Certain congenital heart defects may raise children’s risk of developing infective endocarditis (IE), Canadian researchers found in a study published Sept. 24 in Circulation. Children with cyanotic congenital heart disease (CHD) lesions, left-sided lesions and endocardial cushion defects were at highest risk for IE.

“In developed countries, CHD is the most prevalent underlying cardiac condition in children with IE. However, the risk of IE in a population-based cohort has never been reported, and the identification of CHD lesions at highest risk of IE has relied primarily on case series reports,” wrote the authors, led by Dinela Rushani, MSc, of McGill University in Montreal.

In 2007, the American Heart Association revised its pre-procedural antibiotic prophylaxis guidelines to no longer include certain patients, including those with left-sided lesions or endocardial cushion defects. A year later, a National Institute for Health and Clinical Excellence group hoped to determine the risk of developing IE in children with certain congenital heart conditions by using a population-based cohort design to estimate risks.

Using information from the Quebec CHD database from 1988 through 2010, the researchers, who sought to address the group's questions, performed a population-based analysis of more than 47,000 children with CHD followed for more than 458,000 patient-years. There were 185 cases of IE.

In the subset of patients followed since birth, the cumulative incidence from birth to age 18 was 6.1 per 1,000 children, or an incidence rate of 4.1 per 10,000 years.

In comparison with atrial septal defects, children with cyanotic lesions had the highest risk of IE (adjusted rate ratio 6.44). Children with endocardial cushion defects (adjusted rate ratio 5.34) and left-sided lesions (adjusted rate ratio 1.88) were also at higher risk.

Having cardiac surgery between 0 and six months of age and being younger than three years of age also increased risk of developing IE.

The authors acknowledged that despite the strength of their population-based, longitudinal approach, their data was subject to misclassification. They also did not have any clinical information for the cases, which could make their findings less valid and less generalizable.

However, they argued that their findings could help identify patients who are at risk for a serious infection.

“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.”

In an accompanying editorial, Barbara J.M. Mulder, MD, PhD, of Academic Medical Center in Amsterdam, wrote that Rushani et al made important steps toward future revision of the current guidelines, although much more research is needed.

“Based on studies as reported by the Quebec investigators, a future revision of IE prevention guidelines might lead to future recommendations which are based on much more robust data and substantial evidence,” she wrote.