Cardiac implantable electronic devices (CIEDs) restore safe heart rhythms but carry a risk of infections that can be fatal in one in eight patients.

“As the patient population receiving these invasive devices is increasingly older and more medically complex, CIED infection incidence has doubled over the past decade,” researchers report.¹

“At the same time, the number of patients receiving CIEDs continues to increase, with more than 300,000 new devices placed annually in the United States.”

The authors “[measured] the association between … specific infection prevention interventions and procedure-related [CIED] infections,” finding in some cases practices that are unnecessary and even harmful.

The method was a retrospective cohort review of the infection status of CIED patients at Veterans Health Administration (VA) hospitals. The researchers used a sampling of procedures entered from fiscal years 2008 through 2015.

Out of 2,098 procedures, the researchers “identified 101 procedure-related CIED infections.”

The “factors associated with increased risk for infections” included “wound complications,” “revisions including generator changes,” “an elevated international normalized ratio,” and “methicillin-resistant Staphylococcus colonization [MRSA].”

According to the authors, “Clinically effective prevention interventions included preprocedural skin cleaning with chlorhexidine … and receipt of beta-lactam antimicrobial prophylaxis.”

However, the authors found that many common “interventions are ineffective, and that the simplest strategies (those designed to limit bleeding risk and avoid implantations in patients with active infections) have the strongest potential to improve CIED infection outcomes.”

Hospital Infection Control & Prevention spoke with the study’s corresponding author, Westyn Branch-Elliman, MD, MMSc, an assistant professor of medicine at Harvard Medical School, and an Investigator with the VA Boston Center for Healthcare Organization and Implementation Research. This interview has been edited for length and clarity.

HIC: Did you find any temporal results that would suggest these CIED infections are increasing over time?

Branch-Elliman: We did not specifically evaluate for temporal changes. However, other studies have demonstrated that rates of infection have been increasing with time, in parallel with an increase in the comorbidity index of the patients receiving cardiac device implantation procedures.

HIC: Can you elaborate on the risk factors, such as wound complications and MRSA colonization?

Branch-Elliman: MRSA is a well-characterized risk factor for many types of procedure-related infections, so we were not surprised that it was associated with an increased risk of cardiac device infection in our sample.

The association is probably partially due to factors inherent to the patients who are MRSA-colonized — they tend to be sicker and have more healthcare exposures than patients without MRSA colonization — and partially due to the nature of the organism.

Another factor may be that this organism is resistant to the most commonly used prophylaxis agent, cefazolin; thus, standard prophylaxis regimens may not be as effective in MRSA-colonized patients as in patients without MRSA.

We also found that peripheral arterial disease was related to increased risk of infection. This might be because good blood flow is needed for wound healing and for good immune system functioning.

The host immune system plays a key role in preventing postoperative infections by cleaning up any low-level contamination that may occur around the time of the procedure.

Revision procedures have been demonstrated in other studies to be associated with a higher risk of infection.

This is probably because there is more scar tissue present in these cases, and thus, less blood supply to the area. A good blood supply is critical for both wound healing and clearance of low-level bacterial contamination that may occur after skin incision.

HIC: Was ineffective treatment related to these risk factors — or were these patients at significant risks regardless of treatment?

Branch-Elliman: Any time a device is placed, there is a risk of infection. Infection prevention interventions can reduce the risk of infection, but not entirely eliminate it.

Some patients, based on their personal risk factors and specifics of their cardiac device procedure, are at higher risk of infection than others. These higher-risk patients may derive more absolute benefit from some infection prevention interventions than lower-risk patients.

HIC: Do you have any data on patient mortality related to the infections?

Branch-Elliman: I do not have that information available for this cohort, but prior studies suggest that the mortality rate from deep cardiac device infections approaches one in eight patients.

In work we previously published, we found that almost half of the patients (42%) who developed C. difficile after receiving prolonged prophylaxis died.

HIC: How common were the ineffective practices, such as continuation of antibiotics?

Branch-Elliman: Continuation of antimicrobial prophylaxis after skin closure was extremely common in the cohort — about half of the patients in our sample received this ineffective and likely harmful intervention.

Our group has demonstrated that continuation of antibiotics for greater than 24 hours in this population is associated with increases in postoperative adverse events, including increased rates of C. difficile infections.

In other surgical populations, we have also found that increasing duration of prophylaxis is associated with increases in rates of acute kidney injury, which can lead to long-term chronic kidney disease. These data strongly suggest that we need to find effective ways to de-implement this low-value, and potentially harmful, practice.

HIC: You conclude that frequently used interventions are less effective than simpler strategies. What will it take to change the culture and move away from the interventions that don’t work well?

Branch-Elliman: De-implementation of ineffective practices can be particularly challenging. Our group is actively investigating what factors drive current antimicrobial prescribing practices and what factors are perceived to be associated with positive practice change. We hope that this work will shed light on the best ways to reduce unnecessary antimicrobial use and ultimately to improve clinical care.

REFERENCE

1. Asundi A, Stanislawski M, Mehta P, et al. Real-world effectiveness of infection prevention interventions for reducing procedure-related cardiac device infections: Insights from the veterans affairs clinical assessment reporting and tracking program. Infect Control Hosp Epidemiol 2019; 4:1-8. doi: 10.1017/ice.2019.127. [Epub ahead of print].