Cardiovascular implantable electronic device infection: A complication of medical progress

AREAS OF UNCERTAINTY AND CHALLENGE

Although there is no controversy about the need for complete removal of infected devices in order to effect a cure, the appropriate duration of antibiotic therapy after device removal is less clear. Dababneh and Sohail provide a useful algorithm to help with this decision. Patients usually need a new device to replace the infected one and there is a legitimate reason for concern about undertreating, since one would not want the new device to become infected because of inadequate antibiotic therapy. When endovascular infection is suspected or documented, patients are probably best treated as they would be for infective endocarditis.

Difficulties arise when patients with a CIED develop bacteremia with no echocardiographic evidence of device infection. Finding the source of bacteremia is very important because a diagnosis of CIED infection indicates that the device has to be removed. When there is a clear alternative explanation for the bacteremia, the CIED does not have to be removed. The type of bacterium helps clinicians to gauge the likelihood of CIED infection and to decide on the appropriate course of action. These cases should always be managed in conjunction with an infectious disease specialist and a cardiac electrophysiologist.

Another concern is secondary seeding of an uninfected CIED caused by bacteremia from another source. This concern is particularly acute with S aureus bacteremia. When patients with a CIED and S aureus bacteremia have been studied, endovascular CIED infection was documented in about half, although only a few had evidence of pocket inflammation.^7,8 This suggests that the devices were seeded via the endovascular route.

Medical procedures such as dialysis and total parenteral nutrition require frequent intravascular access—often facilitated by leaving an indwelling vascular catheter in place. Frequent entry into the intravascular compartment puts patients at substantial risk of bloodstream infection, and in patients with a CIED this can be complicated by device infection. In patients with a CIED and an indwelling vascular catheter who develop bacteremia, determining the source of the bacteremia is particularly challenging, as is the treatment. Thus, preventing endovascular infection in such patients is extremely desirable, but there are no easy solutions.

PLACING CIED INFECTIONS IN PERSPECTIVE

The vast majority of patients with a CIED never develop a device infection. Those unfortunate enough to have a CIED infection have little choice other than to have the device removed, but those diagnosed early and treated appropriately generally do well. The development of CIEDs has been an important advance in the practice of cardiac electrophysiology. An appropriate understanding of CIED infection and its treatment will help optimize the diagnosis and management of this complication when it does occur.