The additional hospital costs generated in the management of complications of pacemaker and defibrillator implantations

Impact of delayed device re-implantation on outcomes of patients with cardiovascular implantable electronic device related infective endocarditis

BACKGROUND

Optimal timing of cardiovascular implantable electronic device (CIED) re-implantation following device removal due to infection is undefined. Multinational guidelines reflect this and include no specific recommendation for this timing, while others have recommended waiting at least 14 days in cases of CIED related infective endocarditis (CIED-IE). The current work seeks to clarify this issue.

METHODS

We retrospectively reviewed institutional data at Mayo Clinic, Minnesota of patients aged ≥ 18 years who developed CIED-IE from January 1, 1991 to February 1, 2016. CIED-IE was defined as echocardiogram reported device lead or valvular vegetation. Regression analyses were used to relate the risk of clinical outcomes to the interval between CIED removal and re-implantation and the location of vegetations.

RESULTS

A total of 109 patients met study inclusion criteria. A majority (68.8%) of patients were men and the median age was 68.0 years. Transoesophageal echocardiogram (TEE) was performed in 95.4% of patients, with valve vegetations detected in 33.9% (n = 37). Survival analysis comparing patients in whom device re-implantation was < 14 days vs. ≥14 days, and further categorized by those with and without valve vegetation, showed a significant difference (P = 0.028); patients with valve vegetation and reimplantation interval < 14 days had the lowest (58.7%) 12-month survival. When adjusted for valve vegetation, longer time interval for reimplantation trended toward increased hospital length of stay (P = 0.079).

CONCLUSION

Our findings suggest that the recommended 14-day delay between CIED extraction and re-implantation in CIED-IE patients is associated with a survival benefit, but longer length of hospital stay following re-implantation.

Racial Disparities in Bariatric Surgery Complications and Mortality Using the MBSAQIP Data Registry

Background

Racial disparities in postoperative complications have been demonstrated in bariatric surgery, yet the relationship of race to complication severity is unknown.

Study Design

Adult laparoscopic primary bariatric procedures were queried from the 2015 and 2016 MBSAQIP registry. Adjusted logistic and multinomial regressions were used to examine the relationships between race and 30-day complications categorized by the Clavien-Dindo grading system.

Results

A total of 212,970 patients were included in the regression analyses. For Black patients, readmissions were higher (OR = 1.39, p < 0.0001) and the odds of a Grade 1, 3, 4, or 5 complication were increased compared with White patients (OR = 1.21, p < 0.0001; OR = 1.21, p < 0.0001; OR = 1.22, p = 0.01; and OR = 1.43, p = 0.04) respectively. The odds of a Grade 3 complication for Hispanic patients were higher compared with White patients (OR = 1.59, p < 0.0001).

Conclusion

Black patients have higher odds of readmission and multiple grades of complications (including death) compared with White patients. Hispanic patients have higher odds of a Grade 3 complication compared with White patients. No significant differences were found with other races. Specific causes of these disparities are beyond the limitations of the dataset and stand as a topic for future inquiry.

Use of Biologic Extracellular Matrix in Two Ways to Reduce Cardiac Electronic Device Infection

Cardiac implantable electronic device (CIED) infections are a serious complication of both initial device implants and generator change procedures, and they are associated with a wide range of presentations. Reported rates of CIED infections vary widely from 0.1% to 19.9%, but it is estimated that they occur in 0.5% of initial device implants and 1-7% of subsequent implants. It is widely accepted that the administration of local antibiotics within the pocket as well as extracellular matrices (ECMs) can be utilized to reduce the incidence of CIED infections. We describe a case where the use of an additional biological ECM scaffold sutured directly into the incision site was utilized in addition to a biological ECM pouch in order to reduce the risk of infection. We propose that biological ECM could be utilized to reinforce the incision site directly as well as ECM within the pocket to reduce the instances of CIED infections. Further investigation of the use of biological ECM to prevent infection is warranted and paramount to further decrease the number of complications associated with device implantation.

Is There Always a Need for Permanent Pacemaker Replacement After Device Infection? A Tale of Two Patients

There has been an increase in number of cardiac implantable electronic devices (CIEDs) implantation and with this we have witnessed increased rates of CIED infection mainly in elderly population. It is important to assess conditions that may not reliably improve with cardiac pacing or those who lack adequate beneficial effect from permanent pacing before contemplating implantation or reimplantation of these devices. Sometimes, the initial cardiac pathology may revert obviating the need for reimplantation as in the two cases that we have discussed below. This reduces the chance of further infection of CIED, and decreases mortality and morbidity due to recurrent CIED infection and decreases cost of care.

Effect of battery longevity on costs and health outcomes associated with cardiac implantable electronic devices: a Markov model-based Monte Carlo simulation

Introduction

The effects of device and patient characteristics on health and economic outcomes in patients with cardiac implantable electronic devices (CIEDs) are unclear. Modeling can estimate costs and outcomes for patients with CIEDs under a variety of scenarios, varying battery longevity, comorbidities, and care settings. The objective of this analysis was to compare changes in patient outcomes and payer costs attributable to increases in battery life of implantable cardiac defibrillators (ICDs) and cardiac resynchronization therapy defibrillators (CRT-D).

Methods and results

We developed a Monte Carlo Markov model simulation to follow patients through primary implant, postoperative maintenance, generator replacement, and revision states. Patients were simulated in 3-month increments for 15 years or until death. Key variables included Charlson Comorbidity Index, CIED type, legacy versus extended battery longevity, mortality rates (procedure and all-cause), infection and non-infectious complication rates, and care settings. Costs included procedure-related (facility and professional), maintenance, and infections and non-infectious complications, all derived from Medicare data (2004–2014, 5% sample). Outcomes included counts of battery replacements, revisions, infections and non-infectious complications, and discounted (3%) costs and life years. An increase in battery longevity in ICDs yielded reductions in numbers of revisions (by 23%), battery changes (by 44%), infections (by 23%), non-infectious complications (by 10%), and total costs per patient (by 9%). Analogous reductions for CRT-Ds were 23% (revisions), 32% (battery changes), 22% (infections), 8% (complications), and 10% (costs).

Conclusion

Based on modeling results, as battery longevity increases, patients experience fewer adverse outcomes and healthcare costs are reduced. Understanding the magnitude of the cost benefit of extended battery life can inform budgeting and planning decisions by healthcare providers and insurers.

Electronic supplementary material

The online version of this article (10.1007/s10840-017-0289-8) contains supplementary material, which is available to authorized users.

Positron Emission Tomography and Single-Photon Emission Computed Tomography Imaging in the Diagnosis of Cardiac Implantable Electronic Device Infection: A Systematic Review and Meta-Analysis

BACKGROUND

The use of cardiac implantable electronic devices (CIED) is increasing, and their associated infections result in significant morbidity and mortality. The introduction of better cardiac imaging techniques could be useful for diagnosing this condition and guiding therapy. Our objective was to systematically assess the diagnostic accuracy of Fluor-18-fluorodeoxyglucose positron emission tomography and computed tomography, labeled leukocyte scintigraphy (LS), and Gallium-67 citrate scintigraphy for the diagnosis of CIED infection.

METHODS AND RESULTS

A systematic review of the literature and meta-analysis on the use of all 3 modalities in CIED infection were conducted. Pooled sensitivity, specificity, and summary receiver operating characteristic curves of each imaging modalities were determined. The literature search identified 2493 articles. A total of 13 articles (11 studies for ¹⁸F-FDG PET-CT and 2 for LS), met the inclusion criteria. No studies for ⁶⁷Ga citrate scintigraphy met the inclusion criteria. The pooled sensitivity of ¹⁸F-FDG PET-CT for the diagnosis of CIED infection was 87% (95% CI, 82%-91%) and pooled specificity was 94% (95% CI, 88%-98%). The summary receiver operating characteristic curve analysis demonstrated good overall accuracy, with an area under the curve of 0.935. There were insufficient data to do a meta-analysis for LS, but both studies reported sensitivity above 90% and specificity of 100%.

CONCLUSIONS

Both ¹⁸F-FDG PET-CT and LS yield high sensitivity, specificity, and accuracy, and thus seem to be useful for the diagnosis of CIED infection, based on robust data for ¹⁸F-FDG PET-CT but limited data for LS. When available,¹⁸F-FDG PET-CT may be preferred.

In vivo biocompatibility and pacing function study of silver ion-based antimicrobial surface technology applied to cardiac pacemakers

Introduction

Evidence suggests that the rate of cardiovascular implantable electronic device (CIED) infections is increasing more rapidly than the rates of CIED implantation and is associated with considerable mortality, morbidity and health economic impact. Antimicrobial surface treatments are being developed for CIEDs to reduce the risk of postimplantation infection within the subcutaneous implant pocket.

Methods and analysis

The feasibility of processing cardiac pacemakers with the Agluna antimicrobial silver ion surface technology and in vivo biocompatibility were evaluated. Antimicrobially processed (n=6) and control pacemakers (n=6) were implanted into subcutaneous pockets and connected to a part of the sacrospinalis muscle using an ovine model for 12 weeks. Pacemaker function was monitored preimplantation and postimplantation.

Results

Neither local infection nor systemic toxicity were detected in antimicrobial or control devices, and surrounding tissues showed no abnormal pathology or over-reactivity. Semiquantitative scores of membrane formation, cellular orientation and vascularity were applied over five regions of the pacemaker capsule and average scores compared. Results showed no significant difference between antimicrobially processed and control pacemakers. Silver analysis of whole blood at 7 days found that levels were a maximum of 10 parts per billion (ppb) for one sample, more typically ≤2 ppb, compared with <<2 ppb for preimplantation levels, well below reported toxic levels.

Conclusions

There was no evidence of adverse or abnormal pathology in tissue surrounding antimicrobially processed pacemakers, or deleterious effect on basic pacing capabilities and parameters at 12 weeks. This proof of concept study provides evidence of basic biocompatibility and feasibility of applying this silver ion-based antimicrobial surface to a titanium pacemaker surface.

Worldwide Randomized Antibiotic EnveloPe Infection PrevenTion Trial (WRAP-IT)

BACKGROUND

Cardiac implantable electronic device (CIED) infection is a major complication that is associated with significant morbidity and mortality. The aim of this study is to determine whether Medtronic TYRX absorbable envelope reduces the risk of CIED infection through 12 months of follow-up post procedure.

METHODS

WRAP-IT is a randomized, prospective, multi center, international, single-blinded study. Up to 7,764 subjects who are undergoing CIED generator replacement, upgrade, or revision, or a de novo CRT-D implant, will be enrolled and randomized (1:1) to receive the TYRX envelope or not. The primary endpoint is major CIED infection throughout 12 months of follow up after the procedure. Data will be analyzed with an intention to treat approach. WRAP-IT will also assess the performance of Medtronic's lead monitoring algorithms in subjects whose CIED includes a transvenous right ventricular defibrillation system.

CONCLUSIONS

WRAP-IT is a large randomized clinical trial that will assess the efficacy of TYRX absorbable envelope in reducing CIED infection, define its cost effectiveness, and will also provide a unique opportunity to better understand the pathophysiology and risk factors for CIED infection.

Perioperative management for the prevention of bacterial infection in cardiac implantable electronic device placement

Cardiac implantable electronic devices (CIEDs) have become important in the treatment of cardiac disease and placement rates increased significantly in the last decade. However, despite the use of appropriate antimicrobial prophylaxis, CIED infection rates are increasing disproportionately to the implantation rate. CIED infection often requires explantation of all hardware, and at times results in death. Surgical site infection (SSI) is the most common cause of CIED infection as a pocket infection. The best method of combating CIED infection is prevention. Prevention of CIED infections comprises three phases: before, during, and after device implantation. The most critical factors in the prevention of SSIs are detailed operative techniques including the practice of proper technique by the surgeon and surgical team.

Clinical use of antibacterial mesh envelopes in cardiovascular electronic device implantations

Cardiovascular implantable electronic device system infection is a serious complication of cardiac device implantation and carries with it a risk of significant morbidity and mortality. In the last 15 years, expansions of indications for cardiac devices have resulted in much higher volumes of much sicker patients being implanted, carrying significant risk of infection. Coagulase (-) Staphylococcus and Staphylococcus aureus are responsible for the majority of these infections, and these organisms are increasingly resistant to methicillin. The Aigis™ envelop is a Food and Drug Administration-approved implantable mesh that is impregnated with antibiotics that can be placed in the surgical incision prior to closure. The antibiotics elute off the mesh for 7-10 days, providing in vivo surgical site coverage with rifampin and minocyclin. This paper reviews the three retrospective clinical trials published in peer-reviewed journals and the interim analysis of the two ongoing prospective trials that have been presented at international conferences. Overall consensus is that the Aigis™ offers significant risk reduction for cardiovascular implantable electronic device infection. We then give a comprehensive discussion of how to use the Aigis™ envelop in the clinical setting, comparing the manufacturer's recommendations with our extensive clinical experience.

Rates of and Factors Associated With Infection in 200 909 Medicare Implantable Cardioverter-Defibrillator Implants

Background—

The rate of implantable cardioverter-defibrillator (ICD) infections has been increasing faster than that of implantation. We sought to determine the rate and predictors of ICD infection in a large cohort of Medicare patients.

Methods and Results—

Cases submitted to the ICD Registry from 2006 to 2009 were matched to Medicare fee-for-service claims data using indirect patient identifiers. ICD infections occurring within 6 months of hospital discharge after implantation were identified by ICD-9 codes. Logistic regression was used to examine factors associated with risk of ICD infection. Of 200 909 implants, 3390 patients (1.7%) developed an ICD infection. The infection rate was 1.4%, 1.5%, and 2.0% for single, dual, and biventricular ICDs, respectively ( P <0.001). Generator replacement had a higher rate compared with initial implant (1.9% versus 1.6%, P <0.001). The factors associated with infection were adverse event during implant requiring reintervention (odds ratio [OR], 2.692; 95% confidence interval [CI], 2.304–3.145), previous valvular surgery (OR, 1.525; 95% CI, 1.375–1.692), reimplantation for device upgrade, malfunction, or manufacturer advisory (OR, 1.354; 95% CI, 1.196–1.533), renal failure on dialysis (OR, 1.342; 95% CI, 1.123–1.604), chronic lung disease (OR, 1.215; 95% CI, 1.125–1.312), cerebrovascular disease (OR, 1.172; 95% CI, 1.076–1.276), and warfarin (OR, 1.155; 95% CI, 1.060–1.257).

Conclusions—

Patients who developed an ICD infection were more likely to have had peri-ICD implant complications requiring early reintervention, previous valve surgery, device replacement for reasons other than battery depletion, and increased comorbidity burden. Efforts should be made to carefully consider when to reenter the pocket at any time other than battery replacement.

FDG-PET in cardiac infections

Cardiac infections include a group of conditions involving the heart muscle, the pericardium, or the endocardial surface of the heart. Infections can extend to prosthetic material or the leads in case of the implantation of devices. Despite their relative low incidence, these conditions that are associated with high morbidity and mortality involve a relevant burden of diagnostic workup. Early diagnosis is crucial for adequate management of patient, as early treatment improves the prognosis; unfortunately, the clinical manifestations are often nonspecific. Accurate and timely diagnosis typically requires the correlation of imaging findings with laboratory data. (18)F-FDG-PET is a well-established imaging modality for the diagnosis and management of malignancies, and evidence is also increasing regarding its value for assessing infectious and inflammatory diseases. This article summarizes published evidence on the usefulness of (18)F-FDG-PET for the diagnosis of cardiac infections, mainly focused on endocarditis and cardiovascular device infections. Nevertheless, the diagnostic potential of (18)F-FDG-PET in patients with pericarditis and myocarditis is also briefly reviewed, considering the most likely future advances and new perspectives that the use of PET/magnetic resonance would open in the diagnosis of such conditions.

Radiolabeled WBC scintigraphy in the diagnostic workup of patients with suspected device-related infections

OBJECTIVES

The aim of this study was to investigate the diagnostic performance of (99m)Tc-hexamethypropylene amine oxime labeled autologous white blood cell ((99m)Tc-HMPAO-WBC) scintigraphy in patients with suspected infections associated with cardiovascular implantable electronic devices (CIEDs).

BACKGROUND

Early, definite recognition of CIED-related infections combined with accurate localization and quantification of disease burden is a prerequisite for optimal treatment strategies.

METHODS

All 63 consecutive patients underwent clinical examination, blood chemistry, microbiology, and echography of the cardiac region/venous pathway of the device. Final diagnosis of infection was established in 32 of 63 patients and in 23 of 32 by microbiology.

RESULTS

Sensitivity of (99m)Tc-HMPAO-WBC single-photon emission computed tomography/computed tomography (SPECT/CT) was 94% for both detection and localization of CIED-associated infection. SPECT/CT imaging had a definite added diagnostic value over both planar and stand-alone SPECT. Pocket infection was often associated with lead(s) involvement; the intracardiac portion of the lead(s) more frequently exhibited (99m)Tc-HMPAO-WBC accumulation and presented the highest rate of complications, infectious endocarditis, and septic embolism. Two false negative cases and no false positive results were observed. None of the patients with negative (99m)Tc-HMPAO-WBC scintigraphy developed CIED-related infection during follow-up of 12 months. Echography of the cardiac region/venous pathway of the device had 90% specificity, but low sensitivity (81% when intracardiac lead[s] infection only was considered). The Duke criteria had 31% sensitivity for the definite category (100% specificity) and 81% for the definite and possible categories (77% specificity).

CONCLUSIONS

(99m)Tc-HMPAO-WBC scintigraphy enabled the confirmation of the presence of CIED-associated infection, definition of the extent of device involvement, and detection of associated complications. Moreover, (99m)Tc-HMPAO-WBC scintigraphy reliably excluded device-associated infection during a febrile episode and sepsis, with 95% negative predictive value.

Comparison of bacterial adherence to titanium versus polyurethane for cardiac implantable electronic devices

Implantation of cardiac implantable electronic devices (CIED) has dramatically increased over the past several years. Although several preventive measures have been implemented, there has been a disproportional increase in the number of CIED-related infections. To evaluate the adherence of bacteria to polyurethane and titanium, the 2 surfaces that coat the CIED, we proceeded with an in vitro study using the most common microorganisms responsible for CIED-related infections. Original, unused 1 × 1 centimeter titanium and polyurethane flat plates were incubated with coagulase-negative staphylococci, methicillin-resistant Staphylococcus aureus, and Pseudomonas aeruginosa. Each experiment was repeated 5 times. After incubating the titanium and polyurethane plates for 3, 6, 12, or 24 hours, all 3 organisms displayed a higher grade of bacterial adherence to the polyurethane versus titanium surfaces (p = 0.01). In conclusion, to decrease the rate of bacterial adherence, especially during the immediate postimplantation period when the CIED is at high risk for bacterial adherence, colonization, and infection, it may be prudent to consider constructing CIED surfaces with a higher proportion of titanium over polyurethane. Animal studies are warranted to explore the relevance of these laboratory findings.

Rate, causes, and impact on patient outcome of implantable device complications requiring surgical revision: large population survey from two centres in Italy

AIMS

The long-term impact of implantable device-related complications on the patient outcome has not been thoroughly evaluated. The aims of this retrospective, bi-centre study were to analyse the rate and nature of device-related complications requiring surgical revision in a large series of patients undergoing device implantation, elective generator replacement and pacing system upgrade and to systematically assess the impact of such complications on patient outcome and healthcare utilization.

METHODS AND RESULTS

Data from 2671 consecutive procedures (1511 device implantations, 1034 elective generator replacements, and 126 pacing system upgrades) performed between January 2006 and March 2011 were retrospectively analysed. The outcome measures recorded were complication-related mortality, number of re-operations, need for complex surgical procedures, number of re-hospitalizations, and additional hospital treatment days. Over a median follow-up of 27 months, the overall rate of complications was 2.8% per procedure-year [9.5% in cardiac resynchronisation therapy (CRT) device implantation, 6.1% in pacing system upgrade, 3.5% in implantable cardioverter defibrillator implantation, 1.7% in pacemaker implantation, and 1.7% in generator replacement). The procedure with the highest risk of complications was CRT device implantation (odds ratio: 6.6; P < 0.001); these complications primarily involved coronary sinus lead dislodgement and device infection. Patients with complications had a significantly higher number of device-related hospitalizations (2.3 ± 0.6 vs. 1.0 ± 0.1; P < 0.001) and hospital treatment days (15.7 ± 25.1 vs. 3.6 ± 1.1; P < 0.001) than those without complications. Device infection was the complication with the greatest negative impact on patient outcome.

CONCLUSION

Cardiac resynchronisation therapy implantation was the procedure with the highest risk of complications requiring surgical revision. Complications were associated with substantial clinical consequences and a significant increase in the number and length of hospitalizations.

Risk factors for infection of implantable cardiac devices: data from a registry of 2496 patients

AIMS

The increased use of implantable cardiac devices has been accompanied by an increase in infection. However, risk factors for infection of implanted devices are poorly documented. We aimed to identify risk factors in patients with long-term follow-up after implantation of cardiac devices.

METHODS AND RESULTS

Patients with first implantation of a cardiac device in our centre between October 1996 and July 2007 were entered in a registry. Each confirmed infection of the implanted device was matched to two controls for age, sex, and implantation year. We recorded cardiovascular risk factors (hypertension, diabetes), previous history of heart disease, renal failure, antiplatelet or anticoagulant therapy, as well as pre- and post-procedural characteristics (antibiotic prophylaxis, hyperthermia, number of leads, associated interventions, and early complications). During the study period, 2496 patients underwent implantation of a cardiac device; 35 infections were diagnosed (1.2%). Among these, 75% occurred during the first year after implantation. Early non-infectious complication requiring surgical intervention was observed only in patients with infection (9 of 35, P < 0.001). Factors independently associated with infection were diabetes [odds ratio (OR) 3.5, 95% confidence interval (CI) [1.03, 12.97]], underlying heart disease (OR 3.12, 95% CI [1.13; 8.69]), and use of >1 lead (OR 4.07, 95% CI [1.23, 13.47]). These latter two risk factors were also independently associated with occurrence of infection within 1 year of implantation.

CONCLUSION

Our data show that the presence of diabetes and underlying heart disease are independent risk factors for infection after cardiac device implantation. As regards procedural characteristics, the use of several leads and early re-intervention are associated with a higher infection rate.

Thrombolysis is an appropriate treatment in lead-associated infective endocarditis with giant vegetations located on the right atrial lead

CD endocarditis is a potentially lethal complication after implantation of permanent pacemakers or implantable cardioverter-defibrillators. Complete extraction of the hardware along with antibiotic treatment is the standard therapy. However, there is no standard procedure in the treatment of lead-associated infective endocarditis with large thrombotic vegetations. The authors present the case of a 60-year-old patient with a large vegetation located on the right atrial lead. Due to a high surgical and thrombembolic risk, especially of acute massive pulmonary embolism, the patient received recombinant tissue plasminogen activator to dissolve the thrombus under echocardiographic monitoring. The thrombotic masses were substantially reduced after thrombolysis. Therefore, standard transvenous extraction of the leads could be performed and high risk cardiac re-operation could be avoided.

Infections of cardiac implantable electronic devices: a retrospective multicenter observational study

Infections of cardiac implantable electronic devices (CIED) can cause significant morbidity, mortality, and financial burden. Although staphylococcal organisms account for most infections of these cardiac devices, approximately 20% of all CIED-related infections are caused by non-Staphylococcus species. Herein we describe and compare the demographics, clinical presentation, and outcomes of Staphylococcus aureus and non-staphylococcal infections of CIED.We performed a retrospective, multicenter, observational study of patients from 4 academic hospitals in Houston between 2002 and 2009. All 80 identified non-staphylococcal CIED-related infections were matched, at a 1:1 ratio, to S. aureus infections.Although the demographics and general comorbidities in the 2 study groups were relatively similar, the S. aureus group had a higher proportion of patients with coronary artery disease, diabetes mellitus, and end-stage renal disease. Additionally, 81% of S. aureus compared with only 48.5% of the non-staphylococcal CIED-related infections were health care-associated (p < 0.001). Furthermore, when compared to non-staphylococcal infections, the S. aureus group had more indwelling intravascular foreign material (p < 0.001), more rapid clinical progression (p < 0.001), and overall worse clinical presentation (p < 0.001). However, after stratifying by clinical presentation, the mortality rates in the 2 groups were similar (p = 0.45).Since approximately one-fifth of all CIED-related infections are caused by non-staphylococcal organisms, and untimely antibiotic treatment can result in serious complications, it may be prudent to broaden empiric antimicrobial therapy to cover both Gram-positive and -negative bacteria, until the causative organism is identified.

Complete removal as a routine treatment for any cardiovascular implantable electronic device-associated infection

OBJECTIVE

Pacemaker and implantable cardioverter defibrillator lead endocarditis mandates removal of all foreign material. In supposedly limited (pocket) infections, such a radical approach is still controversial. Thus, some patients are potentially exposed to persistent and recurrent infection because of retained material. Procedural risks and the success of eradicating infection were examined if involvement of the complete system was assumed in any cardiovascular implantable electronic device infection and complete removal was thus mandatory.

METHODS

A 12-year experience with 192 consecutive cases of bacterial pacemaker (152) or defibrillator (40) infections is presented. Complete removal of all prosthetic material was always aimed for. This was followed by antibiotic treatment for 4 to 6 weeks under temporary pacing if required, and then the new system was implanted. A total of 104 parameters concerning patient characteristics and operative and postoperative treatment were examined for their influence on outcome.

RESULTS

Infection was eradicated in 92.8% of patients. Recurrence was predominantly caused by failure to remove all prosthetic material (P < .001). If the protocol was strictly followed, infection was eradicated in 97.4% of patients. Conversely, 71.4% of patients with retained material showed recurrence. Further risk factors were poor dental hygiene and evidence of chronic subclinical infection. Morbidity and mortality of the interventional and open procedures were low. Open lead extraction was performed primarily in 34 patients (17.7%) and secondarily in 3 patients (1.9%). Temporary pacing and long-term antibiotic treatment were well tolerated.

CONCLUSIONS

Complete removal of prosthetic material in any cardiovascular implantable electronic device infection is safe and associated with low morbidity and mortality. Success of eradicating infection is high if all system components are removed. Temporary pacing in dependent patients may be performed safely on an outpatient basis.

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.

Problems with implantable cardiac device therapy

Implantable cardioverter-defibrillators (ICDs) improve survival in patients who have left ventricular dysfunction; however, they are associated with numerous problems at implant and during follow-up. The diagnosis and management of these problems is usually straightforward, but more difficult problems may include the management of patients who have elevated energy requirements to terminate ventricular fibrillation or of those who have postoperative device infections. Long-term issues in ICD patients include the occurrence of inappropriate or frequent appropriate shocks. ICD generators and leads are more prone to failures than are pacing systems alone; management of patients potentially dependent on "recalled" devices to deliver life-saving therapy is a particularly complex issue. The purpose of this article is to review the diagnosis and management of these more troublesome ICD problems.

Infective endocarditis complicating permanent pacemaker and implantable cardioverter-defibrillator infection

OBJECTIVE

To describe management of patients with permanent pacemaker (PPM)- and implantable cardioverter-defibrillator (ICD)-related endocarditis.

PATIENTS AND METHODS

We retrospectively reviewed all cases of infection involving PPMs and ICDs among patients presenting to Mayo Clinic's site in Rochester, MN, between January 1, 1991, and December 31, 2003. Cardiac device-related infective endocarditis (CDIE) was defined as the presence of both vegetation on a device lead or valve and clinical or microbiological evidence of CDIE. Of 189 patients with PPM or ICD infection who were admitted during the study period, 44 met the case definition for CDIE (33 PPM, 11 ICD).

RESULTS

The mean +/- SD age of patients was 67 +/- 14 years. Staphylococci (36 [82%]) were the most commonly isolated pathogens. Nearly all patients (43 [98%]) were treated with a combined approach of complete hardware removal and parenteral antibiotics. The median duration of antibiotic treatment after infected device explantation was 28 days (interquartile range, 19-42 days). Device leads were removed percutaneously in 34 cases (77%); only 7 cases (16%) required surgical lead extraction. Percutaneous extraction was uncomplicated in 15 patients with lead vegetation greater than 10 mm in diameter. Six patients (14%) died during hospitalization. Twenty-seven (96%) of 28 patients remained infection free at their last visit (median follow-up, 183 days; intraquartile range, 36-628 days).

CONCLUSION

Prompt hardware removal and prolonged parenteral antibiotic administration decrease mortality among patients with CDIE. The presence of a large (> 10 mm in diameter) vegetation on a lead is not a contraindication for percutaneous lead extraction.

Life expectancy gains and cost-effectiveness of implantable cardioverter/defibrillators for the primary prevention of sudden cardiac death in patients with hypertrophic cardiomyopathy

BACKGROUND

Sudden cardiac death (SCD) is a devastating complication of hypertrophic cardiomyopathy (HCM). The optimal strategy for the primary prevention of SCD in HCM remains controversial.

METHODS

Using a Markov model, we compared the health benefits and cost-effectiveness of 3 strategies for the primary prevention of SCD: implantable cardioverter/defibrillator (ICD) insertion, amiodarone therapy, or no therapy. We modeled hypothetical cohorts of 45-year-old patients with HCM with no history of cardiac arrest but at significant risk of SCD (3%/y).

RESULTS

Over a lifetime, compared with no therapy, ICD therapy increased quality-adjusted survival by 4.7 quality-adjusted life years (QALYs) at an additional cost of $142,800 ($30,000 per QALY), whereas amiodarone increased quality-adjusted survival by 2.8 QALYs at an additional cost of $104,900 ($37,300 per QALY). Compared with no therapy, ICD therapy would cost < $50,000 per QALY for patients (i) aged 25, with > or = 1 risk factors for SCD, and (ii) aged 45 or 65, with > or = 2 risk factors for SCD.

CONCLUSIONS

An ICD strategy is projected to yield the greatest increase in quality-adjusted life expectancy of the 3 treatment strategies evaluated. Combined consideration of age and the number of risk factors for SCD may allow more precise tailoring of ICD therapy to its expected benefits.

Risk Factors Related to Infections of Implanted Pacemakers and Cardioverter-Defibrillators

Background— The Prospective Evaluation of Pacemaker Lead Endocarditis study is a multicenter, prospective survey of the incidence and risk factors of infectious complications after implantation of pacemakers and cardioverter-defibrillators.

Methods and Results— Between January 1, 2000, and December 31, 2000, 6319 consecutive recipients of implantable systems were enrolled at 44 medical centers and followed up for 12 months. All infectious complications were recorded, and their occurrence was related to the baseline demographic, clinical, and procedural characteristics. Among 5866 pacing systems, 3789 included 2 and 117 had >2 leads; among 453 implantable cardioverter-defibrillators, 178 were dual-lead systems. A total of 4461 de novo implantations occurred and 1858 pulse generator or lead replacements. Reinterventions were performed before hospital discharge in 101 patients. Single- and multiple-variable logistic regression analyses were performed to identify risk factors; adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were calculated. At 12 months, device-related infections were reported in 42 patients (0.68%; 95% CI, 0.47 to 0.89). The occurrence of infection was positively correlated with fever within 24 hours before the implantation procedure (aOR, 5.83; 95% CI, 2.00 to 16.98), use of temporary pacing before the implantation procedure (aOR, 2.46; 95% CI, 1.09 to 5.13), and early reinterventions (aOR, 15.04; 95% CI, 6.7 to 33.73). Implantation of a new system (aOR, 0.46; 95% CI, 0.24 to 0.87) and antibiotic prophylaxis (aOR, 0.4; 95% CI, 0.18 to 0.86) were negatively correlated with risk of infection.

Conclusions— This study identified several factors of risk of device infection and confirmed the efficacy of antibiotic prophylaxis in recipients of new or replacement pacemakers or implantable cardioverter-defibrillators.

Case-control study of surgical site infections associated with pacemakers and implantable cardioverter-defibrillators

OBJECTIVE

In 2000, the rate of surgical site infections (SSIs) associated with pacemaker and implantable cardioverter-defibrillator (ICD) procedures performed in the cardiothoracic operating rooms of hospital A was 16% (19 of 116 procedures resulted in infections). This study investigates risks for SSI associated with these procedures in the cardiothoracic operating room.

DESIGN

Unmatched 1 : 3 case-control study performed over a 12-month period among patients who had undergone implantation of a pacemaker and/or ICD. A standardized observation scrutinized infection control practices in the area where the procedures were performed.

SETTING

The cardiothoracic operating rooms of hospital A, which belongs to a hospital consortium in the midwestern United States.

PATIENTS

Patients with SSI were identified as case patients. Control patients were chosen from the group of uninfected patients who had procedures performed during the same period as case patients.

RESULTS

A total of 19 SSIs associated with pacemaker and ICD procedures were retrospectively identified among the patients who underwent procedures in these cardiothoracic operating rooms. Culture samples were obtained from 7 patients; 2 yielded coagulase-negative Staphylococcus on culture, 2 yielded Staphylococcus aureus, 1 yielded Serratia marcescens, and 2 showed no growth. In the case-control study, age, race, sex, diabetes mellitus, smoking history, timing of antibiotic therapy, and hair removal did not differ significantly between case patients and control patients. Case patients were more likely to have an abdominal device in place (odds ratio [OR], 5.5 [95% confidence interval {CI}, 1.6-19.3]; P=.006) and less likely to have received a new implant (OR 0.3 [95% CI, 0.1-0.8]; P=.02) or to have had new leads placed (OR, 0.2 [95% CI, 0.1-0.6]; P=.003).

CONCLUSIONS

Abdominal placement of implanted devices was associated with occurrence of an SSI after pacemaker and/or ICD procedures.

Management and outcome of permanent pacemaker and implantable cardioverter-defibrillator infections

OBJECTIVES

We describe the management and outcome of permanent pacemaker (PPM) and implantable cardioverter-defibrillator (ICD) infections in a large cohort of patients seen at a tertiary care facility with expertise in device lead extraction.

BACKGROUND

Infection is a serious complication of PPM and ICD implantation. Optimal care of patients with these cardiac device infections (CDI) is not well defined.

METHODS

A retrospective review of all patients with CDI admitted to Mayo Clinic Rochester between January 1, 1991, and December 31, 2003, was conducted. Demographic and clinical data were collected, and descriptive analysis was performed.

RESULTS

A total of 189 patients met the criteria for CDI (138 PPM, 51 ICD). The median age of the patients was 71.2 years. Generator pocket infection (69%) and device-related endocarditis (23%) were the most common clinical presentations. Coagulase-negative staphylococci and Staphylococcus aureus, in 42% and 29% of cases, respectively, were the leading pathogens for CDI. Most patients (98%) underwent complete device removal. Duration of antibiotic therapy after device removal was based on clinical presentation and causative organism (median duration of 18 days for pocket infection vs. 28 days for endocarditis; 28 days for S. aureus infection vs. 14 days for coagulase-negative staphylococci infection [p < 0.001]). Median follow-up after hospital discharge was 175 days. Ninety-six percent of patients were cured with both complete device removal and antibiotic administration.

CONCLUSIONS

Cure of CDI is achievable in the large majority of patients treated with an aggressive approach of combined antimicrobial treatment and complete device removal. Based on findings of our large retrospective institutional survey and previously published data, we submit proposed management guidelines of CDI.

Frequency of Permanent Pacemaker or Implantable Cardioverter-Defibrillator Infection in Patients with Gram-Negative Bacteremia

BACKGROUND

Despite the frequent occurrence of bacteremia due to gram-negative organisms in patients with underlying permanent pacemakers (PPMs) or implantable cardioverter defibrillators (ICDs), the outcome and treatment of these patients has received scant attention. In patients with PPMs or ICDs who have Staphylococcus aureus bacteremia, 45% have PPM/ICD infection.

METHODS

We conducted a retrospective cohort study over a 7-year period to assess the clinical features and frequency of PPM/ICD infection in patients with gram-negative bacteremia, as well as the incidence of relapse in patients for whom the device was not removed.

RESULTS

Forty-nine patients were included in the study; 3 (6%) had either definite (2 patients) or possible (1 patient) PPM/ICD infection. Both patients with definite PPM/ICD infection had clear infection of the generator pocket. None of the other patients with alternate sources of bacteremia developed PPM/ICD infection. Thirty-four patients with retained PPM/ICD were observed for >12 weeks (median time, 759 days), and 2 (6%) developed relapsing bacteremia, although they each had alternative sources of relapse.

CONCLUSIONS

In sharp contrast to S. aureus infection, PPM/ICD infection in patients with gram-negative bacteremia was rare, and no patients appeared to have secondary PPM/ICD infection due to hematogenous seeding of the system. Despite infrequent system removal in these patients, relapsing bacteremia among patients who survived initial bacteremia was rarely seen. If secondary PPM/ICD infection occurs in patients with gram-negative bacteremia, it is either uncommon or it is cured with antimicrobial therapy despite device retention.

Implantable or external defibrillators for individuals at increased risk of cardiac arrest: where cost-effectiveness hits fiscal reality

OBJECTIVES

Implantable cardioverter defibrillators (ICDs) are highly effective at preventing cardiac arrest, but their availability is limited by high cost. Automated external defibrillators (AEDs) are likely to be less effective, but also less expensive. We used decision analysis to evaluate the clinical and economic trade-offs of AEDs, ICDs, and emergency medical services equipped with defibrillators (EMS-D) for reducing cardiac arrest mortality.

METHODS

A Markov model was developed to compare the cost-effectiveness of three strategies in adults meeting entry criteria for the MADIT II Trial: strategy 1, individuals experiencing cardiac arrest are treated by EMS-D; strategy 2, individuals experiencing cardiac arrest are treated with an in-home AED; and strategy 3, individuals receive a prophylactic ICD. The model was then used to quantify the aggregate societal benefit of these three strategies under the conditions of a constrained federal budget.

RESULTS

Compared with EMS-D, in-home AEDs produced a gain of 0.05 quality-adjusted life-years (QALYs) at an incremental cost of $5225 ($104,500 per QALY), while ICDs produced a gain of 0.90 QALYs at a cost of $114,660 ($127,400 per QALY). For every $1 million spent on defibrillators, 1.7 additional QALYs are produced by purchasing AEDs (9.6 QALYs/$million) instead of ICDs (7.9 QALYs/$million). Results were most sensitive to defibrillator complication rates and effectiveness, defibrillator cost, and adults' risk of cardiac arrest.

CONCLUSIONS

Both AEDs and ICDs reduce cardiac arrest mortality, but AEDs are significantly less expensive and less effective. If financial constraints were to lead to rationing of defibrillators, it might be preferable to provide more people with a less effective and less expensive intervention (in-home AEDs) instead of providing fewer people with a more effective and more costly intervention (ICDs).

Cost-Effectiveness of a Microvolt T-Wave Alternans Screening Strategy for Implantable Cardioverter-Defibrillator Placement in the MADIT-II–Eligible Population

OBJECTIVES

This study was designed to compare the cost-effectiveness of implantable cardioverter-defibrillator (ICD) placement with and without risk stratification with microvolt T-wave alternans (MTWA) testing in the MADIT-II (Second Multicenter Automatic Defibrillator Implantation Trial) eligible population.

BACKGROUND

Implantable cardioverter-defibrillators have been shown to prevent mortality in the MADIT-II population. Microvolt T-wave alternans testing has been shown to be effective in risk stratifying MADIT-II-eligible patients.

METHODS

On the basis of published data, cost-effectiveness of three therapeutic strategies in MADIT-II-eligible patients was assessed using a Markov model: 1) ICD placement in all; 2) ICD placement in patients testing MTWA non-negative;, and 3) medical management. Outcomes of expected cost, quality-adjusted life-years (QALYs), and incremental cost-effectiveness were determined for patient lifetime.

RESULTS

Under base-case assumptions, providing ICDs only to those who test MTWA non-negative produced a gain of 1.14 QALYs at an incremental cost of 55,700 dollars when compared to medical therapy, resulting in an incremental cost-effectiveness ratio (ICER) of 48,700 dollars/QALY. When compared with a MTWA risk-stratification strategy, placing ICDs in all patients resulted in an ICER of 88,700 dollars/QALY. Most (83%) of the potential benefit was achieved by implanting ICDs in the 67% of patients who tested MTWA non-negative. Results were most sensitive to the effectiveness of MTWA as a risk-stratification tool, MTWA negative screen rate, cost and efficacy of ICD therapy, and patient risk for arrhythmic death.

CONCLUSIONS

Risk stratification with MTWA testing in MADIT-II-eligible patients improves the cost-effectiveness of ICDs. Implanting defibrillators in all MADIT-II-eligible patients, however, is not cost-effective, with one-third of patients deriving little additional benefit at great expense.