Endograft Research Articles

The Impact of Heli-FX EndoAnchor Application on Endograft Material: An Experimental Study

The Impact of Heli-FX EndoAnchor Application on Endograft Material: An Experimental Study

Outcomes and Economic Impact of Hypogastric Artery Management During Elective Endovascular Aortic Repair for Aorto-Iliac Aneurysms

To analyze clinical outcomes and perform a macro-costing evaluation of endovascular aortic repair (EVAR) for aorto-iliac aneurysms. This is a retrospective, financially unsupported physician-initiated observational cohort study. Patients with iliac artery involvement treated with EVAR between January 1st 2014 and December 31st 2021 were identified. Inclusion criteria were intact aneurysm, elective EVAR with at least one hypogastric artery (HA) treatment, use of bifurcated endograft (EG), and at least 6-months of follow-up. Primary outcomes of interest were overall survival, freedom from aneurysm-related mortality (ARM), freedom from EVAR-related reintervention, and overall EVAR(procedure)-related costs. We studied 122 (9.1%) patients: 119 (97.5%) were male and 3 (2.5%) females. Median age of patients was 76 years (range, 68.75-81). Overall, 107 (87.7%) patients had both HAs preserved according to following strategy: 45 (36.9%) with flared limbs, 13 (10.6%) with bilateral branched device, and 49 (40.2%) with a combination of flared limb on one side and branched device on the contralateral side. Bilateral overstenting was performed in 15 (12.3%) patients. Estimated overall survival was not different between groups of EVAR (Log-rank, P = 0.561). There was only 1 (0.8%) ARM ascertained during the follow-up. Estimated freedom from EVAR-related reintervention was not different among groups (Log-rank, P = 0.464). During the follow-up, 9 (7.4%) patients developed buttock claudication (SVS grade 1, n = 4, SVS grade 2, n = 5), more frequently in HA overstenting (HR: 3.6; 95%CIs: 0.96-13.5, P = 0.058). When all cots were included, branched EVAR still carried the highest burden (P = 0.001) in comparison with the mixed subgroup, the overstenting subgroup, and the flared limbs subgroup. Early mortality and pelvic ischemic syndromes rate were acceptably low in all techniques. Hypogastric artery preservation showed lower complication rate in comparison with HA overstenting which, however, appears to be safe an effective for option with similar overall costs for patients who are not candidates for HA preservation based on aortic anatomy.

Patient-specific modelling for the assessment of the hemodynamics risk of failure in endovascular aneurysm repair

Endovascular aneurysm repair (EVAR), despite its advantages over abdominal aortic aneurysm (AAA) open surgery, still presents risks of failure linked to Endograft (EG) migration. We here explore the link between intravascular blood flow features and Displacement Forces (DFs) acting on the EG. DFs are inversely associated with the amount of helical flow within the EG.

MEG Visual Gamma Oscillations Predict Sensory Perception in Women: The Replication Study

The objective of this study was to collect and critically analyze the current evidence on the modalities and results of treatment of descending thoracic aortic surgical graft (SG) and endograft (EG) infection, which represents a rare but dramatic complication after both surgical and endovascular aortic repair.A comprehensive electronic health database search (PubMed/MEDLINE, Scopus, Google Scholar, and the Cochrane Library) identified all articles that were published up to October 2017 reporting on thoracic aortic SG or EG infection. Observational studies, multicenter reports, single-center series and case reports, case-control studies, and guidelines were considered eligible if reporting specific results of treatment of descending thoracic aortic SG or EG infection. Comparisons of patients presenting with SG or EG infection and between invasive and conservative treatment were performed. Odds ratio (OR) meta-analyses were run when comparative data were available.Forty-three studies reporting on 233 patients with infected SG (49) or EG (184) were included. Four were multicenter studies including 107 patients, all with EG infection, associated with a fistula in 91% of cases, with a reported overall survival at 2 years of 16% to 39%. The remaining 39 single-center studies included 49 patients with SG infection and 77 with EG infection. Association with aortoesophageal fistula was significantly more common with EG (60% vs 31%; P = .01). In addition, time interval from index procedure to infection was significantly shorter with EG (17 ± 21 months vs 32 ± 61 months; P = .03). Meta-analysis showed a trend of increased 1-year mortality in patients with SG infection compared with EG infection (pooled OR, 3.6; 95% confidence interval, 0.9-14.7; P = .073). Surgical management with infected graft explantation was associated with a trend toward lower 1-year mortality compared with graft preservation (pooled OR, 0.3; 95% confidence interval, 0.1-1.0; P = .056).Thoracic aortic EG infection is likely to occur more frequently in association with aortoesophageal fistulas and in a shorter time compared with SG infection. Survival is poor in both groups, especially in patients with SG infection. Surgical treatment with graft explantation seems to be the preferable choice in fit patients.

Multicenter Mid-term Results After Endovascular Aortic Aneurysm Repair with the Incraft® Device

Durability after endovascular aortic aneurysm repair (EVAR) is considered an ongoing topic of investigation and was always a point of concern with smaller profile devices. Recently released five-year clinical trial results using the Incraft® ultralow profile device are encouraging. However, additional real-life experience will need to assist these initial findings. Herein, we investigated the outcomes after EVAR, in real world practice using the Incraft® endograft (EG). Seventy-seven patients with infrarenal abdominal aortic aneurysms (AAA) ≥50mm in diameter treated with the Incraft® device in three vascular centers were enrolled from November 2015 to July 2018. Follow-up was completed in August 2020. Selection of EVAR using the Incraft® device was individualized according to aorto-iliac morphologic features, comorbidities, history of previous abdominal surgery and preference of the patient. At the early phase of the study, we specifically opted for preferential use of this low profile EG mainly in cases of small and tortuous iliac vessels (more challenging access routes). At later stages, it was used according to surgeon preference and not specifically in complex anatomies (real-world conditions). End-points included technical success, perioperative complications, 30-day survival, endoleg patency, presence of endoleaks, sac enlargement >5mm and clinical success. The primary technical success rate was 97.4% before the addition of an aortic cuff and iliac extension for a type Ia and type Ib endoleak respectively, and the repair of a maldeployment iliac component (primary-assisted and secondary technical success, 100%). Intraoperative small type II endoleaks (visible in final angiogram) were noted in 19 patients (24.7%). There were no intraoperative deaths from AAA rupture, primary conversions or conversions to aortounilateral grafts. Two complications occurred, necessitating hybrid techniques for repair (replaced of a dislodged endoleg and distal external iliac artery hemostasis). No deaths were reported within 30days. Occlusion of an endoleg, was observed in two patients, 6 and 14months respectively after implantation (2.6%), and were treated by femoral-femoral PTFE bypass after unsuccessful endovascular recanalization. The latter required open conversion, 3mo later, to repair compromised flow to the inflow iliac axis. Three patients (3.9%) experienced sac enlargement >5mm in diameter compared with the 1-month CT scan. All of these had type II endoleaks and two received embolization procedures. Eleven patients died from causes unrelated to AAA repair. Clinical success was 97.3%, 92.8% and 89.4% through 1, 2 and 3years respectively. EVAR with the Incraft® device might be considered a reliable option in real-world conditions and not specifically only in complex iliac anatomies.

Ten-year outcome analysis of the Italian Excluder Registry with the Gore Excluder endograft for infrarenal abdominal aortic aneurysms

ObjectiveThe objective of this study was to report the 10-year outcomes of the multicenter Italian Excluder Registry for elective endovascular aneurysm repair (EVAR). MethodsA retrospective analysis of all patients who underwent elective EVAR using the Gore Excluder (W. L. Gore & Associates, Flagstaff, Ariz) endograft (EG) at four Italian centers between 1998 and 2006 was carried out. Follow-up consisted of duplex ultrasound scan and computed tomography performed at 1 month, 6 months, and 12 months and yearly thereafter. Long-term outcomes were evaluated according to a life-table analysis. ResultsThe Excluder EG was used in 461 patients (425 men; mean age, 72.9 ± 9.2 years) with abdominal aortic aneurysm (mean diameter, 52.2 ± 11.9 mm) who underwent elective EVAR. The 10-year cumulative survival was 62.5% ± 3.5% (95% confidence interval [CI], 55.5%-69.1%). During the follow-up, 14 (3.03%) patients were lost to follow-up. Estimated freedom from EG-related complication was 90.5% ± 1.5% (95% CI, 87.4%-92.9%) at 5 years, 89.2% ± 1.6% (95% CI, 85.6%-91.9%) at 7 years, and 88.4% ± 1.8% (95% CI, 84.4%-91.5%) at 10 years. Freedom from reintervention at 5, 7, and 10 years was 87.7% ± 1.8% (95% CI, 83.7%-90.8%), 82.4% ± 2.4% (95% CI, 77.2%-86.6%), and 80.6% ± 2.6% (95% CI, 75.5%-84.9%), respectively. On multivariable analysis, we did not find independent predictors of a higher rate of reintervention. There were 127 (27.5%) endoleaks detected during the follow-up. Only one type I endoleak was identified beyond 5-year follow-up. Cumulative freedom from endoleak rate was significantly different between the two different follow-up intervals (0-5 years, 2.6%; 6-10 years, 0.8%; P < .001). Estimated freedom from aorta-related mortality was 97.2% ± 0.8% (95% CI, 49.7%-99.9%) at 10 years. ConclusionsThe Italian Excluder Registry outcomes confirmed sustained EVAR effectiveness at 10-year follow-up using the Gore Excluder EG. Freedom from EG-related complications, endoleaks, and reinterventions was satisfactory and remained acceptable beyond 5 years of follow-up, supporting a reasonable long-term durability of this device.

Estimating the hemodynamic influence of variable main body-to-iliac limb length ratios in aortic endografts.

We conducted a computational study to assess the hemodynamic impact of variant main body-to-iliac limb length (L1/L2) ratios on certain hemodynamic parameters acting on the endograft (EG) either on the normal bifurcated (Bif) or the cross-limb (Cx) fashion. A customary bifurcated 3D model was computationally created and meshed using the commercially available ANSYS ICEM (Ansys Inc., Canonsburg, PA, USA) software. The total length of the EG, was kept constant, while the L1/L2 ratio ranged from 0.3 to 1.5 in the Bif and Cx reconstructed EG models. The compliance of the graft was modeled using a Fluid Structure Interaction method. Important hemodynamic parameters such as pressure drop along EG, wall shear stress (WSS) and helicity were calculated. The greatest pressure decrease across EG was calculated in the peak systolic phase. With increasing L1/L2 it was found that the Pressure Drop was increasing for the Cx configuration, while decreasing for the Bif. The greatest helicity (4.1 m/s2) was seen in peak systole of Cx with ratio of 1.5 whereas its greatest value (2 m/s2) was met in peak systole in the Bif with the shortest L1/L2 ratio (0.3). Similarly, the maximum WSS value was highest (2.74Pa) in the peak systole for the 1.5 L1/L2 of the Cx configuration, while the maximum WSS value equaled 2 Pa for all length ratios of the Bif modification (with the WSS found for L1/L2=0.3 being marginally higher). There was greater discrepancy in the WSS values for all L1/L2 ratios of the Cx bifurcation compared to Bif. Different L1/L2 rations are shown to have an impact on the pressure distribution along the entire EG while the length ratio predisposing to highest helicity or WSS values is also determined by the iliac limbs pattern of the EG. Since current custom-made EG solutions can reproduce variability in main-body/iliac limbs length ratios, further computational as well as clinical research is warranted to delineate and predict the hemodynamic and clinical effect of variable length ratios.

Hemodynamic Profile of Two Aortic Endografts Accounting for Their Postimplantation Position

Endovascular aneurysm repair (EVAR) is a clinically effective technique for treating anatomically eligible abdominal aortic aneurysms (AAAs), involving the deployment of an endograft (EG) that is designed to prevent blood leakage in the aneurysmal sac. While most EGs have equivalent operating principles, the hemodynamic environment established by different EGs is not necessarily the same. So, to unveil the post-EVAR hemodynamic properties, we need an EG-specific computational approach that currently lacks from the literature. Endurant and Excluder are two EGs with similar pre-installation designs. We assumed that the flow conditions in the particular EGs do not vary significantly. The hypothesis was tested combining image reconstructions, computational fluid dynamics (CFD), and statistics, taking into account the postimplantation position of the EGs. Ten patients with Endurant EGs and ten patients with Excluder EGs were included in this study. The two groups were matched with respect to the preoperative morphological characteristics of the AAAs. The EG models are derived from image reconstructions of postoperative computed tomography scans. Wall shear stress (WSS), displacement force, velocity, and helicity were calculated in regions of interest within the EG structures, i.e., the main body, the upper and lower part of the limbs. Excluder generated higher WSS compared to Endurant, especially on the lower part of the limbs (p = 0.001). Spatial fluctuations of WSS were observed on the upper part of the Excluder limbs. Higher blood velocity was induced by Excluder in all the regions of interest (p = 0.04, p = 0.01, and p = 0.004). Focal points of secondary flow were detected in the main body of Endurant and the limbs of Excluder. The displacement force acting on the lower part of the Excluder limbs was stronger compared to the Endurant one (p = 0.03). The results showed that two similar EGs implanted in similar AAAs can induce significantly different flow properties. The delineation of the hemodynamic features associated with the various commercially available EGs could further promote the personalization of treatment offered to aneurysmal patients and inspire ideas for the improvement of EG designs in the future.

Comparison of physiological and post-endovascular aneurysm repair infrarenal blood flow

Endovascular aneurysm repair (EVAR) of abdominal aortic aneurysms results in redirection of blood through the deployed endograft (EG). Even though EVAR is clinically effective, the absolute flow restoration is not warranted. Our purpose was to compare the physiological with the post-EVAR infrarenal flow conditions. We developed patient-specific models based on computed tomography data of five healthy volunteers and ten patients treated with the Endurant® stent-graft system. Wall shear stress (WSS), helicity, pressure and velocity fields were calculated using computational fluid dynamics. The results showed a decrease of peak WSS on the part of the EG that resides in the iliac arteries, compared to the physiological value (p = 0.01). At the abdominal part, the average helicity seems to increase after EVAR, while at the iliac arteries part, the intensity of helical flow seems physiological. Pressure drop and peak velocity in the iliac arteries part are lower than the physiological values (p = 0.04). The comparison revealed that most hemodynamic properties converge to normal levels at the abdominal part whereas statistically significant variations were observed in the iliac arteries part. The delineation of the differences between physiological and postoperative flow data could pave the way for the improvement of EG designs.

Geometrical factors influencing the hemodynamic behavior of the AAA stent grafts: essentials for the clinician.

Endovascular aneurysm repair (EVAR) is considered to be the treatment of choice for abdominal aortic aneurysms (AAA). Despite the initial technical success, EVAR is amenable to early and late complications, among which the migration of the endograft (EG) with subsequent proximal endoleak (Type Ia) leads to repressurization of the AAA sac, exposure to excessive wall stress, and, hence, to potential rupture. This article discusses the influence that certain geometrical factors, such as neck angulation, iliac bifurcation, EG curvature, neck-to-iliac diameter, and length ratios, as well as iliac limbs configuration can exert on the hemodynamic behavior of the EGs. The information provided could help both clinicians and EG manufacturers towards further development and improvement of EG designs and better operational planning.

Analysis of Stroke after TEVAR Involving the Aortic Arch

To analyse the incidence of stroke after thoracic endovascular aortic repair (TEVAR) for aortic arch disease. In the last decade, 393 patients received TEVAR at our Institution; in 143 cases the aortic arch was involved (32 zones ‘0’, 35 zones ‘1’ and 76 zone ‘2’). The left subclavian artery (LSA) was revascularised selectively in 75 cases; the proximal LSA was ligated or occluded with a plug in 55 cases before endograft (EG) deployment. Initial clinical success, perioperative mortality, spinal cord ischaemia and stroke in TEVAR patients with or without arch involvement were, respectively, 86.7% vs. 94.4%, 4.2% vs. 2.4%, 2.1% vs. 3.6% and 2.8% vs. 1.2%. The stroke rate was 9.4% (P < 0.02) in ‘zone 0’, 0% in ‘zone 1’ and 1.3% in ‘zone 2’ with scans showing severe atheroma and/or thrombus in all cases. Stroke was observed in patients with 2.6% or without 2.9% LSA revascularisation; however, it was never observed in patients in whom the LSA was occluded before EG deployment and in 4.5% of patients in whom it was patent at the time of EG deployment. Stroke after TEVAR is not infrequent especially when the arch is involved. Careful patient selection together with a strategy to reduce embolisation such as occlusion of supra-aortic trunks before EG deployment may play a beneficial role.

Analysis of Stroke after TEVAR Involving the Aortic Arch

ObjectiveTo analyse the incidence of stroke after thoracic endovascular aortic repair (TEVAR) for aortic arch disease. MethodsIn the last decade, 393 patients received TEVAR at our Institution; in 143 cases the aortic arch was involved (32 zones ‘0’, 35 zones ‘1’ and 76 zone ‘2’). The left subclavian artery (LSA) was revascularised selectively in 75 cases; the proximal LSA was ligated or occluded with a plug in 55 cases before endograft (EG) deployment. ResultsInitial clinical success, perioperative mortality, spinal cord ischaemia and stroke in TEVAR patients with or without arch involvement were, respectively, 86.7% vs. 94.4%, 4.2% vs. 2.4%, 2.1% vs. 3.6% and 2.8% vs. 1.2%. The stroke rate was 9.4% (P < 0.02) in ‘zone 0’, 0% in ‘zone 1’ and 1.3% in ‘zone 2’ with scans showing severe atheroma and/or thrombus in all cases. Stroke was observed in patients with 2.6% or without 2.9% LSA revascularisation; however, it was never observed in patients in whom the LSA was occluded before EG deployment and in 4.5% of patients in whom it was patent at the time of EG deployment. ConclusionsStroke after TEVAR is not infrequent especially when the arch is involved. Careful patient selection together with a strategy to reduce embolisation such as occlusion of supra-aortic trunks before EG deployment may play a beneficial role.

Acute iatrogenic type A aortic dissection following thoracic aortic endografting

Endovascular intervention has emerged as a less traumatic alternative treatment for several diseases of the thoracic aorta.(1,2) However, depending on the different aortic pathologies, procedure related complications have become increasingly evident: severe complications include type I endoleaks, migration, and endograft (EG) collapse, as well as those observed during conventional surgery (eg, stroke and paraplegia).(3,4) One of the emerging and most alarming complication of thoracic endografting is iatrogenic retrograde type A acute dissection (RTAAD).(5) Retrograde type A acute dissection is defined as acute aortic dissection that originates distally to the ascending aorta with a retrograde flap progression into the ascending aorta.(6) This complication has been previously described during conventional cardiac surgery with high mortality rate; previous case reports suggested that the fragility of the aortic wall and Marfan disease were predisposing factors to such a life-threatening complication.(7-9) This report presents a case of iatrogenic RTAAD after EG repair of a descending thoracic penetrating aortic ulcer, requiring emergent surgical replacement of the ascending aorta and the aortic arch. The available English literature on RTAAD was also reviewed, in order to recognize potential predisposing factors and specific strategies to prevent it.

Morphological and functional modifications of the aneurysm-endograft complex following endoluminal treatment of abdominal aortic aneurysms

The aim of the study was to evaluate quantitatively the main morphological changes of the abdominal aortic aneurysm (AAA)-endograft (EG) complex following endovascular repair of infrarenal AAA and to evaluate the functional consequences of these changes in terms of rate of complications (endoleaks and thrombosis). We also assessed whether these morphological and functional changes were related to the size of the AAA and to the type of EG used. Eighty-five patients (M/F=82/3; mean age at time of operation 70.5+/-3.5 years, range 49.9-89.6 years) who underwent endovascular treatment of infrarenal AAA between April 1997 and October 2004 with a follow-up of at least 1 month were considered. All images of 408 preoperative and postoperative computed tomography (CT) studies were reviewed. Statistical analysis was performed with log-rank test on the 85 patients grouped according to AAA diameter <50 mm or < or =50 mm, and on 75 patients grouped according to EG device used (AneuRx, Talent or Excluder). Morphological and dimensional changes involved the diameter (six cases) and length (14 cases) of AAA proximal neck, diameter (36 cases) and length (51 cases) of the aneurysm sac and shape of the stent-graft (47 cases). The prevalence of endoleaks was 37.6% whereas endoluminal thrombosis was observed in 27.1% of patients. AAA growth was significantly correlated (p=0.002) with the preprocedural diameter of the aneurysm sac whereas shrinkage was significantly correlated (p=0.0005) with the EG used. AAA growth was correlated with the diameter of the aneurysm sac while shrinkage was correlated with the EG used. During follow-up after endovascular repair, patients require careful evaluation of the morphological and dimensional features of the AAA and EG to promptly identify any changes that can anticipate major complications and even conversion to conventional surgery.