Types Of Stent Grafts Research Articles

Multicentric Use of Commercially Available Infrarenal Endografts During Fenestrated Endovascular Aortic Repair: A Feasibility Study.

This study aimed to assess the feasibility and short-term outcomes of different manufactured proximal and distal stent graft components during fenestrated endovascular aortic repair (FEVAR). A multicenter retrospective review was conducted at 3 aortic centers, involving all consecutive patients who underwent FEVAR utilizing a customized Dacron-based tubular proximal and a distal bifurcated polytetrafluoreten (PTFE)-based commercially available stent grafts. Primary outcomes were 30 day mortality, major adverse events, and technical and clinical success. Secondary outcomes assessed stent graft migration, occurrence of types I/III endoleak, and reintervention. A total of 23 FEVAR cases across all centers were included in this study. Technical success was achieved in all cases, with a median procedure time of 183 (153-244) minutes. There were no major adverse events, except for 1 transient acute renal failure. The median follow-up period was 23 (17-28) months. All target vessels retained patent with the exception of 1 right renal fenestration that showed signs of kinking at the first follow-up, and despite secondary intervention with relining and distal extension, there was an occlusion afterward and 1 hepatic artery with a separate fenestration. This and 1 successful relining of a superior mesenteric artery kink were the only reinterventions in this cohort. One case of persistent type 1b endoleak was reported in a patient with chronic type B aortic dissection, which resolved with distal extension on the external iliac artery 5 months after the index procedure. No deaths occurred throughout the follow-up with, and there were no signs of stent graft migration or type 3 endoleak. The use of commercially available PTFE-based bifurcated stent grafts to extend distally the tubular graft appears to be a feasible approach during FEVAR, with promising short-term outcomes. Further studies are necessary to define the applicability of this solution and evaluate long-term outcomes. This multicentric study on fenestrated endovascular aortic repair (FEVAR) demonstrates the feasibility and good short-term outcomes of utilizing a PTFE-based commercially available stent graft to extend the proximal tubular custom-made fenestrated stent graft. The high technical success rate, absence of major adverse events, and low occurrence of complications such as stent graft migration and endoleaks highlight the potential clinical benefits of this approach with an off-the-shelf distal extension whose delivery system does not cross the fenestrations intraoperatively.

A hemodynamic study of blood flow models on various stent graft configurations during aorto-iliac reconstruction.

To compare the hemodynamic performance of three (Bottom Up non-ballet, Top-Down non-ballet, Top Down ballet) idealized stent graft configurations used during endovascular repair of abdominal aortic aneurysms, under the influence of various rheological models. Ten rheological models are assumed and a commercial finite volume solver is employed for the simulation of blood flow under realistic boundary conditions. An appropriate mesh convergence study is performed and five hemodynamic variables are computed: the time average wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), endothelial cell activation potential and displacement force (DF) for all three configurations. The choice of blood flow model may affect results, but does not constitute a significant determinant on the overall performance of the assumed stent grafts. On the contrary, stent graft geometry has a major effect. Specifically, the Bottom Up non-ballet type is characterized by the least favorable performance presenting the lowest TAWSS and the highest OSI, RRT and ECAP values. On the other hand, the Top Down ballet type presents hemodynamic advantages yielding the highest TAWSS and lowest OSI, RRT and ECAP average values. Furthermore, the ballet type is characterized by the lowest DF, although differences observed are small and their clinical relevance uncertain. The effect of the assumed rheological model on the overall performance of the grafts is not significant. It is thus relatively safe to claim that it is the type of stent graft that determines its overall performance rather than the adopted blood flow model.

Low-profile versus standard-profile stent grafts in the treatment of abdominal aortic aneurysm: a case-matched study.

Endovascular aortic repair (EVAR) is nowadays a widespread method of managing abdominal aortic aneurysm (AAA). Low-profile stent grafts (LPSGs) enable treatment of patients with complex and anatomically challenging aneurysms, and facilitate a percutaneous and thus less invasive procedure. To assess the outcomes of EVAR with low-profile versus standard-profile stent grafts (SPSGs). Thirty-one patients with abdominal aortic aneurysms (AAA) were treated by endovascular aortic repair (EVAR) using LPSGs. The control group of patients treated with SPSGs was matched with MedCalc software. The clinical records and the preoperative and follow-up computed tomography angiography of patients who underwent endovascular treatment of AAA were included in this study. Patients in the LPSG group had significantly more often low access vessel diameter (< 6 mm) compared to the SPSG group (38.7% vs. 6.7%, p = 0.003). In 1-year follow-up, there was no rupture, no infection, no conversion to open repair and no aneurysm-related death. Five secondary interventions were necessary in the SPSG group and only 1 in the LPSG group (p = 0.09). Type of stent graft was not a risk factor of perioperative complications, presence of endoleak or reintervention (p > 0.05). Risk factors for perioperative complications were COPD and conical neck (OR = 6.3, 95% CI: 1.5-25, p = 0.01 and OR = 6.2, 95% CI: 1-39.76, p = 0.04). The risk factor for endoleak was lower maximal aneurysm diameter. The risk factor for reintervention was proximal neck diameter (OR = 0.77, 95% CI: 0.-0.97, p = 0.03). Our study showed that use of LPSGs is a safe and viable method for patients with narrow access vessels who are not eligible for standard-profile systems.

Assessment of Bridging Stents in In Situ Laser Fenestrations of Aortic Endografts With Intravascular Ultrasound

ObjectiveTreatment of complex aortic aneurysms with the in situ laser fenestration (ISLF) technique involves implantation of a balloon expandable stent graft (bSG) in the created fenestration. Adequate expansion of this bSG is of importance both to achieve seal and to ensure target vessel stability. This experimental study assessed the expansion rate of different bSGs in the ISLF setting using intravascular ultrasound (IVUS). MethodsA commercially available aortic endograft was used to test the laser fenestration technique (Zenith Alpha, Cook Medical LLC, Bloomington, IN, USA). The ISLF was stented with the following bSGs: two Gore Viabahn VBX balloon expandable endoprostheses (WL Gore & Associates, Bloomington, IL, USA), three BeGraft Peripheral and three BeGraft Plus (Bentley InnoMed GmbH; Hechingen, Germany), and three Advanta V12 (Atrium, Hudson, NH, USA). The bSGs were expanded in three steps: (1) nominal, (2) rated burst pressure, and (3) dilatation with a non-compliant balloon at 15 atmospheres. After each step, an IVUS assessment of the bSG minimal diameter and the area at the fenestration (FA) and in a fully expanded segment distal to the fenestration (SA) was performed. A mean of the three IVUS measurements was used as the value for comparison. An insufficient bSG expansion was defined as a mean of FA/SA of < 0.8 (i.e., < 80% expansion). ResultsThe VBX was the only bSG that could be expanded to its intended diameter (i.e., at least 80%) at nominal pressure. The BeGraft Peripheral and BeGraft Plus showed the lowest expansion degrees after nominal and rated burst pressure. All bSGs that were tested reached a sufficient expansion degree after the use of a higher pressure balloon. ConclusionIn this ex vivo experiment, a dilatation up to nominal pressure showed satisfactory expansion only for the VBX. The consistency of the results when applied to the different types of stent grafts that were analysed reflects structural stent graft specific issues to consider when choosing the right device in cases of ISLF.

Retrograde type A aortic dissection during or after thoracic endovascular aortic repair: a single center 16-year experience.

This article aims to investigate the incidence rate of retrograde type A aortic dissection (RTAD) and the risk factors of RTAD in relation to thoracic endovascular aortic repair (TEVAR). Patients with thoracic aortic disease who underwent TEVAR at Henan Provincial People's Hospital from January 2004 to December 2019 were enrolled in the present research. The risk factors associated with RTAD following TEVAR using univariate and multiple logistic regression analyses. During the study period, A total of 1,688 TEVAR patients were included in this study, and of these, 1,592 cases were included in the type B aortic dissection (TBAD) group, and 96 cases were included in the non-TBAD group. There were 1,230 cases of aortic dissection and 362 cases of aortic intramural hematoma and/or penetrating ulcer in the TBAD group. The non-TBAD group included 68 cases of thoracic aortic aneurysm, 21 cases of thoracic aortic pseudoaneurysm, and seven cases of congenital aortic coarctation. The overall incidence rate of RTAD was 1.1% (18/1,688) in patients, all of which occurred in the TBAD group. The cohort comprised 18 RTAD patients with an average age of 56.78, consisting of 13 males and 5 females. Among them, 13 individuals exhibited hypertension. Ten instances happened within the TEVAR perioperative period, including two cases during the surgery, six cases occurred within three months, two cases occurred after one year, and the longest interval was 72 months following TEVAR. TEVAR was successfully implemented in 17 patients, while the operation technique was temporarily altered in one case. The new entry position for RTAD was identified as the proximal region of the stent graft (SG) in 13 patients, while in five cases, the entry site was more than 2 cm away from the proximal region of the SG. 17 cases were at the greater curvature of the aorta, and one case was at the lesser curvature. Multivariate logistic regression analysis revealed that the SG oversizing ratio is a relevant risk factor for RTAD. However, ascending aortic diameter, aortic arch type, SG type, and anchored region were not directly related to the occurrence of RTAD. RTAD is a rare yet catastrophic complication. It could occur both during the procedure, early and late postoperative periods. Maintaining an appropriate SG oversizing ratio is crucial to minimize the risk of RTAD.

Endovascular Repair of Iatrogenic Inferior Vena Cava and Iliac Vein Injury: A Case Series and Review of the Literature.

Iatrogenic injury to the large abdominopelvic veins can he highly morbid, and open surgical repair is technically challenging. Endovascular repair with covered stenting across the injured segment offers an alternative to open surgical management. We present a series of patients with operative injury to the inferior vena cava (IVC) and iliac veins who were treated utilizing an endovascular approach and review the available literature on this technique. A PubMed keyword and MeSH term search was performed, and titles were reviewed for relevance by the first author. Studies related to endovascular repair of iatrogenic injury to the IVC and iliac veins were then read in detail for possible inclusion in the review. Those deemed appropriate were further analyzed for interventional approach, stent type and size, technical success, post-procedural pharmacologic management, complications and surveillance strategy. The initial search resulted in 6221 publications. A total of 17 met criteria for inclusion, all of which were case reports or series. Twenty-six patients were described as suffering iatrogenic injury to the IVC or iliac veins, treated with various types and sizes of stents. All cases achieved technical success with hemorrhage control. Procedural complications occurred in 15.4% of cases, including 3 cases of acute thrombus formation and 1 case of stenosis caudal to the initial stent edge requiring additional stenting. Two additional patients experienced stent occlusion in the surveillance period. Endovascular repair of iatrogenic injury to the IVC and iliac veins can be an effective management option. However, due to limited data regarding this approach, many technical questions remain, including ideal size and type of stent graft, necessity and duration of post-procedural anticoagulant or antiplatelet therapy and appropriate surveillance. Additionally, long term outcomes in this population have not yet been described.

Type Ic Endoleak after LifeStream Balloon-Expandable Stent Graft and Zenith Iliac Branch Device Placement

Considering the recent advancements in endovascular management of aortoiliac aneurysms, the use of an iliac branch device (IBD) to preserve pelvic blood flow and reduce complications caused by embolization of the internal iliac artery (IIA) is recommended by various guidelines. Although the outcomes reported following IBD placement are mainly positive and durable, IBD-specific complications such as a type Ic endoleak and associated reintervention may occur. Moreover, only one IBD device and one type of balloon-expandable bridging stent graft for IIA are currently available on the domestic market. Here we present two cases of type Ic endoleak following IBD placement. In both cases, IIA diameter was slightly larger than the basic instructions for use. Notably, the initial procedures were considered successful; however, type Ic endoleaks were detected on 1-month follow-up imaging. This finding emphasizes the need for a precise preoperative evaluation, intraoperative manipulation, and postoperative follow-up.

Anatomical feasibility of an endovascular aortic arch repair with the NEXUS endograft in patients treated with a frozen elephant trunk procedure for aortic arch pathology

BackgroundThe aim of this study was to evaluate the feasibility of an endovascular repair, using the NEXUS™ Aortic Arch Stent Graft System, in a real-world cohort of patients, treated with a Frozen Elephant Trunk (FET) procedure for pathology involving the aortic arch.ResultsThe preoperative computed tomography angiography scans of 37 patients were retrospectively analyzed using a dedicated workstation. In total, seven patients (N = 7/37; 18.9%) were eligible for endovascular repair. This number increased to eleven patients (N = 11/37; 29.7%) if an additional relining of the distal aorta would be performed. Device suitability was 47.1% in patients (N = 8/17; 47.1%) with aortic arch aneurysm, 12.5% (N = 1/8; 12.5%) in patients with an acute Stanford type A dissection and 50% (N = 2/4; 50%) in patients with Crawford type II thoraco-abdominal aneurysm. The stent graft was not suitable for any of the two patients with chronic type B dissection (N = 0/2; 0%). In 22 patients (N = 22/37; 59.5%) an endovascular repair with this type of stent graft was not feasible due to an inadequate proximal sealing zone. There was no suitable brachiocephalic trunk landing zone in 13 patients (N = 13/37; 35.1%). There was no suitable distal landing zone distal in 14 patients (N = 14/37; 36.8%). This number decreased to ten patients (N = 10/37; 27.0%) when considering an additional relining of the distal aorta.ConclusionsEndovascular repair with the NEXUS single branch stent graft is feasible in a minority of this real-world cohort that underwent a Frozen Elephant Trunk procedure. However, the applicability of this device probably improves in cases with isolated aortic arch aneurysms.

Association Between Device Type and Type IIIb Endoleaks Following Thoracic Endovascular Aortic Repair

Endoleaks following thoracic endovascular aortic repair (TEVAR) can lead to the need for re-intervention and aortic rupture. Given the recent recall of a specific thoracic stent graft type due to concerns about type IIIb endoleak (T3bE), in which blood leaks through the stent graft fabric, the aim was to characterise patterns of T3bEs among available TEVAR devices. Reports related to thoracic stent grafts in the Food and Drug Administration's (FDA) Manufacturer and User Facility Device Experience (MAUDE) database between 2010 and 2020 were reviewed. Proportional reporting ratios (PRRs) and chi squared tests were used to assess for the presence of a signal of association between device type and T3bE. A PRR > 2 and chi squared value > 4 with three or more reports overall constituted a signal of association. The institutional database of patients undergoing TEVAR for thoracic aneurysms since 2002 was also queried for T3bE. There were 7 328 MAUDE reports available for analysis. When analysing T3bEs in the MAUDE database, the lowest PRR was 0.36 (95% confidence interval [CI] 0 - 1.03 in Gore CTAG, nine T3bE among 1 328 reports) and the highest was 2.07 (95% CI 1.72 - 2.42 in Medtronic Valiant, 64 T3bE among 2 520 reports). The T3bE chi squared value for Medtronic Valiant was 17.3. The relationship between Medtronic Valiant and T3bE was ascertainable by MAUDE data as early as 2013. Among 542 TEVARs for an aneurysm indication at Duke University Hospital since 2002, there were eight T3bEs - all in devices with sutured on graft material. The Medtronic Valiant device met criteria for association with type IIIb endoleaks in the FDA's MAUDE database and met those criteria as early as 2013. A possible relationship between woven graft fabric and T3bEs is supported by the observation that all types of T3bE that occurred among a large number of TEVARs at the institution followed placement of grafts with sutured on woven fabric.

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

Objectives: Appropriateness of device selection, procedure protocol and aortic remodeling effects of entry closure (TEVAR) with stent-graft (SG) for patent false lumen type B aortic dissection (TBAD) were compared between the patients with narrow true lumen (narrow group) and those with aneurysmal dilated false lumen (aneurysmal group).Methods: Twenty-six patients with narrow true lumen (narrow group) and 20 patients with aneurysmal false lumen (aneurysmal group) were included in this study. In narrow group, straight SG was implanted from Zone 3 regardless the distance between the left subclavian artery and entry. In aneurysmal group, straight or taped SG was implanted with proximal landing zone length 20 mm or more. Thoracic aortic anatomy was evaluated by CT and aortic remodeling was defined as true lumen diameter ≥50% of the aortic diameter and occlusion of false lumen. Aorta related death, retrograde type A aortic dissection (RTAD), stentgraft induced new entry (SINE) and aortic maximum diameter enlargement 5 mm or more (aortic expansion) were included in the aortic event.Results: There was no procedure related complication in narrow group and 1 patient died due to aortic rupture in aneurysmal group, Type Ia endoleak by enhanced CT 7 days after TEVAR was detected in one patient in each group. Achievement of aortic remodeling was significantly better in narrow group. Aortic event occurred in only one patient in narrow group, in whom aortic expansion was observed. In aneurysmal group, aortic event occurred 12 patients (60%) and 2 RTAD, 5 SINE, and 8 aorta expansion were observed. Aortic event free rate was significantly better in narrow group.Conclusion: TEVAR procedure for the TBAD patients with narrow true lumen seemed to be appropriate, however, different TEVAR procedure or additional procedures would be required for those with aneurysmal dilated false lumen to obtain favorable outcomes. (This is secondary publication from Jpn J Vasc Surg 2021; 30: 347–357.)

Aortic remodeling, distal stent-graft induced new entry and endoleak following frozen elephant trunk: A systematic review and meta-analysis.

The introduction of the frozen elephant trunk (FET) technique for total arch replacement (TAR) has revolutionized the field of aortovascular surgery. However, although FET yields excellent results, the risk of certain complications requiring secondary intervention remains present, negating its one-step hybrid advantage over conventional techniques. This systematic review and meta-analysis sought to evaluate controversies regarding the incidence of FET-related complications, with a focus on aortic remodeling, distal stent-graft induced new entry (dSINE) and endoleak, in patients with type A aortic dissection (TAAD) and/or thoracic aortic aneurysm. A comprehensive literature search was conducted using multiple electronic databases including EMBASE, Scopus, and PubMed/MEDLINE to identify evidence on TAR with FET in patients with TAAD and/or aneurysm. Studies published up until January 2022 were included, and after applying exclusion criteria, a total of 43 studies were extracted. A total of 5068 patients who underwent FET procedure were included. The pooled estimates of dSINE and endoleak were 2% (95% confidence interval[CI] 0.01-0.06, I2 = 78%) and 3% (95% CI 0.01-0.11, I2 = 89%), respectively. The pooled rate of secondary thoracic endovascular aortic repair (TEVAR) post-FET was 7% (95% CI 0.05-0.12, I2 = 89%) whilethe pooled rate of false lumen thrombosis at the level of stent-graft was 91% (95% CI 0.75-0.97, I2 = 92%). After subgroup analysis, heterogeneity for distal stent-graft induced new entry(dSINE) and endoleak resolved among European patients, where Thoraflex Hybrid (THP) and E-Vita stent-grafts were used (both I2 = 0%). In addition, heterogeneity for secondary TEVAR after FET resolved among Asians receiving Cronus (I2 = 15.1%) and Frozenix stent-grafts (I2 = 1%). Our results showed that the FET procedure in patients with TAAD and/or aneurysm is associated with excellent results, with a particularly low incidence of dSINE and endoleak as well as highly favorable aortic remodeling. However the type of stent-graft and the study location were sources of heterogeneity, emphasizing the need for multicenter studies directly comparing FET grafts. Finally, THP can be considered the primary FET device choice due to its superior results.

In Situ Laser Fenestration Technique: Bench-Testing of Aortic Endograft to Guide Clinical Practice

Purpose: In situ laser fenestration (ISLF) is a recently introduced technology that offers the potential to perform total endovascular treatment of aortic arch and thoracoabdominal aortic pathologies in the acute setting. This experiment’s aim was to assess ISLF in some currently common aortic endografts and bridging stent-grafts. Materials and Methods: Three different aortic endografts were evaluated: (1) Zenith Alpha, (2) Zenith TX2, and (3) Conformable GORE TAG. Each endograft was submerged in 37°C saline to create fenestrations using the 308 nm CVX-300 Excimer Laser System fitted with a 2.3 mm diameter Turbo-Elite laser atherectomy catheter compatible with a 0.018″ guidewire. Three different 8 mm bridging stent-grafts were evaluated: (1) BeGraft peripheral, (2) BeGraft peripheral plus, and (3) GORE VIABAHN VBX Balloon Expandable. All bridging stent-grafts were deployed and exposed to different balloon sizes and pressures. The ISLFs and bridging stent-grafts were then evaluated for any tears, stenoses, and seal. Results: A laser fenestration was consistently rapidly obtained in the Zenith Alpha and the Zenith TX2 endografts while it proved difficult to achieve a timely fenestration in the C-TAG. No fabric tears were noted in the Zenith Alpha and Zenith TX2 when inflating Armada (Abbott) 8 mm balloon in the fenestrations with pressures up to 15 atmospheres (rated burst pressure) nor when flaring bridging stent-grafts with balloons up to 12 mm in diameter at 10 atmospheres, while major tears were frequently noted in the C-TAG when the Armada 8 mm balloons were inflated. BeGraft Peripheral and BeGraft Peripheral Plus were all firmly attached to the fenestrations showing good seal on manual testing, while every sixth VBX bridging stent-graft displayed poorer attachment to the fenestration before dilatation at high pressure. Commonly, significant stenoses remained in the bridging stent-grafts after dilatation at nominal pressure, which could only be eradicated with high-pressure balloons. Conclusion: In this limited bench-test, Dacron endografts responded well to the ISLF technology. Satisfactory deployment of the bridging stent was noted only after inflation and/or flaring with high-pressure balloons. Further work with different types of commercially-available bridging stent-grafts and endografts to assess the durability of in situ fenestration (ISF) and bridging stents in ISF is recommended. Clinical Impact This report on experimental in situ laser fenestration provide important insights for clinicians considering using in situ laser fenestration of aortic stentgrafts in vivo. In particular, different laser settings were tested together with a selection of aortic stentgrafts. Also, the target pressure needed in PTA balloons to dilate the fenestrations and any subsequent tears in the fabric were noted. This was followed by deployment of assorted balloon-expandable stentgrafts with estimation of residual stenosis and seal.

Stent Diameter, Not Cephalic Arch Anatomy, Predicts Stent Graft Patency in Cephalic Arch Stenosis

PurposeTo investigate the relationship between anatomic factors and primary patency of brachiocephalic arteriovenous fistulae (AVFs) after stent graft (SG) placement for cephalic arch stenosis (CAS). Materials and MethodsThis retrospective study reviewed all cephalic arch SGs placed in brachiocephalic AVFs in a tertiary academic medical center between 2014 and 2017. Sixty-three patients were included in the study. The mean patient age at the time of SG placement was 62.6 years ± 19, and the mean patient follow-up was 1,994 days ± 353. A cohort of patients (n = 31) who underwent brachiocephalic fistulograms for CAS but only received percutaneous transluminal angioplasty (PTA) was the control group. Patient demographic characteristics, AVF anatomy, SG type, and clinical outcomes were reviewed. The duration of primary cephalic arch patency after SG placement was compared with that after previous PTA. ResultsThe median AVF age at the time of data retrieval was 345 days. The primary patency of CAS after SG placement at 6 months, 12 months, and 3 years was 64%, 49.9%, and 23.5%, respectively. Primary cephalic arch patency was significantly associated with the SG diameter (P = .007) but not with cephalic vein–axillary vein junction anatomy, size of feeding artery, or SG length (P > .05). The primary patency of CAS in patients treated with PTA only (n = 31) at 6 months, 12 months, and 3 years was 61%, 35%, and 0%, respectively, which was significantly lower than that in patients treated with SG placement (P = .01). ConclusionsThis study showed that the primary patency of CAS after SG placement was significantly higher than that of PTA-only treatment. Moreover, primary cephalic arch patency after SG placement was significantly associated with the SG diameter.

Resultados de los tipos de endoprótesis en la reparación endovascular del aneurisma aórtico abdominal: experiencia a largo plazo de un centro colombiano de alta complejidad, el primer ejemplo latinoamericano

Introduction: Endovascular abdominal aortic aneurysm repair (EVAR) devices are associated with a higher rate of complications at 5-year follow-up. At least 30% of patients with EVAR devices require some type of reintervention (whether endovascular or open) at 10-year follow-up. These complications include endoleak, abdominal aortic aneurysms rupture, graft migration, occlusion or infection. The objective of this paper was to determine the rates of failure for each type of EVAR stent-graft used in our local population. Also, this paper is the first step to create a Colombian and Latin American transnational EVAR device registry. Material and method: Single-center retrospective observational cohort study. Thirty-four patients with abdominal aortic aneurysms (AAA) treated with EVAR were included from 2011 through 2017. Data were collected from the patients’ electronic medical records.Results: The stent-graft Endologicx Ba (Endologix, Irvine, CA, United States), Excluder (W.L. Gore, Newark, DE, United States), Zenith (Cook Medical, Bloomington, IN, United States), and Nellix endovascular aneurysm sealing system (EVAS) (Endologix, Santa Rosa, CA, United States) were not associated with any endoleaks or any type of complications after the EVAR procedure. The Aorfix (Lombard, Didcot, United Kingdom), and Endurant (Medtronic, Minneapolis, MN, United States) stent-grafts had rates of type II endoleak (in 1 and 2 patients) of 2.9% and 5.8%, respectively that closed spontaneously. No stent-graft developed type I, III or IV endoleaks or any endovascular or open reinterventions were needed. Conclusions: This study shows that the different types of stent-graft used for to treat AAA with EVAR can be used in a safe and feasible way with good postoperative clinical outcomes in the Latin American population.

Kinking of Frozen Elephant Trunk Hybrid Prostheses: Incidence, Mechanism, and Management.

IntroductionKinking of the Frozen Elephant Trunk (FET) stent graft is one of the most devastating complications of the FET procedure. It can present post-operatively with reduced arterial pressures in the lower limbs and intermittent claudication. However, it can also be visualized intra-operatively by the surgeons. Unresolved kinking of the stent graft can result in intraluminal thrombus formation and subsequent multi-organ septic emboli.AimsThe main scope of this review is to collate, summarize and present all the evidence in the literature on kinking of FET stent grafts.MethodsWe carried out a comprehensive literature search on multiple electronic databases including PubMed, EMBASE, Ovid, and Scopus to collate all research evidence on the incidence, mechanism, and management of FET graft kinking.ResultsIncidence of kinking is variable, ranging from 0% to 8% in the literature, with varying rates associated with each stent graft type. The Thoraflex HybridTM prosthesis seemed to be the most commonly used and superior graft, and out of all the 15 cases of kinking reported in the literature, 5 (33.3%) were associated with just the Frozenix graft which had the highest incidence. There are multiple theories regarding the mechanism of kinking, including the direction of blood flow, the length of the stent grafts used, and the position of the prosthesis in relation to the flexure of the aorta. Multiple reparative management techniques have been suggested in the literature and include total endovascular repair, open repair, balloon dilatation, and deploying a second stent graft.ConclusionGraft kinking is one of the most critical complications of the FET technique. Its life-threatening sequelae warrant appropriate follow-up of these patients post-operatively, in addition to time management if kinking is suspected. Given the limited evidence in the literature, future studies should incorporate graft kinking into their outcomes reporting.

A new dissection-specific hybrid stent graft for patients with DeBakey type I aortic dissection.

We present our first experience of using a new dissection-specific hybrid stent graft (SG) (the 'Soft Elephant Trunk') in the frozen elephant trunk technique, in patients with non-acute DeBakey type I aortic dissection. Between September 2016 and February 2021, patients with non-acute DeBakey type I aortic dissection underwent the frozen elephant trunk procedure at our centre using 3 SG types: group Z used stiff, distal Z-shaped nitinol SGs (E-Vita, Medtronic); group R used a stiff, ring-shaped nitinol SG (Thoraflex); and group S used a soft, distal dissection-specific SG. Predictors of distal SG-induced new entry were analysed. End points were hospital- and midterm-follow-up results. The study comprised 109 patients with 46 (42.2%), 22 (20.2%) and 41 (37.6%) patients in groups Z, R and S, respectively. No significant differences were found in early outcomes. Freedom from distal SG-induced new entry was comparable in groups Z, R and S (68.9% vs 92.9% vs 100%, log-rank = 0.14). There was no significant difference in follow-up between the groups. Four-year survival rates were 80.44%, 71.59% and 95.06% in groups Z, R and S, respectively. On multivariable analysis, the presence of connective tissue disorders [hazard ratio (HR) = 5.62, P = 0.11] and SG diameter (HR = 1.37, P = 0.034) were strong predictors of distal SG-induced new entry. Dissection-specific hybrid SG with a soft distal end is effective in patients with non-acute DeBakey type I aortic dissection. Compared to non-soft distal SGs, this can reduce the incidence of distal complications. Long-term outcomes are necessary to determine the potential advantages and disadvantages of the new prosthesis.

Effect of Stent-Graft Active Fixation and Oversizing on Aortic Neck Dilation After Endovascular Aneurysm Exclusion For Infrarenal Aortic Aneurysm

IntroductionAortic neck dilation post endovascular aneurysm repair (EVAR) has been implicated in the long-term development of endoleak and the subsequent re-intervention. Optimal endograft sizing is a vital aspect to successful repair. This study looked at percentage of graft oversizing as well as type of fixation on aortic neck dilation. MethodsWe retrospectively evaluated all EVARs completed at Loyola's University from 2006 to 2015 after IRB approval. Patients without follow-up scans within a year were excluded. We collected demographics, comorbidities, graft type, size, aortic neck diameter, maximum sac size diameters from the pre-operative and follow-up scans. We reviewed and collected data on 432 patients but analyzed 154. We measured the largest aortic diameter on axial images 1 cm above and 1 cm below the lowest renal artery. Change in supra and infrarenal aortic measurements were evaluated by calculating the mm difference from each scan compared to the pre-operative scan. Linear mixed effects models were used to estimate patients’ mean differences over time. ResultsWe compared three groups of neck fixation grafts. Those with active suprarenal fixation had a significant change in suprarenal aortic diameter at four-year follow-up (1.86 mm, CI:0.65–3.06), compared to those with active infrarenal (0.22 mm, CI: -0.67 to -1.11) or passive suprarenal fixation (1.52 mm, CI: -0.11 to -3.15) (Fig. 1). Those with active suprarenal fixation were the only ones to have significant increase in suprarenal aortic diameter (P = 0.0026). Degree of oversizing was also divided into three groups. Oversizing by <10% had less impact on the suprarenal aorta than >15% oversizing at 4 years (0.41 mm, CI: -0.31 to -1.14 vs. 3.26 mm, CI: 1.63–4.88, P < 0.001) (Fig. 2). Oversizing had a more pronounced effect on the infrarenal aorta: 3.01 mm, CI: 2.18–3.83; 5.95 mm, CI: 3.26–8.64; and 5.05 mm, CI: 3.41–6.69 for <10%, 10–15%, and >15% oversizing at four years, respectively. ConclusionStent-grafts with active fixation below the renal arteries as well as oversizing by <10% seem to have the least effect on aortic neck dilation over time. These factors should be considered when performing EVARs, as aortic neck dilation could lead to endoleak and need for further intervention. Further research defining the optimal stent-graft type, self-expanding versus balloon expandable, type of fixation and degree of oversizing.

A three-dimensional biomodel of type A aortic dissection for endovascular interventions.

Thoracic endovascular aortic repair is widely used for type B aortic dissection. However, there is no favorable stent-graft for type A aortic dissection. A significant limitation for device development is the lack of an experimental model for type A aortic dissection. We developed a novel three-dimensional biomodel of type A aortic dissection for endovascular interventions. Based on Digital Imaging and Communication in Medicine data from the computed tomography image of a patient with a type A aortic dissection, a three-dimensional biomodel with a true lumen, a false lumen, and an entry tear located at the ascending aorta was created using laser stereolithography and subsequent vacuum casting. The biomodel was connected to a pulsatile mock circuit. We conducted four tests: an endurance test for clinical hemodynamics, wire insertion into the biomodel, rapid pacing, and simulation of stent-graft placement. The biomodel successfully simulated clinical hemodynamics; the target blood pressure and cardiac output were achieved. The guidewire crossed both true and false lumens via the entry tear. The pressure and flow dropped upon rapid pacing and recovered after it was stopped. This simulation biomodel detected decreased false luminal flow by stent-graft placement and detected residual leak. The three-dimensional biomodel of type A aortic dissection with a pulsatile mock circuit achieved target clinical hemodynamics, demonstrated feasibility for future use during the simulated endovascular procedure, and evaluated changes in the hemodynamics.

The short-term safety and effectiveness of a new distal perforating stent graft in Type B aortic dissection: a retrospective study

BackgroundSpinal artery ischemia (SCI) events can result from over coverage of the descending thoracic aorta with a coated stent during Thoracic Endovascular Aortic Repair (TEVAR). The aim of this study was to determine whether a new distal perforating stent could reduce the incidence of spinal cord ischemia while remodeling the true lumen.MethodsTBAD patients treated with Talos stent in the vascular surgery Department of Yan 'an Hospital affiliated to Kunming Medical University between December 2017 and October 2019 were retrospectively analyzed to investigate the short-term safety and effectiveness of Talos stent.ResultsA total of the 20 patients, including 14 males and 6 females, with an average age of 52.65 ± 8.98 years (range 37–68 years), were included in the analysis. Stent-grafts were successfully implanted in all patients under local anesthesia, with a technical success rate of 100%. The average operation time was 50.75 ± 13.01 min. A total of 2 cases (10%) presented chest pain associated with intercostal artery ischemia that was relieved on the 3rd and 5th postoperative day, respectively. Postoperative mean follow-up was 16.15 ± 3.99 months. No paraplegia or other complications occurred. And stenting did not induce new tears. No migration, deformation, or fracture of the stents occurred. There was a significant difference in the remolding of the true lumen preoperatively and at 12 months postoperatively (P < 0.05).ConclusionsTalos stent has achieved satisfactory clinical treatment results in short term.

Current trends in reduction or elimination of the aortic impulse during stent-graft deployment and balloon moulding during thoracic endovascular aortic repair.

A survey was performed to evaluate the methods used for reduction or elimination of the aortic impulse (REAI) to facilitate precise stent graft placement and balloon moulding during thoracic endovascular aortic repair (TEVAR). A total of 127 physicians (1 per hospital) were contacted and asked to fill out a short, comprehensive questionnaire on an internet-based platform. Fifty physicians (39.4%) responded and completed the survey. Routine use of REAI for stent graft deployment is most frequently used in the ascending aorta and less frequently in the aortic arch and the descending aorta (86.4% vs 69.4% vs 56%). Some physicians based the decision of whether to use REAI on the type of stent graft in the respective location (13.6% vs 24.5% vs 24.0%). Stent-graft deployment without REAI, irrespective of the type of stent graft used, was never done in the ascending aorta (0.0%), in 3 centres in the aortic arch (6.1%) and in 10 centres in the descending aorta (20%). The REAI method most frequently used was dependent on the aortic segment (ascending aorta vs aortic arch vs descending aorta) rapid right ventricular pacing (90.9% vs 59.2% vs 28.0%), followed by pharmacological blood pressure reduction (13.6% vs 53.1% vs 64.0%) and venous inflow occlusion (13.6% vs 14.3% vs 4.0%), respectively. Tip capture and non-occlusive deployment systems were frequently quoted as reasons for not using REAI. REAI is the fundament for TEVAR in all thoracic aortic segments, with a decline in usage from proximal (ascending) to distal (descending). Rapid right ventricular pacing is the preferred REAI method used in TEVAR. Most procedures are performed with the patient under general anaesthesia. The types of stent grafts and moulding balloons used have an impact on the use or non-use of REAI.