Cardiac Device-Related Infective Endocarditis

Abstract & Commentary

By John P. DiMarco, MD, PhD, Professor of Medicine, Division of Cardiology, University of Virginia, Charlottesville. Dr. DiMarco does research for Medtronic, is a consultant for Medtronic, Novartis, and St. Jude, and is a speaker for Boston Scientific.

Source: Athan E, et al, for the ICE-PCS Investigators. Clinical characteristics and outcome of infective endocarditis involving implantable cardiac devices. JAMA 2012;307:1727-1735.

This study reports data from the International Collaboration on Endocarditis-Prospective Cohort Study (ICE-PCS) on the clinical characteristics of infective endocarditis related to pacemakers and ICDs. ICE-PCS collected data on 3284 patients with endocarditis from 64 centers in 28 countries in a central database. Patients were enrolled if they met criteria for possible or definite infective endocarditis based on modified Duke criteria. This study includes only patients with definite infective endocarditis. The major outcomes of interest analyzed were in-hospital and 1-year mortality. Definite cardiac device infected endocarditis (CDIE) was present when valvular or lead vegetations were detected by echocardiography or the Duke criteria for infective endocarditis were met. Nosocomial infections were defined as infective endocarditis cases that developed in a patient hospitalized for more than 48 hours prior to the onset of signs or symptoms. Non-nosocomial health care associated infections were defined if endocarditis developed as a result of a health care intervention, e.g., an indwelling intravascular line. Community-acquired infective endocarditis was defined as those cases that developed before hospitalization or extensive out-of-hospital contact with health care interventions.

CDIE was diagnosed in 177 (6.4%) of the 2760 patients with definite infective endocarditis. This group included 152 patients with permanent pacemakers, 21 with ICDs, and four patients with an unknown type device. The median age was 71.2 years; 27.1% had diabetes mellitus; 74% were male. The most common agents involved were staphylococcal species (Staphylococcus aureus — 35.0%; coagulase-negative staphylococci — 31.6%). Vegetations were seen on echocardiography in 159 patients (89.8%), and in 135 patients vegetations were attached to the intracadiac leads. Coexisting valve infection was found in 66 patients. As might be expected, the tricuspid valve was the valve most commonly involved. Concomitant valve infection increased the risk for in-hospital mortality with an odds ratio of 3.31. Device and lead removal was performed in 141 of 177 patients. Thirty patients also underwent valve surgery during the index hospitalization. Twenty-six of the 177 patients (14.7%) died during the index hospitalization. The death rate was 12.8% among those who underwent device removal and 23.5% among those who did not. After hospital discharge, an additional 15 patients died and 10 were lost to follow-up. For the entire group, 126 of 177 patients were alive at 1 year, 41 (22%) had died, and 10 (5.6%) were lost to follow-up. Device removal during the index hospitalization was associated with improved 1-year survival. A presence of concomitant valve infection was found to confer worse survival. The device-related infection was thought to be health care associated in 81 (45.8%) patients with 61 nosocomial and 20 non-nosocomial infections. Health-care-associated infections were more often associated by S. aureus and were associated with persistent bacteremia and increased in-hospital mortality.

The authors conclude that cardiac device-related infective endocarditis is frequently associated with health care interventions, has a high rate of complications — especially concomitant valve infection — and results in high in-hospital and 1-year mortality. Device removal is associated with better survival at 1 year.

Commentary

There are almost 2 million patients in the United States with pacemakers and ICDs. These patients often live many years with their implanted devices. As a result, the incidence of cardiac device-related infections is rising. As shown in this study, the consequences of a systemic infection involving a cardiac device are very serious with a high in-hospital and 1-year mortality.

Infections that appear within the first year after a device implant are fairly easy to manage. The device and leads can usually be removed easily and safely, and the major problem is treating the infection and supporting the patient until a new device can be implanted. When the device has been in place longer, leads become more difficult to remove and the risks of lead extraction, although low in experienced centers, increase. In current practice, more device-related infections arise after device generator changes or upgrades than with new implants, so these extraction procedures are often quite complicated.

Prevention of device infection is clearly the most important strategy. Prophylactic antibiotics around the time of device procedures have been shown to be beneficial. Whether prophylactic antibiotics should be used in all device patients undergoing any intravascular procedure or therapy is a question that will have to be addressed in future studies. Extreme caution should be exercised in any cardiac device patients with other indwelling catheters in the hospital.

Financial Disclosure: Clinical Cardiology Alert's Editor, Michael H. Crawford, MD, reports no financial relationships relevant to this field of study, and peer reviewer, Ethan Weiss, MD, is a scientific advisory board member for Bionovo. Managing Editor, Neill Kimball, and Executive Editor, Leslie Coplin, report no financial relationships relevant to this field of study.