Management of bacteremia in patients living with cardiovascular implantable electronic devices

Risk of Cardiac Implantable Electronic Device Infection in Patients with Bloodstream Infection: Microbiologic Effect in the Era of Positron Emission Tomography-Computed Tomography

PURPOSE OF REVIEW

Bloodstream infection (BSI) in patients with cardiac implantable electronic devices (CIEDs) is common and can prompt challenges in defining optimal management. We provide a contemporary narrative review of this topic and propose a pathogen-dependent clinical approach to patient management.

RECENT FINDINGS

BSI due to staphylococci, viridans group streptococci, and enterococci is associated with an increased risk of underlying CIED infection, while the risk of CIED infection due to other organisms is poorly defined. There is growing evidence that positron emission tomography-computed tomography may be helpful in some patients with BSI and underlying CIED. Twenty studies were included to examine the impact of microbiologic findings on the risk of CIED infection among patients with BSI. Diagnosis of CIED infection in patients with BSI without pocket findings is often difficult, necessitating the use of novel diagnostic tools to help guide the clinician in subsequent patient management.

Candidemia in Patients With Cardiovascular Implantable Electronic Devices: Uncertainty in Management Based on Current International Guidelines

Background

In contrast to bloodstream infection due to a variety of bacteria in patients with cardiovascular implantable electronic devices (CIED), there are limited data regarding candidemia and risk of CIED infection.

Methods

All patients with candidemia and a CIED at Mayo Clinic Rochester between 2012 and 2019 were reviewed. Cardiovascular implantable electronic device infection was defined by (1) clinical signs of pocket site infection or (2) echocardiographic evidence of lead vegetations.

Results

A total of 23 patients with candidemia had underlying CIED; 9 (39.1%) cases were community onset. None of the patients had pocket site infection. The duration between CIED placement and candidemia was prolonged (median 3.5 years; interquartile range, 2.0-6.5). Only 7 (30.4%) patients underwent transesophageal echocardiography and 2 of 7 (28.6%) had lead masses. Only the 2 patients with lead masses underwent CIED extraction, but device cultures were negative for Candida species. Two (33.3%) of 6 other patients who were managed as candidemia without device infection subsequently developed relapsing candidemia. Cardiovascular implantable electronic device removal was done in both patients and device cultures grew Candida species. Although 17.4% of patients were ultimately confirmed to have CIED infection, CIED infection status was undefined in 52.2%. Overall, 17 (73.9%) patients died within 90 days of diagnosis of candidemia.

Conclusions

Although current international guidelines recommend CIED removal in patients with candidemia, the optimal management strategy remains undefined. This is problematic because candidemia alone is associated with increased morbidity and mortality as seen in this cohort. Moreover, inappropriate device removal or retention can both result in increased patient morbidity and mortality.

Pseudoaneurysm Infection Ballooning Out of Control Following Sequential Cardiac Catheterizations: A Case Report

A femoral artery pseudoaneurysm (PSA) is a potential complication of vascular access procedures, such as cardiac catheterizations, that can have serious consequences if left untreated. Although the incidence of PSA formation has decreased due to the advent of improved surgical techniques, this case demonstrates that such complications should be considered in a clinical setting. This report presents a case of right femoral PSA, pacemaker infection, and high-grade methicillin-resistant Staphylococcus aureus (MRSA) bacteremia status post multiple cardiac catheterizations. Treatment included open repair of his femoral artery PSA, antibiotics tailored to culture sensitivities, and pacemaker removal. The potential complications, diagnosis, management, and alternative treatment options for PSAs are discussed in order to encourage clinical awareness of a rare complication.

Bacteremia due to Non-Staphylococcus aureus Gram-positive Cocci and Risk of Cardiovascular Implantable Electronic Device Infection

Background

Cardiovascular implantable electronic device (CIED) infection carries significant morbidity and mortality with bacteremia being a possible marker of device infection. A clinical profile of non-Staphylococcus aureus gram-positive cocci (non-SA GPC) bacteremia in patients with CIED has been limited.

Objective

To examine characteristics of patients with CIED who developed non-SA GPC bacteremia and risk of CIED infection.

Methods

We reviewed all patients with CIED who developed non-SA GPC bacteremia at the Mayo Clinic between 2012 and 2019. The 2019 European Heart Rhythm Association Consensus Document was used to define CIED infection.

Results

A total of 160 patients with CIED developed non-SA GPC bacteremia. CIED infection was present in 90 (56.3%) patients, in whom 60 (37.5%) were classified as definite and 30 (18.8%) as possible. This included 41 (45.6%) cases of coagulase-negative Staphylococcus (CoNS), 30 (33.3%) cases of Enterococcus, 13 (14.4%) cases of viridans group streptococci (VGS), and 6 (6.7%) cases of other organisms. The adjusted odds of CIED infection in cases due to CoNS, Enterococcus, and VGS bacteremia were 19-, 14-, and 15-fold higher, respectively, as compared with other non-SA GPC. In patients with CIED infection, the reduction in risk of 1-year mortality associated with device removal was not statistically significant (hazard ratio 0.59; 95% confidence interval 0.26-1.33; P = .198).

Conclusions

The prevalence of CIED infection in non-SA GPC bacteremia was higher than previously reported, particularly in cases due to CoNS, Enterococcus species, and VGS. However, a larger cohort is needed to demonstrate the benefit of CIED extraction in patients with infected CIED due to non-SA GPC.

Risk of cardiac device-related infection in patients with late-onset bloodstream infection. Analysis on a National Cohort

OBJECTIVES

To determine the incidence of cardiac device-related infection (CDRI) among patients with cardiac device (CD) during late-onset bloodstream infection (BSI) and to identify the risk factors associated with CDRI.

METHODS

Patients with a CD (cardiac implantable electronic devices -CIED- and/or prosthetic heart valve -PHV-) and late-onset-BSI (>1 year after the CD implantation/last manipulation) were selected from the PROBAC project, a prospective, observational cohort study including adult patients with bacteraemia consecutively admitted to 26 Spanish hospitals from October 2016 to March 2017. Multivariate analyses using logistic regression were performed to identify the risk factors associated with CDRI.

RESULTS

317 BSI from patients carrying a CD were registered, 187 (56.2%) were late-onset-BSI. A total of 40 (21.4%) CDRI were identified during late-onset-BSI. The CDRI cumulative incidence in Gram-positive-BSI was 41.8% (38/91), with S. aureus, Enterococcus spp. and viridans streptococci showing the greatest percentages: 40% (12/30), 42% (11/26) and 75% (6/8), respectively. Independent predictors of CDRI were an unknown source of infection (OR: 2.88 [CI 95%:1.18-7.06], p=0.02), Gram-positive-aetiology (23.1 [5.23-102.1], p<0.001) and persistent bacteraemia (4.81 [1.21-19], p=0.03). In an exploratory analysis, S. aureus (3.99 [1.37-11.65], p=0.011), Enterococcus spp. (5.21 [1.76-15.4], p=0.003) and viridans streptococci (28.7 [4.71-173.5], p<0.001) aetiology were also found to be risk factors for CDRI.

CONCLUSIONS

CDRI during late-onset-BSI is a frequent phenomenon. Risk of CDRI differs among species, happening in almost half of the Gram-positive-BSI. An unknown source of the primary infection, Gram-positive-aetiology -especially S. aureus, Enterococcus spp. and viridans streptococci-, and persistent bacteraemia were identified as risk factors for CDRI.

Vancomycin-decorated microbubbles as a theranostic agent for Staphylococcus aureus biofilms

Bacterial biofilms are a huge burden on our healthcare systems worldwide. The lack of specificity in diagnostic and treatment possibilities result in difficult-to-treat and persistent infections. The aim of this in vitro study was to investigate if microbubbles targeted specifically to bacteria in biofilms could be used both for diagnosis as well for sonobactericide treatment and demonstrate their theranostic potential for biofilm infection management. The antibiotic vancomycin was chemically coupled to the lipid shell of microbubbles and validated using mass spectrometry and high-axial resolution 4Pi confocal microscopy. Theranostic proof-of-principle was investigated by demonstrating the specific binding of vancomycin-decorated microbubbles (vMB) to statically and flow grown Staphylococcus aureus (S. aureus) biofilms under increasing shear stress flow conditions (0-12 dyn/cm²), as well as confirmation of microbubble oscillation and biofilm disruption upon ultrasound exposure (2 MHz, 250 kPa, and 5,000 or 10,000 cycles) during flow shear stress of 5 dyn/cm² using time-lapse confocal microscopy combined with the Brandaris 128 ultra-high-speed camera. Vancomycin was successfully incorporated into the microbubble lipid shell. vMB bound significantly more often than control microbubbles to biofilms, also in the presence of free vancomycin (up to 1000 µg/mL) and remained bound under increasing shear stress flow conditions (up to 12 dyn/cm²). Upon ultrasound insonification biofilm area was reduced of up to 28%, as confirmed by confocal microscopy. Our results confirm the successful production of vMB and support their potential as a new theranostic tool for S. aureus biofilm infections by allowing for specific bacterial detection and biofilm disruption.

Staphylococcus bacteremia without evidence of cardiac implantable electronic device infection

BACKGROUND

Staphylococcus bacteremia (SB) in the presence of a cardiac implantable electronic device (CIED) is frequently associated with CIED infection. In patients without clear CIED infection but SB, the role of empirical CIED removal is unclear.

OBJECTIVE

The purpose of this study was to describe the natural history of SB in the setting of a CIED and the effect of CIED removal on mortality in patients with concurrent SB without evidence of CIED infection.

METHODS

Three hundred sixty consecutive patients (mean age 61 ± 17 years; 255 (71%) men; 329 (92%) Staphylococcus aureus) with a CIED and concurrent SB were reviewed.

RESULTS

At the initial presentation with SB, 178 patients had no evidence of CIED infection. Of these, 132 (74%) had another identified source of infection. Among the 178 patients without CIED infection, 18 (10%) had empirical CIED removal during the initial bacteremia. Among those who did not undergo CIED removal, SB subsequently relapsed in 19% and relapse rates were not different for those with or without another identifiable source at the initial presentation. Relapse was strongly associated with the duration of SB >1 day (odds ratio 9.99; 95% confidence interval 3.24-30.86). Despite the absence of CIED infection, 1-year mortality was 35% and empirical device removal during the initial presentation was associated with survival benefit (hazard ratio 0.28; 95% confidence interval 0.08-0.95).

CONCLUSION

For patients with SB without evidence of CIED infection, relapse is predicted by the duration of bacteremia. Empirical CIED removal appears to be associated with a survival benefit, although there are likely clinical situations in which this could be deferred.

Clinical Presentation, Timing, and Microbiology of CIED Infections: An Analysis of the WRAP-IT Trial

OBJECTIVES

This study characterized the microbiology of major cardiac implantable electronic device (CIED) infections that occurred during the WRAP-IT (Worldwide Randomized Antibiotic Envelope Infection Prevention Trial) study.

BACKGROUND

The WRAP-IT study offers a unique opportunity for further understanding of the pathogens involved in major CIED infections in a prospective dataset, with implications for clinical practice and infection management.

METHODS

A total of 6,800 patients randomized 1:1 to receive an antibacterial envelope or not (control subjects) were included in this analysis. Patient characteristics, infection manifestation (pocket vs. systemic), and infection microbiology were evaluated through all follow-up (36 months). Data were analyzed using Cox proportional hazards regression.

RESULTS

A total of 3,371 patients received an envelope, and 3,429 patients were control subjects. Major CIED infection occurred in 32 patients who received an envelope and 51 control subjects (36-month Kaplan-Meier estimated event rate, 1.3% and 1.9%, respectively; p = 0.046). A 61% reduction in major pocket infection was observed within 12 months of the procedure in the envelope group (hazard ratio: 0.39, 95% confidence interval: 0.21 to 0.73; p = 0.003). Among 76 patients with major infections who had a sample taken, causative pathogens were identified in 47 patients. Staphylococcus species were the predominate pathogen (n = 31) and envelope use resulted in a 76% reduction in Staphylococcus-related pocket infections (n = 4 vs. 17; p = 0.010). Envelope use was not associated with delayed onset of pocket infections and did not affect the presentation of infections.

CONCLUSIONS

Antibacterial envelope use resulted in a significant reduction of major CIED pocket infections and was particularly effective against Staphylococcus species, the predominant cause of pocket infections. (Worldwide Randomized Antibiotic Envelope Infection Prevention Trial [WRAP-IT]; NCT02277990).

Antibiotic eluting poly(ester urea) films for control of a model cardiac implantable electronic device infection

Cardiac implantable electronic device (CIED) infections acquired during or after surgical procedures are a major complication that are challenging to treat therapeutically, resulting in chronic and sometimes fatal infections. Localized delivery of antibiotics at the surgical site could be used to supplement traditional systemic administration as a preventative measure. Herein, we investigate a cefazolin-eluting l-valine poly(ester urea) (PEU) films as a model system for localized antibiotic delivery for CIEDs. Poly(1-VAL-8) PEU was used to fabricate a series of antibiotic-loaded films with varied loading concentrations (2%, 5%, 10% wt/wt) and thicknesses (40 µm, 80 µm, 140 µm). In vitro release measurements show thickness and loading concentration influence the amount and rate of cefazolin release. Group 10%-140 µm (load-thickness) showed 22.5% release of active pharmaceutical ingredient (API) in the first 24 h and 81.2% of cumulative percent release through day 14 and was found most effective in bacterial clearance in vitro. This group was also effective in clearing a bacterial infection in a model in vivo rat study while eliciting a limited inflammatory response. Our results suggest the feasibility of cefazolin-loaded PEU films as an effective sustained release matrix for localized delivery of antibiotics. SIGNIFICANCE STATEMENT: Implant-associated infections acquired during surgical procedures are a major complication that have proven a challenge to treat clinically, resulting in chronic and sometimes fatal infections. In this manuscript, we investigate an antibiotic-eluting L-valine poly(ester urea) (PEU) films as a model system for localized delivery of cefazolin. Significantly, we demonstrate a wide variation in temporal delivery and dosing within this family of PEUs and show that the delivery can be extended by varying the film thickness. The in vivo results show efficacy in an infected wound model and suggest antibiotic loaded PEU films function as an effective sustained release matrix for localized delivery of antibiotics across a number of clinical indications.

Approach to Diagnosis of Cardiovascular Implantable-Electronic-Device Infection

Device infection remains a significant challenge as clinical indications for cardiovascular implantable electronic device (CIED) therapy continue to expand beyond the prevention and treatment of cardiac arrhythmias. Patients receiving CIED therapy are now older and have significant comorbidities, placing them at higher risk of complications, including infection. CIED infection warrants complete device removal, as retention is associated with an unacceptably high risk of relapse and increased mortality. However, accurate diagnosis of CIED infections remains a significant challenge that is based on a combination of findings on physical examination, microbiological and laboratory testing, and advanced imaging, such as transesophageal echocardiography or positron emission tomography. Isolating a causative pathogen and performing susceptibility testing are crucial for appropriate choice, route, and duration of antimicrobial therapy. In this review, we present an evidence-based approach to diagnosis of CIED infection.

The "3M" Approach to Cardiovascular Infections: Multimodality, Multitracers, and Multidisciplinary

Cardiovascular infections are associated with high morbidity and mortality. Early diagnosis is crucial for adequate patient management, as early treatment improves the prognosis. The diagnosis cannot be made on the basis of a single symptom, sign, or diagnostic test. Rather, the diagnosis requires a multidisciplinary discussion in addition to the integration of clinical signs, microbiology data, and imaging data. The application of multimodality imaging, including molecular imaging techniques, has improved the sensitivity to detect infections involving heart valves and vessels and implanted cardiovascular devices while also allowing for early detection of septic emboli and metastatic infections before these become clinically apparent. In this review, we describe data supporting the use of a Multimodality, Multitracer, and Multidisciplinary approach (the 3M approach) to cardiovascular infections. In particular, the role of white blood cell SPECT/CT and [¹⁸F]FDG PET/CT in most prevalent and clinically relevant cardiovascular infections will be discussed. In addition, the needs of advanced hybrid equipment, dedicated imaging acquisition protocols, specific expertise for image reading, and interpretation in this field are discussed, emphasizing the need for a specific reference framework within a Cardiovascular Multidisciplinary Team Approach to select the best test or combination of tests for each specific clinical situation.

International survey of knowledge, attitudes, and practices of cardiologists regarding prevention and management of cardiac implantable electronic device infections

BACKGROUND

Cardiovascular implantable electronic devices (CIEDs) can be life-saving. However, complications from CIED infection can be life-threatening, often requiring device removal. Despite publication of CIED infection management guidelines, there remains marked variation in clinical practice.

OBJECTIVE

To better understand and quantify these differences, we conducted a multinational survey of practitioners of CIED management.

METHODS

An electronic survey was sent to Heart Rhythm Society members, spanning 70 countries across six continents. All responses were collected anonymously.

RESULTS

227 out of 3,600 (6.3%) responded to the survey. The majority of surveys were completed by practitioners from the United States (168; 68.3%) and 53.8% of these practiced in academic medical centers. The large majority (92.7%) of sites had protocols to ensure appropriate timing of prophylactic antibiotics. Superficial (incisional) site infections were treated with antibiotics alone 52.5% of the time (consistent with guidelines); in contrast, deep pocket infections were treated with antibiotics (with device removal) in accordance to guidelines only 37.4% of the time. Almost all providers (98.7%) were inclined to perform complete hardware removal in cases of CIED-related endocarditis. In contrast, 82.2% of survey participants suggested complete CIED system removal in patients with an occult Gram-positive bacteremia, 65.5% with occult Gram-negative bacteremia, and 59.3% with prolonged bacteremia due to a source other than CIED.

CONCLUSIONS

These data suggest wide variability in clinical practice in managing CIED infection with significant deviations from published guidelines. There is critical need to increase awareness and develop institutional protocols to ensure adherence with evidence-based guidelines to optimize outcomes.

The Risk of Cardiac Device-Related Infection in Bacteremic Patients Is Species Specific: Results of a 12-Year Prospective Cohort

BACKGROUND

The species-specific risk of cardiac device-related infection (CDRI) among bacteremic patients is incompletely understood.

METHODS

We conducted a prospective cohort study of hospitalized patients from October 2002 to December 2014 with a cardiac device (CD) and either Staphylococcus aureus bacteremia (SAB) or Gram-negative bacteremia (GNB). Cardiac devices were defined as either prosthetic heart valves (PHVs), including valvular support rings, permanent pacemakers (PPMs)/automatic implantable cardioverter defibrillators (AICDs), or left ventricular assist devices (LVADs).

RESULTS

During the study period, a total of 284 patients with ≥1 CD developed either SAB (n = 152 patients) or GNB (n = 132 patients). Among the 284 patients, 150 (52.8%) had PPMs/AICDs, 72 (25.4%) had PHVs, 4 (1.4%) had LVADs, and 58 (20.4%) had >1 device present. Overall, 54.6% of patients with SAB and 16.7% of patients with GNB met criteria for definite CDRI (P < .0001). Multivariable logistic regression analysis revealed that 3 bacterial species were associated with an increased risk for CDRI: Staphylococcus aureus (odds ratio [OR] = 5.57; 95% confidence interval [CI], 2.16-14.36), Pseudomonas aeruginosa (OR = 50.28; 95% CI, 4.16-606.93), and Serratia marcescens (OR = 7.75; 95% CI, 1.48-40.48).

CONCLUSIONS

Risk of CDRI among patients with bacteremia varies by species. Cardiac device-related infection risk is highest in patients with bacteremia due to S aureus, P aeruginosa, or S marcescens. By contrast, it is lower in patients with bacteremia due to other species of Gram-negative bacilli. Patients with a CD who develop bacteremia due to either P aeruginosa or S marcescens should be considered for diagnostic imaging to evaluate for the presence of CDRI.