Lead-Associated Endocarditis: The Important Role of Methicillin-Resistant Staphylococcus aureus

Atypical pathogens associated with cardiac implantable electronic device infections

BACKGROUND

Cardiovascular implantable electronic device (CIED) infections are associated with significant morbidity and mortality making the identification of the causative organism critical. The vast majority of CIED infections are caused by Staphylococcal species. CIED infections associated with atypical pathogens are rare and have not been systematically investigated. The objective of this study is to characterize the clinical course, management and outcome in patients with CIED infection secondary to atypical pathogens.

METHODS

Medical records of all patients who underwent CIED system extraction at the University of Chicago Medical Center between January 2010 and November 2020 were retrospectively reviewed to identify patients with CIED infection. Demographic, clinical, infection-related and outcome data were collected. CIED infections were divided into typical and atypical groups based on the pathogens isolated.

RESULTS

Among 356 CIED extraction procedures, 130 (37%) were performed for CIED infection. Atypical pathogens were found in 5.4% (n = 7) and included Pantoea species (n = 2), Kocuria species (n = 1), Cutibacterium acnes (n = 1), Corynebacterium tuberculostearicum (n = 1), Corynebacterium striatum (n = 1), Stenotrophomonas maltophilia (n = 1), and Pseudozyma ahidis (n = 1). All patients with atypical CIED infections were successfully treated with total system removal and tailored antibiotic therapy. There were no infection-related deaths.

CONCLUSIONS

CIED infections with atypical pathogens were rare and associated with good outcome if diagnosed early and treated with total system removal and tailored antimicrobial therapy. Atypical pathogens cultured from blood, tissue or hardware in patients with CIED infection should be considered pathogens and not contaminants.

The emergence of Staphylococcus aureus as the primary cause of cardiac device-related infective endocarditis

BACKGROUND

Increasing use of cardiovascular implantable electronic devices (CIED), as permanent pacemakers (PPM), implantable cardioverter defibrillators (ICD), or cardiac resynchronization therapy (CRT), is associated with the emergence of CIED-related infective endocarditis (CIED-IE). We aimed to characterize CIED-IE profile, temporal trends, and prognostic factors.

METHODS

CIED-IE diagnosed at Rennes University Hospital during years 1992-2017 were identified through computerized database, and included if they presented all of the following: (1) clinical signs of infection; (2) microbiological documentation through blood and/or CIED lead cultures; (3) lead or valve vegetation, or definite IE according to Duke criteria. Data were retrospectively extracted from medical charts. The cohort was categorized in three periods: 1992-1999, 2000-2008, and 2009-2017.

RESULTS

We included 199 patients (51 women, 148 men, median age 73 years [interquartile range, 64-79]), with CIED-IE: 158 PPMs (79%), 24 ICD (12%), and 17 CRT (9%). Main pathogens were coagulase-negative staphylococci (CoNS: n = 86, 43%), Staphylococcus aureus (n = 60, 30%), and other Gram-positive cocci (n = 28, 14%). Temporal trends were remarkable for the decline in CoNS (P = 0.002), and the emergence of S. aureus as the primary cause of CIED-IE (24/63 in 2009-2017, 38%). Factors independently associated with one-year mortality were chronic obstructive pulmonary disease (COPD: hazard ratio 3.84 [1.03-6.02], P = 0.03), left-sided endocarditis (HR 2.25 [1.09-4.65], P = 0.03), pathogens other than CoNS (HR 3.16 [1.19-8.39], P = 0.02), and CIED removal/reimplantation (HR 0.41 [0.20-0.83], P = 0.01).

CONCLUSIONS

S. aureus has emerged as the primary cause of CIED-IE. Left-sided endocarditis, COPD, pathogens other than CoNS, and no CIED removal/reimplantation are independent risk factors for one-year mortality.

A Review of Cardiac Implantable Electronic Device Infections for the Practicing Electrophysiologist

Cardiovascular implantable electronic device (CIED) infections are morbid, costly, and difficult to manage. This review explores the pathophysiology, diagnosis, and management of CIED infections. Diagnostic accuracy has been improved through increased awareness and improved imaging strategies. Pocket or bloodstream infection with virulent organisms often requires complete system extraction. Emerging prophylactic interventions and novel devices have expanded preventative strategies and options for re-implantation. A clear and nuanced understanding of CIED infection is important to the practicing electrophysiologist.

Clinical manifestations of device-related infective endocarditis in cardiac resynchronization therapy recipients

INTRODUCTION

The aim of the study was to analyse microbiological characteristics and clinical manifestations of cardiac device-related infective endocarditis (CDRIE) in cardiac resynchronization therapy (CRT) recipients, and to compare the diagnostic value of modified Duke (MDC) versus modified Duke lead criteria (MDLC; including to MDC local infection and pulmonary infection or embolism as major criteria).

MATERIAL AND METHODS

The study population comprised 765 consecutive CRT patients from a high-volume, tertiary care centre from 2002 to 2015. All patients were screened for CDRIE.

RESULTS

During a median follow-up of 1692 days (range: 457-3067) 5.36% of patients (n = 41) developed CDRIE, which was accompanied by CRT pocket infection in 17.1% (n = 7) and recurrent pulmonary infection or pulmonary embolism in 29.3% (n = 12). Fever was present in 95.1% of patients (n = 39), whereas blood cultures were positive in 65.9% (n = 27). Staphylococcus was the most prevalent pathogen in 59.3% (n = 16), Gram-negative bacteria in 25.9% (n = 7). Transoesophageal echocardiography showed intracardiac vegetations in 73.2% of patients (n = 30). Non-different pathogen types with the most common methicillin-sensitive Staphylococcus aureus were observed for early versus late CDRIE (endocarditis ≤ 6 vs. > 6 months from CRT or other device-related procedure). All 3 inflammatory markers (C-reactive protein, white blood cells, procalcitonin) were normal in 4.9% of patients (n = 2). MDC versus MDLC indicated definite CDRIE in 48.8% versus 80.5%, respectively (p = 0.003).

CONCLUSIONS

Fever is the most common symptom of CRT-related CDRIE, and transoesophageal echocardiography allows vegetations to be visualised in nearly 3/4 of patients with CDRIE. Although the most common pathogens were Staphylococci, Gram-negative bacteria accounted for a quarter of CDRIE. Modified Duke lead criteria proved superior to MDC.

High prevalence of anti-HEV antibodies among patients with immunosuppression and hepatic disorders in eastern Poland

INTRODUCTION

The incidence of hepatitis E virus (HEV) infections in Poland is largely unknown. This study aimed to describe seroprevalence of markers of HEV infection among patients with immunodeficiency of diverse etiology and patients with advanced chronic liver diseases.

MATERIAL AND METHODS

Four hundred fifty patients were enrolled; among them, 180 persons were solid organ transplant recipients, 90 patients were HIV-infected and 180 persons had confirmed liver cirrhosis of different etiology. Serum anti-HEV-IgG, IgM antibodies and HEV-antigen were detected by ELISA (Wantai, China).

RESULTS

In the group of transplant recipients, serum anti-HEV-IgG antibodies were detected in 40.6%, IgM in 1.1% and HEV-Ag in 2.8% of subjects. In the HIV-infected population 37.7% had anti-HEV-IgG, 1.1% had anti-HEV-IgM and none had HEV-Ag. Among patients with advanced chronic liver diseases the highest prevalence of anti-HEV-IgG was recorded in alcohol-related liver cirrhosis (52.1%) (p = 0.049). In the population of all liver cirrhotics anti-HEV-IgG seroprevalence was 48.3%, anti-HEV-IgM seroprevalence was 5.0% and HEV-Ag seroprevalence was 1.7%. Older age and male gender were significant risk factors associated with increased anti-HEV-IgG prevalence, p = 0.0004 and p = 0.02, respectively.

CONCLUSIONS

In this large cohort a high seroprevalence of anti-HEV-IgG was detected in comparison to other European countries, with the highest rates in patients with alcoholic liver disease and in transplant recipients.

Rate, Time Course, and Predictors of Implantable Cardioverter Defibrillator Infections: An Analysis From the SIMPLE Trial

Background

The number of implantable cardioverter defibrillator (ICD) infections is increasing due to an increased number of ICD implants, higher-risk patients, and more frequent replacement procedures, which carry a higher risk of infection. Reducing the morbidity, mortality, and cost of ICD-related infections requires an understanding of the current rate of this complication and its predictors.

Methods

The Shock Implant Evaluation Trial (SIMPLE) trial randomized 2500 ICD recipients to defibrillation testing or not. Over an average of 3.1 years, patients were seen every 6 months and examined for evidence of ICD infection, which was defined as requiring device removal and/or intravenous antibiotics.

Results

Within 24 months, 21 patients (0.8%) developed infection. Fourteen patients (67%) with infection presented within 30 days, 20 patients by 12 months, and only 1 patient beyond 12 months. Univariate analysis demonstrated that patients with primary electrical disorders (3 patients, P = 0.009) and those with a secondary prevention indication (13 patients, P = 0.0009) were more likely to develop infection. Among the 2.2% of patients who developed an ICD wound hematoma, 10.4% developed an infection. Among the 8.3% of patients requiring an ICD reintervention, 1.9% developed an infection.

Conclusions

This cohort of ICD recipients at high-volume centres have a low risk of device-related infection. However; strategies to reduce wound hematoma and the need for ICD reintervention could further reduce the rate of infection.

Prevention of Arrhythmia Device Infection Trial: The PADIT Trial

BACKGROUND

Infection of implanted medical devices has catastrophic consequences. For cardiac rhythm devices, pre-procedural cefazolin is standard prophylaxis but does not protect against methicillin-resistant gram-positive organisms, which are common pathogens in device infections.

OBJECTIVE

This study tested the clinical effectiveness of incremental perioperative antibiotics to reduce device infection.

METHODS

The authors performed a cluster randomized crossover trial with 4 randomly assigned 6-month periods, during which centers used either conventional or incremental periprocedural antibiotics for all cardiac implantable electronic device procedures as standard procedure. Conventional treatment was pre-procedural cefazolin infusion. Incremental treatment was pre-procedural cefazolin plus vancomycin, intraprocedural bacitracin pocket wash, and 2-day post-procedural oral cephalexin. The primary outcome was 1-year hospitalization for device infection in the high-risk group, analyzed by hierarchical logistic regression modeling, adjusting for random cluster and cluster-period effects.

RESULTS

Device procedures were performed in 28 centers in 19,603 patients, of whom 12,842 were high risk. Infection occurred in 99 patients (1.03%) receiving conventional treatment, and in 78 (0.78%) receiving incremental treatment (odds ratio: 0.77; 95% confidence interval: 0.56 to 1.05; p = 0.10). In high-risk patients, hospitalization for infection occurred in 77 patients (1.23%) receiving conventional antibiotics and in 66 (1.01%) receiving incremental antibiotics (odds ratio: 0.82; 95% confidence interval: 0.59 to 1.15; p = 0.26). Subgroup analysis did not identify relevant patient or site characteristics with significant benefit from incremental therapy.

CONCLUSIONS

The cluster crossover design efficiently tested clinical effectiveness of incremental antibiotics to reduce device infection. Device infection rates were low. The observed difference in infection rates was not statistically significant. (Prevention of Arrhythmia Device Infection Trial [PADIT Pilot] [PADIT]; NCT01002911).

Biofilms: Survival and defense strategy for pathogens

Studies on biofilm related infections are gaining prominence owing to their involvement in majority of clinical infections. Biofilm, considered as a generic mechanism for survival used by pathogenic as well as non-pathogenic microorganisms, involves surface attachment and growth of heterogeneous cells encapsulated within a matrix. The matrix provides ecological niche where partnership of cells endows a community like behaviour that not only enables the cohort to survive local microenvironment stress but also channelizes them to evolve, disseminate and cause resurgence of infections. In this mini-review we highlight the mechanisms used by microbes to develop and sustain biofilms, including the influence of the microbiota. Several strategies to target biofilms have been validated on certain groups of microorganisms and these basically target different stages in the life cycle of biofilm, however comprehensive methods to target microbial biofilms are relatively unknown. In the backdrop of recent reports suggesting that biofilms can harbour multiple species of organisms, we need to relook and devise newer strategies against biofilms. Effective anti-biofilm strategies cannot be confined to a single methodology that can disrupt one pathway but should simultaneously target the various routes adopted by the microorganisms for survival within their ecosystem. An overview of the currently available drugs, their mode of action, genomic targets and translational therapies against biofilm related infection are discussed.

Strategies to prevent infections associated with cardiovascular implantable electronic devices

INTRODUCTION

Infections involving cardiovascular implantable electronic devices (CIED) are associated with high morbidity and mortality and substantial financial cost. In the past two decades, the rate of CIED infections has increased disproportionate to the number of devices implanted, likely due to aging patient population with multiple comorbidities. Microbial contamination of the generator pocket and or leads by skin flora at the time of implantation is a major mechanism for early CIED infections. Due to resistance to host immune cells and antibiotics caused by biofilm formation, complete removal of the device generator and leads is required to achieve cure. Areas covered: In this manuscript, we review the published literature regarding epidemiology, risk factors, and pathogenesis of CIED infections with primary focus on the preventative strategies to reduce the incidence of device infections. Expert commentary: Strict adherence to infection control measures at the time of CIED implantation is critical in reducing the risk of device infection while adjunctive strategies such as use of antimicrobial envelopes might help in certain high-risk individuals. Technological advances in device manufacturing with availability of subcutaneous devices without transvenous leads and self-contained intracardiac devices without leads and generator show promise with lower risk of infection.

Cardiac Implantable Electronic Device Infection in Patients at Risk

The incidence of infection following implantation of cardiac implantable electronic devices (CIEDs) is increasing at a faster rate than that of device implantation. Patients with a CIED infection usually require hospitalisation and complete device and lead removal. A significant proportion die from their infection. Transvenous lead extraction (TLE) is associated with rare but serious complications including major vascular injury or cardiac perforation. Operator experience and advances in lead extraction methods, including laser technology and rotational sheaths, have resulted in procedures having a low risk of complication and mortality. Strategies for preventing CIED infections include intravenous antibiotics and aseptic surgical techniques. An additional method to reduce CIED infection may be the use of antibacterial TYRX™ envelope. Data from non-randomised cohort studies have indicated that antibacterial envelope use can reduce the incidence of CIED infection by more than 80 % in high-risk patients and a randomised clinical trial is ongoing.

The effect of preheated versus room-temperature skin disinfection on bacterial colonization during pacemaker device implantation: a randomized controlled non-inferiority trial

Background

In clinical practice, patients who are awake often comment that cold surgical skin disinfectant is unpleasant. This is not only a problem of patients’ experience; heat loss during the disinfection process is a problem that can result in hypothermia. Evidence for the efficacy of preheated disinfection is scarce.

We tested whether preheated skin disinfectant was non-inferior to room-temperature skin disinfectant on reducing bacterial colonization during pacemaker implantation.

Methods

This randomized, controlled, non-inferiority trial included 220 patients allocated to skin disinfection with preheated (36 °C) or room-temperature (20 °C) chlorhexidine solution in 70 % ethanol. Cultures were obtained by swabbing at 4 time-points; 1) before skin disinfection (skin surface), 2) after skin disinfection (skin surface), 3) after the incision (subcutaneously in the wound), and 4) before suturing (subcutaneously in the wound).

Results

The absolute difference in growth between patients treated with preheated versus room-temperature skin disinfectant was zero (90 % CI −0.101 to 0.101; preheated: 30 of 105 [28.6 %] vs. room-temperature: 32 of 112 [28.6 %]). The pre-specified margin for statistical non-inferiority in the protocol was set at 10 % for the preheated disinfectant. There were no significant differences between groups regarding SSIs three month postoperatively, which occurred in 0.9 % (1 of 108) treated with preheated and 1.8 % (2 of 112) treated with room-temperature skin disinfectant.

Conclusion

Preheated skin disinfection is non-inferior to room-temperature disinfection in bacterial reduction. We therefore suggest that preheated skin disinfection become routine in clean surgery.

Trial registration

The study is registered at ClinicalTrials.gov (NCTO2260479).

Clinical and Microbiological Characterization of Late Breast Implant Infections after Reconstructive Breast Cancer Surgery

BACKGROUND

Implant infections represent a relevant problem after immediate breast cancer reconstruction. In addition to difficulties in distinguishing early infections from other post-surgical complications (such as hematoma, seroma, and liponecrosis) late breast implant infections still represent a grey area of our knowledge with regards to heir definition and management. To address this issue, we prospectively monitored breast cancer patients at their center.

METHODS

Between February 1, 2009, and May 31, 2013, we enrolled all patients undergoing breast implant reconstruction or expander-to-prosthesis substitution. Patients without at least 6 mo of post-operative observation were excluded. We collected data from patient records including age, days from surgery (DFS), chemotherapy/radiotherapy, infecting microorganism, type of implant, antibiotic management and eventual implant removal. Sixty days from surgery were defined as the clinical threshold between early and late infection. Infections were further classified according to a graded scale into possible, probable and microbiologically proved.

RESULTS

Seventy-eight infections were recorded out of 766 surgical procedures (10.2%). Fifty-three (67%) cases occurred early ≤60 DFS, and 25 (33%) occurred late (i.e., beyond 60 d). By defining infection types as possible, probable or proved, the majority of late infections were classified as proved (84%) compared with 56% of early infections (p=0.0014). Microbiological isolate distribution was similar in proved early infections compared with proved late infections. Among late infections, a delayed occurrence was observed after prosthesis placement compared with expander insertion. Late infections were fraught with lower treatment success rates (12% vs. 41%, p=0.009).

CONCLUSION

Late infection represents a consistent proportion of infections after immediate breast implant reconstruction or prosthesis placement and bear lower chance of salvage after treatment. An increased attention is warranted to improve prevention and treatment strategies.

Management of Cardiovascular Implantable Electronic Devices Infections in High-Risk Patients

The incidence of infection following implantation of cardiovascular implantable electronic devices (CIEDs) is increasing, as is the number of pulse generator replacements and upgrades. The rate of infections is rising faster than the rate of device implantation, mainly due to the increasing age and number of comorbidities of patients receiving the devices. Patients with a CIED infection usually require hospitalisation, multiple consultations, prolonged intravenous antibiotics and, in the majority of cases, CIED explantation and replacement. A significant proportion die of their infection. CIED infection therefore represents a substantial health and economic burden, and management of infections is critical. Numerous risk factors have been identified including host, procedure and device-related factors. Established strategies for preventing CIED infections include intravenous antibiotics and aseptic techniques. The TYRX™ Absorbable Antibacterial Envelope offers potential as an effective method to reduce CIED infections. Several studies have found a statistically significant association between antibacterial envelope use and reduced incidence of CIED infection in high-risk patients. A prospective, randomised trial to further evaluate this potentially important strategy for CIED infection prophylaxis is underway.

Predicting risk of endovascular device infection in patients with Staphylococcus aureus bacteremia (PREDICT-SAB)

BACKGROUND

Prompt recognition of underlying cardiovascular implantable electronic device (CIED) infection in patients presenting with Staphylococcus aureus bacteremia (SAB) is critical for optimal management of these cases. The goal of this study was to identify clinical predictors of CIED infection in patients presenting with SAB and no signs of pocket infection.

METHODS AND RESULTS

All cases of SAB in CIED recipients at Mayo Clinic from 2001 to 2011 were retrospectively reviewed. We identified 131 patients with CIED who presented with SAB and had no clinical signs of device pocket infection. Forty-five (34%) of these patients had underlying CIED infection based on clinical or echocardiographic criteria. The presence of a permanent pacemaker rather than an implantable cardioverter-defibrillator (odds ratio, 3.90; 95% confidence interval, 1.65-9.23; P=0.002), >1 device-related procedure (odds ratio, 3.30; 95% confidence interval, 1.23-8.86; P=0.018), and duration of SAB ≥4 days (odds ratio, 5.54; 95% confidence interval, 3.32-13.23; P<0.001) were independently associated with an increased risk of CIED infection in a multivariable model. The area under the receiver operating characteristics curve for the multivariable model was 0.79, indicating a good discriminatory capacity to distinguish SAB patients with and without CIED infection.

CONCLUSIONS

Among patients presenting with SAB and no signs of pocket infection, the risk of underlying CIED infection can be calculated based on the type of device, number of device-related procedures, and duration of SAB. We propose that patients without any of these high-risk features have a low risk of underlying CIED infection and may be monitored closely without immediate device extraction. Prospective studies are needed to validate this risk prediction model.

Clinical manifestations of lead-dependent infective endocarditis: analysis of 414 cases

It is important to identify clinical manifestations of lead-dependent infective endocarditis (LDIE), as it begins insidiously with the slow development of nonspecific symptoms. Clinical data from 414 patients with the diagnosis of LDIE according to Modified Duke Lead Criteria (MDLC) were analyzed. Patients with LDIE had been identified in a population of 1,426 subjects submitted to transvenous lead extraction (TLE) in the Reference Clinical Cardiology Center in Lublin between 2006 and 2013. The symptoms of LDIE and pocket infection were detected in 62.1 % of patients. The mean duration of LDIE symptoms prior to referral for TLE was 6.7 months. Fever and shivers were found in 55.3 % of patients, and pulmonary infections in 24.9 %. Vegetations were detected in 67.6 % of patients, and positive cultures of blood, lead, and pocket in 34.5, 46.4, and 30.0 %, respectively. The most common pathogens in all type cultures were coagulase-negative staphylococci (CNS), with Staphylococcus epidermidis domination; the second most common organism was Staphylococcus aureus. 76.3 % of patients were treated with empirical antibiotic therapy before hospitalization due to TLE. In the laboratory tests, the mean white blood cell count was 9,671 ± 5,212/μl, mean erythrocyte sedimentation rate 43 mm, C-reactive protein (CRP) 46.3 mg/dl ± 61, and procalcitonin 1.57 ± 4.4 ng/ml. The multivariate analysis showed that the probability of LDIE increased with increasing CRP. The diagnosis of LDIE based on MDLC may be challenging because of a relatively low sensitivity of major criteria, which is associated with early antibiotic therapy and low usefulness of minor criteria. The important clinical symptoms of LDIE include fever with shivering and recurrent pulmonary infections. The most specific pathogens were Staphylococcus epidermidis and Staphylococcus aureus. Laboratory tests most frequently revealed normal white blood cell count, relatively rarely elevated procalcitonin level, and significantly increased erythrocyte sedimentation rate (ESR) and CRP. This constellation of signs should prompt a more thorough search for LDIE.

Canadian Cardiovascular Society guidelines on the use of cardiac resynchronization therapy: implementation

Recent studies have provided the impetus to update the recommendations for cardiac resynchronization therapy (CRT). This article provides guidance on the implementation of CRT and is intended to serve as a framework for the implementation of CRT within the Canadian health care system and beyond. These guidelines were developed through a critical evaluation of the existing literature, and expert consensus. The panel unanimously adopted each recommendation. The 9 recommendations relate to patient selection in the presence of comorbidities, delivery and optimization of CRT, and resources required to deliver this therapy. The strength of evidence was weighed, taking full consideration of any risk of bias, and any imprecision, inconsistency, and indirectness of the available data. The strength of each recommendation and the quality of evidence were adjudicated. Trade-offs between desirable and undesirable consequences of alternative management strategies were considered, as were values, preferences, and resource availability. These guidelines were externally reviewed by experts, modified based on those reviews, and will be updated as new knowledge is acquired.

[What must intensive care physicians know about implantable cardioverter defibrillator?]

The first implantable cardioverter defibrillator (ICD) was implanted in the USA in 1980. After the publication of the landmark studies MADIT I and AVID (primary prevention in high risk patients and secondary prevention after sudden cardiac death) implantation rates dramatically increased worldwide. Due to the increasing number of implantations in elderly patients, intensive care units and emergency departments are confronted more often with patients with ICDs. Therefore, intensive care practitioners have to be familiar with these devices. This article summarizes the current literature and focuses on the management of emergencies and malfunction of ICDs.

Analysis of extracted cardiac device leads for bacteria type: clinical impact

The use of cardiac implantable electronic devices (CIED) increased over time, followed by rise of CIED-related complications, mainly infections and malfunctions. A clear diagnosis of CIED infection is of pivotal importance. When infection is confirmed, transvenous lead extraction (TLE) becomes mandatory, with associated risks and mortality. Local lesions at the device pocket often return negative swabs and tissue specimens, but conservative interventions are inconclusive, raising risks of systemic dissemination of infection and difficulties of subsequent TLE any more. When local bacteriological analyses are positive, once again, a contamination effect cannot be excluded. So traditional local swabs and tissue specimens exhibit low sensitivity and specificity for diagnosis of CIED infection. On the contrary, in cases sepsis, blood samples show high specificity, while the sensibility remains low, due to possible negative results in patients on antibiotics. In this scenario, the analysis of extracted device leads seems more appropriate for diagnostic purposes.

Clinical features and outcomes of cardiovascular implantable electronic device infections due to staphylococcal species

Staphylococci account for the bulk of cardiovascular implantable electronic device (CIED) infections. However, a detailed analysis of clinical features and outcomes of CIED infections due to staphylococcal species has not been published. We retrospectively reviewed all cases of CIED infection seen at the Mayo Clinic from 1991 through 2008. Differences in device and host factors, clinical features, and patient outcomes were compared between cases of early and late Staphylococcus aureus and coagulase-negative staphylococci (CoNS) CIED infections. Of 280 cases of staphylococcal CIED infections, 43.9% were due to S. aureus and 56.0% were due to CoNS. Staphylococcus aureus CIED infection cases more frequently involved initially implanted devices. Late S. aureus CIED infection cases compared to late CoNS cases were associated with corticosteroid therapy, hemodialysis, implanted catheters, prosthetic valves, and remote sources of bacteremia. Cases of S. aureus endovascular infections had longer duration of bacteremia (56.0% vs 20.3% ≥3 days), longer hospitalization (37.4% vs 15.2% >20 days), and increased mortality (25.2% vs 9.5%) compared to cases of CoNS endovascular infections (p <0.001 for all comparisons). Overall, CoNS CIED infections compared to S. aureus were associated with a history of multiple device revisions and a higher number of total and abandoned leads at presentation (p <0.001 for all comparisons). In conclusion, CIED infections due to S. aureus and CoNS have distinct clinical features and outcomes.

Device-related infective endocarditis, with special consideration of implanted intravascular and cardiac devices in a predominantly male population

BACKGROUND

The relationship between invasive medical devices and infective endocarditis (IE) has not been comprehensively assessed. We describe our experience of patients with IE, with particular attention to the role of pre-existing intravascular catheters and implanted cardiac devices in the pathogenesis.

METHODS

We performed a retrospective review of hospital records over a 10-y period (1997-2007), and included patients with 'definite' or 'possible' IE as per the modified Duke criteria. The complete electronic medical record was reviewed for the presence of intravascular devices prior to the onset of IE, including intravascular catheters and implanted cardiac devices (defibrillators and pacemakers).

RESULTS

We identified 155 patients with IE. Infection involved a native valve in 124 (80%) patients and a prosthetic valve in 15 (9.7%). In the remaining 16 (10.3%) patients, infection was attributed to an implanted cardiac device. The most commonly identified source of infection was a central venous catheter, accounting for 17.4% of patients, followed by an implanted cardiac device in 10.3% of patients. Staphylococcus aureus was the most commonly isolated organism in catheter-associated IE and cardiac device-associated IE (31.9% and 62.5%, respectively). Thirty-five (22.5%) patients died within 90 days. Mortality was 31.9% in patients with IE caused by methicillin-resistant S. aureus (MRSA).

CONCLUSIONS

Intravascular catheters and cardiac implantable devices are common sources of infection leading to IE, and the intracardiac devices themselves often become infected, with MRSA as the predominant pathogen.

Timing of the most recent device procedure influences the clinical outcome of lead-associated endocarditis results of the MEDIC (Multicenter Electrophysiologic Device Infection Cohort)

OBJECTIVES

The purpose of this study was to determine whether the timing of the most recent cardiac implantable electronic device (CIED) procedure, either a permanent pacemaker or implantable cardioverter-defibrillator, influences the clinical presentation and outcome of lead-associated endocarditis (LAE).

BACKGROUND

The CIED infection rate has increased at a time of increased device use. LAE is associated with significant morbidity and mortality.

METHODS

The clinical presentation and course of LAE were evaluated by the MEDIC (Multicenter Electrophysiologic Device Cohort) registry, an international registry enrolling patients with CIED infection. Consecutive LAE patients enrolled in the Multicenter Electrophysiologic Device Cohort registry between January 2009 and May 2011 were analyzed. The clinical features and outcomes of 2 groups were compared based on the time from the most recent CIED procedure (early, <6 months; late, >6 months).

RESULTS

The Multicenter Electrophysiologic Device Cohort registry entered 145 patients with LAE (early = 43, late = 102). Early LAE patients presented with signs and symptoms of local pocket infection, whereas a remote source of bacteremia was present in 38% of patients with late LAE but only 8% of early LAE (p < 0.01). Staphylococcal species were the most frequent pathogens in both early and late LAE. Treatment consisted of removal of all hardware and intravenous administration of antibiotics. In-hospital mortality was low (early = 7%, late = 6%).

CONCLUSIONS

The clinical presentation of LAE is influenced by the time from the most recent CIED procedure. Although clinical manifestations of pocket infection are present in the majority of patients with early LAE, late LAE should be considered in any CIED patient who presents with fever, bloodstream infection, or signs of sepsis, even if the device pocket appears uninfected. Prompt recognition and management may improve outcomes.

Lead extraction in the contemporary setting: the LExICon study: an observational retrospective study of consecutive laser lead extractions

OBJECTIVES

This study sought to examine the safety and efficacy of laser-assisted lead extraction and the indications, outcomes, and risk factors in a large series of consecutive patients.

BACKGROUND

The need for lead extraction has been increasing in direct relationship to the increased numbers of cardiovascular implantable electronic devices.

METHODS

Consecutive patients undergoing transvenous laser-assisted lead extraction at 13 centers were included.

RESULTS

Between January 2004 and December 2007, 1,449 consecutive patients underwent laser-assisted lead extraction of 2,405 leads (20 to 270 procedures/site). Median implantation duration was 82.1 months (0.4 to 356.8 months). Leads were completely removed 96.5% of the time, with a 97.7% clinical success rate whereby clinical goals associated with the indication for lead removal were achieved. Failure to achieve clinical success was associated with body mass index <25 kg/m(2) and low extraction volume centers. Procedural failure was higher in leads implanted for >10 years and when performed in low volume centers. Major adverse events in 20 patients were directly related to the procedure (1.4%) including 4 deaths (0.28%). Major adverse effects were associated with patients with a body mass index <25 kg/m(2). Overall all-cause in-hospital mortality was 1.86%; 4.3% when associated with endocarditis, 7.9% when associated with endocarditis and diabetes, and 12.4% when associated with endocarditis and creatinine > or =2.0. Indicators of all-cause in-hospital mortality were pocket infections, device-related endocarditis, diabetes, and creatinine > or =2.0.

CONCLUSIONS

Lead extraction employing laser sheaths is highly successful with a low procedural complication rate. Total mortality is substantially increased with pocket infections or device-related endocarditis, particularly in the setting of diabetes, renal insufficiency, or body mass index <25 kg/m(2). Centers with smaller case volumes tended to have a lower rate of successful extraction.