Bio-absorbable antibiotic impregnated beads for the treatment of prosthetic vascular graft infections

Human gelatin thrombin matrix with rifampin for the treatment of prosthetic vascular graft infections

We aim to describe and report on a novel graft preservation technique using a human gelatin thrombin matrix with rifampin for the treatment of vascular graft infections. Eight patients with vascular graft infections were included, one with bilateral infections, for a total of nine cases from January 2016 through June 2021. All the patients underwent wound exploration and placement of human gelatin thrombin matrix with rifampin. No deaths or allergic reactions had been reported at the 30-day follow-up, with only one major amputation. The graft and limb salvage rates were 77.8% at the 1-year follow-up. The mean time to a major amputation was 122 days, and the mean time to graft excision was 30 days.

Regional Antibiotic Delivery for Implanted Cardiovascular Electronic Device Infections

BACKGROUND

Present guidelines endorse complete removal of cardiovascular implantable electronic devices (pacemakers/defibrillators), including extraction of all intracardiac electrodes, not only for systemic infections, but also for localized pocket infections.

OBJECTIVES

The authors evaluated the efficacy of delivering continuous, in situ-targeted, ultrahigh concentration of antibiotics (CITA) into the infected subcutaneous device pocket, obviating the need for device/lead extraction.

METHODS

The CITA group consisted of 80 patients with pocket infection who were treated with CITA during 2007-2021. Of them, 9 patients declined lead extraction because of prohibitive operative risk, and 6 patients had questionable indications for extraction. The remaining 65 patients with pocket infection, who were eligible for extraction, but opted for CITA treatment, were compared with 81 patients with pocket infection and similar characteristics who underwent device/lead extraction as primary therapy.

RESULTS

A total of 80 patients with pocket infection were treated with CITA during 2007-2021. CITA was curative in 85% (n = 68 of 80) of patients, who remained free of infection (median follow-up 3 years [IQR: 1.0-6.8 years]). In the case-control study of CITA vs device/lead extraction, cure rates were higher after device/lead extraction than after CITA (96.2% [n = 78 of 81] vs 84.6% [n = 55 of 65]; P = 0.027). However, rates of serious complications were also higher after extraction (n = 12 [14.8%] vs n = 1 [1.5%]; P = 0.005). All-cause 1-month and 1-year mortality were similar for CITA and device/lead extraction (0.0% vs 3.7%; P = 0.25 and 12.3% vs 13.6%; P = 1.00, respectively). Extraction was avoided in 90.8% (n = 59 of 65) of extraction-eligible patients treated with CITA.

CONCLUSIONS

CITA is a safe and effective alternative for patients with pocket infection who are unsuitable or unwilling to undergo extraction. (Salvage of Infected Cardiovascular Implantable Electronic Devices [CIED] by Localized High-Dose Antibiotics; NCT01770067).

Extra-anatomic Bypass and Excision is Superior to Graft Salvage Attempts with Antibiotic Beads to Treat Vascular Graft Infections in the Groin

OBJECTIVES

To determine if conventional extra-anatomic bypass and graft removal vs aggressive attempts at graft preservation has better survival and limb salvage in patients with localized groin wound infections of vascular grafts.

METHODS

We conducted a retrospective review of 53 consecutive patients with vascular graft infections presenting in the groin. Treatment groups consisted of group 1) extra-anatomic bypass and graft excision (N=22) and group 2) initial graft preservation attempts with utilization of antibiotic beads (N=31). In group 2, patients underwent serial debridement and placement of antibiotic beads until culture negative wounds were achieved. Significantly more patients underwent muscle flap coverage in group 2 (27 of 31) compared to group 1 (7 of 22) (p<0.001). Data collected included demographics, comorbidities, intraoperative details, and outcomes including patency, limb salvage, mortality, and number of procedures. Continuous variables were examined with Student's t-test and dichotomous variables were examined with Chi-Squared. Linear and logistic regression were used to analyze factors associated with outcomes, and Kaplan-Meier with log rank.

RESULTS

Both groups were similar with respect to demographics. The overall Kaplan-Meier 1- and 3-year survival rates were 66.2% and 34.1% with no statistically significant difference between groups. The Kaplan-Meier 1- and 3-year limb salvage rates were 68.8% and 36.6% for group 1 vs 58.5% and 38.7% for group 2 (p=NS). The 1- and 3-year primary patency rates were 71% and 71% in traditional group 1 vs 72% and 56% in group 2 (p=NS). 1- and 3-year secondary patency rates in traditional group 1 were 83% and 71% vs 85% and 61% in group 2 (p=NS). Patients in group 1 underwent fewer total procedures when compared to group 2 (2.3+.2 vs 5.1 +.7, p=0.03). The late reinfection rate was significantly less in group 1- 4.5% vs group 2- 26% (p=0.04). Freedom from reinfection at 1- and 3-years was 94% and 94% in traditional group 1 vs 74% and 62% in group 2 (p=0.03). Multivariable analysis showed a higher incidence of amputation in patients who suffered reinfection (N=13, p=0.049). There was a higher mortality in patients with septic shock (N=10, p=0.007) and reinfection (N=13, p=0.036). Reinfection was associated with the highest mortality (p=0.03).

CONCLUSIONS

Conventional graft excision with extra-anatomic bypass resulted in similar mortality when compared to aggressive attempts at graft preservation, and trended towards improved limb salvage and patency. However, attempts at graft preservation with antibiotic beads resulted in a significantly higher reinfection rate and greater number of procedures, and therefore this approach should be used very selectively.

Application of Antibiotic-Impregnated Polymethyl-Methacrylate Bone Cement for the Treatment of Infected Cranioplasties: Initial Experience

BACKGROUND

Management of infected cranioplasty implants remains a surgical challenge. Surgical debridement, removal of the infected implant, and prolonged antibiotic therapy are part of the acute management. In addition, cranioplasty removal poses the risk of dural tear. Reconstruction of the cranial defect is usually delayed for several months to years, increasing the difficulty due to soft tissue contraction and scarring.

OBJECTIVE

The aim of the study was to propose an alternative to delayed reconstruction in the face of infection with a dual purpose: treat the infection with a material which delivers antibiotic to the area (polymethyl-methacrylate antibiotic) and which functions as a temporary or permanent cranioplasty.

METHODS

We reviewed the records of 3 consecutive patients who underwent single-stage polymethyl-methacrylate antibiotic salvage cranioplasty.

RESULTS

All patients underwent debridement of infected tissue. Titanium mesh was placed over the bony defect. Polymethyl methacrylate impregnated with vancomycin and tobramycin was then spread over the plate and defect before closure. Patients also received extended treatment with systemic antimicrobials. Early outcomes have been encouraging for both cosmesis and treatment of infection.

CONCLUSIONS

Benefits of this treatment strategy include immediate reconstruction rather than staged procedures and delivery of high concentrations of antibiotics directly to the affected area in addition to systemic antibiotics.

Treatment of Early Deep Wound Infections after Arterial Reconstructions: A Meta-Analysis and Survey

BACKGROUND

Peripheral vascular graft infections, a serious concern after open lower extremity interventions, are treated using multiple strategies. Yet, there is no consensus on the optimal treatment. This study summarizes the literature and compares aggregate effect sizes between graft preservation with antibiotic beads and total graft excision.

METHODS

Manuscripts published between 1972 and 2019 were systematically queried using Ovid Medline and PubMed. Studies were included if they described early (≤4 months of the index procedure) infection-related outcomes after extracavitary and infrainguinal arterial graft infections that were managed with antibiotic-loaded beads or total excisions. Outcomes assessed included the prevalence of graft preservation failure, reinfection, and major amputation. To examine current preferences on this subject, a voluntary, anonymous survey was administered to practicing members of the Society for Clinical Vascular Surgery.

RESULTS

Six graft preservation studies (n = 147 patients) were included in the meta-analysis, based on PRISMA guidelines. The meta-analytic pooled proportion of patients with: (1) graft preservation failure was 0.09 (95% CI: 0.00, 0.46, I² = 88.8%), (2) reinfection was 0.04 (95% CI: 0.00, 0.18, I² = 79.7%), and (3) major amputation was 0.00 (95% CI: 0.00, 0.04, I² = 0%). Five studies addressing total excisions were identified via the systematic review however, their combined sample size (n = 28 patients) impeded use of a meta-analysis. Ninety (19%) licensed surgeons participated in the survey. In a hemodynamically stable, nonseptic patient, 67% (60) of respondents routinely excise the graft, while 31% (28) prefer preservation.

CONCLUSIONS

Study design and patient characteristic-related heterogeneity limited our ability to generate robust, clinical evidence-level outcome estimates. A prospective study is necessary to definitively establish the efficacy of antibiotic beads in the treatment and preservation of vascular graft infections.

Effectiveness and Safety of Biodegradable Calcium Sulfate Antibiotic Beads as Adjuvant Therapy in Vascular Graft Infections

This is a retrospective cohort study evaluating the safety and effectiveness of biodegradable calcium sulfate antibiotic beads in vascular graft infections compared with standard of care. No differences in acute kidney injury or hypercalcemia were observed between the cohorts. Recurrence of infection did not occur in the 13-patient bead cohort compared with 14 patients who had recurrence in the 45-patient nonbead cohort with a number needed to treat of 4.0.

New developments in anti-biofilm intervention towards effective management of orthopedic device related infections (ODRI's)

Orthopedic device related infections (ODRI's) represent a difficult to treat situation owing to their biofilm based nature. Biofilm infections once established are difficult to eradicate even with an aggressive treatment regimen due to their recalcitrance towards antibiotics and immune attack. The involvement of antibiotic resistant pathogens as the etiological agent further worsens the overall clinical picture, pressing on the need to look into alternative treatment strategies. The present review highlightes the microbiological challenges associated with treatment of ODRI's due to biofilm formation on the implant surface. Further, it details the newer anti-infective modalities that work either by preventing biofilm formation and/or through effective disruption of the mature biofilms formed on the medical implant. The study, therefore aims to provide a comprehensive insight into the newer anti-biofilm interventions (non-antibiotic approaches) and a better understanding of their mechanism of action essential for improved management of orthopedic implant infections.

Prospective study of single-stage repair of contaminated hernias with the novel use of calcium sulphate antibiotic beads in conjunction with biologic porcine submucosa tissue graft

SUMMARY

In single-stage hernia repair in the setting of contaminated fields there is a high rate of infection following mesh repair. New strategies to decrease infection in this challenging patient population are needed. Stimulan calcium sulfate antibiotic beads (CSAB) are a biodegradable material that deliver high concentrations of antibiotics locally to a site of insertion. Their use in the prevention of infection has not been described in hernia graft implantation. Here we describe our use of CSAB in a series of 11 patients with modified Ventral Hernia Working Group class III and Centers for Disease Control and Prevention class II-IV wounds undergoing single-stage incisional ventral hernia repair. We found that implantation of CSAB in single-stage hernia repair in the setting of contaminated fields was feasible with low systemic antibiotic levels. Further research should be undertaken to investigate the efficacy of this novel tool in hernia repair.

A Scoping Review on the Use of Antibiotic-Impregnated Beads and Applications to Vascular Surgery

INTRODUCTION

Surgical site infection (SSI) presents a ubiquitous concern to surgical specialties, especially in the presence of prosthetic material. Antibiotic-impregnated beads present a novel and evolving means to combat this condition. This review aims to analyze the quality of evidence and methods of antibiotic bead use, particularly for application within vascular surgery.

METHODS

A systematic scoping review was conducted within Embase, MEDLINE, and the Cochrane Registry of Randomized Controlled Trials. Articles were evaluated by 2 independent reviewers. Level of evidence was evaluated using the Oxford Center for Evidence-Based Medicine Criteria and the Cochrane Risk of Bias Tool for Randomized Controlled Trials.

RESULTS

The search yielded 6951 papers, with 275 included for final analysis. Publications increased in frequency from 1978 to the present. The most common formulation was polymethyl methacrylate; however publications on biodegradable formulations, including calcium sulfate beads, have been published with increasing frequency. Most publications had positive conclusions (94.2%); however, the data was mainly subjective and may be prone to publication bias. Only 11 randomized controlled trials were identified and all but one was evaluated to be at a high risk of bias. The most common indication was for osteomyelitis (52%), orthopedic prosthetic infections (20%), and trauma (9%). Within vascular surgery, beads have been used primarily for the treatment of graft infection, with freedom from recurrence rates being reported from 41% to 87.5%.

CONCLUSIONS

Antibiotic-impregnated beads provide a means to deliver high doses of antibiotic directly to a surgical site, without the risks of parenteral therapy. There has yet to be significant high-level quality data published on their use. There is a large body of evidence that suggests antibiotic beads may be used in SSIs in high-risk patients, prosthetic infections, and other complex surgical infections. Important potential areas of application in vascular surgery include graft infection, prevention of wound infection in high-risk patients, and diabetic foot infection.

iPSCs-based generation of vascular cells: reprogramming approaches and applications

Recent advances in the field of induced pluripotent stem cells (iPSCs) research have opened a new avenue for stem cell-based generation of vascular cells. Based on their growth and differentiation potential, human iPSCs constitute a well-characterized, generally unlimited cell source for the mass generation of lineage- and patient-specific vascular cells without any ethical concerns. Human iPSCs-derived vascular cells are perfectly suited for vascular disease modeling studies because patient-derived iPSCs possess the disease-causing mutation, which might be decisive for full expression of the disease phenotype. The application of vascular cells for autologous cell replacement therapy or vascular engineering derived from immune-compatible iPSCs possesses huge clinical potential, but the large-scale production of vascular-specific lineages for regenerative cell therapies depends on well-defined, highly reproducible culture and differentiation conditions. This review will focus on the different strategies to derive vascular cells from human iPSCs and their applications in regenerative therapy, disease modeling and drug discovery approaches.

Aortic Graft Infection: Graphene Shows the Way to an Infection-Resistant Vascular Graft

Aortic graft infection is a potentially lethal complication of open and endovascular repair of aortic aneurysms. Graphene is the only existing two-dimensional material, and its unique structure gives graphene and its derivatives a plethora of original characteristics. Among other characteristics, graphene demonstrates bacteriostatic and bactericidal effects that could potentially resolve the problem of graft infection in the future. Data already exist in literature supporting this antibacterial effect of graphene oxide and reduced graphene oxide. Combining these materials with other substances enhances the antibacterial effect. Additionally, it looks feasible to expect antibiotic-delivering graphene-based graft materials in the future. Based on already published data, we could conclude that regarding graphene and its derivatives, the blessing of bactericidal effect comes with the curse of human cells toxicity. Therefore, it is important to find a fine balance between the desired antibacterial and the adverse cytotoxic effect before graphene is used in graft materials for humans.

Microflora of Retained Intracochlear Electrodes from Infected Cochlear Implants

Objectives Cochlear implant infections may be refractory to medical management and require device removal with subsequent reimplantation. During device removal, the intracochlear electrode array is commonly left in place to prevent obliteration of the cochlear lumen. If the electrode is colonized with pathogens, this risks contaminating the replacement implant. In this study, we compare the microorganisms detected on infected cochlear implants against those on the retained electrode using culture and microbial gene-sequencing techniques. Study Design Prospective single-cohort study. Setting Tertiary medical center. Subjects and Methods Six patients with refractory cochlear implant infections had the receiver-stimulator and extracochlear electrode removed to facilitate treatment of the infection. The intracochlear electrode was removed at (delayed) reimplantation. Implant specimens were analyzed by microbial culture and 16S DNA gene sequencing. Results Staphylococcus aureus was the organism most commonly identified. None of the 6 patients' intracochlear electrodes yielded microbes by culture. Two intracochlear electrodes revealed bacterial species, and 1 revealed fungal species by gene sequencing. There was no correlation between the microbes on the infected extracochlear implants and the retained intracochlear electrodes. All subjects underwent reimplantation after resolution of their infections. One of 6 subjects developed a second infection after reimplantation, with S aureus in the primary and secondary infections. Conclusions The intracochlear electrodes of infected cochlear implants carry a low microbial burden. Preserving intracochlear electrodes upon removal of infected cochlear implants appears to carry a low risk of contaminating a replacement cochlear implant.