Endograft Configuration Research Articles

Impact of Significant Sac Shrinkage on Endograft Tortuosity at 5 Years Postendovascular Aortic Aneurysm Repair: A Retrospective Analysis

Significant sac shrinkage after endovascular aortic aneurysm repair (EVAR) is generally considered a positive outcome indicative of durable clinical success. However, its impact on endograft configuration is rarely addressed. Sac remodeling and volume loss due to shrinkage can potentially cause deformation of endograft components, resulting in limb angulation and compression. We investigated the hypothesis that significant sac shrinkage could affect endograft tortuosity at 5years post-EVAR. We retrospectively reviewed patients who underwent elective EVAR for infrarenal abdominal aortic aneurysm between June 2007 and December 2018. Patients with early postoperative and 5-year follow-up computed tomography images were included. Patients treated with modular bifurcated endografts (Zenith, Endurant, Excluder, and Incraft) were analyzed. The "shrinkage" group comprised patients with >10mm diameter reduction, while the "stable" group had ± 5mm diameter change at 5years. Tortuosity index (TI) was calculated as the ratio of centerline distance to straight-line distance between proximal and distal endograft edges. The association between sac shrinkage and ≥5% increase of TI (≥5%ΔTI) was analyzed for both ipsilateral and contralateral sides. Of 136 patients enrolled, 80 were in the shrinkage group and 56 in the stable group. On the ipsilateral side, ≥5%ΔTI was observed in 24 cases (17.6%). The patients with ipsilateral ≥5%ΔTI had significantly shorter median neck lengths (22mm vs. 30mm, P=0.030). Sac shrinkage ≥15mm was negatively associated with ≥5%ΔTI compared to stable sac (P=0.027). Logistic regression showing sac shrinkage ≥15mm had a significant negative correlation with ≥5%ΔTI (P=0.025, hazard ratio [95% confidence interval]: 0.218 [0.057-0.824]). On the contralateral side, ≥5%ΔTI (19 cases, 14.0%) was associated with shorter neck length but not with sac shrinkage. In the shrinkage group, cross-leg positioning resulted in a significant increase in ipsilateral TI at 5years compared to straight positioning (median ΔTI: 1.8% vs. 0.0%, P=0.013). No reinterventions for leg-related events were necessary during the 5-year follow-up period. Contrary to our initial hypothesis, significant sac shrinkage does not adversely affect endograft configuration and may help stabilize tortuosity on the ipsilateral side. However, in patients with crossed-leg configuration, continued vigilant observation may be warranted even after achieving sac shrinkage, as it could exacerbate tortuosity. Shorter neck length was associated with increased tortuosity on both sides. Further research is needed to confirm these findings and consider potential confounding factors, including the impact of different endograft designs.

Technical Aspects of Exclusive Transfemoral Route for Total Endovascular Arch Repair: A Custom-Made Device With Only Upward-Facing Inner Branches for Aortic Arch Treatment.

The purpose was to demonstrate a new arch endograft configuration to allow total endovascular aortic arch repair exclusive from transfemoral approach. The custom-made multi-branched arch endograft (Cook Medical, Bloomington, Indiana) features 3 inner branches (IBs) for supra-aortic vessels incorporation and complete endovascular arch repair. Traditionally, the innominate and left carotid branches are anterograde IBs, requiring upper access for incorporation of these vessels, and the left subclavian branch is an upward-facing IB that can be incorporated from transfemoral access. We report a novel device configuration with only upward-facing IBs, allowing exclusive transfemoral route for total endovascular arch repair. Technical aspects, implantation technique, and limitations are described thoroughly. Herein is described an arch endograft configuration that simplifies endovascular aortic arch repair, allowing supra-aortic vessel incorporation through a transfemoral route only. This innovative design may serve as another alternative in selected patients. This innovative endograft design, with only upward-facing inner branches, simplifies the total endovascular aortic arch repair by allowing for a exclusively transfemoral approach. This may reduce procedural complexity and minimizes risks associated with multiple access points. It provides another alternative, particularly beneficial for selected high-risk patients for open repair, potentially expanding the applicability of endovascular treatments for aortic arch pathologies.

Exploring Type IIIb Endoleaks: A Literature Review to Identify Possible Physical Mechanisms and Implications.

Endoleaks are common complications following endovascular aneurysm repair (EVAR). They can be classified into low-pressure and high-pressure endoleaks. High-pressure endoleaks, which include Type I and Type III endoleaks, pose a significant risk of rupture and require urgent treatment. The aim of our study is to review published case reports and case series to assess the impact of Type IIIb endoleaks in EVAR and to identify possible mechanisms contributing to these endoleaks. This review targeted case reports and case series published between January 1998 and December 2022. A total of 62 case reports and case series were identified, encompassing 156 patients with Type IIIb endoleaks. Data collection was performed by three consultants who thoroughly discussed each report before registering it into an analyzable data set. Our analysis revealed that, beyond material imperfections, certain endograft configurations or conformations, endograft redundancy, and the physical forces acting on the grafts may lead to increased stress on specific parts of the endografts, potentially exceeding their design limits. Factors contributing to redundancy and unfavorable conformation of the endograft include secondary interventions for any cause (such as other types of endoleaks), EVAR performed outside the instructions for use (IFUs), endograft migrations, or larger initial aneurysm diameter.

Proximal sealing in the aortic arch for inner curve disease using the custom Relay scalloped and fenestrated stent graft

ObjectiveThis study aimed to analyze early and midterm results of custom-made proximal scallop and fenestrated stent grafts for thoracic endovascular aortic repair (TEVAR) with a proximal landing zone (PLZ) in the aortic arch. MethodsAll consecutive patients treated with the custom made proximal scalloped and fenestrated Relay stent grafts (Terumo Aortic Bolton Medical Inc.) in 10 Italian centers between January 2014 and December 2022 were included. The primary end points were technical success, incidence of intraoperative major adverse events, deployment accuracy, and rate of early neurological complications, endoleaks (ELs) and retrograde aortic dissection. ResultsDuring the study period, 49 patients received TEVAR with Relay custom-made endograft in Italy were enrolled. The median patient age was 70.1 years (interquartile range, 23-86 years) and 65.3% were male. The indication for treatment was atherosclerotic aneurysms in 59.2% of cases and penetrating aortic ulcer in 22.4%. The endograft configuration was proximal fenestration in 55.1% and scallop in 44.9%. The proximal landing zone was zone 0 in 25 cases (51%), zone 1 in 14 cases (28.6%), and zone 2 in 10 cases (20.4%). The supra-aortic debranching procedures were 38 (77.5%). Technical success was 97.9% (48/49) owing to one case (2.0%) of inaccurate deployment. Intraoperatively, one (2.0%) type Ia and one (2.0%) type III EL were detected. There were no cases of in-hospital mortality, major adverse events, or retrograde dissection. Three minor strokes (6.1%) (National Institutes of Health Stroke Scale score of ≤4) were observed. At a mean follow-up time of 36.3 ± 21.3 months the rate of types I to III ELs and reintervention was 4.1%, respectively. Four patients (8.2%) died during the follow-up period, one (2.1%) from abdominal aortic rupture and three (6.1%) from nonaortic causes. ConclusionsOur early and midterm outcomes suggest that scalloped and fenestrated TEVAR may provide an acceptable alternative treatment option for aortic arch pathologies. Large-scale studies are needed to assess the long-term durability of this technique.

Patient-specific computational flow simulation reveals significant differences in paravisceral aortic hemodynamics between fenestrated and branched endovascular aneurysm repair

BackgroundEndovascular aneurysm repair with four-vessel fenestrated endovascular aneurysm repair (fEVAR) or branched endovascular aneurysm repair (bEVAR) currently represent the forefront of minimally invasive complex aortic aneurysm repair. This study sought to use patient-specific computational flow simulation (CFS) to assess differences in postoperative hemodynamic effects associated with fEVAR vs bEVAR. MethodsPatients from two institutions who underwent four-vessel fEVAR with the Cook Zenith Fenestrated platform and bEVAR with the Jotec E-xtra Design platform were retrospectively selected. Patients in both cohorts were treated for paravisceral and extent II, II, and V thoracoabdominal aortic aneurysms. Three-dimensional finite element volume meshes were created from preoperative and postoperative computed tomography scans. Boundary conditions were adjusted for body surface area, heart rate, and blood pressure. Pulsatile flow simulations were performed with equivalent boundary conditions between preoperative and postoperative states. Postoperative changes in hemodynamic parameters were compared between the fEVAR and bEVAR groups. ResultsPatient-specific CFS was performed on 20 patients (10 bEVAR, 10 fEVAR) with a total of 80 target vessels (40 renal, 20 celiac, 20 superior mesenteric artery stents). bEVAR was associated with a decrease in renal artery peak flow rate (−5.2% vs +2.0%; P < .0001) and peak pressure (−3.4 vs +0.1%; P < .0001) compared with fEVAR. Almost all renal arteries treated with bEVAR had a reduction in renal artery perfusion (n = 19 [95%]), compared with 35% (n = 7) treated with fEVAR. There were no significant differences in celiac or superior mesenteric artery perfusion metrics (P = .10-.27) between groups. Time-averaged wall shear stress in the paravisceral aorta and branches also varied significantly depending on endograft configuration, with bEVAR associated with large postoperative increases in renal artery (+47.5 vs +13.5%; P = .002) and aortic time-averaged wall shear stress (+200.1% vs −31.3%; P = .001) compared with fEVAR. Streamline analysis revealed areas of hemodynamic abnormalities associated with branched renal grafts which adopt a U-shaped geometry, which may explain the observed differences in postoperative changes in renal perfusion between bEVAR and fEVAR. ConclusionsbEVAR may be associated with subtle decreases in renal perfusion and a large increase in aortic wall shear stress compared with fEVAR. CFS is a novel tool for quantifying and visualizing the unique patient-specific hemodynamic effect of different complex EVAR strategies. Clinical RelevanceThis study used patient-specific CFS to compare postoperative hemodynamic effects of four-vessel fenestrated endovascular aneurysm repair (fEVAR) and branched endovascular aneurysm repair (bEVAR) in patients with complex aortic aneurysms. The findings indicate that bEVAR may result in subtle reductions in renal artery perfusion and a significant increase in aortic wall shear stress compared with fEVAR. These differences are clinically relevant, providing insights for clinicians choosing between these approaches. Understanding the patient-specific hemodynamic effects of complex EVAR strategies, as revealed by CFS, can aid in future personalized treatment decisions, and potentially reduce postoperative complications in aortic aneurysm repair.

Patients’ Radiation Exposure During Endovascular Abdominal Aortic Aneurysm Repair

To investigate associations between patient characteristics, intraprocedural complexity factors, and radiation exposure to patients during endovascular abdominal aortic aneurysm repair (EVAR). Elective standard EVAR procedures between January 2015 and December 2020 were retrospectively analyzed. Patient characteristics and intraprocedural data (i.e., type of device, endograft configuration, additional procedures, and contralateral gate cannulation time [CGCT]) were collected. Dose area product (DAP) and fluoroscopy time were considered as measurements of radiation exposure. Furthermore, effective dose (ED) and doses to internal organs were calculated using PCXMC 2.0 software. Descriptive statistics, univariable, and multivariable linear regression were applied to investigate predictors of increased radiation exposure. The 99 patients were mostly male (90.9%) with a mean age of 74±7years. EVAR indications were most frequently abdominal aortic aneurysm (93.9%), penetrating aortic ulceration (2.0%), focal dissection (2.0%), or subacute rupture of infrarenal abdominal aortic aneurysm (2.0%). Median fluoroscopy time was 19.6minutes (interquartile range [IQR], 14.1-29.4) and median DAP was 86,311 mGycm2 (IQR, 60,160-130,385). Median ED was 23.2 mSv (IQR, 17.0-34.8) for 93 patients (93.9%). DAP and ED were positively correlated with body mass index (BMI) and CGCT. Kidneys, small intestine, active bone marrow, colon, and stomach were the organs that received the highest equivalent doses during EVAR. Higher DAP and ED values were observed using the Excluder endograft, other bi- and tri-modular endografts, and EVAR with ≥2 additional procedures. Multivariable linear regression analysis revealed that BMI, ≥2 additional procedures during EVAR, and CGCT were independent positive predictors of DAP and ED levels after accounting for endograft type. Patient-related and procedure-related factors such as BMI, ≥2 additional procedures during EVAR, and CGCT resulted predictors of radiation exposure for patients undergoing EVAR, as quantified by higher DAP and ED levels. The main intraprocedural factor that increased radiation exposure was CGCT. These data can be of importance for better managing radiation exposure during EVAR.

Driving Technology for Thoracic Endovascular Aortic Repair: An International Analysis of Single-versus Double-Branch RELAY Outcomes

The introduction of endovascular aortic arch repair (EAR) represents a paradigm shift in the management of complex arch pathologies usually treated with open surgical repair (OSR). This shift in treatment of aortic arch disease has also been accompanied with a rise in commercial interest in EAR resulting in the development of several endografts. However, the RELAY™ Branched by Terumo Aortic can be considered the prime endograft choice. In this international original study, a retrospective comparative analysis of international prospective outcomes data on the single- and double-branch RELAY™ stent-grafts is provided. International data on EAR procedures carried out from January 2019 to January 2022 using the single- and double-branch RELAY™ endograft configurations were collected prospectively. Follow-up data was collected at 30 days, 6 months, 12 months, and 24 months postoperatively. Retrospective descriptive analysis, logistic regression, and Kaplan-Meier analysis were performed. A total of 125 patients were included, out of which 17 (13.6%) received the single-branch RELAY™ and 108 the double-branch device. In the single-branch group, no mortalities, strokes or reinterventions were recoded over 24 months of follow-up. The rates of these outcomes were higher in the other group, however, the differences did not reach significance. Target vessel patency was maintained at 100% throughout the study period with the single-branched RELAY™. Overall, our Kaplan-Meier analyses proved that both configurations of RELAY™ Branched yield excellent short- and mid-term survival and freedom from reintervention. Our series has clearly demonstrated that EAR using RELAY™ Branched is a highly efficacious strategy that yields very favourable results which can be considered superior to other EAR devices as well as OSR. Nevertheless, it seems that clinical outcomes with the single-branch RELAY™ are more optimal than with the double-branch device.

The impact of aorto-uni-iliac graft configuration on outcomes of endovascular repair for ruptured abdominal aortic aneurysms

IntroductionEndovascular aneurysm repair has improved outcomes for ruptured abdominal aortic aneurysms (rAAA) compared with open repair. We examined the impact of aorto-uni-iliac (AUI) vs standard bifurcated endograft configuration on outcomes in rAAA. MethodsPatients 18 years or older in the Vascular Quality Initiative database who underwent endovascular aneurysm repair for rAAA from January 2011 to April 2020 were included. Patient characteristics were analyzed by graft configuration: AUI or standard bifurcated. Primary and secondary outcomes included 30-day mortality, postoperative major adverse events (myocardial infarction, stroke, heart failure, mesenteric ischemia, lower extremity embolization, dialysis requirement, reoperation, pneumonia, or reintubation), and 1-year mortality. A subset propensity-score matched cohort was also analyzed. ResultsWe included 2717 patients: 151 had AUI and 2566 had standard bifurcated repair. There was no significant difference between the groups in terms of age, major medical comorbidities, anatomic aortic neck characteristics, or rates of conversion to open repair. Patients who underwent AUI were more commonly female (30% vs 22%, P = .011) and had a history of congestive heart failure (19% vs 12%, P = .013). Perioperatively, patients who underwent AUI had a significantly higher incidence of cardiac arrest (15% vs 7%, P < .001), greater intraoperative blood loss (1.3 L vs 0.6 L, P < .001), longer operative duration (218 minutes vs 138 minutes, P < .0001), higher incidence of major adverse events (46.3% vs 33.3%, P = .001), and prolonged intensive care unit (7 vs 4.7 days, P = .0006) and overall hospital length of stay (11.4 vs 8.1 days, P = .0003). Kaplan-Meier survival analyses demonstrated significant differences in 30-day (31.1% vs 20.2%, log-rank P = .001) and 1-year mortality (41.7% vs 27.7%, log-rank P = .001). The propensity-score matched cohort demonstrated similar results. ConclusionsThe AUI configuration for rAAA appears to be implemented in a sicker cohort of patients and is associated with worse perioperative and 1-year outcomes compared with a bifurcated graft configuration, which was also seen on propensity-matched analysis. Standard bifurcated graft configuration may be the preferred approach in the management of rAAA unless AUI configuration is mandated by patient anatomy or other extenuating circumstances.

Early and Mid-Term Outcomes of the Inverted Limb Configuration Below Fenestrated and Branched Endografts: Experience from Two European Centers

Purpose: To report a European experience on the use of the Inverted Limb (IL) below fenestrated and branched endografts (FB-EVAR) for the treatment of juxta/pararenal (JP-AAAs), thoracoabdominal (TAAAs), and para-anastomotic aortic aneurysms. Materials and Methods: Between 2016 and 2020, all FB-EVAR with distal IL due to previous open (OSR) or endovascular repair (EVAR) or infrarenal aortic length <76 mm at two European university centers were retrospectively analyzed. Technical success, early and mid-term iliac complications (occlusion; type Ib endoleak [EL]), IL-related complications (type III EL), and reinterventions were assessed as primary endpoints; 30-day mortality, survival and freedom from (FF) overall complications/reinterventions were assessed as secondary outcomes. Results: Forty-one high-risk patients (male 30%–73%; mean age 71±10 years; ASA 3–4, 41%–100%) underwent FB-EVAR with distal IL for 8 (19.5%) J/P-AAAs and 33 (80.5%) TAAAs. Sixteen (39%) patients with previous aortic treatment (8 OR, 8 EVAR) were included. Preoperative computed tomographic angiography showed infrarenal aortic length <76 mm in all cases. Custom-made endografts were configured as 31 (75.6%) fenestrated-only, 6 (14.6%) branched-only, and 4 (9.8%) fenestrated+branched for an overall of 158 target visceral vessels (TVVs; 3.8±0.7 TVVs/case). The IL main body was planned with 1-stent, 2-stents, and 3-stents in 6 (14.6%), 23 (56.1%), and 12 (29.3%) cases, respectively. Technical success and 30-day mortality were 97.6% (40/41) and 0%. Thirty-day complications occurred in 2 (4.9%) patients: 1 limb occlusion, requiring reintervention, 1 type III EL, spontaneously resolved. Mean follow-up was 21±16 months. Three After 30-day, 3 (7.3%) iliac complications (2 occlusions; 1 type Ib EL) were successfully managed by endovascular reinterventions; no IL-related complications were observed. The patency of TVVs was 96.8%. No correlation between anatomical characteristics, endograft configuration, and primary outcomes was observed, except for 1-stent IL and type III EL (log rank p=0.01). At 1- and 2-year follow-up survival, FF overall iliac/IL-related complications and FF reinterventions were 90% and 80%, 90% and 84%, and 92% and 87%, respectively. Conclusion: The IL configuration allows a safe endovascular treatment of challenging aortic lesions in high-risk patients although needing a number of adjunctive procedures. A short main body of IL could be associated with intraoperative and perioperative type III EL. Clinical Impact Bifurcated endograft with inverted limb configuration increases the feasibility of a total endovascular approach in patients with challenging anatomy. The use of inverted limb overcomes the anatomical limitations of short-body initial grafts and short distance between lowest target artery and the aortic bifurcation, leading the fixation inside the endograft. Although technically demanding, this advanced technology could avoid surgical reinterventions in previous open or endovascular repair that are burdened with higher rates of morbidities and complications.

“Octafen”: A Noninvestigational Alternative Endograft Configuration for the Treatment of Thoracoabdominal Aortic Aneurysms

Purpose: To demonstrate the feasibility of Octafen technique, a novel endovascular configuration for the treatment of thoracoabdominal aortic aneurysms (TAAA). Technique: Two patients with complex TAAA and high surgical risk were treated with Octafen endograft configuration in a hybrid operating room with computed tomography (CT)-fluoroscopy image fusion guidance, using 3D-3D fusion techniques to facilitate procedural success. The procedure is a modification of the previously-described Octopus technique for endovascular repair of TAAA. The main advantage of this technique is the ability to use devices to repair a TAAA with the combination of off-the-shelf and noninvestigational custom-made devices. The devices used are readily available to most practicing vascular surgeons, which provides an alternative treatment in case of limited access to investigational devices, in time-sensitive cases, and in patients with limited functional capacity who cannot undergo open repair. In the modification described herein, we use a combination of standard bifurcated endovascular aneurysm repair (EVAR) devices (Excluder; W.L. Gore & Associates, Flagstaff, Arizona) in combination with a 2-vessel renal fenestrated device (Z-Fen; Cook Medical, Bloomington, Indiana). The article describes a step-by-step approach to this technique to elucidate pitfalls, benefits, and advantages. Conclusion: The Octafen technique might offer an alternative option for thoracoabdominal aneurysm treatment circumventing the need for access to custom-made, investigational devices. Clinical Impact In this manuscript, we describe a technique for endovascular repair of thoraco-abdominal aortic aneurysms that involves the combination of off-the-shelf and non-investigational, custom-made devices. The ‘Octafen’ technique provides a treatment alternative in case of limited access to investigational devices and can be adjusted according to patient anatomy.

Computational Comparison between the Altura Aortic Endograft Configuration and the Classic Bifurcated Idealized Designs

The Altura (Alt) endograft is a new design, lacking the classic main body with the flow divider. Instead, 2 proximal D-shaped endografts form a round circumference in the aortic neck for secure sealing and land in the iliac arteries in a cross-limb fashion. The aim of this computational study was to compare hemodynamically this model with the classic bifurcated (Bif) and cross-limb (Cx) endograft designs of equal total length. All 3D endograft models were created using the finite volume analysis application ANSYS CFX (Ansys Inc., Canonsburg, PA, USA). The Alt inlet was constructed as 2 opposing D-shaped sections. The flow was quantified by time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), and helicity. The displacement forces were also compared for all models with computational fluid dynamics analysis. The Alt design was associated with lower forces (range 4.0-5.9Ν) than Bif (4.17-6.15N) and Cx (4.43-6.53N). The 2-piece inlet site of the separated limbs of Alt has higher TAWSS than the uniform inlet segment of the Cx and the Bif model. Most importantly, the mid-segment and distal segment of the limbs in the Alt design present higher TAWSS in a greater area than the other 2 models. The inlet of the Alt design showed higher OSI than the other accommodations and similar or comparable OSI values along their mid-limb and distal limb segments. The range, location, and values or RRT were comparable between the 3 models. Helicity in the iliac limbs is more prominent in the crossed accommodations (Alt and Cx). Only small differences in the hemodynamic indices and displacement forces were detected between the Alt and classic accommodations. From this point of view, the Alt design could be theoretically considered not inferior to other widely used endograft configurations.

Suprarenal Aortic Remodeling after Endovascular Aortic Aneurysm Repair among Three Endografts with Different Types of Proximal Fixation System

Remodeling of suprarenal aorta after endovascular aortic aneurysm repair (EVAR) in relation to different endograft designs has not been thoroughly investigated. The aim of this study is to assess the anatomical configuration of the suprarenal aorta after using endografts with different proximal fixation during the first post-EVAR year. A retrospective study including EVAR patients using 3 types of endografts with different proximal fixation systems according to Instructions for Use was undertaken (50: Ovation, Endologix, Irvin, CA; 25: Endurant IIs, Medtronic, Santa Rosa, CA; 25: Excluder C3, W. L. Gore & Associates, Flagstaff, AZ). Comorbidities were recorded. Anatomic variables of the supra-aortic anatomy, abdominal aortic aneurysm (AAA) maximum diameter, and neck angulation were analyzed. Computed tomography angiography was obtained preoperatively at 1 and 12months post-EVAR, while a duplex scan was undertaken at 6months. Comorbidities were not different across the 3 groups. Presence and amount of neck calcification (P=0.139) and thrombus (P=0.116) was similar among groups. Maximum aortic diameter showed significant reduction from preoperative measurements to 12-month postoperative ones, for all groups. (Ovation: 56.5 to 53mm, P<0.001; Endurant: 57 to 51mm, P<0.001; Excluder: 55 to 50mm, P<0.001). Suprarenal angulation was decreased significantly in the Ovation (P<0.001) and Excluder groups (P=0.05), while the infrarenal angulation was decreased in all groups. Among endografts, the decrease in AAA maximum diameter was similar (P=0.99), while the suprarenal aortic diameter was significantly increased in Ovation patients in comparison to the other 2 endografts at the level of 5mm (P=0.02) and 25mm (P=0.01). Suprarenal angulation reduction was similar (P=0.7), while infrarenal angulation was significantly more decreased in Ovation endograft than the other 2 systems (P<0.001). Proximal endograft configuration appears to have different impact on supra-aortic anatomy. Longer follow-up is needed to clarify future remodeling and clinical impact of these observations.

Determination of Endograft Apposition, Position, and Expansion in the Aortic Neck Predicts Type Ia Endoleak and Migration After Endovascular Aneurysm Repair

Purpose: To describe the added value of determining changes in position and apposition on computed tomography angiography (CTA) after endovascular aneurysm repair (EVAR) to detect early caudal displacement of the device and to prevent type Ia endoleak. Methods: Four groups of elective EVAR patients were selected from a dataset purposely enriched with type Ia endoleak and migration (>10 mm) cases. The groups included cases of late type Ia endoleak (n=36), migration (n=9), a type II endoleak (n=16), and controls without post-EVAR complications (n=37). Apposition of the endograft fabric with the aortic neck, shortest distance between the fabric and the renal arteries, expansion of the main body (or dilatation of the aorta in the infrarenal sealing zone), and tilt of the endograft toward the aortic axis were determined on the first postoperative and the last available CTA scan without type Ia endoleak or migration. Differences in these endograft dimensions were compared between the first vs last scan and among the 4 groups. Results: No significant differences in endograft configurations were observed among the groups on the first postoperative CTA scan. On the last CTA scan before a complication arose, the position of the fabric relative to the renal arteries, expansion of the main body, and apposition of the fabric with the aortic neck were significantly different between the type Ia endoleak (median follow-up 15 months) and migration groups (median follow-up 23 months) compared with the control group (median follow-up 19 months). Most endograft dimensions had changed significantly compared with the first postoperative CTA scan for all groups. Apposition had increased in the control group but had decreased significantly in the type Ia endoleak and migration groups. Conclusion: Progressive changes in dimensions of the endograft within the infrarenal neck could be detected on regular CTA scans before the complication became urgent in many patients.

“Over-SIRIX”: A New Method for Sizing Aortic Endografts in Combination with the Chimney Grafts: Early Experience with Aortic Arch Disease

Large gutters after chimney procedures are one of the main causes of type I endoleak (EL-I). This study aims to evaluate a new tailored planning named "Over-SIRIX," based on Osirix Imaging Software, to choose the correct main graft oversizing in order to minimize EL-I incidence. From 2008 to 2015, 34 patients were treated with parallel grafts for aortic arch diseases at our institution. The study included 22 patients with single stent and antegrade flow configuration; they were divided into 2 groups (PRE- and POST-"Over-SIRIX"). "Over-SIRIX" was carried out in the retrospective group (PRE-"Over-SIRIX"), and it was used to plan the endovascular procedure in the prospective group (POST-"Over-SIRIX"). Through the multiplanar reconstruction (MPR) of the preoperative computed tomography angiography (CTA), the proximal neck of the chimney grafts was studied. Stent and endograft configurations were drawn in order to minimize the "gutters." To obtain the ideal main graft sizing (I-Size), a formula was used by adding the custom sizing (C-Size) to the disease oversizing (D-Over). The same MPR imaging was evaluated on postoperative CTA to study gutters area and presence of EL-I. The mean I-Size was 41.67mm that was equivalent to an ideal oversizing of 19.3% (range 10-28%). The gutters area decreased from 7.3 to 1.7mm2 (PRE/POST) and EL-I rate from 28.5% to 0% (PRE/POST). Gutters area bigger than 7.5mm2 and planning made without "Over-SIRIX" were significantly associated (P<0.05) to EL-I. "Over-SIRIX" appears to be a feasible method to customize planning during chimney technique, reducing the risk of EL-I which is significantly related to the presence and size of the gutters.

Reparação endovascular na rutura aorto‐ilíaca

IntroductionRupture has a negative impact on abdominal aortic or iliac pathology. Endovascular aneurysm repair (EVAR) is an established treatment in the elective setting which has increasingly been applied in urgent patients and may be associated with a decrease in perioperative mortality. ObjectivesOur primary outcome was perioperative/early mortality. Secondary outcomes include perioperative hemodynamics and procedure‐related complications. MethodsA prospectively maintained single center database was retrospectively enquired. Patients who underwent rEVAR between March 2008 and March 2014 were included. Rupture was defined as the presence of a retroperitoneal hematoma or extraversion of contrast on a CTA. Although there's no institutional capacity to offer EVAR to all ruptured aneurysms, it is given preference to endovascular repair over open surgery in patients with suitable aortic anatomy for EVAR.Demographic, perioperative hemodynamics and laboratorial data were assessed. Primary outcome was perioperative/early mortality. Secondary outcomes include procedure‐related and systemic complications. ResultsForty‐nine patients were included, 43 of whom (88%) were males and mean age was 73.7±10,61 years (range 47 to 90).Thirty‐five patients presented rAAA (72%) and 9 ruptured iliac aneurysms (18%). Mean aneurysm diameter was 7.6±1.7cm. Other indications for rEVAR were spontaneous/iatrogenic aortic rupture (6%; n=3), late aneurysm rupture following EVAR (n=1) and a case of an anastomotic pseudoaneurysm. Deployed endograft configuration was aortic bi‐iliac in 26 cases (53%), aortic mono‐iliac in 18 (37%) and embolization and endovascular exclusion with iliac branch (10%). Deployed devices were Endurant Medtronic® in 59%, Excluder Gore® in 12%, Zenith Cook® in 22%, Excluder C3 Gore® in 5%, e Talent Medtronic® in 2%. 32% were treated under local anesthesia. The 30 dias/intrahospitalar mortality rate was 26.5%, which progressively decreased during the study period. The 30‐day complication rate was local in 20.4%, systemic in 53%. Abdominal compartment syndrome occurred in 10 cases (20.4%), and was found to be a negative prognostic factor. Median hospitalization duration was 7 days (0‐92) and median stay in the intensive care unit was 2 days (0‐65). ConclusionEVAR is a valid treatment in the urgent setting for patients with abdominal aortic or iliac rupture. Our results are comparable to the randomized controlled studies

The imaging assessment and specific endograft design for the endovascular repair of ascending aortic dissection.

BackgroundEndovascular option has been proposed for a very limited and selected number of Stanford type A aortic dissection (TAAD) patients. We have performed a computed tomography (CT)-based TAAD study to explore appropriate endograft configurations for the ascending aortic pathology.MethodsTAAD patients treated with optimal CT scans were retrospectively reviewed, and their entry tears (ETs) were identified using three-dimensional and multiplanar reconstructions in an EndoSize workstation. After generating a centerline of flow, measurements, including numerous morphologic characteristics of anatomy, were evaluated and a selected subset of patients were determined to be suitable for endovascular treatments. Proximal diameter and distal diameter of endograft were selected based on diameters measured at the ET level and at the innominate artery (IA) level, with 10% oversizing with respect to the true lumen, but not exceeding the original aortic diameter. The length of the endograft was determined by the distance from the sinotubular junction to IA.ResultsThis study covered 126 TAAD patients with primary ET in ascending aorta, among which, according to the assumed criteria, 48 (38.1%) patients were deemed to be suitable for endovascular treatment. The diameters of ascending aorta from the sinotubular junction to the IA level presented a downward trend, and the proximal diameters differed significantly from distal diameters of the endograft for TAAD (39.9 versus 36.2 mm, P<0.01), implying that the conical endograft might be compatible with the ascending pathology. In the ascending aorta, lengths of the endograft should be 50, 60, 70, 80, and 90 mm in five (10.4%), 22 (45.9%), 13 (27.1%), six (12.5%), and two (4.2%) patients, respectively.ConclusionIn this selected number of Chinese patients, the suitability of endovascular repair has been demonstrated based on the CT imaging. Shorter, larger, and bare spring-free conical endografts were preferred in the ascending aortic pathology.

Clinical outcome and morphologic determinants of mural thrombus in abdominal aortic endografts

Endograft mural thrombus has been associated with stent graft or limb thrombosis after endovascular aneurysm repair (EVAR). This study aimed to identify clinical and morphologic determinants of endograft mural thrombus accumulation and its influence on thromboembolic events after EVAR. A prospectively maintained database of patients treated by EVAR at a tertiary institution from 2000 to 2012 was analyzed. Patients treated for degenerative infrarenal abdominal aortic aneurysms and with available imaging for thrombus analysis were considered. All measurements were performed on three-dimensional center-lumen line computed tomography angiography (CTA) reconstructions. Patients with thrombus accumulation within the endograft's main body with a thickness >2 mm and an extension >25% of the main body's circumference were included in the study group and compared with a control group that included all remaining patients. Clinical and morphologic variables were assessed for association with significant thrombus accumulation within the endograft's main body by multivariate regression analysis. Estimates for freedom from thromboembolic events were obtained by Kaplan-Meier plots. Sixty-eight patients (16.4%) presented with endograft mural thrombus. Median follow-up time was 3.54 years (interquartile range, 1.99-5.47 years). In-graft mural thrombus was identified on 30-day CTA in 22 patients (32.4% of the study group), on 6-month CTA in 8 patients (11.8%), and on 1-year CTA in 17 patients (25%). Intraprosthetic thrombus progressively accumulated during the study period in 40 patients of the study group (55.8%). Overall, 17 patients (4.1%) presented with endograft or limb occlusions, 3 (4.4%) in the thrombus group and 14 (4.1%) in the control group (P = .89). Thirty-one patients (7.5%) received an aortouni-iliac (AUI) endograft. Two endograft occlusions were identified among AUI devices (6.5%; overall, 0.5%). None of these patients showed thrombotic deposits in the main body, nor were any outflow abnormalities identified on the immediately preceding CTA. Estimated freedom from thromboembolic events at 5 years was 95% in both groups (P = .97). Endograft thrombus accumulation was associated with >25% proximal aneurysm neck thrombus coverage at baseline (odds ratio [OR], 1.9; 95% confidence interval [CI], 1.1-3.3), neck length ≤ 15 mm (OR, 2.4; 95% CI, 1.3-4.2), proximal neck diameter ≥ 30 mm (OR, 2.4; 95% CI, 1.3-4.6), AUI (OR, 2.2; 95% CI, 1.8-5.5), or polyester-covered stent grafts (OR, 4.0; 95% CI, 2.2-7.3) and with main component "barrel-like" configuration (OR, 6.9; 95% CI, 1.7-28.3). Mural thrombus formation within the main body of the endograft is related to different endograft configurations, main body geometry, and device fabric but appears to have no association with the occurrence of thromboembolic events over time.

Retrograde Aortic Dissection After Thoracic Endovascular Aortic Repair

To provide data regarding the etiology and timing of retrograde type A aortic dissection (RTAD) after thoracic endovascular aortic repair (TEVAR). Details of patients who had RTAD after TEVAR were obtained from the MOTHER Registry supplemented by data from a systematic review of the literature. Univariate analysis and binary logistic regression analysis of patient or technical factors was performed. In MOTHER, RTAD developed in 16 of the 1010 patients (1.6%). Binary logistic regression demonstrated that an indication of TEVAR for aortic dissection (acute P = 0.000212; chronic P = 0.006) and device oversizing (OR 1.14 per 1% increase in oversizing above 9%, P < 0.0001) were significantly more frequent in patients with RTAD. Data from the systematic review was pooled with MOTHER data and demonstrated that RTAD occurred in 1.7% (168/9894). Most of RTAD occurred in the immediate postoperative (58%) period and was associated with a high mortality rate (33.6%). The odds ratio of RTAD for an acute aortic dissection was 10.0 (CI: 4.7-21.9) and 3.4 (CI: 1.3-8.8) for chronic aortic dissection. The incidence of RTAD was not significantly different for endografts with proximal bare stent (2.8%) or nonbare stent (1.9%) (P = 0.1298). Although RTAD after TEVAR is an uncommon complication, it has a high mortality rate. RTAD is significantly more frequent in patients treated for acute and chronic type B dissection, and when the endograft is significantly oversized. The proximal endograft configuration was not associated with any difference in the incidence of RTAD.

VESS2. Retrograde Aortic Dissection After Thoracic Endovascular Aortic Repair

Objective: To provide data regarding the etiology and timing of retrograde type A aortic dissection (RTAD) after thoracic endovascular aortic repair (TEVAR). Methods: Details of patients who had RTAD after TEVAR were obtained from the MOTHER Registry supplemented by data from a systematic review of the literature. Univariate analysis and binary logistic regression analysis of patient or technical factors was performed. Results: In MOTHER, RTAD developed in 16 of the 1010 patients (1.6%). BinarylogisticregressiondemonstratedthatanindicationofTEVARforaortic dissection(acute P = 0.000212;chronic P = 0.006)anddeviceoversizing(OR 1.14 per 1% increase in oversizing above 9%, P < 0.0001) were significantly more frequent in patients with RTAD. Data from the systematic review was pooled with MOTHER data and demonstrated that RTAD occurred in 1.7% (168/9894). Most of RTAD occurred in the immediate postoperative (58%) period and was associated with a high mortality rate (33.6%). The odds ratio of RTAD for an acute aortic dissection was 10.0 (CI: 4.7–21.9) and 3.4 (CI: 1.3– 8.8) for chronic aortic dissection. The incidence of RTAD was not significantly different for endografts with proximal bare stent (2.8%) or nonbare stent (1.9%) ( P = 0.1298). Conclusions: Although RTAD after TEVAR is an uncommon complication, it has a high mortality rate. RTAD is significantly more frequent in patients treated for acute and chronic type B dissection, and when the endograft is sig- nificantly oversized. The proximal endograft configuration was not associated with any difference in the incidence of RTAD

Studying the Flow Dynamics in an Aortic Endograft with Crossed-limbs

To evaluate the flow phenomena within an aortic endograft with crossed-limbs, comparing to an endograft with the ordinary limb bifurcation. An endograft model with crossed-limbs was computationally reconstructed based on Computed Tomography patient-specific data, using commercially available software. Accordingly, its analogue model was reconstructed in the ordinary fashion (ordinary bifurcation). Computational fluid dynamics analysis was performed to determine and compare the flow fields, velocity profiles, pressure and shear stress distribution throughout the different parts of both endograft configurations, in different phases of the cardiac cycle. The flow patterns between the "Ballerina" and the classic endograft were similar, with flow disturbance near the inlet zone at late diastole and smooth flow patterns during the systolic phase. Both configurations presented similar pressure distribution patterns throughout the cardiac cycle. The highest and lowest pressures were demonstrated in the inlet-main body area and the iliac limbs, respectively. Marked differences were observed in the velocity profiles of the proximal limb segments between the two configurations, mostly in the peak- and end-systolic phase. The regions of lower velocities correlated well to low shear values. Differences in the shear stress distribution were noted between the two configurations in the systolic and, predominantly, in the diastolic phase. There are differences in the velocity profiles and shear distribution between the limbs of the two endograft configurations. The pathophysiologic implication of our findings and their possible association with clinical events, such as thrombus apposition, deserves further investigation.