Cardiovascular implantable electrophysiological device-related infections: a review

Cardiac Implantable Electronic Devices Infection Assessment, Diagnosis and Management: A Review of the Literature

The use of increasingly complex cardiac implantable electronic devices (CIEDs) has increased exponentially in recent years. One of the most serious complications in terms of mortality, morbidity and financial burden is represented by infections involving these devices. They may affect only the generator pocket or be generalised with lead-related endocarditis. Modifiable and non-modifiable risk factors have been identified and they can be associated with patient or procedure characteristics or with the type of CIED. Pocket and systemic infections require a precise evaluation and a specialised treatment which in most cases involves the removal of all the components of the device and a personalised antimicrobial therapy. CIED retention is usually limited to cases where infection is unlikely or is limited to the skin incision site. Optimal re-implantation timing depends on the type of infection and on the results of microbiological tests. Preventive strategies, in the end, include antibiotic prophylaxis before CIED implantation, the possibility to use antibacterial envelopes and the prevention of hematomas. The aim of this review is to investigate the pathogenesis, stratification, diagnostic tools and management of CIED infections.

Therapy and outcomes of cardiac implantable electronic devices infections

Cardiac implantable electronic device (CIED) infection causes significant morbidity and mortality without appropriate treatment. It can present as incisional infection, pocket infection, systemic CIED infection, or occult bacteraemia. Complete percutaneous CIED extraction (excepted in case of incisional infection) and appropriate antibiotic therapy are the two main pillars of therapy. Device reimplantation, if needed, should be delayed sufficiently to allow control of the infection. Here, we address the differences in prognosis according to the clinical scenario and the different treatment options.

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.

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).

Cardiac implantable electronic device infections: Observational data from a tertiary care center in Lebanon

With increasing rates of device implantation, there is an increased recognition of device infection. We conducted a retrospective observational study in a tertiary care center in Lebanon, with data collected from medical records of patients presenting with cardiac implantable electronic device (CIED) infection from 2000 to 2017 with the purpose of identifying etiologies, risk factors and other parameters, and comparing them to available data from the rest of the world. We identified a total of 22 CIED infections. The most common microbial etiologies, including involvement in polymicrobial infection, were coagulase-negative staphylococci (45.5%) and Staphylococcus aureus (22.7%). Rare cases of Brucella melitensis, Sphingomonas paucimobilis, and Kytococcus schroeteri device infection were seen. Heart failure was seen in 77.3% of patients, hypertension in 68.2%, and chronic kidney disease in 50%. Skin changes were the most common presenting symptoms (86.4%). Antibiotics were given to all patients and all had their devices removed, with 36.4% undergoing new device implantation. This is the first study of CIED infections in Lebanon and the Middle East. Local epidemiology and occupational exposure must be considered while contemplating the microbial etiology of infection. Close monitoring after device implantation is important in preventing device infection that carries high risk of morbidity and mortality.

Outcomes After the Implementation of Practice Management Guidelines for the Treatment of Cardiovascular Implantable Device Pocket Infections

BACKGROUND

Treatment of cardiovascular implantable device pocket infections (CIDPIs) requires a multimodal approach that includes antimicrobials, device explantation, and local wound care. Our institution implemented a practice management guideline (PMG) to standardize the care of CIDPIs and engage our acute care surgeons in 2013. Our PMG includes wound culture, complete capsulectomy, pulse lavage, and the placement of a negative pressure wound therapy appliance at the time of device extraction. Forty-eight hours later, wounds are irrigated and closed in a delayed primary fashion over drains. Our objective was to compare the outcomes of patients who underwent device extraction before and after the implementation of the PMG for the treatment of CIDPIs.

METHODS

An IRB-approved retrospective review of 155 patients at our institution from 2012 to 2015 who underwent device explantation. Evaluated outcomes measured included days from device explant to wound closure, and postoperative complications. Outcomes data were analyzed before (pre-PMG) and after (post-PMG) enactment of the PMG.

RESULTS

Fifty-eight patients (42 males; mean age 68 years) were managed prior to PMG implementation; 97 (72 males; mean age 67) were managed after. Mean days from device explantation to wound closure were compared (pre-PMG 6 ± 3.5 and post-PMG 2.8 ± 1.8), and time to closure was reduced by 3-d post-PMG implementation (P < 0.05). No increase in surgical site infection, hematoma, or unplanned return to operating room was demonstrated between groups (P < 0.05).

CONCLUSIONS

The implementation of a PMG for the management of CIDPIs is effective in reducing the number of days to pocket wound closure; acute care surgeons are well equipped to participate in this practice and improve patient outcomes.

Changing of the guard: reducing infection when replacing neural pacemakers

OBJECTIVE

Infection of deep brain stimulation (DBS) hardware has a significant impact on patient morbidity. Previous experience suggests that infection rates appear to be higher after implantable pulse generator (IPG) replacement surgery than after the de novo DBS procedure. In this study the authors examine the effect of a change in practice during DBS IPG replacements at their institution.

METHODS

Starting in January 2012, patient screening for methicillin-resistant Staphylococcus aureus (MRSA) and, and where necessary, eradication was performed prior to elective DBS IPG change. Moreover, topical vancomycin was placed in the IPG pocket during surgery. The authors then prospectively examined the infection rate in patients undergoing DBS IPG replacement at their center over a 3-year period with at least 9 months of follow-up.

RESULTS

The total incidence of infection in this prospective consecutive series of 101 IPG replacement procedures was 0%, with a mean follow-up duration of 24 ± 11 months. This was significantly lower than the authors' previously published historical control group, prior to implementing the change in practice, where the infection rate for IPG replacement was 8.5% (8/94 procedures; p = 0.003).

CONCLUSIONS

This study suggests that a change in clinical practice can significantly lower infection rates in patients undergoing DBS IPG replacement. These simple measures can minimize unnecessary surgery, loss of benefit from chronic stimulation, and costly hardware replacement, further improving the cost efficacy of DBS therapies.

Risk factors influencing complications of cardiac implantable electronic device implantation: infection, pneumothorax and heart perforation: a nationwide population-based cohort study

As the number of cardiac implantable electronic devices (CIEDs) is increasing annually, CIED-related complications are becoming increasingly important. The aim of the study was to assess the risks associated with CIEDs by a nationwide database. Patients were selected from the Taiwan National Health Insurance Database. Admissions for CIED implantation, replacement, and revision were evaluated and the evaluation period was 14 years. Endpoints included CIED-related infection, pneumothorax, and heart perforation. The study included 40,608 patients with a mean age of 71.8 ± 13.3 years. Regarding infection, the incidence rate was 2.45 per 1000 CIED-years. Male gender, younger age, device replacement, and previous infection were risks for infection while old age and high-volume centers (>200 per year) were protectors. The incidence of pneumothorax was 0.6%, with an increased risk in individuals who had chronic obstructive lung disease (COPD) and cardiac resynchronized therapy (CRT). The incidence of heart perforation was 0.09%, with an increased risk in individuals who had pre-operation temporal pacing and steroid use. High-volume center was found to decrease infection rate while male gender, young people, and individuals who underwent replacements were associated with an increased risk of infection. Additionally, pre-operation temporal pacing and steroid use should be avoided if possible. Furthermore, COPD patients or those who accept CRTs should be monitored closely.

Surgical management of superior vena cava syndrome following pacemaker lead infection: a case report and review of the literature

Superior vena cava (SVC) syndrome is a known but rare complication of pacemaker lead implantation, accounting for approximately less than 0.5% of cases. Its pathophysiology is due to either infection or endothelial mechanical stress, causing inflammation and fibrosis leading to thrombosis, and therefore stenosis of the SVC. Due to the various risks including thrombo-embolic complications and the need to provide symptomatic relief, medical and surgical interventions are sought early. We present the case of a 48-year Caucasian male who presented with localised swelling and pain at the site of pacemaker implantation. Inflammatory markers were normal, but diagnostic imaging revealed three masses along the pacemaker lead passage. A surgical approach using cardiopulmonary bypass and circulatory arrest was used to remove the vegetations. Culture from the vegetations showed Staphylococcus epidermidis. The technique presented here allowed for safe and effective removal of both the thrombus and infected pacing leads, with excellent exposure and minimal post-procedure complications.

Combination prophylactic therapy with rifampin increases efficacy against an experimental Staphylococcus epidermidis subcutaneous implant-related infection

The incidence of infections related to cardiac devices (such as permanent pacemakers) has been increasing out of proportion to implantation rates. As management of device infections typically requires explantation of the device, optimal prophylactic strategies are needed. Cefazolin and vancomycin are widely used as single agents for surgical prophylaxis against cardiac device-related infections. However, combination antibiotic prophylaxis may further reduce infectious complications. To model a localized subcutaneous implant-related infection, a bioluminescent strain of Staphylococcus epidermidis was inoculated onto a medical-procedure-grade titanium disc, which was placed into a subcutaneous pocket in the backs of mice. In vivo bioluminescence imaging, quantification of ex vivo CFU from the capsules and implants, variable-pressure scanning electron microscopy (VP-SEM), and neutrophil enhanced green fluorescent protein (EGFP) fluorescence in LysEGFP mice were employed to monitor the infection. This model was used to evaluate the efficacies of low- and high-dose cefazolin (50 and 200 mg/kg of body weight) and vancomycin (10 and 110 mg/kg) intravenous prophylaxis with or without rifampin (25 mg/kg). High-dose cefazolin and high-dose vancomycin treatment resulted in almost complete bacterial clearance, whereas both low-dose cefazolin and low-dose vancomycin reduced the in vivo and ex vivo bacterial burden only moderately. The addition of rifampin to low-dose cefazolin and vancomycin was highly effective in further reducing the CFU harvested from the implants. However, vancomycin-rifampin was more effective than cefazolin-rifampin in further reducing the CFU harvested from the surrounding tissue capsules. Future studies in humans will be required to determine whether the addition of rifampin has improved efficacy in preventing device-related infections in clinical practice.

Complications of cardiac implants: handling device infections

Managing patients with cardiac implantable electrophysiological devices (CIED) infections can be challenging. The first step should be prevention, which involves patient selection, timing of implantation, and the procedure itself. After implantation, a high degree of suspicion should be applied in order to correctly diagnose patients with infected implanted devices. It is necessary to recognize that patients can present with a wide variety of signs and symptoms. Once diagnosed, the next step is determining if it is a local pocket infection or system infection. In almost every patient, in addition to antibiotics, complete removal of ALL hardware is required. Transvenous lead extraction is now safe and effective, but should only be performed at experienced centres with a practiced extraction team, all possible needed equipment, and cardiothoracic surgical backup. After extraction, the indication for CIED therapy should be re-evaluated to determine re-implantation is warranted. Timing of re-implantation depends on a variety of factors such as type of infection or valvular involvement and should be made in concordance with an infectious disease specialist. This review is aimed at introducing the steps needed to manage patients with infected cardiac devices.