Baltimore et al Infective Endocarditis in Childhood: 2015 Update 1489 increased the risk of IE in children with structurally normal hearts. Currently, in approximately 8% to 10% of pediatric IE develops without structural heart disease or any other readily identifiable risk factors. In these situations, the infection usually involves the aortic or mitral valve second- ary to Staphylococcus aureus bacteremia.6,10 12 Recent initia- tives developed to reduce central line bloodstream infections will likely improve the prognosis for all critically ill children, including those with cardiac conditions, and may impact IE development further in the diverse group of vulnerable patients with central lines. Interestingly, children with congenital or acquired immunodeficiencies but without identifiable risk factors for IE do not appear to be at increased risk for endo- carditis compared with the general population. Furthermore, factors often associated with IE in adults, such as intravenous drug abuse and degenerative heart disease, are not common predisposing factors in children.7 11 IE in Children With Previous Cardiac Surgery or After Placement of Transcatheter Devices Corrective surgery with no residual defect eliminates the attrib- utable risk for endocarditis in children with ventricular and atrial septal defects or patent ductus arteriosus 6 months after surgery. However, surgery itself, including such elements as central vas- cular catheters, intravenous alimentation, and days the patient resides in the intensive care unit, may be important risk fac- tors for the development of IE. Approximately 50% of children with IE complicating CHD have had previous cardiac surgery, particularly palliative shunt procedures or complex intracardiac repairs. Morris et al12 reviewed cumulative incidences of endo- carditis for a number of congenital cardiac lesions in a follow- up series of Oregon residents. The highest annualized risk for IE was found in children who had had repair or palliation of cyanotic CHD. 