Endocarditis in congenital heart disease: who is at highest risk?

T he risk of infective endocarditis (IE) remains a major concern in patients with congenital heart disease (CHD), whether unrepaired, palliated, or corrected. The overall incidence of endocarditis in adults with CHD has been reported to be 11 per 100 000 person-years, which is a considerable increase compared with the general population, in which a rate of 1.5 to 6.0 per 100 000 patient-years has been reported. 1,2 In children, the incidence of IE in the general population is ≈3 times lower. CHD is the most prevalent underlying cardiac condition in patients with IE. Despite recommendations for antibiotic pro-phylaxis of IE, increased survival of children with CHD and the use of conduits and prostheses in corrective surgery may have contributed to an increasing incidence of IE. 4 However, CHD-associated IE mortality has decreased substantially to 10% because of improvements in the diagnosis of IE, antimicrobial treatment, cardiac surgery, and interventional therapy. Given the prognosis, morbidity, and high cost of management of IE, IE prophylaxis has long been recommended in an attempt to minimize the incidence of IE. However, no randomized study has been conducted yet to elucidate the efficacy and usefulness of IE prophylaxis. Based on case-control studies, expert opinions, and daily practice, guidelines on IE prophylaxis from international cardiology societies in 2008/2009 were greatly simplified and resulted in a drastic reduction in and limitation of cardiac diseases and procedures in which IE prophylaxis is indicated. 6,7 The guidelines now emphasize the role of primary prevention and limit antibiotic prophylaxis to the highest-risk patients undergoing the highest-risk procedures. Motivated largely by lack of robust evidence of the effectiveness of antibiotic prophy-laxis and a growing recognition of the importance of bacte-remias from routine daily activities in causing IE, antibiotic prophylaxis was deemed reasonable in only a select group of high-risk patients. However, changes in the preexisting guidelines were based on limited data. Owing to a lack of evidence , all recent recommendations are Class IIa and Level of Evidence B or C, similar to the level of evidence of the previous recommendations. At this time, surveillance with administrative databases and more detailed record review may be useful in ascertaining whether the adoption of the revised IE prophylaxis guidelines has changed the prevalence of IE. In addition, for improvement in future IE prevention guidelines, further studies are needed to gain insight into cardiac lesions and procedures at highest risk of developing IE. …