Infections of implantable cardioverter-defibrillators: frequency, predisposing factors and clinical significance

Epidemiology of cardiac implantable electronic device infections: incidence and risk factors

Cardiac implantable electronic device (CIED) infection is a potentially devastating complication of CIED procedures, causing significant morbidity and mortality for patients. Of all CIED complications, infection has the greatest impact on mortality, requirement for re-intervention and additional hospital treatment days. Based on large prospective studies, the infection rate at 12-months after a CIED procedure is approximately 1%. The risk of CIED infection may be related to several factors which should be considered with regards to risk minimization. These include technical factors, patient factors, and periprocedural factors. Technical factors include the number of leads and size of generator, the absolute number of interventions which have been performed for the patient, and the operative approach. Patient factors include various non-modifiable underlying comorbidities and potentially modifiable transient conditions. Procedural factors include both peri-operative and post-operative factors. The contemporary PADIT score, derived from a large cohort of CIED patients, is useful for the prediction of infection risk. In this review, we summarize the key information regarding epidemiology, incidence and risk factors for CIED infection.

Strategies to Prevent Cardiac Implantable Electronic Device Infection

The association between the risk of mortality and cardiovascular implantable electronic device (CIED) infections has been well-established in the literature. As CIED implantations have increased in frequency in the past few decades, the incidence of CIED-related infections has also risen. Given the morbidity, mortality, and health-care costs associated with CIED infections, the prevention of device-related infection is a critical goal. Risk factors for developing CIED infections can be categorized as patient-, procedure-, or device-related. Numerous studies have highlighted different strategies for preventing CIED-related infections, which include patient optimization, device selection, and periprocedural preparation and treatment. Nonetheless, as the comorbidity burden of patients undergoing CIED implantation continues to increase, significant challenges in the successful elimination of CIED-related infections remain. This review provides a comprehensive overview of available evidence-based approaches and strategies to reduce the risk of CIED infections.

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.

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.

Wound management and restrictive arm movement following cardiac device implantation - evidence for practice?

BACKGROUND

The rate of cardiac device implantation has risen significantly secondary to an increase in the number of indications. Wound infection and lead displacement are two common and potentially life-threatening complications. No national/international guidelines address postoperative care and controversy exists regarding wound management and arm movement following cardiac device implantation.

AIMS

We aimed to explore and review the evidence behind current practice but found that certain aspects of established practice.

METHODS

An electronic search of the databases EMBASE, British Nursing Index, CINAHL, Cochrane and PubMed to identify evidence regarding wound management and lead displacement.

FINDINGS

We found that certain aspects of established practice are based on tradition rather than evidence. Recent guidelines on wound management published by The National Institute for Health and Clinical Excellence in the UK recommend covering the wound postoperatively for 48 h with a low-adherent transparent dressing and letting patients shower thereafter. Since specific guidelines for cardiac device patients are lacking, we suggest that further research address whether or not the NICE guidelines can be extrapolated to this area. Studies showed that early mobilisation and allowing a full range of arm movements following device implantation is safe. Further research must validate these findings.

CONCLUSION

We discuss the reasons behind these gaps in the evidence base and support the idea that nursing education has not placed enough emphasis on how to critically appraise research. This accounts for the very small proportion of nurses that get involved in conducting research and generating guidelines. Additionally, we argue that nurses can play a key role in identifying and addressing research questions that lead to improved patient outcome. Thus, we support proposals to enhance nurses' opportunities to pursue academic careers to achieve adequate research skills.

Implantable cardioverter-defibrillator deactivation at the end of life: a physician survey

BACKGROUND

Among older adults, implantable cardioverter-defibrillator (ICD) use is increasing. ICD shocks can occur at end of life (EOL) and cause substantial distress, warranting consideration of ICD deactivation discussions. This nationwide physician survey sought to (1) determine if physicians discuss ICD deactivation at the EOL, (2) identify predictors of those discussions, and (3) ascertain physicians' knowledge/attitudes about ICD use.

METHODS

We surveyed 4,876 physicians stratified by specialty (cardiologists, electrophysiologists, general internists, and geriatricians). The mailed survey presented 5 vignettes (eg, end-stage chronic obstructive pulmonary disease, advanced dementia) wherein ICD deactivation might be considered and 17 Likert-scaled items.

RESULTS

Five hundred fifty-eight (12%) physicians returned surveys. Respondents were largely men (77%) and white (69%). Most physicians (56%-83%) said they would initiate deactivation discussions in all 5 vignettes, whereas significantly more (82%-94%) would discuss advance directives and do not resuscitate status. In logistic regression analyses, a history of prior deactivation discussions was an independent predictor of willingness to discuss deactivation (adjusted OR range, 2.8-8.8) in 4 of the 5 vignettes. General internists and geriatricians were less likely than electrophysiologists to agree that ICD shocks are painful and to distinguish between the ICD's pacing and defibrillator functions. Finally, most physicians believed that informed consent for ICD implantation should include information about deactivation (77%) and endorsed the need for expert guidance in this area (58%).

CONCLUSIONS

Most physicians would discuss ICD deactivation at EOL. The strongest predictor of this was a history of prior discussions. Knowledge about ICDs varies by specialty, and most expressed a desire for more expert guidance about ICD management at EOL.

Infection after ICD implantation: operating room versus cardiac catheterisation laboratory

BACKGROUND/OBJECTIVES

Since the insertion of an implantable cardioverter-defibrillator (ICD) has become technically comparable to pacemaker implantation, these procedures are increasingly being performed in a cardiac catheterisation laboratory (CCL) instead of the operating room (OR). This study aims to describe the relationship between incidence of ICD infection and procedure setting and to describe the characteristics of ICD infection.

METHODS

A retrospective study was performed of first ICD implantation in 677 patients admitted to our hospital between 1996 and 2006. Implantations were performed in the OR until 2003, after 2003 they were carried out in the CCL. The follow-up was censored at one year after implantation. ICD infections were defined as pocket infection or ICD-related endocarditis and a descriptive analysis was performed.

RESULTS

Cardiothoracic surgeons implanted 366 ICDs in the OR Electrophysiologists performed 301 implantations in the CCL. Pulse generators were inserted using a pectoral approach with transvenous lead systems. We identified seven ICD infections (incidence rate 1.2/100 person-years), three of which had been implanted in the OR and four in the CCL.

CONCLUSION

In this single-centre study no difference in the incidence of ICD infection was observed between implantation in OR and CCL. However, a larger study will be necessary to rule out a relationship with certainty. (Neth Heart J 2009;17:95-100.).

Endocarditis caused by Staphylococcus aureus: A reappraisal of the epidemiologic, clinical, and pathologic manifestations with analysis of factors determining outcome

Staphylococcus aureus is the leading cause of infectious endocarditis and its mortality has remained high despite better diagnostic and therapeutic procedures over time. We conducted a retrospective review of 133 cases of definite S. aureus endocarditis seen at a single tertiary care hospital over 22 years to assess changes in the epidemiology and incidence of the infection, manifestations, outcome, risk factors for mortality, and impact of cardiac surgery on prognosis.Patients were classified into 2 groups: 1) right-sided endocarditis (64 patients) and 2) left-sided endocarditis (69 patients). While the number of cases of left-sided endocarditis remained steady at 1-3 cases per 10,000 admissions, the incidence of right-sided endocarditis, after a peak in the early 1990s, declined to almost disappear in 2001. Among the cases of right-sided endocarditis, we found 2 subsets of patients with different clinical features and prognosis: the first subset comprised 53 intravenous drug abusers, and the second subset comprised 11 patients with catheter-associated S. aureus bacteremia and endocarditis. Fifty-one patients were human immunodeficiency virus (HIV)-positive drug abusers, most of whom (80.3%) had right-sided endocarditis. We did not find differences in mortality between HIV-positive and HIV-negative individuals; mortality seemed to depend more on the site of the heart involved than on HIV status.Among the cases of left-sided endocarditis, the mitral valve was more commonly involved than the aortic valve (61% vs. 30%). Overall, 74% of patients with left-sided endocarditis developed 1 or more cardiac or extracardiac complication. In comparison, only 23.4% of patients with right-sided endocarditis developed complications.Prosthetic valve endocarditis (PVE) was hospital-acquired more frequently than native valve endocarditis (NVE). Patients with PVE had a shorter duration of symptoms until diagnosis and presented with or developed cardiac murmurs less frequently than patients with NVE. Cardiac failure (49%), renal failure (43%) and central nervous system (CNS) events (35%) were frequently observed in patients with both PVE and NVE. Valve replacement was more frequently needed and more rapidly performed in patients with PVE than in their counterparts with NVE.The overall mortality of patients with right-sided endocarditis was 17%. While the mortality of right-sided endocarditis in injection drug users was 3.7%, the mortality of patients with right-sided endocarditis associated with infected intravenous catheters was 82% (odds ratio [OR], 0.01; 95% confidence interval [CI], 0.001-0.07). For left-sided endocarditis mortality was 38% and was not significantly different in patients with NVE or PVE (OR, 0.65; 95% CI, 0.23-1.87). CNS complications were associated with mortality in both NVE (OR, 6.55; 95% CI, 1.78-24.04) and PVE (OR, 32; 95% CI, 2.63-465.40). Development of 2 or 3 complications was associated with an increased risk of mortality (OR, 5.59; 95% CI, 1.08-28.80 and OR, 9.25; 95% CI, 1.36-62.72 for 2 vs. 1 complication and for 3 vs. 2 complications, respectively).Surgical treatment did not significantly influence mortality in cases of NVE, (OR, 3.19; 95% CI, 0.76-13.38) but significantly improved the prognosis of patients with PVE (OR, 69; 95% CI, 2.89-1647.18).S. aureus endocarditis is an aggressive, often fatal, infection. The results of the current study suggest that valve replacement will improve the outcome of infection, particularly in patients with PVE.

Management of patients with ICDs at the end of life (EOL): a qualitative study

PURPOSE

Implantable cardioverter defibrillator shocks at the end of life are distressing and warrant consideration of implantable cardioverter defibrillator deactivation discussions. A nationwide survey collected physicians' comments regarding such discussions.

METHODS

Vignettes ascertained respondents' practices regarding implantable cardioverter defibrillator deactivation discussions. Respondents' comments were analyzed to identify themes.

RESULTS

About 177 respondents (32%) provided 310 comments. One third reported that initiating the discussion would depend on specific circumstances, such as do not resuscitate status (35%); 21% advocated life-prolonging therapies; 17% said the patient/family or another physician should initiate the discussion; and 9% expressed inadequate education/awareness about implantable cardioverter defibrillator functions. Geriatricians and general internists expressed inadequate knowledge most frequently (12 writers, 75% in this theme), while electrophysiologists most frequently suggested further treatments/procedures (22 writers, 58%), and another doctor (13 writers, 76%) or the patient (8 writers, 62%) should begin the discussion.

CONCLUSIONS

Improving the end of life care for patients with implantable cardioverter defibrillators will require additional physician education and increased commitment by subspecialists to deactivation discussions.