1. The Duke Clinical Research Institute, Durham, NC (D.T., C.P.H., K.D.H.).
2. Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (A.S.W.).
3. Division of Cardiac Surgery, Department of Surgery, Johns Hopkins School of Medicine, Durham, NC (M.L.J.).
4. Department of Pediatrics, Duke University Medical Center, Durham, NC (C.P.H., G.F.F.).
5. Department of Pediatrics, The Medical University of South Carolina, Charleston (J.M.C.).
6. Department of Surgery, All Children’s Hospital and John Hopkins University, Baltimore, MD (J.P.J.).
7. Department of Cardiovascular and Thoracic Surgery, University of Texas Southwestern (R.D.B.J.).
8. Department of Pediatrics, Cincinnati Children’s Hospital, OH (B.H.G.).