Stent Graft Material Research Articles

Stent-Graft Fabrics Incorporating a Specific Corona Ready to Fenestrate.

In situ fenestration of endovascular stent-grafts has become a mainstream bailout technique to treat complex emergent aneurysms while maintaining native anatomical visceral and aortic arch blood supplies. Fabric tearing from creating the in situ fenestration using balloon angioplasty may extend beyond the intended diameter over time. Further tearing may result from the physiologic pulsatile motion at the branching site. A resultant endoleak at the fenestrated sites in stent-grafts could ultimately lead to re-pressurization of the aortic sac and, eventually, rupture. In an attempt to address this challenge, plain woven fabrics were designed. They hold a specific corona surrounding a square-shaped cluster with a plain weave fabric structure, a 2/2 twill, or a honeycomb. The corona was designed to stop potential further tearing of the fabric caused by the initial balloon angioplasty and stent or later post-implantation motion. The cluster within the corona was designed with relatively loose fabric structures (plain weave, 2/2 twill weave, and honeycomb) to facilitate the laser fenestration. Two commercial devices, Anaconda (Vascutek, Terumo Aortic) and Zenith TX2 (Cook), were selected as controls for comparison against this new design. All the specimens were characterized by morphology, thickness, and water permeability. The results demonstrated that all specimens with a low thickness and water permeability satisfied the requirements for a stent graft material that would be low profile and resistant to endoleaks. The in situ fenestrations were performed on all fabrics utilizing an Excimer laser followed by balloon angioplasty. The fabrics were further observed by light microscopy and scanning electron microscopy. The dimension of the fenestrated apertures was smaller than the balloon's diameter. The tearing was effectively confined within the corona. The clinical acceptability of this concept deserves additional bench testing and animal experimentation.

Abstract 530: Explantation Vs Graft Preserving Strategy Following Primary Endovascular Aneurysm Repair

Background: Continuous sac expansion could result in rupture, requiring aggressive management with re-intervention to abolish the risk of rupture. Re-intervention could be achieved through salvage of the primary endograft through graft preserving strategy or explantation as necessary. We aim to scrutinise our 20 years of EVAR practice, strategies indications for management and re-interventions following primary endovascular aneurysm repair (EVAR). Methods: We performed 1555 aortic interventions over study period, including 910 EVARs. Using conventional and innovative diagnostic modalities with Prone contrASt enHanced computed tomography Angiography (PASHA), 136 endoleaks (ELs) were identified (15 type I, 98 type II; 18 type III; 5 type IV). Results: In total, 4.84% (44/910) patients underwent re-intervention post-primary EVAR; 18 EVAR GORE SalvAge Fabric Technique (ARAFAT), 12 double breastings, and 14 explantations (Figure 1) . Mean EL detection duration following primary EVAR was 53.3 ± 6.82 months, while re-intervention time was 70.2 ± 6.98 months. Mean sac size before the primary EVAR and re-intervention were 6.00 and 7.51 cm. Polyester (61.40%, 12/18) was the most commonly employed stent-graft material. Factors associated with the need for reintervention and likelihood of chronic fabric fatigue failure (CFFF) included the use of more than three modular stent-graft components (3.42 ± 1.31); with the proximal stent-graft diameter of 31.6 ± 3.80 cm and the use of iliac limbs more than 18 mm. We had one peri-operative mortality following explantation due to sepsis-induced multiorgan failure. Conclusions: Increasing complications post-EVAR necessitates developing and studying re-intervention strategies to salvage existing endograft and/or address graft-related complications. Re-intervention could be achieved through salvage of the primary endograft through graft preserving strategy or explantation as necessary.

TEVAR and EVAR, the unknown knowns of the cardiovascular hemodynamics; and the immediate and long-term consequences of fabric material on major adverse clinical outcome.

This review discusses the impact of endovascular aneurysm repair on cardiovascular (CV) hemodynamics and the role of stent-graft material, i.e., polytetrafluoroethylene (PTFE) vs. polyester in post-procedural outcomes. Endovascular aneurysm repair has been widely employed in the last decades for thoracic and abdominal aneurysm repair. However, aortic endografts are stiff and alter the native flow hemodynamics. This failure to simulate the native aorta could lead to added strain on the heart, manifesting as increased left ventricular strain, higher pulse pressure, and congestive heart failure later. This could result in adverse CV outcomes. Also, evidence is mounting to support the implication of stent-graft materials, i.e., PTFE vs. polyester, in adverse post-procedural outcomes. However, there is an absence of level one evidence. Therefore, the only way forward is to plan and perform a randomised controlled trial to demonstrate the alterations in the CV hemodynamics in the short and long run and compare the available stent-graft materials regarding procedural and clinical outcomes. We believe the best solution, for now, would be to reduce the stented length of the aorta. At the same time, in the longer term, encourage continuous improvement in stent-graft materials and design.

The contemporary design of endovascular aneurysm stent-graft materials: PTFE versus polyester.

Endovascular aneurysm repair of the abdominal aorta (EVAR) and of the thoracic aorta (TEVAR) have revolutionised therapeutic strategies in the management of aortic pathology, and endovascular repair is now an established and attractive alternative to open surgical repair (OSR) due to its superior short-term safety profile. However, opinions are divided regarding its long-term cost-effectiveness, which is reflected in the controversial NICE guidelines on abdominal aortic aneurysm (AAA) repair published in 2018, which advised against EVAR for elective aortic repair due to high secondary intervention rates and resultant associated costs. There is no doubt that OSR continues to have a valuable role to play in aortic repair, but it is not universally applicable, especially in older and sicker patients. Therefore, we should not dismiss EVAR and TEVAR without examining the reasons for long-term failure, and the most obvious starting point is stent graft material properties. Polytetrafluoroethylene (PTFE) and polyester are the two most common stent-graft materials; however, there has been no objective comparison of PTFE and polyester stent-graft post-procedural outcomes in EVAR and TEVAR, or even OSR. This lack of definitive data on different stent-graft materials and their configuration necessitates a comprehensive review to elucidate the post-procedural outcome in terms of endograft failure, cardiovascular events, and aortic-related mortality and morbidity.

Two decades of experience in explantation and graft preserving strategies following primary endovascular aneurysm repair and lessons learned.

We aim to scrutinize our evolving re-intervention strategies following primary endovascular aortic aneurysm repair (EVAR) - EVAR GORE SalvAge Fabric Technique (ARAFAT), aortic sac double breasting with endograft preservation, and stent-graft explantation. We performed 1,555 aortic interventions over the study period, including 910 EVARs. Factors associated with the need for reintervention and the likelihood of chronic fabric fatigue failure (CFFF) were investigated. Using conventional and innovative diagnostic modalities with Prone contrASt enHanced computed tomography Angiography (PASHA), 136 endoleaks (ELs) were identified (15 type I, 98 type II; 18 type III; 5 type IV). Forty-four (4.84%) patients underwent re-intervention post-primary EVAR; 18 ARAFATs, 12 double breastings, and 14 explantations. Choice of re-intervention was based on patient fitness and mode of failure. Mean EL detection duration following primary EVAR was 53.3 ± 6.82 months, while mean time to re-intervention was 70.20 ± 6.98 months. The mean sac size before the primary EVAR and re-intervention was 6.00 ± 1.75 cm and 7.51 ± 1.94 cm, respectively. Polyester (61.40%) was the most commonly employed stent-graft material. Use of more than three modular stent-graft components (3.42 ± 1.31, p = 0.846); with the proximal stent-graft diameter of 31.6 ± 3.80 cm (p = 0.651) and the use of iliac limbs more than 17 mm (p = 0.364), all added together are contributing factors. We had one peri-operative mortality following explantation due to sepsis-induced multiorgan failure. Our re-intervention strategies matured from stent graft explantation to graft preservation with endovascular relining of the stent-graft. Graft preservation with aortic sacotomy and double breasting were used to manage concealed ELs due to aortic hygroma.

O077 Explantation vs graft preserving strategy following primary endovascular aneurysm repair: two decades of EVAR and lessons learned

Abstract Introduction Continuous sac expansion could result in rupture, requiring aggressive management with reintervention to abolish the risk of rupture. Re-intervention could be achieved through salvage of the primary endograft through graft preserving strategy or explantation as necessary. We aimed to scrutinise our 20 years of EVAR practice, strategies indications for management and reinterventions following primary endovascular aneurysm repair (EVAR). Methods We performed 1480 aortic interventions over the study period, including 910 EVARs. Using conventional and innovative diagnostic modalities with Prone contrASt enHanced computed tomography Angiography (PASHA), 133 endoleaks (ELs) were identified (15 type I, 98 type II; 18 type III; 5 type IV). Results In total, 44 patients underwent re-intervention post-primary EVAR;18 EVAR GORE SalvAge Fabric Technique (ARAFAT), 12 double breastings, and 14 explantations. Mean EL detection duration following primary EVAR was 53.3 ± 6.82 months, while re-intervention time was 70.2 ± 6.98 months. Mean sac size before the primary EVAR and re-intervention were 6.00 and 7.51 cm. Polyester (61.40%) was the most commonly employed stent-graft material. Factors associated with the need for reintervention and the likelihood of chronic fabric fatigue failure (CFFF) included the use of more than three modular stent-graft components (3.42 ± 1.31); with the proximal stent-graft diameter of 31.6 ± 3.80 cm and the use of iliac limbs more than 18 mm. We had one peri-operative mortality following explantation due to sepsis-induced multiorgan failure. Conclusion Increasing complications post-EVAR necessitates developing and studying reintervention strategies to salvage existing endograft and/or address graft-related complications. Take-home message Increasing complications post-EVAR necessitates developing and studying re-intervention strategies to salvage existing endograft and/or address graft-related complications.

Factors Associated With Noninfectious Fever After Endovascular Aortic Aneurysm Repair

Purpose: The post–endovascular abdominal aortic aneurysm repair (EVAR) inflammatory response, which is very often associated with fever, has been ascribed to a wide range of proinflammatory mediators and operative events. The aim of this study was to evaluate the impact of such factors in the development of fever of noninfectious origin after elective EVAR. Materials and Methods: A retrospective analysis of prospectively collected data of patients treated with standard elective EVAR between February 2017 and December 2020 was undertaken. The database included patients’ demographics and comorbidities, as well as laboratory inflammatory markers (white blood cell count, neutrophils, and C-reactive protein [CRP]) and anatomical characteristics (sac diameter, inferior mesenteric artery [IMA] patency and diameter, number of patent lumbar arteries, internal iliac artery [IIA] patency or occlusion). Intraoperative details, such as type of stent graft material and IIA overstenting, were also analyzed. Patients with infectious postoperative complications or previously receiving systemic anti-inflammatory medication were excluded. Statistical analysis was performed by SPSS 22.0 for Windows software (IBM Corp, Armonk, New York). Results: From 332 patients treated with elective EVAR between 2017 and 2020, 268 patients (all men) were included in the analysis. The mean age was 72.1±7.5 years and the mean aneurysm diameter was 59.1±12.1 mm. Seventeen patients were excluded due to a known infection site. From the study cohort, 114 (42.5%) patients presented with fever. Multivariate regression analysis confirmed that the occlusion of IMA ≥5 mm (p<0.008) and higher CRP (p<0.001) were independent factors associated with postoperative fever. A subanalysis was performed only on patients with patent IMA before EVAR. In the multivariate regression analysis of this subgroup, IMA ≥5 mm (p=0.008), presence of dyslipidemia (p=0.037), and higher CRP (p<0.001) were related to fever. Conclusion: Occlusion of an existing wide (≥5 mm) and patent IMA prior to EVAR may contribute to the development of post-EVAR pyrexia. The CRP is a reliable marker for post-EVAR fever. Further prospective studies are needed to corroborate these findings.

Artifacts in Contrast-Enhanced Ultrasound during Follow-up after Endovascular Aortic Repair: Impact on Endoleak Detection in Comparison with Computed Tomography Angiography

The study described here systematically analyzed how specific artifacts in contrast-enhanced ultrasound (CEUS) can affect the detection of endoleaks during follow-up after endovascular aortic repair (EVAR). Patients undergoing EVAR of atherosclerotic or mycotic abdominal aortic aneurysms using various standard and branched stent-graft material for visceral and iliac preservation were enrolled over 5 y and followed up with computed tomography angiography (CTA) and CEUS simultaneously. CEUS artifacts were frequently identified after EVAR procedures (59% of examinations) and were caused mainly by contrast agent, different prosthesis or embolization material and postinterventional changes in the aneurysm sac. This article describes how to identify important artifacts and how to avoid false-negative or false-positive interpretations of endoleaks. Despite artifacts, CEUS had higher sensitivity for endoleak detection after EVAR than CTA. CEUS was superior to CTA in the identification of late endoleaks type II and in follow-up examinations after embolization procedures, where beam-hardening artifacts limited CTA.

Development and Assessment of a 3D-Printed Scaffold with rhBMP-2 for an Implant Surgical Guide Stent and Bone Graft Material: A Pilot Animal Study.

In this study, a new concept of a 3D-printed scaffold was introduced for the accurate placement of an implant and the application of a recombinant human bone morphogenetic protein-2 (rhBMP-2)-loaded bone graft. This preliminary study was conducted using two adult beagles to evaluate the 3D-printed polycaprolactone (PCL)/β-tricalcium phosphate (β-TCP)/bone decellularized extracellular matrix (bdECM) scaffold conjugated with rhBMP-2 for the simultaneous use as an implant surgical guide stent and bone graft material that promotes new bone growth. Teeth were extracted from the mandible of the beagle model and scanned by computed tomography (CT) to fabricate a customized scaffold that would fit the bone defect. After positioning the implant guide scaffold, the implant was placed and rhBMP-2 was injected into the scaffold of the experimental group. The two beagles were sacrificed after three months. The specimen block was obtained and scanned by micro-CT. Histological analysis showed that the control and experimental groups had similar new bone volume (NBV, %) but the experimental group with BMP exhibited a significantly higher bone-to-implant contact ratio (BIC, %). Within the limitations of this preliminary study, a 3D-printed scaffold conjugated with rhBMP-2 can be used simultaneously as an implant surgical guide and a bone graft in a large bone defect site. Further large-scale studies will be needed to confirm these results.

Electromagnetically Navigated In Situ Fenestration of Aortic Stent Grafts: Pilot Animal Study of a Novel Fenestrated EVAR Approach.

Assess electromagnetically guided in situ fenestration of juxtarenal aortic stent grafts in an in vivo model. Using a newly developed electromagnetic guidance system together with a modified, electromagnetically guidable catheter with steerable tip, an electromagnetically trackable guidewire and a custom in situ fenestrateable stent graft, a series of seven animal experiments was performed. In a swine model, stent grafts were placed juxtarenally, covering the renal arteries. Subsequently, the perfusion of the renal arteries was restored using electromagnetically guided in situ fenestration of the graft at the renal ostia followed by covered stent placement. Intervention times and technical success were assessed. The individual components were successfully combined for the animal experiments. Thirteen of fourteen fenestration experiments in seven animals were successful in restoring perfusion through in situ fenestration. Fenestration (catheter introduction-guidewire placement in renal artery across graft) could be achieved in on average 10.5 ± 9.2min, and subsequent covered stent placement (guidewire placement-covered stent placement) took on average 32.7 ± 17.5min. No significant differences between left and right side reperfusion times could be detected. Reperfusion in<30min was achieved in 3/14 attempts. Electromagnetically navigated in situ aortic fenestration for juxtarenal aortic stent grafts was feasible in a healthy animal model. Identified remaining challenges were: shortening the procedure to avoid long warm ischemia times, using an aortic aneurysm animal model, and improving the stability of the stent graft material.

Should We be Concerned About the Inflammatory Response to Endovascular Procedures?

Endovascular surgery represents a minimally invasive procedure for the treatment of occlusive and aneurysmal arterial disease. However, it is followed by inflammatory response, with a rise in specific inflammatory biomarkers, such as C-reactive protein, serum amyloid A and fibrinogen. Shear stress during balloon inflation and vascular injury represents triggering events for the inflammatory process, stimulating the production of proinflammatory molecules and activation of circulating monocytes. The current literature indicates that stent implantation induces more prominent inflammatory reaction. Additionally, it has been shown that muscular arteries of femoropopliteal segment react to a greater extent to stent implantation, compared with elastic carotid or iliac arteries. The endovascular treatment of thoracic and abdominal aortic aneurysm is frequently followed with post-implantation inflammatory syndrome. Most recent findings point out that stent graft material plays a significant role in the inflammatory response, representing a challenge for clinicians. Future studies should consider the pathophysiology of the inflammatory response associated with endovascular procedures as well as predictors and risk factors including preventive strategies and therapeutic algorithms. Although the potential role of anti-inflammatory drugs after endovascular procedures has been observed, it needs to be validated in upcoming trials. The Neutrophil Lymphocyte Ratio, platelet count, Platelet-to-Lymphocyte Ratio and other biomarkers should be considered in future trials to assess the inflammatory response after endovascular procedures. Inflammatory markers may also become therapeutic targets.

Experimental Evaluation of Complete Endovascular Arch Reconstruction by In Situ Retrograde Fenestration

The aim of this experimental study was to assess the feasibility of complete endovascular arch reconstruction by in situ retrograde fenestration and toinvestigate the impact of stent-graft material on stent-graft fenestrations. The experiments were performed using 8cadaveric human thoracic aortas (aortic arch) using 2different stent-graft types: woven polyester (Valiant Captivia; Medtronic Vascular, Santa Rosa, CA) andexpanded polytetrafluoroethylene (conformable [C]-TAG; W.L. Gore & Associates, Flagstaff, AZ). Abenchtop aortic pulsatile flow model was used. Stent-grafts were deployed into the aortic arch, covering the ostia of the supraaortic trunks. A 5-mm 30-degree angioscope was introduced into the ascending aorta to monitor the procedure. Retrograde fenestration and deployment of the balloon expandable stent-graft was performed sequentially for eachsupraaortic trunk. Subsequent to stent-graft explantation, macroscopic evaluation of each fenestration was performed. All attempts to fenestrate the C-TAG and Valiant stent-grafts and implant the covered stent through the supraaortic trunks were successful. In all cases, branch stents were patent and no endoleak was evident. The Valiant stent-graft was easier to puncture because of the higher radial force of the stent-graft providing better counterpressure; however, stent-graft material had no impact on the quality of fenestrations. Total endovascular repair of the aortic arch through in situ retrograde fenestration of stent-grafts is feasible. The behavior of the 2 types of stent-graft was significantly different while the fenestrations were fashioned, but stent-graft material had no impact on the quality of fenestrations.

Development of Off-the-shelf Stent Grafts for Juxtarenal Abdominal Aortic Aneurysms

IntroductionThe use of EVAR for more complex aneurysm anatomy has become more widespread over the past decade. Fenestrated and branched stent grafts for the visceral and iliac segment show promising short- and midterm outcome and these procedures have become routine in many vascular centers. However, at present, such grafts are customized to the individual patient and planning and manufacturing leads to significant treatment delay subjecting the patients to the risk of rupture during the waiting period. The purpose of this report is to describe the first experience in treating juxta/suprarenal aneurysms using the first version of a new fenestrated stent graft Material and MethodsA fenestrated device was designed with two renal fenestrations, an SMA fenestration and a scallop for the coeliac artery. The renal arteries were designed with an inner 6 mm fenestration and an outer 15 mm diameter creating a dome to allow renal artery catheterization for a range of renal artery distribution. Seven patients with complex visceral artery anatomy were treated with customized stent grafts containing these pivot renal fenestrations. ResultsTechnical success was uniform with 100% target vessel catheterization and 0% 30-day mortality. In one case, the graft was displaced slightly during delivery resulting in a renal artery stent occlusion at 2 months postoperatively. ConclusionsThe development of a modified fenestrated device has shown this to be feasible and it has the potential to reduce the need for extensive preoperative graft customization and establishing a true off the shelf platform for juxta- and suprarenal AAA.

Welche Nachkontrolle ist bei endovaskulärer Versorgung von abdominellen Aortenaneurysmen empfehlenswert?

In the past, multislice computed tomography angiography (CTA) with arterial and venous phase was recommended as the gold standard in follow-up after endovascular abdominal aneurysm repair (EVAR). Iodine-containing contrast agents and frequent radiation exposure are limitations for use in elderly patients with chronic renal insufficiency. Colour-coded Doppler sonography (CCDS) and, especially, contrast-enhanced ultrasound (CEUS) are non-invasive methods that are time and cost effective. Both provide a reliable alternative to CTA in surveillance after EVAR. CEUS seems to be superior in characterisation of the type of endoleaks and can be established in order to reduce iodine-containing contrast agent and radiation exposure in follow-up. In contrast to CTA scans, CEUS can be offered to patients with chronic renal insufficiency and allows a dynamic examination and perfusion analysis (e. g., in fenestrated and branched stentgrafts). Routine combination with X-ray allows control of stentgraft material and location of the branches.

Closure of a Penetrating Ulcer of the Descending Aorta Using an Amplatzer Occluder

Symptomatic patients with penetrating atherosclerotic ulcers of the descending thoracic aorta have traditionally been treated by using an open surgical repair. The emergence of thoracic aortic stent-graft technologies has introduced a less invasive treatment option, which often involves covering excess portions of a normal aorta with stent-graft material. We describe the mid-term follow-up of a patient with a symptomatic penetrating atherosclerotic ulcer of the descending thoracic aorta treated with an Amplatzer septal occluder device (AGA Medical Corp, Plymouth, MN), which is typically used for structural heart disease.

Thin-film nitinol (NiTi): A feasibility study for a novel aortic stent graft material

Although technological improvements continue to advance the designs of aortic stent grafts, miniaturization of the required delivery systems would allow their application to be available to a wider range of patients and potentially decrease the access difficulties that are encountered. We performed this feasibility study to determine if thin-film NiTi (Nitinol) could be used as a covering for stent grafts ranging from 16 mm to 40 mm in diameter. Specifically, we wished to determine the profile reduction attainable and improve the flexibility of our design. Using a novel hot-sputter deposition technique, we created sheets of thin-film NiTi (TFN) with a tensile strength of >500 Megapascal (MPa) and thickness of 5-10 microns. TFN was used to cover stents, which were then deployed in vitro. Patterned thin film was fabricated via a lift-off technique; grafts were constructed with stents ranging from 16-40 mm and deployed in a pulsatile flow system from the smallest diameter polymer tubing into which the stent and TFN would fit. The bending/stiffness ratio vs similar sized expanded polytetrafluoroethylene (ePTFE)-covered stents was also determined. TFN was created in both non-patterned and patterned forms, with a tensile strength of >100 MPa for the latter. We created devices that were successfully deployed via delivery systems half the size of fabric-covered stent grafts (ie, the 16 mm stent graft that originally was delivered via a 16French (F) system was reduced to 8F, and the 40 mm stent graft delivered via a 24F system was reduced to 12F). No migration of the devices was observed with deployment in both straight and curved tubing, which was sized so that the stent grafts were oversized by 20%. Both forms of the thin-film were noted to be more flexible than the same sized ePTFE stent graft, and the patterned graft had an additional 15-30% flexibility vs the non-patterned film. These in vitro results demonstrate the feasibility of TFN for covering stent grafts designed for placement in the aorta. The delivery profile can be significantly reduced across a wide range of sizes, while the material remained more flexible than ePTFE.

In Vitro Assessment of Aortic Stent-Graft Integrity following Exposure to Onyx Liquid Embolic Agent

Endovascular stent-grafts are increasingly being used for treatment of abdominal and thoracic aortic aneurysms. Postprocedural complications include development of endoleaks. Recently, an embolic agent known as Onyx has been employed to treat type II endoleaks. Onyx is a biocompatible copolymer dissolved in dimethyl sulfoxide (DMSO). Although DMSO is known to damage some angiographic catheters, little is known concerning whether this compound damages stent-graft material. The current study was undertaken to directly explore this issue. Four stent-grafts were evaluated: the Excluder, Zenith, AneuRx, and Talent. Stent-grafts were incubated for 24 hours at 37 degrees C under each of the following conditions: DMSO alone, 50/50 mixture of DMSO/Onyx, mixture of 1 part 50/50 DMSO/Onyx and 9 parts whole blood, and untreated control. Stent-grafts were microdissected into 15-mm sections, after which they were evaluated with scanning electron microscopy. No appreciable differences between stent-grafts exposed to DMSO and untreated controls were seen. Although liquid embolic agent was seen coating stent-grafts exposed to a 50/50 mixture of DMSO and Onyx, no evidence of fiber breakdown was noted. Stent-grafts exposed to DMSO/Onyx/whole blood demonstrated a thin coating of clot and Onyx without visual evidence of fiber compromise. The current study provides compelling evidence that short-term exposure of endograft material to DMSO, DMSO/Onyx, or DMSO/Onyx/whole blood is not associated with acute structural compromise of four commonly used aortic endografts. Future in vivo studies will help to further establish the safety of this agent.

Thoracic aorta emergencies: is the endovascular treatment the new gold standard?

The endovascular treatment for acute traumatic aorta rupture has been proven to be safe in emergency. Technical aspects concerning the device fixation, the materials' durability, and the patients' selection criteria are still under discussion. We present our clinical experience and the mid-term follow-up. Between January 2001 and January 2005, twenty-five patients have been diagnosed with acute traumatic aorta wall rupture in our emergency department. An angio computed tomography scan (CT-scan) was performed to confirm the diagnosis and to localize the aortic lesions. Eighteen patients with isolated intimal lesion, aorta wall hematoma or aorta wall tear up to 1/3 of the circumference, received the endovascular treatment. The intravascular ultrasound (IVUS) and the fluoroscopy control were used routinely. The procedure was considered to have succeeded in the case of complete aortic wall tear occlusion. A CT-scan follow-up was organized 1 week and 1 year after the procedure. Eighteen patients underwent endovascular treatment and 17 of these patients presented associated multiple injuries. The mean age was 40.7+/-12 years. The hospital mortality rate was 0%. In one patient the distal part of the graft was accidentally deployed into the brachiocephalic trunk and was surgically removed 8 weeks later. Two patients (11.1%) suffered from transitory neurological disturbances and 4 patients (22.2%) had the left subclavian artery ostia occluded by the graft, without developing symptoms. The mean follow-up time was 21+/-3 months: 1 patient (5.5%) died 1 month after the procedure for acute aortic rupture and no endoleaks were reported. The endovascular treatment for traumatic aortic rupture is an interesting alternative to conventional open surgery for a selected patient cohort. The stent graft material and the fixation to the normal aortic wall are safe and reliable in the mid-term. The results lead us to choose this approach as the treatment of choice in selected patients with traumatic aortic wall rupture.

In vitro and in vivo study of He + ion irradiated collagen for development of small diameter stent graft material

Recently, stent graft technology for endovascular treatment of aortic dissections has made tremendous advances. It is now possible to apply this minimally invasive technique to a wider range of pathology. The aim of this study was to develop anti-thrombogenic coronary stent and graft materials using ion-beam technology. Our previous study indicted that collagen surfaces irradiated with He + ion at a fluence of 1 × 10 14 ions/cm 2 have excellent blood compatibility. The ion-beam-irradiated collagen grafts demonstrated a high anti-thrombogenicity and graft patency. 150 keV-He +-irradiated collagen with a fluence of 1 × 10 14 ions/cm 2 has the properties of anti-thrombogenicity and cell attachment. In vitro plasma protein adsorption was evaluated to investigate the mechanisms of anti-thrombogenicity of these surfaces. From these results, anti-thrombogenicity of the He +-irradiated collagen was caused by the reduction of the plasma protein adsorption, such as fibrinogen or von Willebrand factor, by ion-beam irradiation. Japanese white rabbits weighing 3–4.5 kg were used in this animal study. Collagen-coated graft material implanted with He + ions at a fluence of 1 × 10 14 ions/cm 2 exhibited excellent anti-thrombogenicity and demonstrated patency for one year.

Iohexol-Induced Neutrophil Myeloperoxidase Release and Activation Upon Contact With Vascular Stent-Graft Material: A Mechanism Contributing to the Postimplantation Syndrome?

Iohexol-Induced Neutrophil Myeloperoxidase Release and Activation Upon Contact With Vascular Stent-Graft Material: A Mechanism Contributing to the Postimplantation Syndrome?