Post-operative Infection of Prosthetic Materials or Stents Involving the Supra-aortic Trunks: A Comprehensive Review

Brazilian Angiology and Vascular Surgery Society Guidelines for the treatment of extracranial cerebrovascular disease

Extracranial cerebrovascular disease has been the subject of intense research throughout the world, and is of paramount importance for vascular surgeons. This guideline, written by the Brazilian Society of Angiology and Vascular Surgery (SBACV), supersedes the 2015 guideline. Non-atherosclerotic carotid artery diseases were not included in this document. The purpose of this guideline is to bring together the most robust evidence in this area in order to help specialists in the treatment decision-making process. The AGREE II methodology and the European Society of Cardiology system were used for recommendations and levels of evidence. The recommendations were graded from I to III, and levels of evidence were classified as A, B, or C. This guideline is divided into 11 chapters dealing with the various aspects of extracranial cerebrovascular disease: diagnosis, treatments and complications, based on up-to-date knowledge and the recommendations proposed by SBACV.

Diagnosis and treatment of carotid-left subclavian bypass graft infection complicated with mitral valve aneurysm and perforation following hybrid TEVAR: A case report

Hybrid thoracic endovascular aortic repair (TEVAR) has been proved to be an effective and reliable treatment option for aortic arch diseases requiring extension of the proximal landing zone. However, hybrid TEVAR was associated with potential risk of post-operative complications, including cerebral infarction, endoleaks and paraplegia. Here we reported a rare case of bypass graft infection complicated with mitral valve aneurysm and perforation following landing zone 2 hybrid TEVAR procedure, who presented with symptoms of fever, major bleeding and anastomotic pseudoaneurysm and received emergency bypass graft removal and stent implantation with acceptable short and midterm follow-up results.

Zein nanospheres assisting inorganic and organic drug combination to overcome stent implantation-induced thrombosis and infection

The complication of stent implantation is the biggest obstacle to the success of its clinical application. In this study, we developed a combination way of 3D printing and the coating technique for preparation of functional polyurethane stents against stent implantation-induced thrombosis and postoperative infection. SEM, XPS, static water contact angle, and XRD demonstrated that the functional polyurethane stent had a 37 μm-thickness membrane composed of zein nanospheres (250-350 nm). Meanwhile, ZnO nanoparticles were encapsulated in zein nanospheres while heparin was adsorbed on the surface, causing 97.1 ± 6.4 % release of heparin in 120 min (first-order kinetic model) and 62.7 ± 5.6 % release of Zn²⁺ in 9 days (Korsmeyer-Peppas model). The mechanical analysis revealed that the functional polyurethane stents had about 8.61 MPa and 2.5 MPa tensile strength and bending strength, respectively. The in vitro biological analysis showed that the functional polyurethane stents had good EA.hy926 cells compatibility (97.9 ± 3.8 %), anti-coagulation response (comparable plasma protein, platelet adhesion and suppressed clotting) and sustained antibacterial activities by comparison with the bare polyurethane stent. The preliminary evaluation by rabbit ex vivo carotid artery intervention experiment demonstrated that the functional polyurethane stents could maintain blood circulation under the continuous stresses of blood flow. Meanwhile, the detailed data from the simulated implant infection experiment in vivo showed the functional polyurethane stents could effectively reduce microbial infection by 3-6 times lower and improve fibrosis and macrophage infiltration.

Infection of Vascular Prostheses: A Comprehensive Review

Vascular graft or endograft infection (VGEI) is a complex disease that complicates vascular-surgery and endovascular-surgery procedures and determines high morbidity and mortality. This review article provides the most updated general evidence on the pathogenesis, prevention, diagnosis, and treatment of VGEI. Several microorganisms are involved in VGEI development, but the most frequent one, responsible for over 75% of infections, is Staphylococcus aureus. Specific clinical, surgical, radiologic, and laboratory criteria are pivotal for the diagnosis of VGEI. Surgery and antimicrobial therapy are cornerstones in treatment for most patients with VGEI. For patients unfit for surgery, alternative treatment is available to improve the clinical course of VGEI.

Stent infection and pseudoaneurysm formation after carotid artery stent treated by excision and in situ reconstruction with polytetrafluoroethylene graft: A case report

Background:

Stent infection after carotid artery stenting (CAS) can be a life-threatening postoperative complication, but there is a paucity of data due to its exceedingly low frequency. We report a case of stent infection with pseudoaneurysm formation after CAS that was treated through replacing the infected stent and pseudoaneurysm with a polytetrafluoroethylene (PTFE) synthetic vessel graft.

Case Description:

An 86-year-old man was treated for the right internal carotid artery with CAS in local hospital. One month after stenting, he suffered aspiration pneumonia and septicemia. Three months after stenting, swelling and tenderness of the right side of his neck appeared. His general condition deteriorated due to septicemia and he was unable to ingest anything by mouth as a result of decreasing levels of consciousness. He was transferred to our hospital. Computed tomography and digital subtraction angiography showed the presence of a pseudoaneurysm around the stent. The neck mass enlarged daily and surgical intervention was required to prevent closure of the airway. Stent and pseudoaneurysm resection and in situ reconstruction with a PTFE synthetic vessel graft were performed. The patient returned to his local hospital 36 days after surgery and had a modified Rankin Score of 5.

Conclusion:

Although the risk of reinfection is high due to the nature of artificial material, stent/pseudoaneurysm resection and in situ reconstruction with a PTFE synthetic vessel graft might be one of the best options for patients suffering stent infection after CAS. To the best of our knowledge, this is the first report of treatment using this material.

Infection of expanded polytetrafluoroethylene and Dacron-coated stents with Staphylococcus epidermidis: an experimental study in pigs

Background

Diagnosis of the etiologic agent of endoprosthesis infections is essential to enable treatment, since these infections constitute important complications of endovascular procedures. Sonication of explanted tissue and materials is a technique that can be used to facilitate detection of biofilm-producing bacteria.

Objectives

To evaluate infection of pigs' aortas after implantation of nitinol stents coated with polytetrafluoroethylene (ePTFE) or Dacron, previously infected with biofilm-producing Staphylococcus epidermidis. Intimal thickening and the inflammatory response in the aortic wall were also evaluated.

Methods

11 ePTFE-coated nitinol stents and 10 Dacron stents infected with S. epidermidis strains were implanted in the infrarenal aorta of 21 8-week-old pigs. After 2 weeks, the aorta containing the stents was removed. A vortex mixer and ultrasound were used to homogenize the samples and remove the biofilm. Subsequently, the number of colony-forming units was counted.

Results

There were no significant differences between the two groups in terms of the number of colony-forming units or of inflammation in the arterial wall. With the exception of one specimen from the Dacron group, all aortic stent cultures were positive for S. epidermidis.

Conclusions

There were no significant differences in the inflammatory response or infection rate between ePTFE and Dacron-coated stents actively infected with biofilm-producing S. epidermidis. Intimal thickening and the inflammatory response to infection of endoprostheses were similar. These results suggest that the two most widely used stent lining materials have a similar infection rate.

Biodegradable Iron-Based Materials-What Was Done and What More Can Be Done?

Iron, while attracting less attention than magnesium and zinc, is still one of the best candidates for biodegradable metal stents thanks its biocompatibility, great elastic moduli and high strength. Due to the low corrosion rate, and thus slow biodegradation, iron stents have still not been put into use. While these problems have still not been fully resolved, many studies have been published that propose different approaches to the issues. This brief overview report summarises the latest developments in the field of biodegradable iron-based stents and presents some techniques that can accelerate their biocorrosion rate. Basic data related to iron metabolism and its biocompatibility, the mechanism of the corrosion process, as well as a critical look at the rate of degradation of iron-based systems obtained by several different methods are included. All this illustrates as the title says, what was done within the topic of biodegradable iron-based materials and what more can be done.

Stent infection after carotid angioplasty - Treatment with dual layer stent

Stent infection is extremely rare, especially in stents placed in the internal carotid artery (ICA). Treatment in these cases remains controversial and no consensus has been reached, resulting in high mortality in all cases. We report the case of a 78-year-old man undergoing stent placement in the left ICA who, 20 days later, presented with infection at the stent site and a large pseudoaneurysm. The primary infectious focus was the teeth. The patient was treated with antibiotics and placement of a Casper stent, a dual layer braided metal stent with micro-mesh, intended to determine flow diversion and arterial wall reconstruction. Although the procedure was able to reduce the pseudoaneurysm, the patient eventually died of sepsis. We believe that the use of dual layer stents, with a flow-diverting effect, may be a treatment option in selected cases. However, further studies are needed to confirm this hypothesis.

Nanostructured Titanium for Improved Endothelial Biocompatibility and Reduced Platelet Adhesion in Stent Applications

Although coronary stents have improved the early and long-term consequences of arterial lesions, the prevention of restenosis and late stent thrombosis is key to prevent a new obstruction of the vessel. Here we aimed at improving the tissue response to stents through surface modification. For that purpose, we used two different approaches, the use of nanostructuration by electrochemical anodization and the addition of a quercitrin (QR) coating to the Ti surface. Four surfaces (Ti, NN, TiQR and NNQR) were characterized by atomic force microscopy, scanning electronic microscopy and contact angle analysis and QR content was evaluated by fluorescent staining. Cell adhesion, cytotoxicity, metabolic activity and nitric oxide (NO) production was evaluated on primary human umbilical cord endothelial cells (HUVECs). Platelet adhesion, hemolysis rate and Staphylococcus epidermidis CECT 4184 adhesion at 30 min were analyzed. Nanostructuration induced an increase on surface roughness, and QR coating decreased the contact angle. All surfaces were biocompatible, with no hemolysis rate and lower platelet adhesion was found in NN surfaces. Finally, S. epidermidis adhesion was lower on TiQR surfaces compared to Ti. In conclusion, our results suggest that NN structuration could improve biocompatibility of bare metal stents on endothelial cells and reduce platelet adhesion. Moreover, QR coating could reduce bacterial adhesion.

Microbial Modulation of Coagulation Disorders in Venous Thromboembolism

Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), is the third leading cause of cardiovascular death in the world. Important risk factors of thrombosis include bed restraint, surgery, major trauma, long journeys, inflammation, pregnancy, and oral contraceptives, previous venous thromboembolism, cancer, and bacterial infections. Sepsis increases the risk of blood clot formation 2–20 times. In this review, we discussed various mechanisms related to the role of bacteria in venous thrombosis also taking into consideration the role of the human microbiome. Many known bacteria, such as Helicobacter pylori, Chlamydia pneumoniae, Mycoplasma pneumoniae, Haemophilus influenzae, Streptococcus pneumoniae, Staphylococcus aureus, and Escherichia coli, causing infections may increase the risk of thrombotic complications through platelet activation or may lead to an inflammatory reaction involving the fibrinolytic system. Additionally, the bacteria participate in the production of factors causing or increasing the risk of cardiovascular diseases. An example can be trimethylamine N-oxide (TMAO) but also uremic toxins (indoxyl sulfate), short-chain fatty acids (SCFA) phytoestrogens, and bile acids. Finally, we presented the involvement of many bacteria in the development of venous thromboembolism and other cardiovascular diseases.

Management of Vascular Infections in Low- and Middle-Income Countries

Background: Vascular infections are rare and challenging conditions with significant deaths and morbidity. Their management necessitates a multi-disciplinary approach and substantial human and financial resources. The management selected may be influenced by the available resources in low- and middle-income countries (LMICs), where such resources may be variable. Methods: We reviewed the published literature and reviewed the management options for various vascular infections with a focus on carotid, aortic, infrainguinal, and dialysis access infections. Results: Recommendations related to prevention and treatment will be offered from the perspective of LMICs. The general principles for prevention are in compliance with established surgical site infection guidelines and minimize the use of prosthetic material. Early detection and intervention by removing all infected prosthetic material, debridement, drainage, and coverage of the infected field with vascularized tissue are essential steps in the management of the infection. Revascularization using an extra-anatomic or in situ approach is individualized based on the resources and expertise available. Conclusions: The prevention and management of vascular infections in LMICs are effective by adhering to time-proven principles even with limited resources.