Mark D. Reller

Prevalence of Congenital Heart Defects in Metropolitan Atlanta, 1998-2005

OBJECTIVE To determine an accurate estimate of the prevalence of congenital heart defects (CHD) using current standard diagnostic modalities. STUDY DESIGN We obtained data on infants with CHD delivered during 1998 to 2005 identified by the Metropolitan Atlanta Congenital Defects Program, an active, population-based, birth defects surveillance system. Physiologic shunts in infancy and shunts associated with prematurity were excluded. Selected infant and maternal characteristics of the cases were compared with those of the overall birth cohort. RESULTS From 1998 to 2005 there were 398 140 births, of which 3240 infants had CHD, for an overall prevalence of 81.4/10 000 births. The most common CHD were muscular ventricular septal defect, perimembranous ventricular septal defect, and secundum atrial septal defect, with prevalence of 27.5, 10.6, and 10.3/10 000 births, respectively. The prevalence of tetralogy of Fallot, the most common cyanotic CHD, was twice that of transposition of the great arteries (4.7 vs 2.3/10 000 births). Many common CHD were associated with older maternal age and multiple-gestation pregnancy; several were found to vary by sex. CONCLUSIONS This study, using a standardized cardiac nomenclature and classification, provides current prevalence estimates of the various CHD subtypes. These estimates can be used to assess variations in prevalence across populations, time, or space.

The importance of nomenclature for congenital cardiac disease: implications for research and evaluation.

BACKGROUND Administrative databases are often used for congenital cardiac disease research and evaluation, with little validation of the accuracy of the diagnostic codes. METHODS Metropolitan Atlanta Congenital Defects Program surveillance records were reviewed and classified using a version of the International Pediatric and Congenital Cardiac Code. Using this clinical nomenclature as the referent, we report the sensitivity and false positive fraction (1 - positive predictive value) of the International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis codes for tetralogy of Fallot, transposition of the great arteries, and hypoplastic left heart syndrome. RESULTS We identified 4918 infants and foetuses with congenital cardiac disease from the surveillance records. Using only the International Classification of Diseases diagnosis codes, there were 280 records with tetralogy, 317 records with transposition, and 192 records with hypoplastic left heart syndrome. Based on the International Pediatric and Congenital Cardiac Code, 330 records were classified as tetralogy, 163 records as transposition, and 179 records as hypoplastic left heart syndrome. The sensitivity of International Classification of Diseases diagnosis codes was 83% for tetralogy, 100% for transposition, and 95% for hypoplastic left heart syndrome. The false positive fraction was 2% for tetralogy, 49% for transposition, and 11% for hypoplastic left heart syndrome. CONCLUSIONS Analyses based on International Classification of Diseases diagnosis codes may have substantial misclassification of congenital heart disease. Isolating the major defect is difficult, and certain codes do not differentiate between variants that are clinically and developmentally different.

Review of studies evaluating ductal patency in the premature infant

A series of investigations has been performed to assess the timing of physiologic closure of the ductus arteriosus in premature infants with and without respiratory distress syndrome. The data from these studies emphasize the concept of physiologic ductal patency and give normative data for expected closure rates through the fourth day of life. On the basis of these data, patency on or beyond the fourth day of life is abnormal irrespective of gestational age, and prematurity, in the absence of respiratory distress syndrome, is not a risk factor for persistent patent ductus arteriosus. We also found that persistent patent ductus arteriosus in larger premature infants (> or = 30 weeks of gestation) with respiratory distress syndrome is relatively uncommon. Last, ductal patency was evaluated in a group of low birth weight infants with severe respiratory distress syndrome in a randomized, double-blind trial of exogenous surfactant administration. We concluded that the beneficial effects of exogenous surfactant are not associated with either a greater clinical need for indomethacin or any increased risk of delayed closure of the ductus arteriosus.

Duration of ductal shunting in healthy preterm infants: An echocardiographic color flow doppler study

The purpose of this investigation was to assess the duration of ductal shunting after birth in healthy preterm infants (30 to 37 weeks gestational age) without evidence of respiratory distress. Thirty-six infants were evaluated in the first 12 hours of life by means of two-dimensional echocardiography and color flow Doppler techniques, and then once daily until no ductal flow was detected (defined as functional closure). Preterm infants were subdivided into two groups by gestational age: group 1 = 30 to 33 weeks (n = 12); group 2 = 34 to 37 weeks (n = 24). Sixteen full-term infants (38 to 41 weeks) were similarly evaluated as control subjects (Group 3). One infant from each group had a closed ductus at the time of the first study (performed at a mean of 7.7 +/- 3.2 hours). Subsequent studies for the entire group were performed at a mean of 31.3 +/- 5.4 hours (day 2), 55.0 +/- 4.5 hours (day 3), and 80.3 +/- 6.1 hours (day 4). For the three groups, the rates of ductal closure ranged from 50.0% to 58.3% on day 2 and 81.3% to 87.5% on day 3. For the entire group, all but one infant had demonstrated closure of the ductus arteriosus by day 4. Within the range of gestational ages studied, we conclude that prematurity, in the absence of respiratory distress syndrome, does not prolong the initial duration of physiologic ductal shunting.

Turner syndrome is an independent risk factor for aortic dilation in the young

OBJECTIVE. Because aortic dilation increases the risk for dissection in the general adult population, and dissection occurs with greater frequency at a young age with Turner syndrome, we studied the prevalence, magnitude, and determinants of aortic dilation in a large group of girls and young women with Turner syndrome. PATIENTS AND METHODS. Participants at annual Turner syndrome society meetings completed a questionnaire regarding their medical history. Echocardiographic measurements of their aorta were converted to z scores by using data from a larger group of normal control female subjects. Bivariable and multivariable analyses evaluated the effects of Turner syndrome features, such as a bicuspid aortic valve, coarctation, growth-hormone therapy, blood pressure, and karyotype, on aortic size. RESULTS. Among 138 individuals with Turner syndrome <18 years old, 49% had the 45,X karyotype, 26% had bicuspid aortic valve, 17% had a history of coarctation, 78% had a history of growth-hormone therapy, and 40% had hypertension. Aortic z scores were calculated by using data from 407 control subjects. Bivariable analyses revealed that a bicuspid aortic valve, growth hormone, and 45,X karyotype predicted a larger proximal aorta at ≥1 level. Multivariable analysis predicted a larger proximal aorta at all of the levels only for bicuspid aortic valve individuals and at the annular level for those who received growth hormone. Importantly, all of the analyses revealed that Turner syndrome predicted a larger proximal aorta independent of these characteristics. CONCLUSIONS. Among young individuals with Turner syndrome, a bicuspid aortic valve predicts a larger proximal aorta, and growth-hormone use may predict a larger aortic annulus. Compared with a control population, Turner syndrome alone is an independent risk factor for aortic dilation.

Fetal lamb ventricles respond differently to filling and arterial pressures and to in utero ventilation

ABSTRACT. Right and left ventricular function were investigated in 12 fetal lambs (127-140 days gestation) instrumented with electromagnetic flow sensors on the ascending aorta and the main pulmonary artery, and with vascular catheters. Nine fetuses were equipped with a postductal aortic occluder and the trachea was cannulated in eight. Control arterial blood values were pH 7.36 ± 0.02 (SD), PCO2 49.3 ± 2.3 torr, PO2 18.4 ± 1.7 torr, and hematoerit 37.3 ± 4.4%. Biventricular function curves relating stroke volume to mean right and left atrial pressure were generated by rapid withdrawal and reinfusion of fetal blood. Both function curves were composed of steep ascending and plateau limbs that intersected at a breakpoint. Stroke volumes at the breakpoints were 0.94 ± 0.19 ml · kg-1and 0.63 ± 0.15 ml · kg-1 for right and left ventricle, respectively (p<0.001). During postductal aortic occlusion, arterial pressure increased by 19.3 ± 7.9 torr while right ventricular stroke volume decreased by ∼48% and left ventricular stroke volume decreased by ∼9%. In utero ventilation increased arterial pressure, heart rate, PO2, and oxygen content. Right atrial pressure increased from 3.9 ± 1.3 to 5.8 ± 2.9 torr (p<0.05); left atrial pressure from 3.5 ± 1.5 to 10.0 ± 4.4 torr (p<0.05). Aortic now nearly doubled (112 ± 29 to 211 ± 3 5 ml · min-1 · kg-1) (p < 0.05), and the left ventricular function curve shifted upward. The right ventricular function curve was shifted downward during ventilation. We conclude that the fetal ventricles differ significantly in their outputs, response to changes in arterial pressure, and to the onset of in utero ventilation.

Accuracy of Plasma B-Type Natriuretic Peptide to Diagnose Significant Cardiovascular Disease in Children: The Better Not Pout Children! Study

OBJECTIVES The purpose of this study was to assess the ability of plasma B-type natriuretic peptide (BNP) to diagnose significant cardiovascular disease (CVD) in the pediatric population. BACKGROUND BNP has been shown to be reliable in detecting ventricular dysfunction and heart failure in adults. Timely and accurate identification of significant pediatric heart disease is important but challenging. A simple blood test could aid the front-line physician in this task. METHODS Subjects without a history of heart disease with findings possibly attributable to significant CVD in the acute care setting requiring a cardiology consult were enrolled. Clinicians were blinded to the BNP result, and confirmation of disease was made by cardiology consultation. RESULTS Subjects were divided into a neonatal (n = 42, 0 to 7 days) and older age group (n = 58, >7 days to 19 years). CVD was present in 74% of neonates and 53% of the older age group. In neonates with disease, median BNP was 526 pg/ml versus 96 pg/ml (p < 0.001) for those without disease. In older children with disease, median BNP was 122 pg/ml versus 22 pg/ml in those without disease (p < 0.001). Subjects with disease from an anatomic defect, a longer hospital stay, or who died had higher BNP. A BNP of 170 pg/ml yielded a sensitivity of 94% and specificity of 73% in the neonatal group and 87% and 70% in the older age group, respectively, using a BNP of 41 pg/ml. CONCLUSIONS BNP is a reliable test to diagnose significant structural or functional CVD in children. Optimal cutoff values are different from adult values.

Evaluation of systolic and diastolic ventricular performance of the right ventricle in fetuses with ductal constriction using the Doppler Tei index

Fetal ductal constriction (DC) can depress right ventricular (RV) function. However, noninvasive assessment of fetal RV function remains difficult. We evaluated RV and left ventricular (LV) performance in fetuses with DC using the Doppler-derived Tei index. The Tei index measures the ratio of total time spent in isovolumic contraction and relaxation (isovolumic time) to the ejection time. Tricuspid inflow and RV outflow Doppler traces for the derivation of RV Tei indexes and mitral inflow and LV outflow traces for LV Tei indexes were measured in 78 fetuses of pregnant women who received indomethacin and 70 normal fetuses (gestational ages ranging from 20 to 39 weeks). DC occurred in 23 fetuses, defined as pulsatility index <1.9. In fetuses with DC, the RV isovolumic time was prolonged and RV ejection time was shortened, and the RV Tei index was high compared with those in fetuses that received indomethacin without DC and normal fetuses. Also, the RV Tei index clearly separated the fetuses with DC from normal and fetuses that received indomethacin without DC (0.74 +/- 0.14 vs 0.35 +/- 0.07 and 0.37 +/- 0.06, respectively; p <0.0001). The LV Tei index was not affected by DC. Serial study in 7 fetuses with DC showed that the RV Tei index decreased from 0.69 +/- 0.12 to 0.38 +/- 0.04 (p = 0.0002) after discontinuation of indomethacin coincident with ductal relaxation, although it remained elevated in 2 cases at the time of ductal relaxation. Thus, the Tei index is a useful and sensitive indicator for detecting abnormal RV performance in fetuses with DC.

Is Down syndrome a risk for poor outcome in after repair of congenital heart defects

Abstract Down syndrome is commonly associated with significant congenital heart disease with the potential for early development of pulmonary hypertension. As such, children with Down syndrome may be at increased risk for both perioperative and long-term mortality. The purpose of this study, using data collected from a population-based outcomes study, is to analyze the potential role that Down syndrome plays in the outcome of surgically “corrected” congenital heart disease. Data were collected from a registry of all Oregon residents who, in the period 1958 to the present, had a reparative operation for one of 14 congenital cardiac malformations when younger than 18 years ( N = 3965 patients). Down syndrome was present in 289 (7%) of the total registry patients. In evaluating the cardiac mortality associated with Down syndrome for each of the repaired cardiac malformations, only complete atrioventricular septal defect was associated with significantly higher perioperative (13% vs 5%) as well as higher overall late cardiac mortality through 20 years after the operation (20% vs 5%; p = 0.04). The survival outcomes for each of the other cardiac malformations were similar for children with and without Down syndrome. (J Pediatr 1998;132:738-41.)

Fetal atrial septal aneurysm: A cause of fetal atrial arrhythmias

Atrial arrhythmias are commonly found during fetal echocardiography performed during pregnancy to evaluate fetal arrhythmias. An association between atrial arrhythmias and an atrial septal aneurysm has been noted in children and adults. In this study, 105 fetuses were evaluated by fetal echocardiography, 39 (37%) referred to evaluate fetal arrhythmia and 66 (63%) to rule out congenital heart disease. An atrial septal aneurysm was found in 42 (40%) of the fetuses and an atrial arrhythmia in 37 (35%). An atrial septal aneurysm was found in 25 (64%) of the 39 fetuses referred to evaluate a fetal arrhythmia compared with only 17 (26%) of the 66 fetuses referred to rule out congenital heart disease. In this study, the association of an atrial septal aneurysm with an atrial arrhythmia was highly significant (p less than 0.001).