The April 25 issue of JAMA reports that patients with infective endocarditis, an inflammation of the inner layer of the heart, who have implanted cardiac devices have a higher rate of complications, including valve infections, heart failure, persistent bacteremia, as well as high in-hospital and 1-year mortality rates, especially if it involves the heart valves.

Background information in the study states:

“Cardiac electronic devices, including permanent pacemakers and implantable cardioverter-defibrillators (ICDs), are increasingly implanted worldwide, with estimates of more than 4.2 million patients with a permanent pacemaker or ICD implanted in the United States between 1993 and 2008.

Cardiac device infection is a serious, emerging disease with a 210 percent increase in incidence between 1993 and 2008. In-hospital charges for this complication are estimated to be at least U.S. $146,000 per case. The management of cardiac device infective endocarditis (CDIE) is complex and usually requires prolonged antibiotic therapy, percutaneous or surgical removal of the device, and possible device reimplantation.”

Eugene Athan, M.D., of Barwon Health in Geelong, Australia, and her team decided to assess CDIE’s characteristics and outcomes in terms of health care linked infections, as well as to determine prognostic factors in relationship to in-hospital and 1-year mortality and outcomes after device removal.

Using data from 2,760 patients with definite infective endocarditis who participated in the International Collaboration on Endocarditis-Prospective Cohort Study (ICE-PCS), which was conducted in 61 centers in 28 countries between June 2000 until August 2006, the team diagnosed 177 or 6.4% of patients with definite infective endocarditis, which included 152 or 85.9% of patients with a permanent pacemaker, whilst 21 or 11.9% of patients had an ICD, and 4 or 2.3% of patients had an unspecified type of device.

The majority of the patients, i.e. 74% were male and on average 71 years old. 149 patients or 84.2% had positive blood cultures, with isolates being predominantly staphylococcal (Staphylococcus aureus, 35.0% and 31.6% of coagulase-negative staphylococci). 26 CDIE patients (14.7%) died during the index hospitalization, which included 18 of 141 patients (12.8%) who had their device surgically removed and 8 of 34 patients (23.5%) who had not. The findings revealed that 15 patients died and 10 were lost to follow-up between hospital discharge and 1-year follow-up. The outcome was that 126 (71.2%) of CDIE patients from all 177 were alive at 1-year, whilst 41 patients (23.2%) had died.

66 patients (37.3%) had coexisting valve infections, whilst 15.3% suffered heart failure complications and 15.8% persistent bacteremia. The researchers comment:

“Several of these complications were found to be associated with in-hospital and 1-year mortality in patients with CDIE. The high rates of mortality emphasize the need for improved preventive measures, including optimal skin decontamination and appropriate antibiotic administration at the time of cardiac device insertion or manipulation, as well as careful attention to any invasive or intravascular procedures performed after device implantation.”

81 of CDIE patients, i.e. 45.8% suffered from health care-related infection, which included 61 patients or 34.5% with nosocomial, i.e. hospital-acquired infection and 20 or 11.3% of patients with nonnosocomial infections.

A further assessment demonstrated a survival benefit at 1-year for device removal during the initial hospitalization in 28 out of 141 patients, i.e. 19.9% of patients who underwent device removal during the index hospitalization had died at 1 year, compared with 13 out of 34 patients, or 38.2% who had no device removal.

The researchers conclude:

“Given that numbers of cardiovascular implantable electronic devices placed are increasing rapidly, further studies on the prevention and treatment of this serious complication are needed.”

Written By Petra Rattue