Infections of intravascular bare metal stents: a case report and review of literature

Open Surgical Conversion of Popliteal Endograft Infection: Case Reports and Literature Review

BACKGROUND

Endovascular treatment of popliteal aneurysms (PA) has increased in the last few years, quickly becoming the main treatment performed in many vascular centers, based on the acceptable and promising outcomes reported in the literature. However, endograft infections after endovascular popliteal aneurysm repair (EPAR) are the most dangerous complications to occur as they involve serious local compromise and usually require open surgical conversion and device explantation to preserve the affected extremity.

CASE REPORT

We report two patients who were admitted to the emergency room of our hospital for pain and edema in the lower leg. Both patients had undergone exclusion of a ruptured PA a few years before by endovascular graft. CTA testing showed a significant volume of fluid-corpuscular collection related to perianeurysmal abscess collection in both cases. Blood cultures and drained material cultures were positive for Staphylococcus capitis in the first case and S. aureus in the second. Prophylactic antibiotics were administered for 10 days, then patients underwent an open surgical conversion with the complete explantation of endovascular material and a femoro-popliteal bypass using an autologous vein in the first case and a biological bovine pericardium prosthesis in the second case. The infective department of our hospital had defined a discharged specific antibiotic therapy for each patient, based on intraoperative microbiological samples. Furthermore, we have examined the literature and found six more cases described in case report articles that refer to popliteal graft infections by different microorganisms, mostly presenting acute limb ischemia as the first symptom and suggesting endograft explantation with open conversion and autologous vein bypass as the commonest therapeutic choice.

CONCLUSIONS

The open surgical conversion of popliteal endograft infection is the best strategy to manage peripheral infection after an endovascular popliteal aneurysm repair procedure.

Mycotic Coronary Aneurysm Associated With Biventricular Fistula

The incidence of coronary artery aneurysm is between 1.4% and 4.9% based on autopsy or angiographic series. Mycotic coronary arteries aneurysms are very rare and represent less than 3% of all coronary aneurysms. We report the case of a patient who presented with multiple coronary mycotic aneurysms.

Infective endarteritis of coronaries following percutaneous coronary intervention (stentocarditis) leading to pseudoaneurysm - a retrospective study of eleven cases

Background

Coronary endarteritis and stent abscess following percutaneous coronary intervention (PCI) are rare and challenging conditions with no clear treatment guidelines available.

Aims

This retrospective study aims to present the clinical features, patient and procedural factors, management strategies, and outcomes in 11 consecutive cases referred between 2018 and 2022.

Methods

We retrospectively analysed 11 cases of coronary endarteritis and stent abscess post-PCI that were referred from various centres. We recorded clinical features, patient demographics, procedural factors, and management approaches, and evaluated treatment outcomes.

Results

Among the 11 patients, 7 (63.6%) were male. PCIs had been performed in the right coronary artery (6, 54.5%), left anterior descending artery (3, 27.3%), and circumflex artery (2, 18.2%). The presenting symptoms included fever, pericarditis with effusion, tamponade, and postinterventional angina due to stent occlusion. Fever occurred in 10 (90.9%) patients, and the majority (70%) of patients experienced fever within one week of PCI. Staphylococcus aureus was the predominant organism (54.5%), followed by Pseudomonas aeruginosa. Transthoracic echocardiography revealed abscess cavities in 10 patients. All patients received vancomycin and piperacillin-tazobactam. Surgery was considered in 7 cases with abscesses >2 cm; one patient refused and responded to antibiotics for 4 weeks. Possible risk factors included repeated use of local sites, reuse of hardware, multiple guidewire manipulations, prolonged catheterisation, inadequate sterility, and diabetes.

Conclusions

This study provides insights into coronary endarteritis and stent abscess following PCI. The lack of clear treatment guidelines highlights the challenges in managing this condition. Identifying risk factors may aid in preventive strategies. Further research is needed to develop standardised approaches for effective management.

Nonspecific Presentation of an Infected Aorto-Iliac Artery Stent Following Endovascular Revision and Stent Insertion

Over the last few decades, the use of covered stent grafts became increasingly popular; as it plays a pivotal role in the management of various atherosclerotic diseases that are rising in both incidence and prevalence. Subsequently, vascular stent infections, although rare, are becoming a well-recognized complication with possibly devastating consequences, owing to the difficulties associated with its diagnosis and treatment. This has prompted significant interest in the condition regarding its pathophysiology, modifiable and non-modifiable risk factors, diagnostic and therapeutic approaches, and the possible implementation of prophylactic measures. We herein present a case of a patient with an infected aortoiliac stent 4 weeks after endovascular revision with atherectomy and additional stent insertion. The patient initially developed nonspecific symptoms and later developed a life-threatening hemorrhage, which was urgently controlled using a percutaneously inserted covered stent at the infected site. Definitive treatment using extraanatomical bypass implantation and an explantation of the infected stents was performed with excellent clinical response.

A case report of left circumflex stent infection and mycotic aneurysm: a rare but life-threatening complication of percutaneous coronary intervention

BACKGROUND

Coronary stent infections are an uncommon but deadly complication of percutaneous coronary intervention. Mortality remains as high as 40-60% even with adequate treatment. We report such an interesting case of left circumflex stent (LCX) infection and mycotic aneurysm that was successfully managed with antibiotics and surgery.

CASE PRESENTATION

A middle-aged man who underwent percutaneous coronary intervention (PCI) to the left circumflex artery four weeks prior was referred as a case of pyrexia of unknown origin, not responding to antibiotics, and colchicine started for suspected Dressler syndrome. Although the inflammatory markers were elevated, the results of the blood culture did not show any growth. Echocardiography showed a doubtful echogenic structure in the left atrioventricular groove and mild pericardial effusion, and a stent infection was suspected. PET scan showed focal metabolic activity in the region of the LCX stent, with metabolically active supraclavicular and paratracheal lymph nodes, and a coronary angiogram revealed an aneurysm arising distal to the stented LCX. A diagnosis of stent infection and associated mycotic aneurysm was made, and the patient underwent surgery which included aneurysm repair, stent retrieval, and coronary artery bypass graft (CABG) to the major and terminal OM. The postoperative course was uneventful, and the patient was discharged without complications.

CONCLUSIONS

It is important to investigate the possibility of coronary stent infection in individuals experiencing prolonged fever following PCI. PET scans and coronary angiograms can aid in diagnosis when echocardiograms are inconclusive. Adequate antibiotic therapy and timely surgery are crucial for successfully managing coronary stent infections.

Preparation and Characterization of Nano-Silver-Loaded Antibacterial Membrane via Coaxial Electrospinning

The coaxial electrospinning process has been widely used in the biomedical field, and its process parameters affect product quality seriously. In this paper, the influence of key process parameters of coaxial electrostatic spinning (solution concentration, electrospinning voltage, acceptance distance and liquid supply velocity) on the preparation of a membrane with Chitosan, Polyethylene oxide and nano-silver as the core layer and Polycaprolactone as the shell layer was studied. The optimal combination of key process parameters was obtained by using an orthogonal test, scanning electron microscope, transmission electron microscope and macro-characterization diagram. The results showed that the coaxial electrospun membrane had good mechanical properties (tensile strength is about 2.945 Mpa), hydrophilicity (the water contact angle is about 72.28°) and non-cytotoxicity, which was conducive to cell adhesion and proliferation. The coaxial electrospun membrane with nano-silver has an obvious inhibitory effect on Escherichia coli and Staphylococcus aureus. In summary, the coaxial electrospun membrane that we produced is expected to be used in clinical medicine, such as vascular stent membranes and bionic blood vessels.

Coronary Stent Infections - A Systematic Review and Meta-Analysis

BACKGROUND

Coronary stent infection (CSI) represents a rare but potentially fatal complication of percutaneous coronary interventions (PCI). A systematic review and meta-analysis of published reports was performed to profile CSI and its management strategies.

METHODS

Online database searches were performed using MeSH and keywords. The primary outcome of the study was in-hospital mortality. A unique Artificial Intelligence-based predictive model was developed for need for delayed surgery and probability of survival on medical therapy alone.

RESULTS

A total of 79 subjects were included in the study. Twenty eight (35.0 %) patients had type 2 diabetes mellitus. Subjects most commonly reported symptoms within the first week of the procedure (43 %). Fever was the most common initial symptom (72 %). Thirty eight percent of patients presented with acute coronary syndrome. The presence of mycotic aneurysms was described in 62 % of patients. Staphylococcus species were the most common (65 %) isolated organism. The primary outcome of in-hospital mortality was seen in a total of 24 patients out of 79 (30.3 %). A comparative univariate analysis comparing those encountering in-hospital mortality versus otherwise revealed the presence of structural heart disease (83 % mortality vs 17 % survival, p = 0.009), and the presence of non ST elevation acute coronary syndrome (11 % mortality vs 88 % survival, p = 0.03), to be a statistically significant factor predicting in-hospital mortality. In an analysis between patients with successful versus failed initial medical therapy, patients from private teaching hospitals (80.0 % vs 20.0 %; p = 0.01, n = 10) had a higher survival with medical therapy alone.

CONCLUSION

CSI is a highly under-studied disease entity with largely unknown risk factors and clinical outcomes. Larger studies are needed to further define the characteristics of CSI. (PROSPERO ID CRD42021216031).

An Infected, Noncoronary, Bare Metal Stent Presenting as a Right Groin Abscess

Bare metal stent infections complicating peripheral endovascular stenting are rare but can be associated with devastating morbidities. The current standard of care necessitates explantation and extra-anatomical bypass of the affected limb. We report the case of a patient presenting with a right groin abscess with draining sinuses secondary to an infected common femoral and right external iliac artery bare metal stent. In addition, a portion of the stent was explanted into the subcutaneous tissues instead of where it was placed intravascularly one year prior. The patient was not an ideal candidate for explantation and bypass due to significant medical comorbidities and underwent local debridement and long-term antibiotic management instead. His postoperative course was uncomplicated, and he had a successful outcome with management utilizing antibiotics and debridement. We aim to highlight the importance of recognizing bare metal stent infections along with their deceptive cutaneous manifestations in order to prevent the development of significant morbidity and mortality.

Current Status and Outlook of Temporary Implants (Magnesium/Zinc) in Cardiovascular Applications

Medical application materials must meet multiple requirements, and the designed material must mimic the structure, shape. and support the formation of the replacing tissue. Magnesium (Mg) and Zinc alloys (Zn), as a “smart” biodegradable material and as “the green engineering material in the 21st century”, have become an outstanding implant material due to their natural degradability, smart biocompatibility, and desirable mechanical properties. Magnesium and Zinc are recognized as the next generation of cardiovascular stents and bioresorbable scaffolds. At the same time, improving the properties and corrosion resistance of these alloys is an urgent challenge. particularly to promote the application of magnesium alloys. A relatively fast deterioration rate of magnesium-based materials generally results in premature mechanical integrity compromise and local hydrogen build-up, resulting in restricted applicability. This review article aims to give a comprehensive comparison between Zn-based alloys and Mg-based alloys, focusing primarily on degradation and biocompatibility for cardiovascular applications. The recent clinical trials using these biodegradable metals have also been addressed.

Coronary stent infection: a systematic review

Coronary stent infection (CSI) is the rarest complication associated with the percutaneous coronary intervention, occurring in less than 0.1% of cases. So far, all reported instances are limited to case reports. CSI presents itself in various, often confusing, ways in clinical settings. Therefore, the current systematic review summarizes reports of CSI's clinical presentations, causative pathogens, diagnoses and treatments. This systematic review considered three online databases, using reference lists as an additional source. All case reports or case series with stent infection in the coronary artery were included - however, reviews or commentaries, articles not published in English, and articles mentioning a history of hemodialysis or any surgery were excluded. Thirty-two studies on 34 CSI patients were included in the final qualitative analysis. CSI predominantly affected males of a wide range of ages. The most common symptoms were chest pain and fever with various onsets. Interestingly, CSI usually occurred during the first stent implantation. Cultures and coronary angiography were the most common methods used to diagnose CSI. Furthermore, drug-eluting stents had a higher risk of infection than bare-metal stents. Aneurysms were the most frequent abnormalities observed in infected stents. The bacteria that most often caused CSI were Staphylococcus aureus and Pseudomonas aeroginosa. More than 90% of the reports mentioned using various antibiotics, and 74% mentioned carrying out surgery. Finally, a mortality rate of 26.47% among CSI patients was calculated.

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.

A unique case report of mitral valve endocarditis associated with coronary stent infection

Background

Despite increasing use of percutaneous coronary intervention and stenting, septic complications such as coronary stent infections are rare. We report a unique case of mitral valve infective endocarditis and associated coronary stent infection which emerged 6 months after index stent insertion.

Case summary

A 56-year-old previously healthy man underwent percutaneous coronary intervention and stenting of left circumflex (LCx) coronary artery in the setting of non-ST-segment elevation myocardial infarction. Six months later, he represented with inferior ST-segment elevation myocardial infarction and was found to have a coronary pseudoaneurysm of stented segment of LCx. The pseudoaneurysm was treated with insertion of a covered stent, and immediately following that he developed sepsis with methicillin-sensitive Staphylococcus aureus bacteraemia. Comprehensive work-up resulted in the diagnosis of mitral valve endocarditis complicated by coronary stent infection and myocardial abscess formation. He was managed with initial prolonged systemic antibiotic treatment followed by mitral valve replacement. Post-operative course was uneventful with a short duration of oral antibiotics. At 6-year follow-up, the patient was well with the satisfactory echocardiographic result.

Discussion

This is a very rare case of mitral valve endocarditis with extensive cardiac involvement including coronary stent infection and surrounding myocardial abscess. Stents can act as an ideal vector for bacterial adherence from which bacteria could spread to the arterial wall and adjacent myocardium. This case suggests a potential complication of delayed endothelialization and risk of infective complication due to bacterial seeding or embolization.

Very Late Coronary Stent Infection and Abscess following Staphylococcus aureus Bacteremia

•

A unique case of S. aureus coronary stent infection occurred 5 years after index PCI.

•

Prompt diagnosis was made with coronary angiography and echocardiography.

•

Successful treatment included prolonged antibiotics and surgical intervention.

•

Delayed coronary stent endothelialization might have contributed to late infection.

Coronary stent infection: Are patients amenable to surgical treatment? A systematic review and narrative synthesis

OBJECTIVE

Coronary stent infection is a fearsome complication with high mortality rate. Since antibiotics may have only partial efficacy, invasive surgery may be needed. We present a systematic review about outcomes achieved by surgical versus medical treatment in this scenario.

METHODS

A literature search through Medline and Google Scholar was performed over a 30-years period according to PRISMA guidelines. Demographics, clinical data, imaging findings and treatment modalities were collected. Outcomes were analysed according to treatment.

RESULTS

Among 1727 articles identified, after duplicate removal the title/abstract screening excluded 821 articles. After full-text screening, 31 studies were included totalling 34 patients (n 28, 82.4% male, mean age 61.7 SD +/- 10 years old). The majority of infection were sustained by S. Aureus (n 28, 82.4%), occurred within one month (median 7 days, range 1-1440) from stenting and mostly over drug-eluting stents (n21, 61.8%). The majority of patients (n30, 88.2%) underwent antibiotics at first: 12 patients (35.3%) didn't undergo additional treatment because they died, were unfit or refused major surgery or responded favorably to medical treatment; surgery was scheduled in a total of 20 patients (58.8%), as an emergent approach (n2) or after failure of antibiotics (n18). More than half of patients medically treated died (n6/11, 54.5%) versus 35% (n7/20) in surgery group.

CONCLUSIONS

Coronary stent infections are associated with high morbi-mortality rate. Medical treatment may be the only possible approach in extremely fragile patients, however timely surgical referral is the only definitive treatment, and it is recommended whenever possible.

Zn-Mg and Zn-Cu alloys for stenting applications: From nanoscale mechanical characterization to in vitro degradation and biocompatibility

In the recent decades, zinc (Zn) and its alloys have been drawing attention as promising candidates for bioresorbable cardiovascular stents due to its degradation rate more suitable than magnesium (Mg) and iron (Fe) alloys. However, its mechanical properties need to be improved in order to meet the criteria for vascular stents. This work investigates the mechanical properties, biodegradability and biocompatibility of Zn-Mg and Zn-Cu alloys in order to determine a proper alloy composition for optimal stent performance. Nanoindentation measurements are performed to characterize the mechanical properties at the nanoscale as a function of the Zn microstructure variations induced by alloying. The biodegradation mechanisms are discussed and correlated to microstructure, mechanical performance and bacterial/cell response. Addition of Mg or Cu alloying elements refined the microstructure of Zn and enhanced yield strength (YS) and ultimate tensile strength (UTS) proportional to the volume fraction of secondary phases. Zn-1Mg showed the higher YS and UTS and better performance in terms of degradation stability in Hanks' solution. Zn-Cu alloys presented an antibacterial effect for S. aureus controlled by diffusion mechanisms and by contact. Biocompatibility was dependent on the degradation rate and the nature of the corrosion products.

In Situ Revascularization with a Rifampicin-Soaked Prosthesis to Treat Bare Iliac Artery Stent Infection: A Case Report

Bare stent infection is an extremely rare complication of endovascular treatment. In such cases, surgical resection of the infected bare stent and revascularization are recommended; however, the revascularization strategy remains controversial. We present a case of a 78-year-old man with an infected aneurysm caused by a bare iliac artery stent infection. We resected the infected aneurysm and performed in situ anatomic reconstruction using a rifampicin-soaked prosthesis with omental coverage. The patient had no reinfection at the 3-year follow-up. Therefore, this procedure may be a useful treatment for bare iliac artery stent infections.

Late onset infection of covered and bare metal arterial stents

OBJECTIVE

The objective was to present the case of a late covered iliac stent late infection and report a comprehensive literature review on diagnosis and outcomes in this setting.

METHODS

A comprehensive review of the literature was performed through MedLine by two independent reviewers from 1990 to 2020 on reported cases of arterial stent late onset infection over arterial stents. The data about on the risk factors, clinical presentation, treatment and outcomes were collected.

RESULTS

Twenty-two studies were selected as pertinent for the analysis, totalling 24 patients including the indexed case. Infection occurred at a median of 22 months postoperatively (range 2-120 months) over a bare metal stent in 66.7% (n 16) of cases versus 33.3% (n 8) over a covered stent. Clinical presentation included local symptoms (local pain, oedema, petechiae or skin rash) in 21 (87.5%) cases and non-specific systemic symptoms (fever, sepsis, chills and leucocytosis) in 8 cases (33.3%). In 4 cases (16.7%), patients presented with haemorrhagic shock upon arterial rupture. The bacteria most frequently encountered were S. aureus (54.2% of cases). Several factors were supposed to be responsible for the infection including among which procedure-related (non-aseptic technique, lack of prophylactic antibiotics and repetitive punctures at the access site) or related to pre-existing patient's clinical conditions (immunosuppression, diabetes and concurrent infection) have been considered responsible for the infection. Treatment consisted in antibiotics alone (2 patients, 8.3%) or in association with surgical explant, both with or and without revascularization (n 21, 87.5%). In one case, an endovascular coiling was performed. Complications occurred in 29.2% (n 7) of cases and included the need for amputation, bowel resection, endocarditis, pulmonary failure or pneumonia. Overall, three patients (12.5%) died from a septic shock or multi-organ failure.

CONCLUSIONS

Intravascular stent infection is a rare but fearsome condition associated with high morbidity and mortality.

3D-Printing of Drug-Eluting Implants: An Overview of the Current Developments Described in the Literature

The usage of 3D-printing for drug-eluting implants combines the advantages of a targeted local drug therapy over longer periods of time at the precise location of the disease with a manufacturing technique that easily allows modifications of the implant shape to comply with the individual needs of each patient. Research until now has been focused on several aspects of this topic such as 3D-printing with different materials or printing techniques to achieve implants with different shapes, mechanical properties or release profiles. This review is intended to provide an overview of the developments currently described in the literature. The topic is very multifaceted and several of the investigated aspects are not related to just one type of application. Consequently, this overview deals with the topic of 3D-printed drug-eluting implants in the application fields of stents and catheters, gynecological devices, devices for bone treatment and surgical screws, antitumoral devices and surgical meshes, as well as other devices with either simple or complex geometry. Overall, the current findings highlight the great potential of the manufacturing of drug-eluting implants via 3D-printing technology for advanced individualized medicine despite remaining challenges such as the regulatory approval of individualized implants.

Iliac-femoral stent-graft infection after hybrid procedure redo: Case report

Introduction

Stent-graft infection in peripheral arteries is rare and potentially dangerous. The use of hybrid procedures, in complicated patients previously treated, involves an increase of infective risk especially in no collaborative patients.

Presentation of case

We report a case of rare stent-graft infection in a patient treated for a Rutherford IV Multiple Peripheral Arterial Disease (MPAD) involving the right iliac-femoral axis with stenosis on deep femoral artery due to a previously stenting procedure for Superficial Femoral artery (SFA) stenosis. The first simultaneous hybrid intervention consisted of an endovascular iliac stent-graft placement and a surgical common femoral patch angioplasty. After two months the patient was readmitted to our unit for a purulent secretion through a fistulous channel and a suspect infection of stent-graft. Subsequently, the stent-graft was completely removed without possibility to have a surgical revascularization. An amputation major amputation was needed for irreversible ischemia of right leg.

Discussion

The incidence of stent-graft infection after endovascular aortic aneurysm repair had been reported as 0.4–1.0% while Aortoiliac graft infection occurs in 2–6% of patients. Hybrid procedures are secure and need close follow-up for cases of redo and patient with comorbidities.

Conclusions

Graft infection is a rare complication after endovascular treatments. Hybrid procedures outcomes are good with less morbidity but in patient with high risk of infection is important a close follow-up.

•

Stent-graft infection in peripheral arteries is rare and potentially dangerous.

•

Stent-graft infection after angioplasty Aortoiliac occurs in 2–6% of patients.

•

Hybrid procedures are useful, patients high risk for infection need a close followup.

An Infected Popliteal Aneurysm after Plain Old Balloon Angioplasty

The case was a 76-year-old man with chronic limb-threatening ischemia. Plain old balloon angioplasty (POBA) was performed on the popliteal artery. Subsequently, he suffered from cellulitis around the POBA site, followed by reocclusion. Staphylococcus aureus was detected in a blood culture. After re-revascularization with POBA, both purulent gonitis and an infected popliteal aneurysm were observed to occur. We performed aneurysmectomy and bypass grafting with the saphenous vein and then continued antibiotic therapy. Although treatment consisted of endovascular therapy (EVT) with nothing left behind, management was difficult because of secondary infectious complications. We conclude that prophylactic antibiotics before EVT should be considered in such cases.

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.

Efficacy of antiseptic impregnation of aortic endografts with rifampicin compared to silver against in vitro contamination with four bacteria that frequently cause vascular graft infections

OBJECTIVE

This in vitro study investigates the antimicrobial efficacy of impregnation of commercially available aortic endografts (EG) with rifampicin (RIF) and nanocolloidal silver.

METHODS

Endografts were flushed with 50 mL of RIF 600 mg, 70 mL of a silver-based aqueous solution (AG), or 50 mL of phosphate-buffered saline (PBS) over 15 minutes. Endografts were then retrieved from the sheath and cut in 1 × 1 cm sized graft units (n = 80 of each impregnation), which were then incubated for 1 hour separately with inoculates containing 10⁶ or 10³ bacteria per milliliter (bact/mL) of each of the following bacteria: Staphylococcus epidermidis, Escherichia coli, multisensitive Staphylococcus aureus, and Pseudomonas aeruginosa. After sonication of the graft units, bacterial counts were measured by plating out twice the sonication solution on Mueller-Hinton plates.

RESULTS

RIF showed a statistically significant decrease of colony forming units per milliliter for all four bacterial strains in both concentrations compared with PBS and AG, except for 10³ bact/mL of E coli. AG showed a significant decrease of colony forming units per milliliter compared with PBS only for 10⁶ bact/mL of E coli and was statistically significantly inferior to RIF for all four bacterial strains in both concentrations with the exception of E coli at a concentration of 10³ bact/mL.

CONCLUSIONS

This in vitro study demonstrated infectivity resistance of aortic EG after flushing with RIF. Moreover, the feasibility of flushing aortic EG with a new silver-based agent could be demonstrated, but without statistically significant antimicrobial efficacy compared with native EG.

Multimodal Imaging of Post-Stenting Mycotic Coronary Pseudoaneurysm Complicated by Device Fracture and Myocardial Abscess

Mycotic coronary aneurysm and pseudoaneurysm are rare infective complications of percutaneous coronary interventions, associated with poor prognosis. Multimodality imaging is recommended to achieve a correct diagnosis. We present a case of post-stenting mycotic coronary pseudoaneurysm complicated by myocardial abscess in which we used different imaging tools, each carrying additional information. (Level of Difficulty: Advanced.)

Infectious stentitis after treatment of coarctation of the aorta: a case report

Background

Aortitis is a rare condition that can be caused by inflammatory or infectious aetiologies. The clinical presentation of aortitis includes a heterogeneous range of symptoms and clinical signs.

Case summary

We present a 53-year-old man whose medical history included presence of a ventricular septal defect, a bicuspid aortic valve, and coarctation of the aorta. The coarctation was treated with percutaneous stent implantation. One and a half years later, he presented to our hospital with complaints of fatigue, night sweats, and shivers. Physical examination revealed a fever, tachycardia, and hypertension. Imaging studies showed no signs of endocarditis. Positron emission tomography-computed tomography (PET-CT) showed an increase in ¹⁸F-fluorodeoxyglucose uptake at the distal end of the stent in the descending aorta. Blood cultures revealed a Streptococcus gordonii and antibiotic treatment was adjusted accordingly. The patients' functional status improved quickly, the fever resolved, and the laboratory markers of inflammation returned to normal.

Discussion

Aortitis is extremely rare after stent implantation. Risk factors for aortitis include congenital vascular malformation and stent implantation. Computed tomography is currently the imaging study of choice for aortitis, while PET-CT seems ideal for identification of stent infection. Mortality associated with infectious aortitis ranges from 21% to 44%, with generally higher mortality if managed with antibiotics alone. The differential diagnosis of stent infection should be taken into account in patients presenting with fever and chills after previous stent procedures.

Coronary Drug-Eluting Stent Infection Complicated by Coronary Artery Aneurysm and Purulent Pericarditis: Complete Resolution Without Surgery

Coronary stent infection is considered to be a rare but catastrophic complication of percutaneous coronary intervention. In this report, we present a 72-year-old man who developed a coronary stent infection complicated by coronary aneurysm and purulent pericarditis. Coronary artery aneurysm resolved over a period of 8 months following the successful management of infection with intensive antibiotic therapy alone. This case suggests that conservative therapy can be a therapeutic option in patients with high operative risks.

Resection of a large mycotic aneurysm of the left anterior descending coronary artery

A 50-year-old Indigenous woman, on home haemodialysis, was found to have a large mycotic aneurysm of the proximal left anterior descending coronary artery at the site of a previous drug-eluting stent. Blood cultures grew methicillin-sensitive S taphylococcus aureus bacteraemia. She underwent a complex operation involving resection of the mycotic aneurysm, removal of the stent and a coronary artery bypass graft to the distal left anterior descending (LAD) coronary artery using the left internal mammary artery. She had a complicated intensive care unit admission with pericardial tamponade on day 1 postoperatively requiring reopening and removal of clot and type 1 respiratory failure requiring reintubation on day 10 postoperatively. Once extubated, she developed prolonged hyperactive delirium and a significant decline in mobility. Over the course of a 6-week hospital admission, she received extensive multidisciplinary care and was discharged for rehabilitation to a peripheral hospital. She was discharged home after rehabilitation with ongoing follow-up with infectious diseases.

Early Onset of Acute Lower Limb Drug-eluting Stent Infection

The present case describes acute and early infection of a superficial femoral artery drug-eluting stent (DES) in a 65-year-old patient 2 days after its implantation in outpatient clinic, with intense clinical presentation. The initial indication was Rutherford 3 peripheral artery disease. Radical treatment by means of stent explantation and femoro-femoral bypass using autogenous vein was performed. Both stent and blood cultures were positive for methicillin-sensitive Staphylococcus aureus. Informative imaging and intraoperative view are provided. Local evolution was satisfactory but endocarditis occurred secondarily. The pathophysiology of this first reported DES infection and the management of the infected vessel are discussed, in light of data derived from coronary literature and open vascular surgery.

Antimicrobial and Antibiofilm Effects of Peptides from Venom of Social Wasp and Scorpion on Multidrug-Resistant Acinetobacter baumannii

Intravascular stent infection is a rare complication with a high morbidity and high mortality; bacteria from the hospital environment form biofilms and are often multidrug-resistant (MDR). Antimicrobial peptides (AMPs) have been considered as alternatives to bacterial infection treatment. We analyzed the formation of the bacterial biofilm on the vascular stents and also tested the inhibition of this biofilm by AMPs to be used as treatment or coating. Antimicrobial activity and antibiofilm were tested with wasp (Agelaia-MPI, Polybia-MPII, Polydim-I) and scorpion (Con10 and NDBP5.8) AMPs against Acinetobacter baumannii clinical strains. A. baumannii formed a biofilm on the vascular stent. Agelaia-MPI and Polybia-MPII inhibited biofilm formation with bacterial cell wall degradation. Coating biofilms with polyethylene glycol (PEG 400) and Agelaia-MPI reduced 90% of A. baumannii adhesion on stents. The wasp AMPs Agelaia-MPI and Polybia-MPII had better action against MDR A. baumannii adherence and biofilm formation on vascular stents, preventing its formation and treating mature biofilm when compared to the other tested peptides.

In vitro and in vivo evaluation of a dextran-graft-polybutylmethacrylate copolymer coated on CoCr metallic stent

Introduction: The major complications of stent implantation are restenosis and late stent thrombosis. PBMA polymers are used for stent coating because of their mechanical properties. We previously synthesized and characterized Dextrangraft-polybutylmethacrylate copolymer (Dex-PBMA) as a potential stent coating. In this study, we evaluated the haemocompatibility and biocompatibility properties of Dex-PBMA in vitro and in vivo. Methods: Here, we investigated: (1) the effectiveness of polymer coating under physiological conditions and its ability to release Tacrolimus®, (2) the capacity of Dex-PBMA to inhibit Staphylococcus aureus adhesion, (3) the thrombin generation and the human platelet adhesion in static and dynamic conditions, (4) the biocompatibility properties in vitro on human endothelial colony forming cells ( ECFC) and on mesenchymal stem cells (MSC) and in vivo in rat models, and (5) we implanted Dex-PBMA and Dex-PBMA_TAC coated stents in neointimal hyperplasia restenosis rabbit model. Results: Dex-PBMA coating efficiently prevented bacterial adhesion and release Tacrolimus®. Dex-PBMA exhibit haemocompatibility properties under flow and ECFC and MSC compatibility. In vivo, no pathological foreign body reaction was observed neither after intramuscular nor intravascular aortic implantation. After Dex-PBMA and Dex-PBMA_TAC coated stents 30 days implantation in a restenosis rabbit model, an endothelial cell coverage was observed and the lumen patency was preserved. Conclusion: Based on our findings, Dex-PBMA exhibited vascular compatibility and can potentially be used as a coating for metallic coronary stents.

Biodegradable Zwitterionic Polymer Coatings for Magnesium Alloy Stents

Degradable metallic stents, most commonly composed of Mg-based alloys, are of interest as an alternative to traditional metallic stents for application in cardiac and peripheral vasculature. Two major design challenges with such stents are control of the corrosion rate and acute presentation of a nonthrombogenic surface to passing blood. In this study, several types of sulfobetaine (SB)-bearing biodegradable polyurethanes were developed and assessed as physical, chemical, and combination-type coatings for a model degradable Mg alloy, AZ31. For physical coatings, poly(ester sulfobetaine)urethane ureas, PESBUUs were synthesized using variable monomers that allowed the incorporation of a varying extent of carboxyl groups. Introduction of the carboxyl groups was associated with faster polymer degradation time. Simple physical coating of PESBUUs reduced macro- and microscopic thrombogenic deposition together with good stability of the coating attachment compared to a control coating of polylactic- co-glycolic acid. For PESBUUs incorporating carboxyl groups (PESBUUs-COOH), these groups could be converted to siloxane groups (PESBUUs-Si), thus creating polymers that could be surface reacted with the oxidized or phytic acid treated AZ31 surface. Chemical (silanization) attachment of these polymers reduced underlying alloy corrosion rates, but following the salination reaction with physical coating most reduced corrosion rates and protected the surface better from the consequences of oxidation occurring under the coating, such as blistering. The application of a multilayered coating approach using a sulfobetaine-based biodegradable elastomer thus offers options for degradable metallic stent design where thromboresistance is desired in combination with a means to control both polymeric coating degradation rates and underlying alloy corrosion rates.

Late coronary stent infection: a difficult to diagnose rare complication after percutaneous coronary intervention

Percutaneous transluminal coronary angioplasty (PTCA) with drug-eluting stent placement is a well-established treatment modality for coronary stenotic lesions. Although infection involving implanted stent is rare, it can occur at any point of time, leading to high morbidity and mortality. We describe a rare case of infected coronary stents complicated with recurrent stent thrombosis, sepsis, and myocardial abscess formation after 2 years of percutaneous cornary intervention (PCI). Using multi-modality imaging final diagnoses to evaluate the precise location, extent and morphology of myocardial abscess (MA) was done. "On pump" coronary artery bypass graft (CABG) was performed, left anterior descending (LAD) artery intramyocardially was opened up, about 7-10 ml of pus was evacuated, and two drug-eluting stents (DES) were removed. The isolated identified organism was Pseudomonas aeruginosa which had remained dormant and restricted to the stent area for almost 2 years thinning the myocardium; an unusual trait of a very virulent bacterium which otherwise spreads fast to cause septicemia. The present case exemplifies the high index of clinical sensitivity with early multi-modality diagnosis, aggressive medical therapy, multidisciplinary care, and timely surgical intervention saving the patient's life in otherwise fatal condition.

Coronary stent infection: Interesting cases with varied presentation

Stent infection after drug-eluting stent implantation is uncommon but is a critical event. In this study, we describe two such cases of coronary stent infection but with varied presentation. The first patient presented with recurrent stent thrombosis and acute coronary syndrome while the second patient was erroneously diagnosed as having tubercular pericarditis and was started on anti-tubercular therapy. Due to their possible fatal outcome, we herein report our experience with this uncommon clinical entity to help in rapid diagnosis and treatment. <Learning objective: Infection involving implanted stents is rare, it can, however, occur with high morbidity and mortality. In absence of diagnostic criteria or classic signs and symptoms, one should be aware of its presence and risk factors associated with it. Certain rare conditions such as JAK2 V617F mutation significantly alter hemogram leading to changes in red blood cell, white blood cell, and platelet counts facilitating coronary thrombosis should also be kept in mind.>.

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

OBJECTIVE

The aim of this paper was to provide recommendations for diagnosis and management in the setting of infection following open or endovascular reconstructions of the supra-aortic trunks.

METHODS

A review of the Medline database was performed from 1997 to 2017 by a combined strategy of MeSh terms.

RESULTS

The literature search identified 49 publications: 36 studies addressing prosthetic material infections and 13 studies addressing stent infections. A total of 140 cases of prosthetic material infections were reported, mostly involving carotid patches. Surgical treatment was mostly based on complete removal of the infected material followed by in situ arterial reconstruction (86 cases, 62.3%). Peri-operative complications included cranial nerve injury in 17 cases (12.5%), stroke in eight (6.7%), bleeding in four (2.9%), re-infection in five (3.6%), and cardiac failure in three cases (2.2%). Stent infections were reported in 12 patients: eight carotid stents, three subclavian stents and one tandem brachiocephalic subclavian stent. Treatment was not described for one case, was conservative in one case, consisted of stent removal with venous reconstruction in six cases, stent removal without reconstruction because of carotid thrombosis in two cases, and carotid embolisation in two cases. Complications included intra-operative death in one case (9.1%), stroke in two (18.2%), reinfection in one (9.1%), bleeding in one (9.1%), and cardiac failure in one case (9.1%).

CONCLUSION

Appropriate pre-operative imaging is mandatory and treatment modality should be determined by patient condition. Complete removal of the infected material, followed by in situ arterial reconstruction with venous material seems advisable, despite high morbidity. However, alternative strategies may be considered for fragile and high risk patients. A multidisciplinary approach is mandatory to ensure optimum results.

Coronary artery stent infection presenting as coronary cameral fistula: a case report

Introduction

Coronary artery stent infection is a rare event. We report a case of delayed coronary artery stent infection with coronary cameral fistula presented as pyrexia of unknown origin, 1 year after coronary intervention.

Case Presentation

A 66-year-old man presented with paroxysmal low-grade fever of 2 years duration. He underwent percutaneous coronary intervention (PCI) with stent to right coronary artery (RCA) for inferior wall myocardial infarction in July 2014. He had non-ST-elevation myocardial infarction in December 2014. Repeat PCI with two stents to same vessel was done for total occlusion of stent. Repeated evaluations by family physician for fever did not yield any discrete diagnosis, and he was treated with empirical antibiotics. He had worsening of fever since last 2 months. Whole body positron emission tomography scan showed increased tracer uptake in RCA with perivascular abscess involving lateral wall of right ventricle. Coronary angiogram showed presence of small coronary cameral fistula from RCA draining into right atrium. Blood cultures grew Pseudomonas aeruginosa. He was taken for surgery and the infected portion of the RCA including the stents was removed.

Discussion

This case reports delayed coronary stent infection. Patient presented 1 year after procedure. Presence of bare metal stent increases risk of infection in presence of bacteraemia. Antiproliferative effects of drug eluting stents may predispose more to infection. This case was unique in its late presentation, presence of coronary cameral fistula and was successfully treated with surgery.

Initial Inoculation Concentration Does Not Affect Final Bacterial Colonization of In vitro Vascular Conduits

BACKGROUND

Despite improved peri-operative care, prosthetic graft infections continue to cause substantial morbidity and mortality. Contemporary graft infection models have tested a conduit's infectability using varying concentrations without standardization. Using a static assay in vitro model, we sought to evaluate the impact of inoculation concentration on vascular conduit attachment.

METHODS

The 2-hour and 24-hour attachment of Staphylococcus aureus TCH1516 and Pseudomonas aeruginosa PA01-UW were determined on polytetrafluoroethylene (PTFE), Dacron^®, nitinol, cobalt chromium, and Viabahn^® (W.L. Gore and Associates, Newark, DE) endoprotheses. Individually and in combination, concentrations at 10⁴, 10⁵, 10⁶, 10⁷, and 10⁸ were tested on 2-mm sections of each graft. After each time interval, the prosthetics were rinsed to remove non-attached bacteria, sonicated to release the attached bacteria, spiral plated, and then analyzed for the attached concentration.

RESULTS

After two hours, the higher initial inoculation concentration translated into a higher attachment percentage, but the mean attachment percentage was only 14.8% in the 10⁸ group. Pseudomonas aeruginosa had the greatest mean attachment across all material and concentration groups. The sequence of attachment on the conduits followed a constant order: Dacron, PTFE, cobalt, nitinol, and Viabahn with no difference between Dacron and PTFE. Although there were still differences at the 24-hour mark, the median attachment at each concentration was greater than the highest initial concentration (10⁸).

CONCLUSIONS

Initial attachment percentage is poor consistently regardless of inoculation concentration, however, Staphylococcus aureus and Pseudomonas aeruginosa are still able to achieve full attachment after 24 hours. A concentration of less than 10⁷ should be used in vascular graft infection models to ensure adequate bacterial attachment.

A common pathogen in an uncommon site: coronary artery stent meticillin-resistant Staphylococcus aureus infection

Introduction. Coronary artery stents are an uncommon site for infection. Only a handful of case reports describe this condition, and Staphylococcus aureus is the most frequent pathogen. Although rare, coronary stent infections are associated with a high mortality rate. Case presentation. We describe the case of a 50-year-old man with a past medical history of seven prior meticillin-resistant S. aureus (MRSA) infections over the previous 12 months, who presented with fever and was found to have persistent MRSA bacteraemia. During his hospital course, he developed chest pain and underwent coronary angiography, which revealed a left circumflex coronary to left atrium fistula, presumably due to endarteritis/sent infection. He was treated with combination parenteral antibiotics that were succeeded by oral suppressive therapy. Six months after his diagnosis of coronary stent infection, he suffered a fatal cardiac arrest. Conclusion. Coronary artery stents are an infrequent source of infection; when they occur, they are typically due to S. aureus, have a high mortality and ideally are treated with surgical intervention.

Iliac Artery Reconstruction with Femoral Vein After Bare Metal Stent Infection

Introduction

Primary infection of a bare metal stent is a rare condition, associated with significant morbidity and mortality. Definitive treatment includes stent removal and arterial reconstruction.

Report

This study details a common iliac stent infection after re-intervention for iliac stent occlusion, complicated by pseudoaneurysm formation and septic embolisation. Potential risk factors for stent infection were identified. An open surgical resection of the affected artery along with all stent material was performed, followed by reconstruction with autologous interposition superficial femoral vein. There were no complications and no recurrent infection at 6 months follow-up.

Conclusion

Although rare, bare metal stent infection may occur, and a high index of suspicion is required. Stent surgical removal and arterial in situ reconstruction with autologous femoral vein proved to be a definitive procedure with no mid-term morbidity.

•

Iliac bare metal stent infection is a rare complication associated with morbidity.

•

Pseudoaneurysm formation and septic embolization are presentation signs.

•

Stent resection and in situ reconstruction with femoral vein is a definitive treatment.

•

Re-intervention and use of local antimitotic drugs could be potential risk factors.

Acute infection of Viabahn stent graft in the popliteal artery

Peripheral stents are increasingly used for treatment of peripheral arterial disease, yet all implanted devices are potentially at risk for infection. We describe a 51-year-old man who underwent stenting in the femoropopliteal artery and presented 3 days later with leg pain, fever, and evidence of peripheral stigmata of embolization. Blood cultures grew methicillin-resistant Staphylococcus aureus and remained persistently positive despite antibiotic therapy. At surgical exploration, the popliteal artery had essentially been disintegrated by the infection, with only visible stent graft maintaining arterial continuity. Acute stent graft infections are rare and must be managed promptly to reduce morbidity.