Cardiovascular implantable electronic device (CIED) infections are hazardous and debilitating. The rate of these infections has swelled over the past decade, hindering patient outcomes and increasing healthcare costs. Numerous questions remain, including the causes for this spike, and what strategies are most helpful to curb them.
Between 1997 and 2004, device implantation rates for pacemakers and implantable cardioverter-defibrillators (ICDs) increased 19 percent and 60 percent, respectively, according to the American Heart Association (AHA) (Circulation 2010;121:458-477). Device infection rates have simultaneously risen with an increase in the number of devices. Between 1996 and 2003, the rates of CIED infection rose almost three-fold for pacemakers and six-fold for ICDs, according to a National Hospital Discharge Survey (J Am Coll Cardiol 2006;48:590-591).
While the incidence rate may be small at three to four infections per 1,000 device implants, many infections may be preventable, providing a target for improving outcomes and keeping costs in check.
The source of infection
"Any infection is too many," says Paul A. Friedman, MD, professor of medicine in the division of cardiovascular disease at the Mayo Clinic in Rochester, Minn. But what are the factors that put patients at a greater risk for a device infection? According to the AHA, these factors include: oral anticoagulation use; comorbidities; periprocedural factors, including the failure to administer preoperative antimicrobial prophylaxis; device revision/replacement; amount of implanted hardware; operator experience; and the microbiology of bloodstream infection in patients with devices.
Patients on long-term steroids, with malignancies or with permanent central venous catheters also are at risk, Friedman offers. "Any of these factors would make a patient prone to infection," he adds. "Whenever you are breaking into skin, you are breaking down a barrier that keeps bacteria outside of the body."
With a device infection, it is imperative to distinguish whether the infection is in the local pocket or the blood stream, Friedman notes. "One must pinpoint whether the device is infected or whether the patient with the infection just happens to have a device to understand the proper method of treatment," Friedman says. Common treatments are removal of the infected device or antimicrobial treatment, among others.
Device-related infections also increase costs. M. Rizwan Sohail, MD, assistant professor in the division of infectious disease at the Mayo Clinic in Rochester, et al found that patients with device infections had higher rates of mortality and longer length of stay, which contributed to higher in-hospital and out-of-hospital costs (Arch Intern Med Sept. 12, 2011, online). They reported that mean length of stay was three-fold higher and that total hospitalization costs were 55 to 118 percent higher for patients with infection compared with those without. Not including the cost of a device, costs were $16,000 per patient more for infection.
Operator, what's your volume?
Device infection occurs at the hands of even the most experienced operators; however, some have argued that as indications for ICD implantation have expanded, more inexperienced operators who practice in lower volume centers have begun performing these procedures. "Device implantations performed by these less experienced operators may create a higher risk of infection, but whether this relates to the heightened infection rate, we are still not sure," says Samir Saba, MD, director of cardiac electrophysiology at the University of Pittsburgh Medical Center in Pennsylvania.
However, results from a study by Al-Khatib et al showed that physicians with the highest device implant volume saw the lowest rates of complications compared with physicians who had the lowest volume of device implants, 3.8 percent vs. 6 percent, respectively (J Am Coll Cardiol 2005;46:1536-1540). While 90-day mortality rates did not significantly differ between the two groups, patients who had ICDs implanted in all but the highest volume quartile had an increased risk of developing infection.
On the flip side, Arnold J. Greenspon, MD, director of cardiac electrophysiology at Thomas Jefferson University Hospital in Philadelphia, and colleagues surmised in a 16-year study of device infection trends that the rate of overall infection may be driven by the increased number of ICD implantations, and the fact that patients