Congenitally Malformed Hearts and Prematurity The diagnosis and preoperative care of the preterm neonate with a congenitally malformed heart is challenging The combination of immaturity, low birth weight, and other maturational factors increases the risk of both morbidity and mortality in the preoperative, perioperative, and postoperative domains Extremely low birth weight neonates are an exceptionally difficult group to treat.181–183 There are no published data or guidelines on best practice for the management of preterm neonates with congenital cardiovascular malformations Most of the current practices incorporate best evidence for the care of preterm neonates with treatments normally used for full-term infants More important, these neonates are often best cared for in tertiary neonatal centers with a critical mass of preterm neonates with such malformations, and comprehensive anesthesia, cardiology, critical care, neonatology, nursing, surgery, and support services.269–271 Data are accumulating to support these suppositions, and the public reporting of such outcomes is becoming increasingly debated.272 The effects of preterm birth on the heart are currently an important area of focus and may have lifelong consequences with respect to cardiac function.273 Echocardiography Two-dimensional echocardiography plays a critical role in the care of the preterm neonate with CHD Functions include establishment of an anatomic diagnosis, monitoring ductal patency, evaluation of myocardial performance, and estimation of pulmonary arterial pressures Extremely low birth weight infants may require several studies before intervention to monitor cardiovascular status and the effects of the cardiac defects on other systems indicators such as pulmonary arterial pressure This serial information can help to establish the time frame by which to use interventions or additional imaging techniques.274 Indeed, close coordination of cardiac services has made new interventional techniques possible that may one day transform care of these patients, and accumulating data suggest that outcomes may improve with prenatal planning.275,276 Cardiovascular Care The care of the preterm neonate with structural heart disease should focus on those issues related to prematurity and the specific, anatomic defect These should not be considered mutually exclusive, nor should they be ranked in terms of the overall care plan, because each influences the other In the early postnatal period, therapies are predominantly medical Although somewhat controversial, surgical interventions or other invasive procedures are sometimes delayed until the neonate reaches a maturity and weight at which the risks of an expectant approach outweigh the risks of the specific intervention There is substantial literature examining the impact of both prematurity and low birth weight on the outcome of neonates undergoing repair for CHD.277–280 However, the protocols associated with surgical or interventional approaches to these complex patients are not standardized between centers Indeed, there can be substantial variation even within centers The balance of data now suggests that for many lesions, size and low birth weight, although important, are imperfect predictors of surgical outcome Several series demonstrate superb results with even the smallest of patients.281–283 Exceptions may be made for some extremely low birth weight and those with single ventricle physiology.284–286 Therefore the historical approach of waiting until a patient grows to a designated size is now under reconsideration In contrast, prematurity and/or low birth weight are consistently associated with worse outcomes compared with their full-term/normal birth weight counterparts and must be considered by the treatment team.281,287–290 Unfortunately, simply waiting until a patient reaches gestational age does not fix the problems associated with preterm birth (Fig 15.14) However, careful coordination of care among practitioners is important in the rare child who requires an emergent intervention.291 FIG 15.14 CHD, Congenital heart disease; ICU, intensive care unit Prostaglandin Treatment Neonates with a ductal-dependent cardiac defect require continuous intravenous prostaglandin E2 therapy to ensure ongoing patency In the early phase of stabilization, the dose required ranges from 0.01 to 0.2 µg/kg per minute Once the clinical and hemodynamic state is stable, the agent is normally weaned to the lowest effective dose to avoid excessive pulmonary vasodilation and other side effects.292–294 Again, this is particularly relevant for neonates with functionally single ventricle physiology, where a profound or sustained fall in pulmonary vascular resistance can lead to excessive pulmonary blood flow at the expense of systemic perfusion In rare cases, treatment is required for extended periods waiting surgical intervention This increases the risks of complications related to chronic administration, including apnea, gastric outlet obstruction, and hyperostosis.295–297 Regardless, the principle of adequate feeding and weight gain are exceptionally important in this population to optimize surgical results Monitoring The stability of the systemic circulation should be assessed first and foremost by