Update on cardiovascular implantable electronic device infections and their management: a scientific statement from the American Heart Association

Cardiovascular implantable device infections

As life expectancy continues to increase and biotechnology advances, the use of cardiovascular implantable devices will continue to rise. Unfortunately, despite modern medical advances, the infection and mortality rates remain excessively elevated. This article reviews the pathophysiology and general concepts of cardiac device-related infections, including the physical and chemical characteristics of the medical device, host response to the medical device, and the microbiologic virulence factors. Infections of the most commonly utilized cardiovascular implantable devices, including cardiovascular implantable electronic devices, bioprosthetic and mechanical valves, ventricular assist devices, total artificial hearts, and coronary artery stents, are reviewed in detail.

16-year trends in the infection burden for pacemakers and implantable cardioverter-defibrillators in the United States 1993 to 2008

OBJECTIVES

We analyzed the infection burden associated with the implantation of cardiac implantable electrophysiological devices (CIEDs) in the United States for the years 1993 to 2008.

BACKGROUND

Recent data suggest that the rate of infection following CIED implantation may be increasing.

METHODS

The Nationwide Inpatient Sample (NIS) discharge records were queried between 1993 and 2008 using the 9th Revision of the International Classification of Diseases (ICD-9-CM). CIED infection was defined as either: 1) ICD-9 code for device-related infection (996.61) and any CIED procedure or removal code; or 2) CIED procedure code along with systemic infection. Patient health profile was evaluated by coding for renal failure, heart failure, respiratory failure, and diabetes mellitus. The infection burden and patient health profile were calculated for each year, and linear regression was used to test for changes over time.

RESULTS

During the study period (1993 to 2008), the incidence of CIED infection was 1.61%. The annual rate of infections remained constant until 2004, when a marked increase was observed, which coincided with an increase in the incidence of major comorbidities. This was associated with a marked increase in mortality and in-hospital financial charges.

CONCLUSIONS

The infection burden associated with CIED implantation is increasing over time and is associated with prolonged hospital stays and high financial costs.

Toward total implantability using free-range resonant electrical energy delivery system: achieving untethered ventricular assist device operation over large distances

Heart failure is a terminal disease with a very poor prognosis. Although the gold standard of treatment remains heart transplant, only a minority of patients can benefit from transplants. Another promising alternative is mechanical circulatory assistance using ventricular assist devices. The authors envision a completely implantable cardiac assist system affording tether-free mobility in an unrestricted space powered wirelessly by the innovative Free-Range Resonant Electrical Energy Device (FREE-D) system. Patients will have no power drivelines traversing the skin, and this system will allow power to be delivered over room distances and will eliminate trouble-prone wirings, bulky consoles, and replaceable batteries.

Critical appraisal of cardiac implantable electronic devices: complications and management

Population aging and broader indications for the implant of cardiac implantable electronic devices (CIEDs) are the main reasons for the continuous increase in the use of pacemakers (PMs), implantable cardioverter-defibrillators (ICDs) and devices for cardiac resynchronization therapy (CRT-P, CRT-D). The growing burden of comorbidities in CIED patients, the greater complexity of the devices, and the increased duration of procedures have led to an augmented risk of infections, which is out of proportion to the increase in implantation rate. CIED infections are an ominous condition, which often implies the necessity of hospitalization and carries an augmented risk of in-hospital death. Their clinical presentation may be either at pocket or at endocardial level, but they can also manifest themselves with lone bacteremia. The management of these infections requires the complete removal of the device and subsequent, specific, antibiotic therapy. CIED failures are monitored by competent public authorities, that require physicians to alert them to any failures, and that suggest the opportune strategies for their management. Although the replacement of all potentially affected devices is often suggested, common practice indicates the replacement of only a minority of devices, as close follow-up of the patients involved may be a safer strategy. Implantation of a PM or an ICD may cause problems in the patients’ psychosocial adaptation and quality of life, and may contribute to the development of affective disorders. Clinicians are usually unaware of the psychosocial impact of implanted PMs and ICDs. The main difference between PM and ICD patients is the latter’s dramatic experience of receiving a shock. Technological improvements and new clinical evidences may help reduce the total burden of shocks. A specific supporting team, providing psychosocial help, may contribute to improving patient quality of life.

Infective endocarditis in congenital heart disease

Congenital heart disease (CHD) has become the leading risk factor for pediatric infective endocarditis (IE) in developed countries after the decline of rheumatic heart disease. Advances in catheter- and surgery-based cardiac interventions have rendered almost all types of CHD amenable to complete correction or at least palliation. Patient survival has increased, and a new patient population, referred to as adult CHD (ACHD) patients, has emerged. Implanted prosthetic material paves the way for cardiovascular device-related infections, but studies on the management of CHD-associated IE in the era of cardiovascular devices are scarce. The types of heart malformation (unrepaired, repaired, palliated) substantially differ in their lifetime risks for IE. Streptococci and staphylococci are the predominant pathogens. Right-sided IE is more frequently seen in patients with CHD. Relevant comorbidity caused by cardiac and extracardiac episode-related complications is high. Transesophageal echocardiography is recommended for more precise visualization of vegetations, especially in complex type of CHD in ACHD patients. Antimicrobial therapy and surgical management of IE remain challenging, but outcome of CHD-associated IE from the neonate to the adult is better than in other forms of IE.

CONCLUSION

Primary prevention of IE is vital and includes good dental health and skin hygiene; antibiotic prophylaxis is indicated only in high-risk patients undergoing oral mucosal procedures.

Antimicrobial prophylaxis in adults

Antimicrobial prophylaxis is commonly used by clinicians for the prevention of numerous infectious diseases, including herpes simplex infection, rheumatic fever, recurrent cellulitis, meningococcal disease, recurrent uncomplicated urinary tract infections in women, spontaneous bacterial peritonitis in patients with cirrhosis, influenza, infective endocarditis, pertussis, and acute necrotizing pancreatitis, as well as infections associated with open fractures, recent prosthetic joint placement, and bite wounds. Perioperative antimicrobial prophylaxis is recommended for various surgical procedures to prevent surgical site infections. Optimal antimicrobial agents for prophylaxis should be bactericidal, nontoxic, inexpensive, and active against the typical pathogens that can cause surgical site infection postoperatively. To maximize its effectiveness, intravenous perioperative prophylaxis should be administered within 30 to 60 minutes before the surgical incision. Antimicrobial prophylaxis should be of short duration to decrease toxicity and antimicrobial resistance and to reduce cost.

Future challenges and treatment of Staphylococcus aureus bacteremia with emphasis on MRSA

Staphylococcus aureus bacteremia (SAB) is an urgent medical problem due to its growing frequency and its poor associated outcome. As healthcare delivery increasingly involves invasive procedures and implantable devices, the number of patients at risk for SAB and its complications is likely to grow. Compounding this problem is the growing prevalence of methicillin-resistant S. aureus (MRSA) and the dwindling efficacy of vancomycin, long the treatment of choice for this pathogen. Despite the recent availability of several new antibiotics for S. aureus, new strategies for treatment and prevention are required for this serious, common cause of human infection.

High-dose daptomycin and fosfomycin treatment of a patient with endocarditis caused by daptomycin-nonsusceptible Staphylococcus aureus: case report

Background

Emergence of daptomycin-nonsusceptible (DNS) Staphylococcus aureus is a dreadful problem in the treatment of endocarditis. Few current therapeutic agents are effective for treating infections caused by DNS S. aureus.

Case presentation

We describe the emergence of DNS S. aureus. in a patient with implantable cardioverter-defibrillator (ICD) device -related endocarditis who was priorily treated with daptomycin. Metastatic dissemination as osteomyelitis further complicated the management of endocarditis. The dilemma was successfully managed by surgical removal of the ICD device and combination antimicrobial therapy with high-dose daptomycin and fosfomycin.

Conclusions

Surgical removal of intracardiac devices remains an important adjunctive measure in the treatment of endocarditis. Our case suggests that combination therapy is more favorable than single-agent therapy for infections caused by DNS S. aureus.

Impact of relaxation training on patient-perceived measures of anxiety, pain, and outcomes after interventional electrophysiology procedures

BACKGROUND

Electrophysiology procedures vary in invasiveness, duration, and anesthesia utilized. While complications are low and efficacy high, cases are elective and patient experiences related to anxiety, pain, and perceived outcomes are not well studied. We sought to determine if a 30-minute audio compact disc (CD) that teaches relaxation techniques and wellness perception prior to an elective procedure impacts validated measures of anxiety, pain, and procedural outcomes.

METHODS

Sixty-one patients were randomly assigned to a control group (CG) (N(CG) = 31) or interventional group (IG) (N(IG) = 30). Both groups answered a baseline Hospital Anxiety and Depression Scale (HADS-A) survey consisting only of anxiety assessment questions. The IG listened to the CD the night prior to their procedure. Heart rate and blood pressure were monitored on admission and prior to the procedure. Postprocedure, both groups completed two HADS-A surveys as well as two Patient Experience Surveys (PES). There was no statistical difference in the demographics and the rate of procedural complications between the groups. The statistical significance of our data was determined using a Student's t-test and χ(2) test.

RESULTS

At baseline, both groups had equal amounts of anxiety prior to their procedures (P = 0.2). The patients in the IG had lower systolic blood pressures during admission and prior the administration of analgesics in comparison to the CG. Postprocedure, results from administering the HADS-A demonstrated that the IG had 33% lower anxiety (P = 0.02) than CG patients.

CONCLUSION

The implementation of basic relaxation teaching techniques prior to planned electrophysiology procedures lowers systolic blood pressure and postprocedural anxiety.

Infective endocarditis

Infective endocarditis (IE) is lethal if not aggressively treated with antibiotics alone or in combination with surgery. The epidemiology of this condition has substantially changed over the past four decades, especially in industrialized countries. Once a disease that predominantly affected young adults with previously well-identified valve disease--mostly chronic rheumatic heart disease--IE now tends to affect older patients and new at-risk groups, including intravenous-drug users, patients with intracardiac devices, and patients exposed to healthcare-associated bacteremia. As a result, skin organisms (for example, Staphylococcus spp.) are now reported as the pathogen in these populations more often than oral streptococci, which still prevail in the community and in native-valve IE. Moreover, progress in molecular diagnostics has helped to improve the diagnosis of poorly cultivable pathogens, such as Bartonella spp. and Tropheryma whipplei, which are responsible for blood-culture-negative IE more often than expected. Epidemiological data indicate that IE mostly occurs independently of medico-surgical procedures, and that circumstantial antibiotic prophylaxis is likely to protect only a minute proportion of individuals at risk. Therefore, new strategies to prevent IE--including improvement of dental hygiene, decontamination of carriers of Staphylococcus aureus, vaccination, and, possibly, antiplatelet therapy--must be explored.

Dental treatment of a patient with an implanted left ventricular assist device: expanding the frontiers

BACKGROUND

The left ventricular assist device (LVAD) is used as a bridge to heart transplantation. Currently, these devices are being used for longer periods of time than in previous years for the purpose of bridge to life, thus the need for dental assistance will emerge.

CASE DESCRIPTION

A female with severe acute congestive heart failure, owing to dilated cardiomyopathy, needed implantation of an LVAD as a bridge to heart transplantation. Six months after insertion of the device she suffered from spontaneous gingival bleeding and sought dental treatment. She presented with several dento-medical problems that required resolution before commencement of dental treatment.

CONCLUSIONS

Management of a patient with LVAD opens new frontiers for the dental team regarding treatment of the medically severely compromised patient who may present with multiple intervening medical aspects: profound antithrombotic therapy, high risk of device infection, possible magnetic interference with dental instruments, and even assessment of vital signs.

Pacemaker lead thrombo-endocarditis in an intravenous drug abuser

We report a 30-year-old male intravenous drug abuser presenting with persistent pacemaker lead thrombosis with superimposed pacemaker lead endocarditis. He underwent urgent surgery, but expired due to refractory sepsis. This case confirms that patients with pacemakers are at risk of developing pacemaker lead thrombosis. In addition, they are at high risk of developing pacemaker lead endocarditis if additional risk factors for endocarditis are present. We believe this case report is unusual on account of pacemaker lead thrombosis as well as endocarditis occurring in a patient with history of intravenous drug abuse. Whether pacemaker patients with multiple leads need to be on long-term antiplatelet or anticoagulation therapy necessitates further studies.

Management of a remnant electrode in a patient with cardioverter-defibrillator infection after refusal of intravascular electrode removal

Treatments of choice for cardiac implantable electronic device (CIED) infections are the removal of the entire CIED system, control of infection, and new device implantation. Occasionally, a complete CIED removal can not be performed for several reasons, such as very old age, severe comobidity, limited life expectancy, or refusal by a patient. We encountered a male patient who developed traumatic CIED infection five years after cardioverter-defibrillator implantation. An intravenous electrode could not be removed by a simple transvenous extraction procedure, and he refused surgical removal of the remnant electrode. After control of local infection, the tips of the electrode were separated and buried between muscles, and the wound was closed with a local flap. CIED infection did not recur for 12 months even without relying on long-term antimicrobial treatment.

A comparison of single-lead atrial pacing with dual-chamber pacing in sick sinus syndrome

AIMS

In patients with sick sinus syndrome, bradycardia can be treated with a single-lead pacemaker or a dual-chamber pacemaker. Previous trials have revealed that pacing modes preserving atrio-ventricular synchrony are superior to single-lead ventricular pacing, but it remains unclear if there is any difference between single-lead atrial pacing (AAIR) and dual-chamber pacing (DDDR).

METHODS AND RESULTS

We randomly assigned 1415 patients referred for first pacemaker implantation to AAIR (n = 707) or DDDR (n = 708) pacing and followed them for a mean of 5.4 ± 2.6 years. The primary outcome was death from any cause. Secondary outcomes included paroxysmal and chronic atrial fibrillation, stroke, heart failure, and need for pacemaker reoperation. In the AAIR group, 209 patients (29.6%) died during follow-up vs. 193 patients (27.3%) in the DDDR group, hazard ratio (HR) 1.06, 95% confidence interval (CI) 0.88-1.29, P = 0.53. Paroxysmal atrial fibrillation was observed in 201 patients (28.4%) in the AAIR group vs. 163 patients (23.0%) in the DDDR group, HR 1.27, 95% CI 1.03-1.56, P = 0.024. A total of 240 patients underwent one or more pacemaker reoperations during follow-up, 156 (22.1%) in the AAIR group vs. 84 (11.9%) in the DDDR group (HR 1.99, 95% CI 1.53-2.59, P < 0.001). The incidence of chronic atrial fibrillation, stroke, and heart failure did not differ between treatment groups.

CONCLUSION

In patients with sick sinus syndrome, there is no statistically significant difference in death from any cause between AAIR pacing and DDDR pacing. AAIR pacing is associated with a higher incidence of paroxysmal atrial fibrillation and a two-fold increased risk of pacemaker reoperation. These findings support the routine use of DDDR pacing in these patients.

CLINICAL TRIAL REGISTRATION

URL http://www.clinicaltrials.gov. Unique identifier: NCT00236158.

Clinical practice guidelines by the infectious diseases society of america for the treatment of methicillin-resistant Staphylococcus aureus infections in adults and children

Evidence-based guidelines for the management of patients with methicillin-resistant Staphylococcus aureus (MRSA) infections were prepared by an Expert Panel of the Infectious Diseases Society of America (IDSA). The guidelines are intended for use by health care providers who care for adult and pediatric patients with MRSA infections. The guidelines discuss the management of a variety of clinical syndromes associated with MRSA disease, including skin and soft tissue infections (SSTI), bacteremia and endocarditis, pneumonia, bone and joint infections, and central nervous system (CNS) infections. Recommendations are provided regarding vancomycin dosing and monitoring, management of infections due to MRSA strains with reduced susceptibility to vancomycin, and vancomycin treatment failures.

Outcomes in Patients With Cardiovascular Implantable Electronic Devices and Bacteremia Caused by Gram-Positive Cocci Other Than Staphylococcus Aureus

Background—

Infection is a serious complication of cardiovascular implantable electronic device (CIED) placement and requires device removal for attempted cure.

Methods and Results—

We studied the rate, risk factors, and outcomes of CIED infection in 74 consecutive patients with bacteremia caused by Gram-positive cocci (GPC) other than Staphylococcus aureus between 2001 and 2007. CIED infection was defined as the presence of signs of infection at the generator site, lead vegetations seen on echocardiography, or microbiological growth from device cultures. Twenty-two (30%) of 74 patients with non– S aureus GPC bacteremia had CIED infections. Coagulase-negative staphylococci (CoNS) accounted for 73% of CIED infections. The rate of CIED infection in patients with CoNS bacteremia was almost 2-fold that of non-CoNS GPC bacteremia (36% versus 20%, P =0.13). The number of leads, the presence of abandoned leads, and prior generator replacement were associated with CIED infection. Among 33 patients without identifiable CIED infection at initial evaluation who did not undergo device removal, 5 (15%) had relapsing bacteremia within 12 weeks of completing antibiotic therapy. CoNS accounted for all relapses, and none had evidence of CIED infection at relapse.

Conclusions—

Patients with a CIED and bacteremia caused by GPC other than S aureus frequently had evidence of underlying CIED infection on clinical evaluation that included transesophageal echocardiography. This was particularly true among those with CoNS bacteremia. No evidence of underlying CIED infections was identified in the subgroup of patients who did not have manifestations of CIED infection on initial evaluation but subsequently had relapsing bacteremia caused by CoNS.

Contemporary management of cardiovascular implantable electronic device infections

Cardiovascular implantable electronic device (CIED) implantation rate has substantially risen in the foregoing decades. Unfortunately, this upsurge in CIED implantation rate has been accompanied by a disproportionate rise in the rate of CIED infections. Device infection is a major complication of CIED implantation, necessitating removal of an infected device followed by systemic antimicrobial therapy and reimplantation of a new system. In this article, we review the current epidemiology, risk factors, diagnostic strategy and contemporary management of CIED infection. In addition, we address the vexing question of how to best manage patients with Staphylococcus aureus bacteremia, in the setting of an implanted device, but no overt clinical signs of CIED infection. Lastly, we discuss the preventive strategies to minimize risk of CIED infection.

Pacemaker lead endocarditis due to multidrug-resistant Corynebacterium striatum detected with sonication of the device

Corynebacterium striatum is a commensal of human skin and has been recently recognized as an emerging pathogen. A case of nosocomial pacemaker lead endocarditis due to a multidrug-resistant C. striatum strain is described, highlighting the role of sonication as a diagnostic tool in cardiac device infections.

The dental treatment of patients with joint replacements: a position paper from the American Academy of Oral Medicine

BACKGROUND

In February 2009, the American Academy of Orthopaedic Surgeons (AAOS) published an information statement in which the organization "recommends that clinicians consider antibiotic prophylaxis [AP] for all total joint replacement patients prior to any invasive procedure that may cause bacteremia." The leadership of the American Academy of Oral Medicine (AAOM) thought that there was a need to respond to this new statement.

METHODS

The authors reviewed the literature on this subject as it relates to the AAOS's February 2009 information statement. The draft of the resulting report was reviewed and approved by the leadership of the AAOM and several dentists in North America who have expertise on this subject.

RESULTS

The risk of patients' experiencing drug reactions or drug-resistant bacterial infections and the cost of antibiotic medications alone do not justify the practice of using AP in patients with prosthetic joints.

CONCLUSIONS

The authors identified the major points of concern for a future multidisciplinary, systematic review of AP use in patients with prosthetic joints. In the meantime, they conclude that the new AAOS statement should not replace the 2003 joint consensus statement.

CLINICAL IMPLICATIONS

Until this issue is resolved, dentists have three options: inform their patients with prosthetic joints about the risks associated with AP use and let them decide; continue to follow the 2003 guidelines; or suggest to the orthopedic surgeon that they both follow the 2003 guidelines.

[Implantation of cardioverter-defibrillators. How much anesthesia is necessary?]

Updated cardiologic guidelines constitute the background for an extended spectrum of indications for the implantation of automatic implantable cardioverter defibrillators (AICDs) and lead to an increasing number of operative implantations of AICDs. Moreover, during implantation of devices for cardiac resynchronization therapy the anesthesiologist is responsible for the most critically ill patients with the longest duration of surgery. As a result anesthesiologists face an increasing number of critically ill patients, whose management contributes to perioperative outcome. Automatic implantable cardioverter defibrillators can be implanted either during general anesthesia, local anesthesia or during a combination of local anesthesia combined with deep conscious sedation accomplished by an anesthesiologist. Besides economic aspects there is an increasing demand for anesthesia with the least cardiovascular side effects and rapid recovery in the often seriously ill patient with preexisting limitations of cardiac and pulmonary functions. Accordingly procedure and anesthesia-associated risks are reviewed and an algorithm for anesthesia management is suggested.

Effect of electrical stimulus parameters on the development and propagation of action potentials in short excitable fibres

Intracellular action potentials (IAPs) produced by short fibres in response to their electrical stimulation were analysed. IAPs were calculated on the basis of the Hodgkin-Huxley (1952) model by the method described by Joyner et al. (1978). Principal differences were found in processes of activation of short (semilength L less than 5 lambda) and long fibres under near-threshold stimulation. The shorter the fibre, the lower was the threshold value (Ithr). Dependence of the latency on the stimulus strength (Ist) was substantially non-linear and was affected by the fibre length. Both fibre length and stimulus strength influenced the IAP amplitude, the instantaneous propagation velocity (IPV) and the site of the first origin of the IAP (and, consequently, excitability of the short fibre membrane). With L less than or equal to 2 lambda and Ithr less than or equal to Ist less than or equal to 1.1Ithr, IPV could reach either very high values (so that all the fibre membrane fired practically simultaneously) or even negative values. The latter corresponded to the first origin of the propagated IAP, not at the site of stimulation but at the fibre termination or at a midpoint. The characters of all the above dependencies were unchanged irrespective of the manner of approaching threshold (variation of stimulus duration or its strength). Reasons for differences in processes of activation of short and long fibres are discussed in terms of electrical load and latency. Applications of the results to explain an increased jitter, velocity recovery function and velocity-diameter relationship are also discussed.