Multidisciplinary Treatment Approach for Prosthetic Vascular Graft Infection in the Thoracic Aortic Area

From Pixels to Pathology: Employing Computer Vision to Decode Chest Diseases in Medical Images

Radiology has been a pioneer in the healthcare industry's digital transformation, incorporating digital imaging systems like picture archiving and communication system (PACS) and teleradiology over the past thirty years. This shift has reshaped radiology services, positioning the field at a crucial junction for potential evolution into an integrated diagnostic service through artificial intelligence and machine learning. These technologies offer advanced tools for radiology's transformation. The radiology community has advanced computer-aided diagnosis (CAD) tools using machine learning techniques, notably deep learning convolutional neural networks (CNNs), for medical image pattern recognition. However, the integration of CAD tools into clinical practice has been hindered by challenges in workflow integration, unclear business models, and limited clinical benefits, despite development dating back to the 1990s. This comprehensive review focuses on detecting chest-related diseases through techniques like chest X-rays (CXRs), magnetic resonance imaging (MRI), nuclear medicine, and computed tomography (CT) scans. It examines the utilization of computer-aided programs by researchers for disease detection, addressing key areas: the role of computer-aided programs in disease detection advancement, recent developments in MRI, CXR, radioactive tracers, and CT scans for chest disease identification, research gaps for more effective development, and the incorporation of machine learning programs into diagnostic tools.

Tissue-engineered small-diameter vascular grafts containing novel copper-doped bioactive glass biomaterials to promote angiogenic activity and endothelial regeneration

Small-diameter vascular grafts frequently fail because of obstruction and infection. Despite the wide range of commercially available vascular grafts, the anatomical uniqueness of defect sites demands patient-specific designs. This study aims to increase the success rate of implantation by fabricating bilayer vascular grafts containing bioactive glasses (BGs) and modifying their composition by removing hemostatic ions to make them blood-compatible and to enhance their antibacterial and angiogenesis properties. The porous vascular graft tubes were 3D printed using polycaprolactone, polyglycerol sebacate, and the modified BGs. The polycaprolactone sheath was then wrapped around the 3D-printed layer using the electrospinning technique to prevent blood leakage. The results demonstrated that the incorporation of modified BGs into the polymeric matrix not only improved the mechanical properties of the vascular graft but also significantly enhanced its antibacterial activity against both gram-negative and gram-positive strains. In addition, no hemolysis or platelet activity was detected after incorporating modified BGs into the vascular grafts. Copper-releasing vascular grafts significantly enhanced endothelial cell proliferation, motility, and VEGF secretion. Additionally, In vivo angiogenesis (CD31 immunofluorescent staining) and gene expression experiments showed that copper-releasing vascular grafts considerably promoted the formation of new blood vessels, low-grade inflammation (decreased expression of IL-1β and TNF-α), and high-level angiogenesis (increased expression of angiogenic growth factors including VEGF, PDGF-BB, and HEBGF). These observations indicate that the use of BGs with suitable compositional modifications in vascular grafts may promote the clinical success of patient-specific vascular prostheses by accelerating tissue regeneration without any coagulation problems.

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.

Infected thoracic aortic graft in a woman with Darier disease: a case report

BACKGROUND

Patients with Darier disease often present with staphylococcal skin infections and are at risk for complications when they undergo cardiothoracic surgery, such as acute aortic dissection repair.

CASE SUMMARY

A 39-year-old woman with hypertension and Darier disease suffered an acute type A aortic dissection, requiring emergency operation with a Dacron graft. Twenty-five days post-operatively, she developed pneumonia and staph hominis was isolated in blood cultures and Bronchoalveolar Lavage. Following completion of antibiotics, multiple relapses occurred during a 6-month period, each time treated with appropriate antibiotic therapy. An 18F-fluorodeoxyglucose positron emission tomography computerized tomography showed persistent graft uptake and re-operation was performed. At 22 months of follow-up, the patient remains asymptomatic and the 18F-FDG PET/CT shows significant reduction in FDG uptake.

DISCUSSION

Graft infection is a rare but serious complication. Antibiotic therapy is often inadequate and re-operation is needed. As staphylococcal skin infections often occur in patients with Darier disease, adequate preprocedural skin preparation and sterilization are very important in these patients.

Secondary aorto-esophageal fistula treated by covered esophageal stent and muscle wrapping

Secondary aorto-esophageal fistula is rare, but associated with serious complications and high mortality. We devised a treatment strategy involving a covered esophageal stent, instead of esophageal resection, and placing the latissimus dorsi muscle around the infected aorta without removing the aorta and the stent graft. A 72-year-old man with a history of total arch replacement with a frozen elephant trunk for a thoracic dissecting aneurysm developed aorto-esophageal fistula and underwent surgical treatment using our strategy. He recovered well, and there is no evidence of re-infection 6 months after surgery. This strategy may be a less invasive surgical option.

Systematic approach to diagnosis and management of infected prosthetic grafts in the proximal aorta

Objectives

Management of infected prosthetic aortic grafts in the ascending and or root is complex and multifaceted. We report our diagnostic pathway, management and outcomes, identifying successful strategies.

Methods

This was a retrospective, single center, observational study. Consecutive patients who underwent management of infected aortic grafts in the ascending and/or root at our institution between October 1998 and December 2019 were included. The main outcome measures were: discharge from hospital alive with at least 1 year survival, operative mortality and success of primary treatment strategy.

Results

Twenty‐six patients presented with infection of proximal aortic grafts and were managed through a number of strategies with an overall hospital‐survival of 81% and 1 year survival of 69%. Twenty of them ultimately underwent redo surgery with 25% operative mortality (within 24 h of surgery). Five patients underwent washout and irrigation of which two were successfully treated and cured with adjunctive antibiotics and two went on to have staged explant and definitive surgery. Interval between surgery and infection was 42.5 ± 35.8 months. All patients had at least one major criterion and three minor criterions with no diagnostic uncertainty. The commonest primary strategy was 3a (definitive surgery), (13/26, 50%).

Conclusions

Adopting a systematic and flexible patient specific approach to the diagnosis and management of patients with proximal aortic graft infections results in reasonable overall 1 year survival. In the majority of patients surgery is ultimately required in an attempt to achieve a curative treatment; however this comes with high operative mortality risk.

Current Applications for Nuclear Medicine Imaging in Pulmonary Disease

Purpose of Review

The main goal of the article is to familiarize the reader with commonly and uncommonly used nuclear medicine procedures that can significantly contribute to improved patient care. The article presents examples of specific modality utilization in the chest including assessment of lung ventilation and perfusion, imaging options for broad range of infectious and inflammatory processes, and selected aspects of oncologic imaging. In addition, rapidly developing new techniques utilizing molecular imaging are discussed.

Recent Findings

The article describes nuclear medicine imaging modalities including gamma camera, SPECT, PET, and hybrid imaging (SPECT/CT, PET/CT, and PET/MR) in the context of established and emerging clinical applications. Areas of potential future development in nuclear medicine are discussed with emphasis on molecular imaging and implementation of new targeted tracers used in diagnostics and therapeutics (theranostics).

Summary

Nuclear medicine and molecular imaging provide many unique and novel options for the diagnosis and treatment of pulmonary diseases. This article reviews current applications for nuclear medicine and molecular imaging and selected future applications for radiopharmaceuticals and targeted molecular imaging techniques.

[Surgical treatment of a patient with traumatic rupture of the aortic arch and late oesophageal perforation]

Described herein is a clinical case report regarding a patient presenting with traumatic rupture of the aortic isthmus with the development of a pseudoaneurysm occupying virtually the entire posterior mediastinum and measuring 20?10 cm in size. He was immediately treated as an emergency to undergo prosthetic reconstruction of the portion of the aortic arch and descending thoracic aorta by means of temporary bypass grafting with a synthetic graft in order to protect the visceral organs. The postoperative period was complicated by oesophageal perforation with the formation of an oesophago-paraprosthetic fistula, infection of the vascular graft, accompanied by the development of pleural empyema and mediastinitis. A second operative procedure was performed, consisting of subclavian-iliac bypass grafting on the right with a polytetrafluoroethylene graft measuring 20 mm in diameter, exclusion of the intrathoracic portion of the oesophagus, creation of a gastro- and oesophagostoma, retrieval of the vascular graft followed by suturing of the aorta, pleurectomy, decortication of the lung, and removal of the empyemic sac on the left. There was no evidence of ischaemia of the spinal cord or visceral arteries. One month postoperatively, he underwent a traumatological stage and 4 months thereafter plasty of the oesophagus with an isoperistaltic gastric pedicle, extirpation of the thoracic portion of the oesophagus, to be later on followed by closure of the oesophagostoma. The patient experienced no difficulties either while walking or during other physical activities, with the ankle-brachial index amounting to 0.9. With time, he developed difficult-to-correct pulmonary hypertension. Unfortunately, the patient eventually died of acute cardiopulmonary insufficiency 9 years after right-sided extra-anatomical subclavian-iliac bypass grafting.

Conventional culture diagnostics vs. multiplex PCR for the detection of causative agents of vascular graft infections - results of a single centre observational pilot study

Background: Timely diagnosis of vascular graft infections is of major importance in vascular surgery. The detection of causative microorganisms is needed for specific medical treatment, but conventional culture is often slow, insensitive and inconclusive due to antibiotic pre-treatment. Detection of bacterial DNA by polymerase chain reaction (PCR) might bypass these problems. We hypothesised that multiplex PCR (mPCR) is feasible, fast and sensitive to detect causative microorganisms in vascular graft infections. Patients and methods: We performed a pilot observational prospective study comparing conventional culture and a commercial mPCR. Inclusion criteria were: confirmed graft infection, suspicious imaging, clinical suspicion, anastomotic aneurysm and repeated graft occlusion. Diagnostic methods were performed using identical samples. Time to result, microorganisms and antibiotic resistance in both groups were compared using Student's t-test or nonparametric tests. Results: 22 samples from 13 patients were assessed and 11 samples were negative for bacteria. Some showed multiple germs. In total, we found 15 different organisms. 13 samples matched, 9 had non-concordant results. Out of the mismatches 3 microorganisms identified in PCR were not detected by culture. Time to result with PCR was shorter (median 5 h vs. 72 h, p < 0.001) than with culture. No resistance genes were detected by mPCR, but conventional culture allowed susceptibility testing and revealed resistance in 5 samples. Conclusions: mPCR seems to be a feasible and quick tool to detect causes of vascular graft infections within 24 h and might be helpful in antibiotic pre-treated patients. The detection of antibiotic resistance with mPCR needs improvement for clinical practice.

A 57-Year-Old Man With Subacute Progressive Hemoptysis and Fevers

CASE PRESENTATION

A 57-year-old man was admitted for 1 month of accelerating hemoptysis and hematemesis. Two weeks earlier, he first presented with fevers and hemoptysis of 2 weeks' duration and was diagnosed with community-acquired pneumonia treated with 5 days of ceftriaxone and azithromycin. He improved and was discharged, but his hemoptysis recurred 1 day after discharge and progressed over 9 days, leading to the present admission. He endorsed an 5-kg weight loss, daily fevers up to 39.4°C, and night sweats since discharge. His medical history was significant for peptic ulcer disease complicated by a perforated gastric ulcer 30 years ago, type 2 diabetes, and Barrett esophagus with recent normal upper endoscopy. The patient had coarctation of the aorta repaired 35 years ago. The patient takes aspirin, atorvastatin, and pantoprazole. He emigrated from Mexico 10 years before presentation and lives in Texas with his family. He returns to Mexico several times per year, most recently 2 days before admission. He works at a supermarket. He does not smoke, drink, or use illicit drugs. He denied sick contacts, pets, or incarceration.

Surgical Treatment of Native and Prosthetic Aortic Infection With Xenopericardial Tube Grafts

BACKGROUND

The study sought to report our results of surgical treatment of native and prosthetic aortic infection with xenopericardial tube grafts from the ascending aorta to beyond the bifurcation.

METHODS

Within a 28-month period, 20 patients were treated with a bovine self-made pericardial tube graft to replace infected vascular grafts (after conventional surgical aortic replacement or endovascular stent graft implantation) or to treat a contaminated surgical site. An integrated standardized therapeutic concept was applied in all patients, consisting of complete removal of the infected prosthetic material, extensive debridement, and orthotopic vascular reconstruction with self-made tube grafts constructed from a bovine pericardial patch.

RESULTS

Four patients died perioperatively (20%) due to sepsis, pulmonary failure, or sudden circulatory arrest. The mean follow-up was 18 months (first quartile 2, third quartile 17 months). Interval computed tomography scans revealed 100% freedom from proven aortic reinfection, but reinfection cannot be ruled out in 4 patients who died of unknown causes during follow-up or because of ongoing sepsis. Three patients required aortic reintervention for a suture-line aneurysm, for graft occlusion, and for the development of a neoaortointestinal fistulation, respectively.

CONCLUSIONS

Patients with infectious aortic disease present in a frail state and the initial and the late mortality is substantial. Yet, surgical treatment of native and prosthetic aortic infection with xenopericardial tube grafts shows promising short-term results with regard to durability and freedom from reinfection in any aortic segment. Further studies are needed to learn of the long-term behavior of these grafts.

Phage treatment of an aortic graft infected with Pseudomonas aeruginosa

Management of prosthetic vascular graft infections caused by Pseudomonas aeruginosa can be a significant challenge to clinicians. These infections often do not resolve with antibiotic therapy alone due to antibiotic resistance/tolerance by bacteria, poor ability of antibiotics to permeate/reduce biofilms and/or other factors. Bacteriophage OMKO1 binding to efflux pump proteins in P. aeruginosa was consistent with an evolutionary trade-off: wildtype bacteria were killed by phage whereas evolution of phage-resistance led to increased antibiotic sensitivity. However, phage clinical-use has not been demonstrated. Here, we present a case report detailing therapeutic application of phage OMKO1 to treat a chronic P. aeruginosa infection of an aortic Dacron graft with associated aorto-cutaneous fistula. Following a single application of phage OMKO1 and ceftazidime, the infection appeared to resolve with no signs of recurrence.

Structure and properties of slow-resorbing nanofibers obtained by (co-axial) electrospinning as tissue scaffolds in regenerative medicine

With the rapid advancement of regenerative medicine technologies, there is an urgent need for the development of new, cell-friendly techniques for obtaining nanofibers—the raw material for an artificial extracellular matrix production. We investigated the structure and properties of PCL₁₀ nanofibers, PCL₅/PCL₁₀ core-shell type nanofibers, as well as PCL₅/PCL_Ag nanofibres prepared by electrospinning. For the production of the fiber variants, a 5–10% solution of polycaprolactone (PCL) (M_w = 70,000–90,000), dissolved in a mixture of formic acid and acetic acid at a ratio of 70:30 m/m was used. In order to obtain fibers containing PCL_Ag 1% of silver nanoparticles was added. The electrospin was conducted using the above-described solutions at the electrostatic field. The subsequent bio-analysis shows that synthesis of core-shell nanofibers PCL₅/PCL₁₀, and the silver-doped variant nanofiber core shell PCL₅/PCL_Ag, by using organic acids as solvents, is a robust technique. Furthermore, the incorporation of silver nanoparticles into PCL₅/PCL_Ag makes such nanofibers toxic to model microbes without compromising its biocompatibility. Nanofibers obtained such way may then be used in regenerative medicine, for the preparation of extracellular scaffolds: (i) for controlled bone regeneration due to the long decay time of the PCL, (ii) as bioscaffolds for generation of other types of artificial tissues, (iii) and as carriers of nanocapsules for local drug delivery. Furthermore, the used solvents are significantly less toxic than the solvents for polycaprolactone currently commonly used in electrospin, like for example chloroform (CHCl₃), methanol (CH₃OH), dimethylformamide (C₃H₇NO) or tetrahydrofuran (C₄H₈O), hence the presented here electrospin technique may allow for the production of multilayer nanofibres more suitable for the use in medical field.

First Robinsoniella peoriensis aortic cross homograft mycotic pseudoaneurysm: A case report and review of the literature

Mycotic aortic aneurysm is a rare and challenging complication of aortic homografts caused by an infection and is associated with high morbidity and mortality. We report the first case of an aortic cross homograft mycotic pseudoaneurysm caused by Robinsoniella peoriensis in a 70-year-old man. Our patient underwent surgery for a recurrence of aortic cross mycotic pseudoaneurysm at the level of the aortic homograft he had had 7 years before. A clot-removal of the pseudoaneurysm was surgically carried out and the homograft was completely removed. Anaerobic culture from tissue samples yielded pure growth of a spore-forming Gram-positive rod, identified later as Robinsoniella peoriensis by 16S rRNA gene sequencing. The patient was then discharged with oral clindamycin according to the in vitro susceptibility testing. Identification of R. peoriensis might be challenging in clinical laboratories with no access to molecular methods.