Neonatal Cardiac Care, a Perspective Ganga Krishnamurthy, a Veniamin Ratner, a and Emile Bacha b Every year in the United States approximately 40,000 infants are born with congenital heart disease. Several of these infants require corrective or palliative surgery in the neonatal period. Mortality rates after cardiac surgery are highest amongst neonates, particularly those born prematurely. There are several reasons for the increased surgical mortality risk in neonates. This review outlines these risks, with particular emphasis on the relative immaturity of the organ systems in the term and preterm neonate. Semin Thorac Cardiovasc Surg Pediatr Card Surg Ann 16:21-31 © 2013 Elsevier Inc. All rights reserved. Introduction C ongenital heart disease is the most common birth de- fect. 1 Recent prevalence estimates range from 6 to 10 per 1,000 live births. 2-4 Nearly 40,000 infants are born with a congenital heart defect each year in the United States; world- wide, over 1 million such babies are born every year. 1,5 Many of these infants require surgery to correct or palliate their heart defect during their lifetime; several require surgery in the newborn period. Between 2007 and 2010, approximately 80,000 patients underwent cardiac surgery for congenital heart disease across 96 North American centers. 6 Figure 1 depicts the age distri- bution of these patients. Although neonates comprised only 25% of the total surgical volume, they accounted for more than 50% of all deaths that occurred during this time period (Fig. 2). Tremendous strides in congenital heart surgery, ad- vances in cardiopulmonary bypass techniques, and im- proved preoperative and postoperative management skills have resulted in a general decline in operative mortality across all age groups. 7 However, mortality rates after neonatal cardiac surgery continue to be high. 6,7 One in 10 neonates does not survive to discharge after cardiac surgery. 6 Multiple factors contribute. Premature birth and low birth weight add substantial risk. 8,9 Lesions requir- ing surgery in the neonatal period are often quite complex. Performance of intricate surgical procedures in tiny hearts requires superior technical skills and several years of experi- ence for mastery. Neonates pose technically challenging is- sues related to structure, cannulation, and cardiopulmonary bypass. Abnormal preoperative circulation and effects of car- diopulmonary bypass on immature organ systems are addi- tional factors that place neonates at greater risk for death after surgery. Neonates born prematurely, ie, before 37 completed weeks of gestation, are at greater risk of death after cardiac surgery than those born after 37 weeks. 8,10 This dichotomous distinction, although not untrue, makes an erroneous as- sumption that the risk of death after 37 weeks is uniformly equivalent. Population and single-center studies have dis- proven this theory in babies born with congenital heart dis- ease and in those born without birth defects. 11,12 There is an incremental decline in death rate from 37 to 40 weeks, with the nadir at 39 to 40 weeks. 8,10 Death rates increase again if delivery is delayed beyond 41 weeks. Extension of pregnancy from 37-38 weeks to 39-40 weeks provides a significant sur- vival benefit and reduces the risk of complications. 8,10 The majority of babies with congenital heart disease are born before 39-40 weeks of gestation. 8 Many babies are elec- tively delivered before the due date, for better coordination of delivery, catheter intervention if necessary, and to avoid in- utero demise. The recent spate of single-center and popula- tion studies have shown significant risk of mortality and mor- bidity among near-term babies and should caution against this practice. 8,10-12 Elective delivery of babies before 39 com- pleted weeks of gestation should be discouraged, absent any obstetrical or fetal risk. Local, state, and regional initiatives to eliminate non-medically indicated elective deliveries before 39 weeks are critical endeavors that may help reduce neona- tal death rate, including those after cardiac surgery. 13 Why should birth that occurs only 2 to 3 weeks before the due date confer such a disadvantage? The answer is un- a Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY. b Department of Surgery, College of Physicians and Surgeons, Columbia University, New York, NY. Address correspondence to Ganga Krishnamurthy, MBBS, Assistant Profes- sor of Pediatrics, Division of Neonatology, College of Physicians and Surgeons, Columbia University, 3959 Broadway, BH12 N, #1211, New York, NY 10032. E-mail: gk2008@columbia.edu 21 1092-9126/13/$-see front matter © 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1053/j.pcsu.2013.01.007 Items 5-6