 2016 and December 2017 with patients treated with the conventional TEVAR between January 2013 and December 2015. Outcomes included aortic remodeling and aorta-related adverse events for 2 years postoperatively.

RESULTS

Forty-eight patients were included in this study (24 in the PETTICOAT group, 24 patients in the conventional TEVAR group). Although both groups showed aortic remodeling in the descending thoracic aorta, the PETTICOAT group developed significantly better aortic remodeling in the abdominal aorta compared with the conventional TEVAR group during the observation period. The PETTICOAT group had significantly fewer aorta-related adverse events compared with the conventional TEVAR group (8% vs 54%; P < .001). Aorta-related adverse events more commonly occurred in the poor remodeling group compared with in the good remodeling group (P = .001; hazard ratio, 8.32; 95% confidence interval, 2.26-30.64).

CONCLUSIONS

This study suggests that the PETTICOAT technique for aortic dissection may promote aortic remodeling and decrease the incidence of aorta-related adverse events. Additional studies are required to confirm these preliminary findings.

One-Year Single-Center Results of the Multilayer Flow Modulator Stents for the Treatment of Type B Aortic Dissection

Purpose

To report a single-center series of patients with type B aortic dissection treated with the Multilayer Flow Modulator (MFM).

Materials and Methods

Over a 36-month period, 23 patients (median age 53 years; 20 men) with complicated type B aortic dissections (2 acute, 5 subacute, and 16 chronic) were treated with the MFM. Primary endpoints of rupture or dissection-related death, overall mortality, and reintervention were evaluated using the Kaplan-Meier method; estimates for freedom from the endpoints are reported with the 95% confidence interval (CI). Secondary outcomes included technical success, adverse events, and aortic remodeling. Clinical and imaging data were collected preoperatively, directly postoperatively, and annually to 36 months for analysis using computational fluid dynamics (CFD).

Results

Initial technical success was 91.3%. The estimates of the endpoints at 12 months were 100% for freedom from rupture or aortic-related death, 95.7% for freedom from overall mortality, and 91.3% for freedom from reintervention. No device-related neurological or systemic complications occurred, and no additional reinterventions were needed during follow-up. A total of 144 branches overstented by the MFM remained patent. Morphologic analysis of the aortic dissection showed progressive true lumen volume increase (75.9%, p<0.001) with concomitant false lumen volume decrease (42.8%, p<0.001); the CFD analyses showed increased laminar flow.

Conclusion

In the current series, the MFM provided a safe and feasible treatment option for complicated acute, subacute, and chronic type B aortic dissections, with high technical success, low mortality, and active aortic remodeling. Further studies should elucidate the long-term safety of the MFM and its effectiveness in a larger patient cohort.

Laser aortic septotomy during thoracic endovascular aortic repair for chronic type B aortic dissection

OBJECTIVE

Persistent false lumen perfusion due to the presence of a thick aortic septum is a significant obstacle to successful thoracic endovascular aortic repair for chronic type B aortic dissection (cTBAD). We describe our new approach of laser aortic septotomy to optimize the landing zone.

METHODS

Between 2019 and 2020, 11 patients with cTBAD with degenerative aneurysm underwent laser aortic septotomy during thoracic endovascular aortic repair. A prospectively maintained database was retrospectively reviewed.

RESULTS

The median age was 70.0 years, and 10 (91%) were men. Six (55%) were de novo type B aortic dissection and 5 (45%) were residual type B aortic dissection. The age of aortic dissection was 2.9 years (interquartile range, 1.1-12.1). Technical success was achieved in 91% (10/11). In 1 case (9%), laser aortic septotomy was not feasible due to extremely tortuous aorta. Among successful cases, the median extents of proximal and distal laser fenestrations were Th7.5 and Th11.0, respectively and distal landing zones included zone 4 (40%) and zone 5 (60%). Two (18%) underwent a continuous longitudinal laser fenestration, and 8 (73%) had longitudinal spot laser fenestrations with immediate balloon dilatations. Apposition of the stent-graft to the outer aortic wall of the newly created common aortic lumen with elimination of retrograde false lumen flow was achieved in all cases.

CONCLUSIONS

This is the first description using the laser technology to optimize the distal landing zone for cTBAD. This new technique is safe and reproducible, with excellent controllability to achieve aortic septotomy at the desired target aorta segment.

Management of a Compromised Frozen Elephant Trunk Due to Acute Type B Aortic Dissection

PURPOSE

To report a case who required a thoracic endovascular stenting (TEVAR) following the deployment of frozen elephant trunk due to false lumen expansion.

CASE REPORT

A 47 years old male patient undergone emergency repair of acute type A aortic dissection in 2011 with bioprosthetic aortic root conduit. Seven years later he presented with moderate aortic valve disease and expanding chronic dissection of the aortic arch, therefore a redo operation with replacement of the prosthetic aortic valve, ascending aorta, total arch and deployment of frozen elephant trunk and he was discharged in good health. Several days post discharge he presented with new onset of chest pain and a new dissection involved the thoracoabdominal aorta was noted pressing on the true lumen and the frozen elephant trunk. Following a multi-disciplinary team meeting, TEVAR was deemed as a most appropriate approach and this was achieved successfully, and patient was discharged. At 1 year of follow up, he remains well and asymptomatic.

CONCLUSION

Close imaging follow-up following deployment of a FET is mandatory. A new acute Type B aortic dissection distal to the FET, that causes false lumen propagation parallel to the stented portion, is a surgical emergency and further intervention mandated.

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.

Distal Stent Graft-Induced New Entry After TEVAR or FET: Insights Into a New Disease From EuREC

BACKGROUND

The study sought to learn about incidence and reasons for distal stent graft-induced new entry (dSINE) after thoracic endovascular aortic repair (TEVAR) or after frozen elephant trunk (FET) implantation, and develop prevention algorithms.

METHODS

In an analysis of an international multicenter registry (EuREC [European Registry of Endovascular Aortic Repair Complications] registry), we found 69 dSINE patients of 1430 (4.8%) TEVAR patients with type B aortic dissection and 6 dSINE patients of 100 (6%) patients after the FET procedure for aortic dissection with secondary morphological comparison.

RESULTS

The underlying aortic pathology was acute type B aortic dissection in 33 (44%) patients, subacute or chronic type B aortic dissection in 34 (45%) patients, acute type A aortic dissection in 3 patients and remaining dissection after type A repair in 3 (8%) patients, and acute type B intramural hematoma in 2 (3%) patients. dSINE occurred in 4.4% of patients in the acute setting and in 4.9% of patients in the subacute or chronic setting after TEVAR. After the FET procedure, dSINE occurred in 5.3% of patients in the acute setting and in 6.5% of patients in the chronic setting. The interval between TEVAR or FET and the diagnosis of dSINE was 489 ± 681 days. Follow-up after dSINE was 1340 ± 1151 days, and 4 (5%) patients developed recurrence of dSINE. Morphological analysis between patients after TEVAR with and without dSINE showed a smaller true lumen diameter, a more accentuated oval true lumen morphology, and a higher degree of stent graft oversizing in patients who developed dSINE.

CONCLUSIONS

dSINE after TEVAR or FET is not rare and occurs with similar incidence after acute and chronic aortic dissection (early and late). Avoiding oversizing in the acute and chronic settings as well as carefully selecting patients for TEVAR in postdissection aneurysmal formation will aid in reducing the incidence of dSINE to a minimum.

Rapid false lumen dilation and pseudocoarctation due to inadvertent preferential false lumen perfusion using the frozen elephant trunk technique in a chronic residual aortic dissection

A patient with a chronic postdissection distal arch aneurysm was treated with total arch replacement and frozen elephant trunk. Following uneventful initial recovery, the frozen elephant trunk appeared to be inadvertently perfusing the false lumen through an already present (in retrospect) intimal tear, resulting in rapid dilation of the false lumen and proximal compression of the graft. Treatment consisted, first, of endovascular redirection of flow toward the distal true lumen and, second, open surgical repair of the remaining type IV aneurysm. This case underlines the importance of scrutinizing preoperative imaging for correct use of the frozen elephant trunk.

Effects of longitudinal pre-stretch on the mechanics of human aorta before and after thoracic endovascular aortic repair (TEVAR) in trauma patients

Thoracic endovascular aortic repair (TEVAR) has evolved as a first-line therapy for trauma patients. Most trauma patients are young, and their aortas are compliant and longitudinally pre-stretched. We have developed a method to include longitudinal pre-stretch in computational models of human thoracic aortas of different ages before and after TEVAR. Finite element models were built using computerized tomography angiography data obtained from human subjects in 6 age groups 10-69 years old. Aortic properties were determined with planar biaxial testing, and pre-stretch was simulated using a series of springs. GORE C-Tag stent-graft was computationally deployed in aortas with and without pre-stretch, and the stress-strain fields were compared. Pre-stretch had significant qualitative and quantitative effects on the aortic stress-strain state before and after TEVAR. Before TEVAR, mean intramural aortic stresses with and without pre-stretch decreased with age from 108 kPa and 83 kPa in the youngest age group, to 60 kPa in the oldest age group. TEVAR increased intramural stresses by an average of 73 ± 15 kPa and 48 ± 10 kPa for aortas with and without pre-stretch and produced high stress concentrations near the aortic isthmus. Inclusion of pre-stretch in young aortas increased intramural stresses by 30%, while in > 50-year-old subjects it did not change the results. Computational modeling of aorta-stent-graft interaction that includes pre-stretch can be instrumental for device design and assessment of its long-term performance, and in the future may help more accurately determine the stress-strain characteristics associated with TEVAR complications.