Rushani D, et al. Circulation. 2014;33:173.
Congenital heart disease (CHD) is the most prevalent underlying cardiac condition in children with infective endocarditis (IE) in developed countries. However, the risk of IE in a population-based cohort of children with CHD has never been reported, and the identification of CHD lesions at highest risk of IE has relied primarily on case series reports. Comparisons of risk of IE between cardiac conditions are one important consideration in the development of IE prevention guidelines. The American Heart Association guidelines for the prevention of IE were revised in 2007, with restrictions in the groups of patients for whom antibiotic prophylaxis was indicated before invasive medical procedures. The authors sought to determine the cumulative incidence and predictors for the development of IE in a large population-based cohort of affected children.
The study population consisted of all patients in the Quebec (population 8 million) CHD database who were children (0–18 years of age) born between January 1, 1998, and March 31, 2010. Patients born during the observation period and followed since birth were analyzed. All children identified with IE were matched with 20 controls. Of 34,279 children who were followed since birth and contributed 328,185 person-years up to 18 years of age, 136 cases of IE were observed. Cumulative incidence of IE from birth to 18 years of age, in all CHD lesions combined, was 6.1 first cases per 1000 children, which corresponded to an incidence rate of 4.1 per 10,000 person-years. The lesion group–specific cumulative incidences per 1000 children up to 18 years of age were as follows: cyanotic CHD, 31.0; endocardial cushion defects, 11.1; left-sided lesions, 7.9; right-sided lesions, 4.2; patent ductus arteriosus, 3.2; ventricular septal defect, 3.2; atrial septal defect, 3.0 and other CHD, 5.5. No IE events were observed in children with patent ductus arteriosus past 4 years of age.
Analysis of predictors of IE involved comparison of patients with IE and their calendar time-matched controls from the full population of children with CHD. The most common CHD group among children with IE was cyanotic CHD lesions, present in 34% of cases. Although the next most frequent defects among cases were atrial septal defect (16%) and ventricular septal defect (15%), their proportions were reduced in comparison with controls (27% each).
Children who had undergone cardiac surgery in the previous 6 months were >5 times more likely to develop IE than those who had not. The risk of IE varied substantially across the CHD lesions. Relative to atrial septal defect, the following lesions were most strongly associated with an elevated risk of IE: cyanotic CHD (adjusted rate ratio, 6.44), endocardial cushion defects (adjusted rate ratio, 5.47) and left-sided lesions (adjusted rate ratio, 1.88). Young age was a strong predictor of IE: in comparison with those 6 to 18 years of age, children younger than 3 years were at higher risk of IE, but not those 3 to 6 years old.
Comment: These results help identify groups of children with CHD who are at highest risk of IE. Comparing these findings with the patient groups indicated for prophylaxis in the 2007 American Heart Association guidelines, in line with the current recommendations, cyanotic CHD and cardiac surgery in the previous 6 months were strongly associated with IE. However, 2 other patient groups, children with endocardial cushion defects and left-sided lesions, were also found to be at elevated risk of IE. Patients with these defects were at increased IE risk even if they had no previous cardiac surgery or history of IE. These findings may contribute to informing IE prevention guidelines.