Outcome of preterm infants with congenital heart disease

Short-term outcomes in premature neonates adhering to the philosophy of supportive care allowing for weight gain and organ maturation prior to cardiac surgery

BACKGROUND

Prematurity is a recognized risk factor for morbidity and mortality following cardiac surgery. The purpose of this study was to examine short-term outcomes following cardiac surgery in premature neonates adhering to our institutional philosophy of supportive care allowing for weight gain and organ maturation.

METHODS

Retrospective review of all neonates undergoing cardiac surgery from January 2002 to May 2008. A total of 810 neonates (<30 days of age) were identified. Prematurity defined as less than 36 weeks of gestation. Neonates undergoing ductus arteriosus ligation alone were excluded. In all, 63 neonates comprised the premature group. Term group comprised 244 randomly selected term neonates in a 1:4 ratio. Outcome variables were compared between the 2 groups.

RESULTS

Median gestation 34 weeks, range 24 to 35 weeks. Defects: 2 ventricle, normal arch (41% premature vs 44% term; P = .7), 2 ventricle, abnormal arch (24% vs 22%; P = .8), single ventricle, normal arch (21% vs 15%; P = .2), single ventricle, abnormal arch (14% vs 19%; P = .4). Premature neonates were older and smaller at surgery. Cardiopulmonary bypass procedures were performed less frequently in premature neonates (49% vs 69%; P = .004). Length of mechanical ventilation at our institution (6 days [0.5-54) vs 4 days [0.5-49); P = .06); postoperative hospital stay at our institution (17 days [1-161) vs 15 days [0-153); P = .06); and mortality (16% vs 11%; P = .2) was not different between the 2 groups.

CONCLUSION

Early outcome seems independent of weight, prematurity, cardiopulmonary bypass, and type of first intervention. Importantly, there was no statistical difference in mortality between the 2 groups, regardless of how they were treated. Further long-term follow-up is needed in this patient population.

Survival and morbidity outcomes for very low birth weight infants with Down syndrome

OBJECTIVE

Our objective was to compare survival and neonatal morbidity rates between very low birth weight (VLBW) infants with Down syndrome (DS) and VLBW infants with non-DS chromosomal anomalies, nonchromosomal birth defects (BDs), and no chromosomal anomaly or major BD.

METHODS

Data were collected prospectively for infants weighing 401 to 1500 g who were born and/or cared for at one of the study centers participating in the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network in 1994-2008. Risk of death and morbidities, including patent ductus arteriosus (PDA), necrotizing enterocolitis (NEC), late-onset sepsis (LOS), retinopathy of prematurity, and bronchopulmonary dysplasia (BPD), were compared between VLBW infants with DS and infants in the other groups.

RESULTS

Infants with DS were at increased risk of death (adjusted relative risk: 2.47 [95% confidence interval: 2.00-3.07]), PDA, NEC, LOS, and BPD, relative to infants with no BDs. Decreased risk of death (relative risk: 0.40 [95% confidence interval: 0.31-0.52]) and increased risks of NEC and LOS were observed when infants with DS were compared with infants with other non-DS chromosomal anomalies. Relative to infants with nonchromosomal BDs, infants with DS were at increased risk of PDA and NEC.

CONCLUSION

The increased risk of morbidities among VLBW infants with DS provides useful information for counseling parents and for anticipating the need for enhanced surveillance for prevention of these morbidities.

Analysis of 8681 neonates with transposition of the great arteries: outcomes with and without Rashkind balloon atrial septostomy

BACKGROUND

Rashkind balloon atrial septostomy is a common cardiac procedure aimed at improving systemic oxygenation in newborns with cyanotic congenital cardiac defects, such as transposition of the great arteries. Recent reports on the safety of this procedure were from limited series at single institutions. We analysed two complementary national databases to evaluate clinically relevant outcomes of this procedure.

METHODS AND RESULTS

We performed an analysis of transposition of the great artery patients nationwide using 15 years of the Nationwide In-patient Sample and three complementary years of the Kids' Inpatient Database. Variables included gender, race, age, and co-existing diagnoses. Outcomes included mortality, length of stay, and hospital charges. Comparison between patients undergoing Rashkind procedure or not was performed using Pearson's chi-square and Kruskal-Wallis tests. We identified 8681 patients with transposition of the great arteries, of whom 1742 (20%) underwent Rashkind procedure. Patients undergoing Rashkind procedure had lower mortality (10% versus 12%, p = 0.021), despite higher median co-morbidities and longer median length of stay. Rashkind procedure was not associated with increased risk of necrotising enterocolitis (1% versus 1%, p = 0.630), but was associated with nearly twice the risk of clinically recognised stroke (1% versus 0%, p = 0.046).

CONCLUSIONS

This study represents the largest national analysis of transposition of the great artery patients to date, with a subset treated with Rashkind procedure. Patients not undergoing Rashkind procedure had higher mortality. Rashkind procedure was not associated with increased risk of necrotising enterocolitis, but was associated with twice the risk of stroke.

Morbidity and mortality after surgery for congenital cardiac disease in the infant born with low weight

OBJECTIVE

Low weight at birth is a risk factor for increased mortality in infants undergoing surgery for congenitally malformed hearts. There has been a trend towards performing surgery in patients early, and for amenable lesions, in a single stage rather than following initial palliative procedures. Our goal was to report on the current incidences of morbidities and mortality in infants born with low weight and undergoing surgery for congenital cardiac disease.

METHODS

We made a retrospective review of the data from patients meeting our criterions for entry from July, 2000, through July, 2004. The criterions for inclusion were weight at birth less than or equal to 2500 grams, and congenital cardiac malformations requiring surgery during the initial hospitalization. A criterion for exclusion was isolated persistent patency of the arterial duct. We assessed preoperative, intraoperative, and postoperative variables.

RESULTS

We found a total of 105 patients meeting the criterions for inclusion. The median weight at birth was 2130 grams, and median gestational age was 36 weeks. The most common morbidity identified was infections of the blood stream. Infections, and chronic lung disease, were associated with increased length of stay. Survival overall was 76%. Patients with hypoplastic left heart syndrome, or a variant thereof, had the lowest survival, of 62%. The needs for cardiopulmonary resuscitation, or extracorporeal membrane oxygenation, post-operatively were the only factors identified as independent risk factors for mortality.

CONCLUSION

Patients undergoing surgery during infancy for congenital cardiac disease who are born with low weight have a higher mortality and morbidity than those born with normal weight.

Are black and Hispanic infants with specific congenital heart defects at increased risk of preterm birth?

Congenital heart defects (CHDs) are a leading cause of infant morbidity and mortality. Infants with CHDs have increased risk of preterm birth (PTB) compared to infants without birth defects. Although non-Hispanic (NH) Blacks are more likely to be born preterm and Hispanics have rates similar to those of PTB to NH-Whites, it is unknown if this pattern is present for infants with specific types of CHDs. Our intent was to determine if defect-specific risk of PTB varies by maternal race/ethnicity among infants with CHDs. We conducted a retrospective cohort study with 14,888 singleton infants from the Florida Birth Defects Registry, born in 1998-2003 to resident NH-White, NH-Black, and Hispanic women aged 15-49, diagnosed with 11 CHDs. Covariates were taken from Florida live birth certificates. PTB was defined as 20-36 weeks of gestation. Odds ratios (OR) and P-values were calculated from defect-specific multivariable logistic regression models; statistical significance was set at P < 0.002. The greatest risk of PTB was for NH-Black infants with conotruncal CHDs. NH-Blacks with common truncus, transposition of the great vessels, and tetralogy of Fallot had increased risk of PTB compared to NH-Whites (OR = 4.8, P = 0.015; OR = 3.1, P = 0.004; and OR = 2.0, P = 0.005, respectively). Hispanics with conotruncal CHDs had almost a twofold risk of PTB compared to NH-Whites (P > 0.002). NH-Blacks with tricuspid valve atresia/stenosis had 4.1 times (P = 0.034) and Hispanics had 2.1 times (P = 0.314) the risk for PTB compared to NH-Whites. NH-Blacks with hypoplastic left heart syndrome had 2.0 times (P = 0.047) the risk for PTB as NH-Whites. Both NH-Black and Hispanic infants with CHDs may be at increased risk of PTB, depending on the type of CHD, but the etiology is unknown. Future research is needed to further examine this complex relationship.

The neonatal intestinal vasculature: contributing factors to necrotizing enterocolitis

Based on the demonstration of coagulation necrosis, it is clear that intestinal ischemia plays a role in the pathogenesis of necrotizing enterocolitis (NEC). Intestinal vascular resistance is determined by a dynamic balance between vasoconstrictive and vasodilatory inputs. In the newborn, this balance heavily favors vasodilation secondary to the copious production of endothelium-derived nitric oxide (NO), a circumstance which serves to ensure adequate blood flow and thus oxygen delivery to the rapidly growing intestine. Endothelial cell injury could shift this balance in favor of endothelin (ET)-1-mediated vasoconstriction, leading to intestinal ischemia and tissue injury. Evidence obtained from animal models and from human tissue collected from infants with NEC implicates NO and ET-1 dysregulation in the pathogenesis of NEC. Strategies focused on maintaining the delicate balance favoring vasodilation in the newborn intestinal circulation may prove to be useful in the prevention and treatment of NEC.

Assessment of hydraulic performance and biocompatibility of a MagLev centrifugal pump system designed for pediatric cardiac or cardiopulmonary support

The treatment of children with life-threatening cardiac and cardiopulmonary failure is a large and underappreciated public health concern. We have previously shown that the CentriMag is a magnetically levitated centrifugal pump system, having the utility for treating adults and large children (1,500 utilized worldwide). We present here the PediVAS, a pump system whose design was modified from the CentriMag to meet the physiological requirements of young pediatric and neonatal patients. The PediVAS is comprised of a single-use centrifugal blood pump, reusable motor, and console, and is suitable for right ventricular assist device (RVAD), left ventricular assist device (LVAD), biventricular assist device (BVAD), or extracorporeal membrane oxygenator (ECMO) applications. It is designed to operate without bearings, seals and valves, and without regions of blood stasis, friction, or wear. The PediVAS pump is compatible with the CentriMag hardware, although the priming volume was reduced from 31 to 14 ml, and the port size reduced from 3/8 to (1/4) in. For the expected range of pediatric flow (0.3-3.0 L/min), the PediVAS exhibited superior hydraulic efficiency compared with the CentriMag. The PediVAS was evaluated in 14 pediatric animals for up to 30 days, demonstrating acceptable hydraulic function and hemocompatibility. The current results substantiate the performance and biocompatibility of the PediVAS cardiac assist system and are likely to support initiation of a US clinical trial in the future.

Monochorionic twins in which at least one fetus has a congenital heart disease with or without twin-twin transfusion syndrome

AIMS

To review the course of monochorionic (MC) twin gestations in which one or both fetuses were diagnosed with congenital heart disease (CHD) and to identify clinical characteristics regarding the related intrauterine environmental factors particularly associated with non-twin-twin transfusion syndrome (TTTS).

METHODS

This study is a review of a two-center experience of MC twin pregnancies with CHD born between 2000 and 2006.

RESULTS

There were 87 MC twin pregnancies of which 11 were associated with fetal heart disease. We found concordance of CHD in 2 of the 11 twin sets. Among all of the discordant cases, the size of the affected twin was smaller. TTTS was observed in one case associated with CHD; in this case the donor twin had a coarctation of the aorta. Abnormal cord insertion was observed in 9 (69%) out of the 13 affected infants, and a significant relation was found between the presence of CHD and abnormal cord insertion.

CONCLUSIONS

Of the MC twins, the smaller seemed more likely to be affected by primary structural cardiac anomalies. CHD in MC twins is possibly related to an abnormal cord insertion. Further studies are warranted to determine whether a causal relationship exists.

Current Risk Factors and Outcomes for the Arterial Switch Operation

BACKGROUND

The arterial switch operation is the preferred treatment for dextrotransposition of the great arteries and some forms of double-outlet right ventricle.

METHODS

All patients undergoing an arterial switch operation at a single institution from January 1, 1999, to September 1, 2005, were reviewed.

RESULTS

Of the 168 patients, median age was 2 days (range, 0 to 358) and weight was 3.5 kg (range, 1.9 to 11.8 kg). Eleven patients were less than 36 weeks gestational age. Forty percent had coronary patterns other than usual. Mean cardiopulmonary bypass (CPB) time was 147 +/- 45 minutes, and mean cross-clamp time was 77 +/- 27 minutes. At a mean follow-up of 19 +/- 21 months, there were 10 (6%) hospital and 4 (3%) late deaths. Actuarial 1-month, 1-year, and 3-year survivals were 94%, 90%, and 89%, respectively. Bivariate analysis revealed weight less than 2.5 kg (p = 0.032), gestational age less than 36 weeks (p = 0.002), and CPB time greater than 150 minutes (p = 0.0075) decreased hospital survival. Intermediate-term survival was negatively impacted by weight less than 2.5 kg (p = 0.017), gestational age less than 36 weeks (p = 0.0096), CPB time greater than 150 minutes (p = 0.0050), and age at presentation greater than 4 weeks (p = 0.034). By multivariate analysis, gestational age less than 36 weeks (p = 0.0051) and CPB time greater than 150 minutes (p = 0.016) were independent risk factors for hospital mortality. Gestational age less than 36 weeks (p = 0.0096) and CPB time greater than 150 minutes (p = 0.005) were also independent predictors of intermediate-term mortality. Coronary anatomy could not be shown to affect survival, including no deaths among the 12 patients with intramural coronaries.

CONCLUSIONS

The arterial switch operation can be performed with low mortality regardless of diagnosis or coronary pattern. The premature patient and minimizing CPB time remain as challenges to optimize outcomes for the arterial switch operation.

Outcomes following surgery for congenital heart disease in low-birthweight infants

AIM

To describe cardiac surgery, survival and outcomes for low-birthweight (< or = 2500 g) infants undergoing surgery for congenital heart disease.

METHODS

Using data from a prospectively collected population-based database of admissions to neonatal intensive care units in New South Wales and the Australian Capital Territory, we identified all low-birthweight infants undergoing cardiac surgery between 1992 and 2001. Infants with only a persistent ductus arteriosus were excluded. Two-year cardiac and neurodevelopmental outcome data were sought from hospital medical records.

RESULTS

A total of 121 low-birthweight infants underwent cardiac surgery, of whom 34% had a congenital syndrome or non-cardiac birth defect. Most (81%) underwent a palliative surgical procedure in the neonatal period. There were 19 early (15.7%) and 19 late deaths giving a 2-year mortality of 31%. Factors associated with mortality included birthweight below 1500 g (P = 0.006), low weight at surgery (P = 0.028) and Apgar score at 1 min (P = 0.019). No single factor predicted 30-day mortality. By 2 years of age, 27 (33% of survivors) were known to have neurodevelopmental delay. Although 22 children are known to be developing normally, the neurodevelopmental status of 34 children was not known.

CONCLUSIONS

These surgical data were comparable to previous single-institution studies. This group had a high risk of disability due to prematurity, low birthweight and associated conditions. There is a need to prospectively assess and manage neurodevelopmental outcomes in this group.

Causes of death after congenital heart surgery

BACKGROUND

There has been little research about the causes of death after congenital heart surgery.

METHODS

To determine whether mode of death differs after congenital heart surgery, we evaluated the cause of death for 100 consecutive postoperative deaths at our institution. Mode of death was determined based on retrospective chart review including available autopsy reports. Low output states were categorized into ventricular failure; inadequate postoperative physiology (technically adequate surgery and ventricular function, but persistent low cardiac output); pulmonary hypertension; and atrioventricular valve regurgitation.

RESULTS

There was considerable anatomic diversity among patients who died; 46 patients had single-ventricle physiology. The vast majority of patients (n = 79) were in the intensive care unit before surgery. Surgical repairs were revised at initial operation in 22 cases; 7 patients died in the operating room. Seventy-three patients had technically adequate surgical procedures, 23 had residual anatomic defects, and 4 were indeterminate. Thirty patients underwent additional surgical and 9 catheter-based procedures, although some were classified as rescue procedures performed to address minor anatomic or physiologic abnormalities as a last hope to rescue the patient from impending demise. Of 100 deaths, most (n = 52) were due to low cardiac output: 24 inadequate postoperative physiology, 19 ventricular failure, 8 pulmonary hypertension, and 1 valvar regurgitation. Other significant causes of death included sudden cardiac arrest (n = 11), sepsis (n = 11), and procedural complications (n = 8).

CONCLUSIONS

More than half of the deaths were due to low cardiac output, but not exclusively ventricular failure.

The exceptionally rare (sic) Common Scoter

A 1-month-old infant with congenital heart disease underwent initial cardiac surgery (Mee Shunt) at day 20 but was later readmitted because of poor shunt flow and hypoxemia. Despite therapy, the infant deteriorated and suffered a cardiopulmonary arrest. After 40 minutes of resuscitation, spontaneous cardiac output was reestablished, and subsequently, the child was placed on extracorporeal circulation membrane oxygen (ECMO) support. The infant deteriorated further over the next 3 days with persistent acidosis, marked abdominal distension associated with significant nasogastric aspirates, and the passage of small amounts of bloodstained stool. The presumed diagnosis was necrotizing enterocolitis, and despite the grave prognostic indicators, the decision was taken to undertake laparotomy. At surgery, there was 350 mL of unclotted venous blood in the peritoneal cavity. The bowel was grossly normal. A ruptured, infarcted, hemorrhagic spleen was discovered to be the cause of the bleeding. A splenectomy was performed, and the child made rapid recovery, sufficiently well to undergo redo Mee shunt 2 days later. A splenic infarct was confirmed at pathological examination. The cause of the splenic infarct and rupture is uncertain in this baby but may have been related to either cardiopulmonary resuscitation and/or ECMO. The importance of this case is the similarity in presentation in a baby with congenital heart disease between necrotizing enterocolitis (which is relatively common) and hemoperitoneum secondary to splenic rupture (which is very rare). Medical practice contains many useful maxims such as, "What walks like a duck, talks like a duck, is often a duck." This case demonstrates that not all ducks are the common Mallard (Anas platyrhynchos) but occasionally the exceptionally rare (sic) Common Scoter (Melanitta nigra). The management of neonatal cardiac patients on ECMO therapy continues to be a challenge, and particular diagnostic rigor should be applied in their care.

Outcome after preterm delivery of infants antenatally diagnosed with congenital heart disease

OBJECTIVE

To determine outcome of delivery before 36 weeks gestation in babies diagnosed antenatally with serious congenital heart disease (CHD).

STUDY DESIGN

A retrospective database review at 2 tertiary care fetal cardiology centers. Details of neonatal course and outcome were obtained for those antenatally diagnosed with serious CHD who were live born before 36 weeks gestation.

RESULTS

Between January 1998 and December 2002, 9918 women were referred for fetal echocardiography. Serious CHD was diagnosed in 1191 fetuses (12%), of which 46 (4%) delivered prematurely. Median gestation was 33 (range 24-35) weeks, and median birth weight 1.56 (0.50-3.59) kg. Extracardiac/karyotypic anomalies occurred in 23 (50%). Twenty-six babies (57%) underwent neonatal surgery: 16 a cardiac procedure, 5 a general surgical procedure, and 5 both. Eight died during or after operation (31%). Two babies underwent interventional heart catheterization; both died. The overall mortality rate was 72%. Extracardiac/karyotypic anomalies increased the relative risk of death by a factor of 1.36. Mean hospital stay for those surviving to initial discharge was 46 (2-137) days.

CONCLUSIONS

There is a very high morbidity and mortality rate in this group, particularly for those with extracardiac/karyotypic anomalies. This should be reflected in decisions over elective preterm delivery and when counseling parents.

Management of low birth weight infants with congenital heart disease

Low birth weight infants with congenital heart disease (CHD) have a higher mortality risk and likely a higher morbidity risk than their preterm or appropriate for gestational age counterparts without CHD and term counterparts with CHD. As our understanding of the pathophysiology and treatment of the diseases associated with prematurity and growth restriction improves, the outcomes for these infants should continue to improve. In addition, as more of these infants survive and are referred for surgery, operative techniques and strategies are likely to continue to improve. At this time, there is no adequate evidence that mortality is improved by delaying surgery for weight gain or performing palliative operations initially. Given the challenging physiology in this population, optimal management includes early referral to a tertiary or quaternary facility and a multidisciplinary team approach consisting of cardiologists, neonatologists, surgeons, nurses, perfusionists, and anesthesiologists.

Cardiovascular malformations among preterm infants

OBJECTIVE

Preterm birth and cardiovascular malformations are the 2 most common causes of neonatal and infant death, but there are no published population-based reports on the relationship between them. We undertook this study to determine the prevalence and spectrum of cardiovascular malformations in a preterm population, the prevalence of prematurity among infants with cardiovascular malformations, and the influence of prematurity and cardiovascular malformations on outcomes.

METHODS

We based the study on the population of the former Northern Health Region of England. We identified all live-born infants with cardiovascular malformations diagnosed in the first 1 year of life from the regional pediatric cardiology database, which includes the gestational age and details of the diagnosis. We limited ascertainment to malformations diagnosed by the age of 12 months. Infants with isolated patent ductus arteriosus or atrial septal defect were excluded, to avoid ascertainment bias. Infants with ventricular septal defect were classified according to whether they required surgery in the first 1 year. There are no population data on gestational ages for all births in our population for the era of this study; therefore, we used data published in the literature for populations similar to our own to predict that 0.4% of live births occur at <28 weeks of gestation, 0.9% at 28 to 31 weeks, and 6% at 32 to 36 weeks. Overall, 7.3% of live-born infants are preterm.

RESULTS

Of 521619 live-born infants in 1987-2001, 2964 had cardiovascular malformations (prevalence: 5.7 cases per 1000 live births). Cardiovascular malformations were present at 5.1 cases per 1000 term infants and 12.5 cases per 1000 preterm infants. The odds ratio (OR) for a cardiovascular malformation in prematurity was 2.4 (95% confidence interval [CI]: 2.2-2.7). We found that 474 infants (16%) with cardiovascular malformations were born at <37 weeks of gestation, giving an OR for prematurity among infants with a cardiovascular malformation of 2.4 (95% CI: 2.2-2.7). More infants were born preterm with diagnoses of pulmonary atresia with ventricular septal defect (23%), complete atrioventricular septal defect (22%), and coarctation of the aorta, tetralogy of Fallot, and pulmonary valve stenosis (each 20%). Fewer were born preterm with diagnoses of pulmonary atresia and intact ventricular septum (7%), transposition of the great arteries (8%), and single ventricle (9%). We found that 18% of infants with ventricular septal defect requiring surgery were preterm, compared with 13% in the nonsurgical group. Preterm infants with ventricular septal defect required surgery in 30% of cases, compared with 23% of term infants with ventricular septal defect. These figures show that the excess of cardiovascular malformations among preterm infants cannot be explained by greater ascertainment of minor ventricular septal defects. In our denominator population, 646 live-born infants were recognized as having trisomy 21, and gestational age data were available for 609. Of these, 149 (25%; 95% CI: 21-28%) were preterm. Approximately two thirds of infants with complete atrioventricular septal defect have trisomy 21. Complete atrioventricular septal defect was no more common among preterm infants with trisomy 21 (16%) than among term infants with trisomy 21. However, the increased incidence of prematurity among infants with trisomy 21 probably explains some of the excess of preterm births among infants with complete atrioventricular septal defect. Only 4 (11%) of 38 infants with 22q11 deletion were born preterm. None of those infants had pulmonary atresia with ventricular septal defect; therefore, 22q11 deletion does not explain the excess of preterm births in pulmonary atresia with ventricular septal defect. The OR for death in the first 1 year in the presence of a cardiovascular malformation was 4.4 (95% CI: 3.1-5.5) overall; ORs were 1.8 at <28 weeks of gestation, 3.7 at 28 to 31 weeks, 11.0 at 32 to 36 weeks, and 35.6 at term.

CONCLUSIONS

This study showed that preterm infants have more than twice as many cardiovascular malformations as do infants born at term and that 16% of all infants with cardiovascular malformations are preterm. It also showed, not surprisingly, that there is an increased mortality rate among infants born preterm with a cardiovascular malformation. The additional effect of cardiovascular malformations on mortality rates is most marked for term and near-term infants, for whom mortality rates are otherwise low. The excess of cardiovascular malformations among preterm infants is intriguing but not easy to explain. Previous studies of birth weight among infants with cardiovascular malformations reported a significant increase in the likelihood of being small for gestational age among infants with tetralogy of Fallot, complete atrioventricular septal defect, hypoplastic left heart, or large ventricular septal defect. There is an obvious relationship between birth weight and gestational age, and those studies also showed an increased prevalence of prematurity among infants with tetralogy of Fallot, pulmonary stenosis, aortic stenosis, coarctation of the aorta, complete atrioventricular septal defect, or ventricular septal defect. There is also a high prevalence of cardiovascular malformations among late stillbirths, with major differences in the number and spectrum of cardiovascular malformations, compared with those seen in postnatal life. In particular, there is a greater incidence of coarctation of the aorta, double-inlet left ventricle, hypoplastic left heart, truncus arteriosus, double-outlet right ventricle, and atrioventricular septal defect among stillbirths. This spectrum of malformations is similar to that in our study and to those in other reports. Whether the increased prevalence of cardiovascular malformations among preterm infants and the increase in stillbirths suggest clues to the cause is difficult to say. The influence of preterm birth should be taken into account in risk assessment and risk stratification for surgical repair.

Prolonged treatment with prostaglandin in an infant born with extremely low weight

We describe an infant with duct-dependent cardiac disease diagnosed prenatally who was born prematurely, and at extremely low weight. Treatment by infusion of prostaglandin maintained ductal patency for 66 days, permitting weight to be gained whilst under the care of a regional unit for neonatal intensive care prior to transfer for palliative cardiac surgery.

Non-iatrogenic pathology of the preterm infant

Non-iatrogenic anatomical findings at autopsy provide insight into preterm infant physiology. The different patterns of lipid accumulation in the adrenal may correspond to long-term differences in stress response. Cardiac papillary muscle infarction occurs with asphyxia or shock and can explain myocardial dysfunction. Underdevelopment of preterm kidneys may correlate with susceptibility to renal disease and hypertension in adult life. Immaturity of the lung or immature responses to inflammation, rather than high oxygen concentrations or high ventilation pressures, may underlie chronic lung disease in premature infants. Hepatic extramedullary haematopoiesis is normal but, if excessive or abnormally persistent, can be an indicator of fetal disease. Hypertrophic somatostatin islet cells found with intra-uterine growth retardation may correlate with low serum insulin. Thymic involution may mark the degree of stress. Small thyroglobulin stores may limit the premature neonate's initiation of thermogenesis.

Studien zur Morphogenese und Visualisierung des fr�hen embryonalen Herzens im Hinblick auf die Entwicklung konotrunkaler Herzfehler

Most congenital cardiovascular malformations have their origins during early morphogenesis, and some forms of adult-onset cardiovascular disease also arise during embryonic development. Conotruncal heart defects comprise a major category of congenital heart disease and are found in children with a relative high frequency. These defects are associated with a high mortality risk in utero, and after postnatal surgical repair; embryologically they are linked with dextroposed aorta, which is an anomaly of the ventricular outflow tract with malalignment of the great arteries. The etiology and pathogenesis of dextroposed aorta is not known but is thought to be due to abnormal looping and/or incorrect "wedging" of the outflow tract (i.e., wedged positioning of the aorta between the atrioventricular valves) during early heart development. We have studied the morphology and visual development of the embryonic heart in an animal model of dextropsed aorta in a series of experiments to determine possible mechanisms for dextropositioning of the aorta. At this, we have employed besides established methods for analysis of anatomy and pathology (morphological studies, cardiac morphometry, histology, scanning electron microscopy and immunhistochemistry) also new imaging techniques (videocinephotography and time-lapse studies with a digital high-speed video camera, confocal and scanning electron microscopy, optical coherence tomography (OCT) and magnetic resonance microscopy (MRM) for 3D reconstruction of the heart) to achieve a better visualization of normal and pathological changes during heart development. The paper at hand summarizes the results of these studies.

Developmental and behavioral status of infants and young children awaiting heart or heart-lung transplantation

OBJECTIVE

Research into cognitive development and behavior in children undergoing heart or heart-lung transplantation has focused mainly on older children, with investigation of children undergoing transplantation as infants or toddlers being largely retrospective. This study was conducted, therefore, to obtain pretransplant baseline measures of development and behavior for preschool-aged children.

METHODS

Children <3.5 years old were assessed before transplantation (n = 35) and compared with a group of children awaiting conventional cardiac surgery, a group undergoing bone marrow transplantation, and a group of healthy children. Development was measured by using the Ruth Griffiths Mental Development Scales, and behavior was measured with the Achenbach Child Behavior Checklist.

RESULTS

Within the transplant group, 17 had congenital heart disease (CHD), and 18 had cardiomyopathy (CM). Although the overall mean developmental scores were within the normal range for the transplant, conventional cardiac surgery, and bone marrow transplantation groups, scores were significantly lower than those of the healthy group. Within the transplant group, those with CHD had a significantly lower mean developmental quotient than those with CM. Furthermore, the CHD patients obtained significantly lower scores than those with CM on areas of development covering locomotor abilities, speech and hearing, eye-hand coordination, and performance.

CONCLUSIONS

In common with other groups of ill children, patients awaiting heart or heart-lung transplantation are at risk for developmental delay. Diagnosis is a salient factor in determining outcome in most areas of development. Psychosocial interventions need to be targeted to maximize developmental potential before transplantation.

Changes in cerebral oxygenation in children undergoing surgical repair of ventricular septal defects

There have been few published studies on changes in cerebral oxygenation during paediatric cardiac surgery as measured by conventional near-infrared spectroscopy. We studied changes in cerebral oxygenation in 16 children undergoing surgical repair of ventricular septal defects. Fifteen of the patients showed similar patterns of changes: brain tissue concentrations of oxyhaemoglobin decreased significantly during cardiopulmonary bypass, whereas there was no significant change in brain tissue concentrations of deoxyhaemoglobin. In the remaining patient, who suffered decreased blood flow to the lower body during surgery, the pattern of changes was different to that of the other subjects. This patient suffered postoperative respiratory and renal failure. This study suggests that conventional near-infrared spectroscopy may be useful for clinical monitoring during ventricular septal defect repair.

Shortened outflow tract leads to altered cardiac looping after neural crest ablation

BACKGROUND

Congenital conotruncal malformations frequently involve dextroposed aorta. The pathogenesis of dextroposed aorta is not known but is thought to be due to abnormal looping and/or wedging of the outflow tract during early heart development. We examined the stage of cardiac looping in an experimental model of dextroposed aorta to determine the embryogenesis of this conotruncal malformation.

METHODS AND RESULTS

Hearts were examined from neural crest-ablated embryos by using videocinephotography, scanning electron microscopy, and histological sections. The inflow and outflow limbs of the looped cardiac tube were malpositioned with respect to each other, the inner curvature was diminished, and the outflow limb was straighter and displaced cranially in a manner consistent with diminished length. The altered length could be explained by a significant reduction in the number of cells added to the myocardium of the distal outflow tract from the secondary heart field.

CONCLUSIONS

The data are consistent with research showing that normal looping and wedging are essential for normal alignment of the aorta with the left ventricle. These processes are abnormal in neural crest-ablated embryos because of a failure of the outflow tract to lengthen by the addition of myocardial cells from the secondary heart field.

Poor outcome of very low birthweight babies with serious congenital heart disease

OBJECTIVE

To evaluate incidence and mortality of congenital heart disease in very low birthweight babies.

METHOD

Retrospective analysis of a 12 year period.

RESULTS

Forty seven babies were diagnosed with severe congenital heart disease. The most common lesions were ventricular septal defect and coarctation of the aorta. Mortality attributed to congenital heart disease was 32%. Coarctation of the aorta, the second most common lesion, was fatal in 62% of cases. Closure of a patent ductus arteriosus with indomethacin proved to be detrimental in babies with undiagnosed coarctation, causing rapid deterioration in some.

CONCLUSION

Very low birthweight neonates with severe congenital heart disease have a higher mortality than babies with higher birth weight. A contributing factor is closure of a patent ductus arteriosus if an underlying lesion has not been recognised. This could be of significance if the use of prophylactic treatment with indomethacin becomes more common.

Neonates with congenital heart disease

Early reparative surgery in neonates and infants with congenital heart disease, as opposed to initial palliation and later repair, is now commonplace. Changes to the conduct of cardiopulmonary bypass, timing of surgery and surgical techniques, and perioperative management substantially have reduced the postoperative mortality and morbidity for these patients. The success of this strategy of early reparative surgery now has been extended to the premature and low-birth-weight newborn, and, along with this, new challenges to postoperative care in the intensive care unit. However, the low mortality associated with two-ventricle repairs has not been the experience in newborns undergoing palliation for single-ventricle defects, in particular, hypoplastic left heart syndrome. A number of articles regarding management of newborns with single-ventricle defects have been published during the past 12 months, ranging from classification, prenatal diagnosis, treatment options, and predictors of both early and late outcome, which may provide a guide for patient management. As mortality has declined, there has been an increased emphasis on identifying indices that may predict outcome or morbidity both before and after surgery, along with possible strategies to attenuate adverse clinical responses. The inflammatory response to bypass is heightened in neonates and infants, and several reports have addressed possible techniques for attenuating the response. In addition, reports regarding the risk for necrotizing enterocolitis, the utility of lactate as an index of systemic perfusion, potential markers of myocardial and neurologic injury, and the use of mechanical support of the circulation in newborns with congenital heart disease are summarized.