Infective endocarditis uncommon in kids with congenital heart disease

By MD Will Boggs

NEW YORK (Reuters Health) - Six in 1000 children with congenital heart disease will develop infective endocarditis between birth and age 18 years, researchers from Canada report.

"Consistent with the current American Heart Association guidelines, we found that children with lesions associated with cyanosis at birth and those who had undergone cardiac surgery in the previous six months were at significantly elevated risk of developing infective endocarditis," Dr. Ariane J. Marelli from McGill University, Montreal, Quebec, Canada told Reuters Health.

"However, two patient groups -- children with endocardial cushion defects and those with left-sided lesions -- were also found to be at risk."

Although congenital heart disease (CHD) is the most prevalent underlying cardiac condition in children with infective endocarditis (IE) in developed countries, the risk of infective endocarditis and the identification of CHD lesions at highest risk of IE aren't clear.

Dr. Marelli and colleagues used information on all patients in the Quebec CHD Database who were children between January 1988 and March 2010 to determine the risk of IE in these youngsters.

There were 136 cases of IE among 34,279 children followed since birth. The cumulative incidence from birth to age 18 was 6.1 cases per 1000.

This rate corresponds to an incidence of 4.1 cases per 10,000 person-years - which is lower than the reported 11 cases per 10,000 person-years in adults with CHD, the authors reported September 24 online in Circulation.

"The reduced frequency of IE in children versus adults with CHD parallels the trend in the general population, where the incidence of IE in adults ranges from 15 to 60 cases per million person-years, whereas in children it is lower at 3.9 to 6.4 cases per million person-years," the researchers say.

The cumulative incidences per 1000 to age 18 were highest in children with cyanotic CHD (31.0), endocardial cushion defects (11.1), and left-side lesions (7.9) and were somewhat lower in children with right-sided lesions (4.2), patent ductus arteriosus (PDA) (3.2), ventricular septal defect (3.2), atrial septal defect (3.0), and other CHD (5.5).

In multivariate analysis, the risk of IE was increased 5.34-fold by cardiac surgery in the previous six months and 3.53-fold by age under 3 years.

Compared with atrial septal defect, cyanotic CHD elevated the risk of IE 6.44-fold, endocardial cushion defects elevated the risk 5.47-fold, and left-sided lesions elevated the risk 1.88-fold.

"Similarly to a study on a US national sample of pediatric IE hospitalizations, but in contrast to other IE reports in adults, we observed comparable IE frequency in boys and girls," the investigators note.

"Clinicians treating children with heart defects can help educate parents regarding infective endocarditis and its prevention, particularly in the highest risk groups identified in this study," Dr. Marelli said. "Parents of children with heart birth defects should discuss with their physicians how to prevent these potentially serious infections."

For endocardial cushion defects and left-sided lesions, the authors say, "Currently, these lesions are not indicated for prophylaxis unless they meet other eligibility criteria, such as previous IE episodes or cardiac prostheses. Our findings help identify groups of children with CHD who are at highest risk of IE, inform cost-effectiveness analyses of antibiotic use by providing data on numbers of population at risk and IE cases, and contribute to better interpretation of data collected since the change in guidelines."

Dr. Barbara J. M. Mulder from Academic Medical Center, Amsterdam, The Netherlands, wrote an editorial related to this report. She told Reuters Health, "Our insight in CHD patients at high risk for IE is still limited. Whether the use of antibiotic prophylaxis should be extended to patient groups and procedures not included in the current recommendations requires further research."

"Other crucial studies should include an evaluation of the protective efficacy and cost-effectiveness of prophylaxis and an evaluation of the relative importance of bacteremias from routine daily activities versus invasive procedures in causing IE," Dr. Mulder said.

SOURCE: http://bit.ly/1d36bZW

Circulation 2013.