Duration of ductal shunting in healthy preterm infants: an echocardiographic color flow Doppler study

Hypoplastic Left Heart Syndrome: About a Postnatal Death

BACKGROUND

Hypoplastic left heart syndrome (HLHS) is a congenital heart disease that is associated with high mortality rates in the early neonatal period and during surgical treatments. This is mainly due to missed prenatal diagnosis, delayed diagnostic suspicion, and consequent unsuccessful therapeutic intervention.

CASE REPORT

twenty-six hours after birth, a female newborn died of severe respiratory failure. No cardiac abnormalities and no genetic diseases had been evidenced or documented during intrauterine life. The case became of medico-legal concern for the assessment of alleged medical malpractice. Therefore, a forensic autopsy was performed.

RESULTS

the macroscopic study of the heart revealed the hypoplasia of the left cardiac cavities with the left ventricle (LV) reduced to a slot and a right ventricular cavity that simulated the presence of a single and unique ventricular chamber. The predominance of the left heart was evident.

CONCLUSIONS

HLHS is a rare condition that is incompatible with life, with very high mortality from cardiorespiratory insufficiency that occurs soon after birth. The prompt diagnosis of HLHS during pregnancy is crucial in managing the disease with surgery.

Ductal Flow Ratio as Measure of Transition in Preterm Infants After Birth: A Pilot Study

Background: Cardiovascular changes during the transition from intra- to extrauterine life, alters the pressure gradient across the ductus arteriosus (DA). DA flow ratio (R-L/L-R) has been suggested to reflect the infant's transitional status and could potentially predict neonatal outcomes after preterm birth. Aim: Determine whether DA flow ratio correlates with oxygenation parameters in preterm infants at 1 h after birth. Methods: Echocardiography was performed in preterm infants born <32 weeks gestational age (GA), as part of an ancillary study. DA flow was measured at 1 h after birth. DA flow ratio was correlated with FiO₂, SpO₂, and SpO₂/FiO₂ (SF) ratio. The DA flow ratio of infants receiving physiological-based cord clamping (PBCC) or time-based cord clamping (TBCC) were compared. Results: Measurements from 16 infants were analysed (median [IQR] GA 29 [27-30] weeks; birthweight 1,176 [951-1,409] grams). R-L DA shunting was 16 [17-27] ml/kg/min and L-R was 110 [81-124] ml/kg/min. The DA flow ratio was 0.18 [0.11-0.28], SpO₂ 94 [93-96]%, FiO₂ was 23 [21-28]% and SF ratio 4.1 [3.3-4.5]. There was a moderate correlation between DA flow ratio and SpO₂ [correlation coefficient (CC) -0.415; p = 0.110], FiO₂ (CC 0.384; p = 0.142) and SF ratio (CC -0.356; p = 0.175). There were no differences in DA flow measurements between infants where PBBC or TBCC was performed. Conclusion: In this pilot study we observed a non-significant positive correlation between DA flow ratio at 1 h after birth and oxygenation parameters in preterm infants.

Cardiorespiratory Events in Infants Born Preterm during the Transitional Period

OBJECTIVE

To investigate the features of cardiorespiratory events in infants born preterm during the transitional period, and to evaluate whether different neonatal characteristics may correlate with event type, duration, and severity.

STUDY DESIGN

Infants with gestational age (GA) <32 weeks and/or birth weight <1500 g were enrolled in this observational prospective study. Heart rate (HR) and peripheral oxygen saturation (SpO₂) were recorded continuously over the first 72 hours. Cardiorespiratory events of ≥10 seconds were clustered into isolated desaturation (SpO₂ <85%), isolated bradycardia (HR <100 bpm or <70% of baseline), or combined desaturation/bradycardia and classified as mild, moderate, or severe. The daily incidences of isolated desaturation, isolated bradycardia, and combined desaturation and bradycardia were analyzed. The effects of relevant clinical variables on cardiorespiratory event type and severity were assessed using generalized estimating equations.

RESULTS

Among the 1050 events analyzed, isolated desaturations were the most frequent (n = 625) and isolated bradycardias the least common (n = 171). The number of cardiorespiratory events increased significantly from day 1 to day 2 (P = .028). One in 5 events had severe characteristics; event severity was highest for combined desaturation and bradycardia (P < .001). Compared with other event types, the incidence of combined desaturation and bradycardia was inversely correlated with GA (P = .029) and was higher with the use of continuous positive airway pressure (P = .002). The presence of a hemodynamically significant patent ductus arteriosus was associated with the occurrence of isolated desaturations (P = .001) and with a longer duration of cardiorespiratory events (P = .003).

CONCLUSIONS

Cardiorespiratory events during transition exhibit distinct types, duration, and severity. Neonatal characteristics are associated with the clinical features of these events, indicating that a tailored clinical approach may reduce the hypoxic burden in preterm infants aged 0-72 hours.

Neonatal management of prenatally suspected coarctation of the aorta

OBJECTIVES

(a) To determine the false-positive rate among newborns with prenatally suspected coarctation of the aorta (CoA) within the UCLA Health system, (b) to compare patient and maternal interventions and outcomes between false-positive cases and normal controls, and (c) to determine the timing of clinical presentation of CoA.

METHODS

We performed a single-center, retrospective case control study of all fetuses with suspected isolated CoA who underwent both fetal echocardiographic evaluation and subsequent delivery at UCLA between January 1, 2011, and December 31, 2018. Maternal and neonatal medical records were reviewed for demographic and clinical data, for cases of suspected CoA and for controls. A separate review of our institution's surgical database was performed to identify characteristics of all patients (neonatal and pediatric) with isolated CoA who underwent surgical repair during the same time period.

RESULTS

Among the 50 fetal cases of isolated suspected CoA who delivered at our institution, 47 patients (94%) were found to be normal (false positives). Compared with normal controls, patients with suspected CoA were more likely to have delayed maternal bonding, delayed feeding, admission to the intensive care unit, performance of neonatal echocardiograms, initiation of intravenous fluids and initiation of prostaglandin E1, and a longer length of hospital stay. Among the 38 patients undergoing CoA repair at our institution during the study period, four patients were prenatally diagnosed and no patient presented clinically with symptoms before 48 hours after delivery.

CONCLUSION

Compared with normal controls, patients with prenatally suspected coarctation are more likely to have delayed maternal bonding, delayed feeding, more frequent neonatal echocardiograms, and longer length of hospital stay. Further refinement of neonatal management may improve postnatal care.

Improving maternal-infant bonding after prenatal diagnosis of CHD

BACKGROUND

Infants with prenatally diagnosed CHD are at high risk for adverse outcomes owing to multiple physiologic and psychosocial factors. Lack of immediate physical postnatal contact because of rapid initiation of medical therapy impairs maternal-infant bonding. On the basis of expected physiology, maternal-infant bonding may be safe for select cardiac diagnoses.

METHODS

This is a single-centre study to assess safety of maternal-infant bonding in prenatal CHD.

RESULTS

In total, 157 fetuses with prenatally diagnosed CHD were reviewed. On the basis of cardiac diagnosis, 91 fetuses (58%) were prenatally approved for bonding and successfully bonded, 38 fetuses (24%) were prenatally approved but deemed not suitable for bonding at delivery, and 28 (18%) were not prenatally approved to bond. There were no complications attributable to bonding. Those who successfully bonded were larger in weight (3.26 versus 2.6 kg, p<0.001) and at later gestation (39 versus 38 weeks, p<0.001). Those unsuccessful at bonding were more likely to have been delivered via Caesarean section (74 versus 49%, p=0.011) and have additional non-cardiac diagnoses (53 versus 29%, p=0.014). There was no significant difference regarding the need for cardiac intervention before hospital discharge. Infants who bonded had shorter hospital (7 versus 26 days, p=0.02) and ICU lengths of stay (5 versus 23 days, p=0.002) and higher survival (98 versus 76%, p<0.001).

CONCLUSION

Fetal echocardiography combined with a structured bonding programme can permit mothers and infants with select types of CHD to successfully bond before ICU admission and intervention.

Cardiopulmonary Adaptation During First Day of Life in Human Neonates

OBJECTIVE

To characterize the natural history of cardiopulmonary physiology in the first 24 hours after birth.

STUDY DESIGN

A prospective observational study of healthy newborns was conducted at a large tertiary perinatal center. Echocardiography was performed at <0.5, 2-3, 7-10, and 22-24 hours of age. Specifically, assessment of pulmonary vascular resistance (PVR) (pulmonary artery acceleration time [PAAT], right ventricular ejection time, right ventricular ejection time:PAAT [PVR index], and PAAT indexed to heart rate [PAATi]), ventricular outputs (right and left), and ventricular function (tricuspid annular planar excursion, right ventricular [RV] fractional area change [FAC], RV/left ventricular [LV] global peak longitudinal strain, and LV ejection fraction) were performed. One-way repeated-measures ANOVA analysis was performed for time-dependent variables.

RESULTS

In total, 15 neonates (9 males), born at 40 ± 0.8 weeks and 3.5 ± 0.5 kg, respectively, were studied. We observed increased PAATi (P < .05) by 2-3 hours, followed by a subsequent decline in all indices of PVR (PVR index, PAATi, midsystolic notching, and right-to-left ductal flow [P < .0001]). Although right and left ventricular stroke volume increased over the study interval (P < .001), LV output remained stable. All indices of RV function (tricuspid annular planar excursion, RV fractional area change 4-chamber, and RV global peak longitudinal strain-3 chamber [P < .001]) increased during the study interval.

CONCLUSION

The immediate transition after birth is characterized by lower PVR, reversal of the transductal shunt, and increased biventricular stroke volume. The differential adaptive response of the RV and LV is novel and may relate to loading conditions and patent ductus arteriosus closure.

Prophylactic and early targeted treatment of patent ductus arteriosus

Treatment of a haemodynamically significant patent ductus arteriosus (PDA) in the very preterm infant has been an accepted approach for several decades. However, the rationale for closure of PDA has recently been challenged due to reports of success with conservative approaches and the lack of evidence for longer-term benefits from treatment. In this article, we address an approach to assess treatment of those babies most likely to benefit.

Prevalence and risk factors associated with the patency of ductus arteriosus in premature neonates: a prospective observational study from Iran

BACKGROUND

Patent ductus arteriosus (PDA) is a common problem in the preterm infants. The frequency of PDA varies with the time of study, and the characteristics of the population included in the trial.

AIMS AND OBJECTIVE

To determine the prevalence and prenatal risk factor associated with PDA.

METHODS AND MATERIAL

This prospective cross-sectional observational study was carried out on neonates who had gestational age below 37 weeks during the period of February 2014 to September 2014. Echocardiography was done at 4-7 days of postnatal age. The association between prenatal risk factors of the infants and the PDA was studied.

RESULTS

From a total population of 200 enrolled infants 22.5% had PDA. The mean gestational age and birth weight were 32.1 ± 2.65 (weeks) and 1741 ± 622.85 (g), respectively. Maternal antepartum hemorrhage, respiratory distress syndrome (RDS), need for surfactant, birth weights, female gender, gestational age, Apgar scores at 1 and 5 min of the infants were found to be associated with the prevalence of PDA.

CONCLUSION

Several prenatal factors make preterm newborns susceptible to PDA. These risk factors should be identified as soon as possible for early commencement of PDA management.

Surgical Ligation on Significant Patent Ductus Arteriosus in Very Low Birth Weight Infants: Comparison between Early and Late Ligations

Background

We aimed to evaluate the efficacy and safety of early surgical ligation (within 15 days of age) over late surgical ligation (after 15 days of age) by a comparative analysis of very low birth weight (VLBW) infants undergoing surgical correction for symptomatic patent ductus arteriosus (PDA) over the course of 6 years in our hospital.

Methods

We retrospectively reviewed all the medical records in the neonatal intensive care unit at Hanyang University Seoul Hospital, from March 2007 to May 2013, to identify VLBW infants (< 1,500 g) who underwent surgical PDA ligation.

Results

The gestational age (GA) in the late ligation (LL) group was significantly younger than in the early ligation (EL) group (p=0.010). The other baseline characteristics and preoperative conditions did not differ significantly between the two groups. The intubation period before surgery (p < 0.001) and the age at surgery (p < 0.001) were significantly different. The postoperative clinical outcomes of the study patients, including major morbidity and mortality, are summarized. There were no significant differences in bronchopulmonary dysplasia, sepsis, or mortality between the EL and the LL groups. However, the LL group was significantly associated with an increased risk of necrotizing enterocolitis (p=0.037) and with a prolonged duration of the total parenteral nutrition (p=0.046) after adjusting for GA.

Conclusion

Early surgical ligation for the treatment of PDA that failed to close after medical treatment or in cases contraindicated for medical treatment might be desirable to reduce the incidence of necrotizing enterocolitis and to alleviate feeding intolerance in preterm infants.

Unexpected infant death due to hypoplastic left heart syndrome: a case report

A female infant was found unresponsive at home. The mother alleged that she delivered the baby at home 13 days prior to the death. The mother did not have any prenatal examinations during the pregnancy and the infant was not examined by a doctor until death. The autopsy revealed that the cause of death was hypoplastic left heart syndrome (HLHS) and the infant's chest showed bilateral breast enlargement. Forensic pathologists may encounter very rare pathological findings with unexpected infant deaths. Some, like HLHS, are serious congenital heart defects related to the cause of death, and others are unique phenomena unrelated to the cause of death such as breast swelling and discharge called "witch's milk." In this case, we observed both findings.

Neonatal cyanosis: diagnostic and management challenges

Neonatal central cyanosis is always a sign of serious pathological processes and may involve diverse organs and impose a significant diagnostic and therapeutic challenge. Here, we report an unusual presentation of Ebstein's anomaly, a rare congenital heart malformation, as the cause of central cyanosis in a one-week-old full-term infant. Initiation of PEG₁ therapy in neonates with Ebstein's anomaly always needs a very careful consideration because of a high risk for the development of a “circular shunt” leading to severe deterioration of multiple organs perfusion.

Echocardiography predicts closure of patent ductus arteriosus in response to ibuprofen in infants less than 28 week gestational age

BACKGROUND

Patent ductus arteriosus (PDA) is a frequent problem in preterm infants, and its incidence is inversely correlated with gestational age. The efficacy of medical treatment decreases with decreasing gestational age (GA), and failure rates as well as ductus ligation rates of 40% have been reported in <28 week GA newborns. The aim of this study was to determine whether echocardiographic parameters can predict response to ibuprofen treatment of PDA.

STUDY DESIGN

In a longitudinal study, 29 infants born <28 week GA were screened for a significant PDA (left atrial to aortic root ratio>1.4, anterior cerebral artery resistance index>0.8, and oxygen requirement>35%) at 24-72 h of life and, if a PDA was found, treated with 10-5-5mg/kg ibuprofen intravenously every 24h. Ductal parameters were monitored by serial echocardiography. Infant neurodevelopmental outcomes were assessed at 24 month corrected age.

RESULTS

All 15 infants with significant PDA responded to the ibuprofen loading dose indicated by reduced PDA diameters or increased PDA maximum flow velocities (PDA V(max)), and 7 patients showed an ongoing response resulting in a closed PDA after the 1st cycle (47%). Of the 8 non-responders, 7 received a 2nd cycle with 2 further responders (29%). All non-responders to the 2nd course had a PDA V(max)<or=180 cm/s and increasing ductal diameters after the 3rd ibuprofen dose of the 1st course.

CONCLUSION

Maximum flow velocity and diameter of the PDA at the end of the 1st cycle discriminate between responders and non-responders to further ibuprofen treatment.

Spectrum of congenital heart defects in Croatia

The aim of our study was to investigate the incidence of congenital defects in children born in Croatia during a period of 5 years, its association with extracardiac malformations, its treatment, and outcome. Medical information about the patients was obtained from 14 paediatric cardiology centres that cover the whole country. Diagnosis was made by clinical findings, electrocardiography, chest X-ray, echocardiography, catheterisation, or autopsy. Between October 1, 2002 and October 1, 2007, there were 205,051 live births in Croatia, 1,480 of which were patients diagnosed with congenital heart disease, accounting for 0.72% of the live-born children. The distribution was made up of 34.6% children with ventricular septal defect, 15.9% with atrial septal defect, 9.8% with patency of arterial duct, 4.9% with pulmonary valvar stenosis, 3.3% with tetralogy of Fallot, 3.3% with transposed great arteries, 3.3% with aortic stenosis, 3.2% with aortic coarctation, 4.3% with atrioventricular septal defect and common atrioventricular orifice, 2.3% with hypoplastic left heart syndrome, and 8.3% other with severe defects. The average age in the time of diagnoses is 70.41 days (SD, 188.13), with low average time of diagnoses of severe heart defects, 9.6 days (SD, 32.52). Among patients, 14.5% had chromosomal defects, syndromes, and/or other congenital major anomalies. During the study, 57 patients died because of cardiac anomalies or other related problems, 24 who died were operated. The rates of specific cardiac defects and association with extracardiac malformations are generally comparable with those reported in similar studies. In spite of all problems, mortality rate of 3.85% is low but could be improved.

Surfactant and patent ductus arteriosus

OBJECTIVE

To investigate the relationship between surfactant replacement therapy and the development of a haemodynamically significant ductus arteriosus.

METHODS

All premature infants at 28-32 wk gestation with a clinical diagnosis of respiratory distress syndrome were retrospectively reviewed and subdivided into two groups; intubated, mechanically ventilated and received surfactant (Group 1); and received nasal continuous positive airway pressure alone (Group 2). The relationship between groups and characteristics of the hemodynamically significant ductus arteriosus was analyzed.

RESULTS

Seventy babies were identified of whom 35 (50%) received surfactant. Babies in group I and II were comparable for gestational age, birthweight, antenatal steroids, gender and fluid intake in first week of life. Babies treated with surfactant therapy were found to be more likely to have a haemodynamically significant ductus arteriosus (p<0.01), larger transductal diameter (p=0.01) and increased rate of therapeutic interventions to close the ductus (p<0.01). Ventilation parameters (mean airway pressure and fractional inspired oxygen) were higher in group I.

CONCLUSION

Neonates with respiratory distress syndrome (RDS) who were treated with surfactant replacement are at increased risk of a hemodynamically significant ductus arteriosus that requires therapeutic intervention. Whether the relationship reflects their underlying lung disease or is a direct effect of surfactant requires prospective evaluation.

Factors affecting successful closure of hemodynamically significant patent ductus arteriosus with indomethacin in extremely low birth weight infants

BACKGROUND

The incidence of patent ductus arteriosus (PDA) is high in extremely low birth weight (ELBW) infants. Indomethacin has been widely used in the prophylaxis and treatment of hemodynamically significant PDA. This retrospective study was undertaken to identify factors such as birth weight, gestational age, gender, fetal growth retardation, ductal size, timing of the first dose of indomethacin and side effects of indomethacin, which may affect the successful closure of the PDA with indomethacin in ELBW infants.

METHODS

A cohort of 139 ELBW infants who had received indomethacin treatment for PDA during a consecutive period of more than three years (September 2000 to December 2003) was retrospectively analyzed. Administration

RESULTS

of indomethacin was associated with closure of PDA in 108 (77.7%) of 139 ELBW infants, and only 19.4% of infants required surgical ligation of the ductus eventually. There was no significant relationship between closure of PDA with gestational age, gender, fetal growth retardation, and ductal size. A higher birth weight and early use of indomethacin after birth could significantly increase the closure rate of PDA (P<0.05). Side effects of indomethacin such as transient oliguria and hyponatremia during indomethacin therapy did not affect PDA closure.

CONCLUSIONS

Indomethacin is effective for the treatment of PDA in ELBW infants. A higher rate of ductal closure is related to the increase of birth weight. PDA closure with indomethacin is age-related, and early administration of indomethacin could increase PDA closure and reduce the incidence of hyponatremia. There is no significant difference in major morbidities such as bronchopulmonary dysplasia (BPD), intraventricular hemorrhage (IVH), necrotizing enterocolitis (NEC), and retinopathy of prematurity (ROP) after early treatment. Early screening for hemodynamically significant PDA in ELBW infants and early treatment with indomethacin are recommended.

Towards rational management of the patent ductus arteriosus: the need for disease staging

Perspective on the review by Bose and Laughon (see page 498)

Usefulness of indomethacin for patent ductus arteriosus in full-term infants

The aim of this retrospective study was to evaluate the effectiveness of indomethacin therapy for patent ductus arteriosus (PDA) in full-term infants. The patients were 41 full-term infants with a PDA birth weight (BW) > or =2500 g and a gestational age (GA) > or =37 weeks. The echocardiographic evaluation and medical management of PDA in these infants was similar to that for PDA in low-birth-weight infants. Indomethacin (0.2-0.25 mg/kg/dose) was given intravenously at 12-24-hour intervals within 23 days of birth. Of the 41 infants, 12 showed complete closure, and 13 showed improvement of clinical symptoms. These 25 infants were classified as the responder group (61%). The other 16 infants, who did not show improvement in clinical symptoms, were classified as the nonresponder group. Statistical analysis revealed no difference between the two groups regarding GA, BW, Apgar score at 1 minute, minimum diameter of the DA before treatment, the average age at the initiation of treatment, and DA flow pattern. No severe adverse reactions were observed in any infant. Indomethacin therapy appears to be an effective medical treatment option for PDA in full-term symptomatic infants prior to considering surgical treatment.

B-type natriuretic peptide in pediatrics

OBJECTIVES

There has been growing interest in the use of serum B-type natriuretic peptide (BNP) and the N-terminal segment of its pro-hormone (NT-proBNP) as biomarkers for cardiac disease. The aim of this review is to summarize the current state of knowledge regarding BNP and NT-proBNP measurement in the pediatric population.

DESIGN AND METHODS

A computerized literature search on the National Library of Medicine was done and all articles including BNP and pediatrics were selected and discussed.

RESULTS

The data from several studies suggest that the measurement of BNP may be useful in diagnosing and managing pediatric heart failure, congenital heart disease, cardiac transplantation and patients on chemotherapy. There are difficulties in establishing appropriate reference ranges in children.

CONCLUSION

There is insufficient evidence for the routine use of BNP or NT-proBNP. Further research to clearly define the clinical utility in the pediatric age group is eagerly anticipated.

Comparison of clinical criteria with echocardiographic findings in diagnosing PDA in preterm infants

OBJECTIVE

The purpose of our study was to compare clinical criteria with echocardiographic findings in diagnosing hemodynamically significant patent ductus arteriosus (PDA) in preterm infants.

METHODS

We evaluated 25 preterm infants born at 24-32 weeks of gestation with birth weight from 500 to 1700 g for tachycardia, heart murmur, hyperdynamic chest, presence of dorsalis pedis pulse, hypotension, and worsening of the respiratory status at 48-72 h of life. A pediatric cardiologist blinded to clinical findings performed the echocardiograms. Infants with congenital anomalies and conditions, sepsis, IVH, and necrotizing enterocolitis were excluded.

RESULTS

Out of 25 preterm infants, 12 infants had hemodynamically significant PDA with left-to-right shunt. Two infants had small PDA and in 11 infants the ductus arteriosus was not patent. PDA infants had lower gestational age (P = 0.02) and birth weight (P = 0.03). Their Apgar scores (1 min) were lower (P = 0.03). The heart rate between the two groups differed, but was clinically within normal limits. Systolic (P = 0.05) and mean blood pressures (P = 0.04) were lower in the PDA group. A poor association between heart murmur, hyperdynamic chest and dorsalis pedis pulse, and the presence of PDA was revealed.

CONCLUSION

Echocardiogram is required for early diagnosis of PDA in preterm infants, as clinical signs are not reliable in the first few days of life.

Impaired left ventricular diastolic function in newborn infants of mothers with pregestational or gestational diabetes with good glycemic control

THE AIM OF THE STUDY

We assessed by echocardiography the left ventricular systolic and diastolic function in newborn infants of mothers with well-controlled pregestational type 1 or gestational diabetes (IDM) in comparison to normal term neonates.

SUBJECTS AND METHODS

Two-dimensional/M-mode and Doppler transmitral flow velocity measurements were performed in 18 IDM and 26 control infants of non-diabetic mothers (gestational ages 36-40 and 36-41 weeks, respectively) between days 2 and 5 after birth. In the IDM, there were nine mothers with pregestational (White class C or D) and nine mothers with gestational diabetes (White class A or A/B). Peak early and atrial filling velocity, early deceleration time, early acceleration time, early, atrial and total time velocity integrals were used to examine the left ventricular diastolic performance. We also calculated the early/atrial velocity ratio, early/atrial integral ratio and early/total integral ratio. The fractional shortening, fractional shortening area, midwall fractional shortening (mFS), left ventricular mass and indexed left ventricular mass for body surface area (BSA) and birth weight were used in assessment of left ventricular systolic performance.

RESULTS

The early deceleration time was longer, resulting in higher early integral and early filling fraction (EFF) in the IDM than in the control infants (p<0.01). In the IDM, the fractional shortening was somewhat greater and the left ventricular mass/body surface area ratio was higher than in the control group (p<0.05), although the measures of systolic performance were within the normal range. There were no significant differences in the systolic or diastolic function parameters between the gestational and pregestational groups.

CONCLUSION

In the infants of mothers with well-controlled pregestational or gestational diabetes, we found prolonged deceleration time of early left ventricular diastolic filling, probably reflecting an impaired left ventricular relaxation rather than compliance. The mechanism for the findings may be maternal hyperglycemia during the third trimester and subsequent fetal hyperinsulinaemia leading to neonatal cardiac hypertrophy.

Treatment of patent ductus arteriosus

Patent ductus arteriosus (PDA) continues to be one of the most common problems found in premature infants. The incidence is inversely related to gestation, but may be reduced by use of antenatal steroids, lower volume fluid regimen and judicious use of phototherapy. However, there continues to be controversy as to the appropriate indications for treatment, varying from prophylaxis on the basis of gestation to treatment only when a PDA is demonstrably significant. The situation is further complicated by differing diagnostic criteria for ductal patency or significance. Prophylactic treatment is likely to result in up to 64% of babies being treated unnecessarily. Early treatment of significant or symptomatic PDA depends upon accurate diagnosis. PDA closure can then be achieved using medical means, with surgery reserved for patients in whom this fails or in whom there are contra-indications. However, the optimum timing for intervention remains unknown.

CURRENT CONTROVERSIES IN THE DIAGNOSIS AND TREATMENT OF PATENT DUCTUS ARTERIOSUS IN PRETERM INFANTS

This article presents common misconceptions about the physiologic significance of early ductal shunting and reviews the evidence regarding the preferential use of echocardiography rather than reliance on clinical signs to diagnose patent ductus arteriosus. The rationale for the treatment of symptomatic versus presymptomatic versus prophylactic is compared and contrasted. Finally, a novel but untested treatment approach, using early echocardiographic findings to direct treatment decisions, is proposed as a direction for future research.

Ductus arteriosus with left-to-right shunt during venoarterial extracorporeal membrane oxygenation: effects on cerebral oxygenation and hemodynamics

OBJECTIVE

To investigate the effect on cerebral oxygenation and hemodynamics of a patent ductus arteriosus with left-to-right shunt during venoarterial extracorporeal membrane oxygenation in a lamb model.

DESIGN

Prospective intervention study in animals.

SETTING

Animal research laboratory of a university medical center.

SUBJECTS

Six anesthetized newborn lambs with patent ductus arteriosus and left-to-right shunt, installed on venoarterial extracorporeal membrane oxygenation.

INTERVENTIONS

Six lambs of 140 days gestational age were prepared to keep the ductus arteriosus open by infiltration of the vessel wall with formaline 10%. The animals were installed on standard venoarterial extracorporeal membrane oxygenation. With a mechanical occluder, the ductus was closed.

MEASUREMENTS AND MAIN RESULTS

Changes of mean arterial blood pressure and carotid artery blood flow were measured simultaneously. Using near infrared spectrophotometry, we calculated changes in cerebral concentration of oxyhemoglobin and deoxyhemoglobin (reflecting changes in cerebral oxygen supply) and total hemoglobin (reflecting changes in cerebral blood volume). Also, cerebral oxygen delivery before and after ductus closure was calculated. Before ductus closure there was a left-to-right shunt with a mean +/- SEM of 41 +/- 20% of total body blood flow. Closure of the ductus resulted in an immediate increase in mean arterial blood pressure and carotid artery blood flow. The concentration of oxyhemoglobin increased and the concentration of deoxyhemoglobin decreased, representing increased cerebral oxygen supply. The concentration of total hemoglobin was unchanged, representing unchanged cerebral blood volume. There was an increase in cerebral oxygen delivery.

CONCLUSIONS

In this lamb model, a considerable left-to-right shunt over the ductus during venoarterial extracorporeal membrane oxygenation reduced cerebral circulation and oxygenation.

The incidence of congenital heart disease

This study was designed to determine the reasons for the variability of the incidence of congenital heart disease (CHD), estimate its true value and provide data about the incidence of specific major forms of CHD. The incidence of CHD in different studies varies from about 4/1,000 to 50/1,000 live births. The relative frequency of different major forms of CHD also differs greatly from study to study. In addition, another 20/1,000 live births have bicuspid aortic valves, isolated anomalous lobar pulmonary veins or a silent patent ductus arteriosus. The incidences reported in 62 studies published after 1955 were examined. Attention was paid to the ways in which the studies were conducted, with special reference to the increased use of echocardiography in the neonatal nursery. The total incidence of CHD was related to the relative frequency of ventricular septal defects (VSDs), the most common type of CHD. The incidences of individual major forms of CHD were determined from 44 studies. The incidence of CHD depends primarily on the number of small VSDs included in the series, and this number in turn depends upon how early the diagnosis is made. If major forms of CHD are stratified into trivial, moderate and severe categories, the variation in incidence depends mainly on the number of trivial lesions included. The incidence of moderate and severe forms of CHD is about 6/1,000 live births (19/1,000 live births if the potentially serious bicuspid aortic valve is included), and of all forms increases to 75/1,000 live births if tiny muscular VSDs present at birth and other trivial lesions are included. Given the causes of variation, there is no evidence for differences in incidence in different countries or times.

Diastolic flow velocity of the left pulmonary artery of patent ductus arteriosus in preterm infants

BACKGROUND

The usefulness of diastolic pulmonary flow velocity determined by echocardiography in the assessment of symptomatic patent ductus arteriosus (sPDA) in preterm infants has not been confirmed.

METHODS

Echocardiography was performed daily in infants ranging from 23 to 31 gestational weeks of age, and diastolic flow velocity of the left pulmonary artery (DFLPA) was measured. The DFLPA data before indomethacin administration for sPDA were compared with data obtained after indomethacin administration. The normal range of DFLPA was also determined from serial measurements performed in infants who did not develop sPDA during the first 7 days of life. Then, this range was compared with data from infants who did develop sPDA during this time.

RESULTS

In infants who underwent indomethacin treatment, DFLPA increased with the development of sPDA and decreased when the symptoms of sPDA disappeared. On the basis of results from serial DFLPA measurement, the sensitivity and specificity of DFLPA for assessing sPDA was found to be 0.82 and 0.83, respectively.

CONCLUSIONS

Measurement of DFLPA by echocardiography is a useful method for assessing sPDA in preterm infants.

Diagnosis of patent ductus arteriosus

This review shows that clinical signs cannot be relied on to reveal left-to-right ductal shunting in the preterm. Echocardiography can define many of the haemodynamic features, including occult ventricular dysfunction, and categorize shunts into small, moderate or large, without defining "significance" which is multifactorial. Large shunts have an elevated left atrial:aortic root ratio (>1.3:1 or >1.5:1, depending on fluid and diuretic policy) a ductal diameter >1.4 mm and retrograde diastolic flow in the descending aorta exceeding 30% of the antegrade flow. The neonatal clinician and echocardiographer is reminded to remain wary of occult congenital heart disease, particularly before closing the ductus.

A preliminary study of the application of the transductal velocity ratio for assessing persistent ductus arteriosus

OBJECTIVE

To compare the transductal velocity ratio (TVR) of the persistent ductus arteriosus (PDA) with other echocardiographic criteria for haemodynamic significance of a PDA.

METHODS

This was a prospective study (from January 1997 to August 1998) in the nurseries of the Royal Women's Hospital, Melbourne. Infants with a clinically suspected PDA were eligible and included if the echocardiogram showed a PDA with a structurally normal heart and the TVR had been measured. The PDA was assessed for evidence of left heart dilatation, the presence of reverse or absent diastolic flow in the descending aorta, the pattern of Doppler flow velocity waveform in the ductus arteriosus, and subjective assessment of ductal diameter on the real time image. The peak systolic velocity (PSV) was obtained from the pulmonary and aortic ends of the PDA, and the TVR calculated by dividing the PSV at the pulmonary end by the PSV at the aortic end.

RESULTS

Forty two infants had 59 echocardiographs with their TVR calculated. Mean (SD) birth weight was 1008 (362) g. Mean (SD) gestational age at birth was 27.4 (2.2) weeks with a mean (SD) corrected gestational age of 28.7 (2.7) weeks. The mean TVR was decreased in those infants with a high left atrial diameter/aortic diameter (LA/Ao) ratio (1.9 v 2.8, p = 0.0032) or reverse/absent diastolic flow in the descending aorta (2.1 v 3.0, p = 0.02). This difference was greater if those two criteria were combined (1.7 v 3.4, p = 0.0027). The mean TVR was decreased in infants with a wide open duct seen on two dimensional imaging (1.5 v 3.0, p < 0.0001) or pulsatile flow seen on pulsed Doppler in the PDA (1.9 v 3.4, p = 0.0001). The LA/Ao and left ventricle internal diameter/aortic diameter (LVIDd/Ao) ratios were higher in the group with a TVR < 1.8 than in the other two groups; these differences were statistically significant.

CONCLUSIONS

The TVR as a measure of the degree of constriction of a PDA is associated with other echocardiographic criteria for a haemodynamically significant PDA. A low TVR (signifying a poorly constricted duct) is associated with echocardiographic features of a significant left to right shunt, and vice versa. Further research is required to determine the usefulness of the TVR in predicting closure or likely continuing patency of a PDA and the need for treatment.

Delayed postnatal adaptation of pulmonary hemodynamics in infants of diabetic mothers

OBJECTIVE

To test the hypothesis with Doppler ultrasound method that the postnatal adaptation of the pulmonary and ductal hemodynamics in infants of diabetic mothers is disturbed.

STUDY DESIGN

Infants of diabetic mothers are prone to respiratory distress caused by characteristic fetal metabolic abnormalities such as hyperglycemia and hyperinsulinemia with subsequent excess fetal growth. However, the postnatal course of the pulmonary and ductal hemodynamics is poorly known in these neonates. The presence of ductal shunting and the mean aortopulmonary pressure difference across the ductus arteriosus reflecting pulmonary artery pressure, as well as the left ventricular output, were serially evaluated with Doppler ultrasound method at 2, 12, 24, 48, and 72 hours of age in 47 infants of diabetic mothers and 37 control neonates of nondiabetic mothers.

RESULTS

The infants of diabetic mothers had a higher incidence of patent ductus arteriosus at 12 (p = 0.03) and 48 hours (p = 0.006) of life than control infants, but none of the infants of diabetic mothers needed ductal closure. Bidirectional ductal shunting was found more frequently in infants of diabetic mothers than control infants during the first day of life. The mean ductal aortopulmonary pressure difference was significantly higher in the control infants than in infants of diabetic mothers during the first 24 hours of life (p = 0.002). The mean systemic pressure values were higher in the infants of diabetic mothers than control infants (p = 0.002), but no significant differences in the left ventricular output were seen between the study groups during the first 3 days of life.

CONCLUSIONS

The closure of the ductus arteriosus and postnatal decrease in pulmonary artery pressure are delayed in infants of diabetic mothers when compared with control infants during the first days of life. Left ventricular output values in infants of diabetic mothers do not differ from those of the control infants.

Pulmonary artery pressure in term and preterm neonates

Systolic pulmonary artery pressure (PAP) during the first 4 days after birth was determined in 41 healthy term and 46 preterm infants by measuring ductal Doppler flow velocity and systemic arterial pressure (SAP). Among preterm infants, 21 had respiratory distress syndrome (RDS) and 25 did not. Sequential indices within 96 h of age were presented respectively. At the ages of 2 and 12 h the ratio between pulmonary and systemic arterial pressure was significantly higher in term than in preterm infants without RDS (p < 0.05). At the age of 24 h, PAP to SAP ratio was similar in all study groups. Between 48 and 72 h, PAP to SAP ratio was significantly higher in preterm infants with RDS than in infants without RDS (p < 0.05). Our findings indicated that: (1) in healthy fullterm infants pulmonary artery pressure fell to subsystemic level during the first 12 h, indicating the critical time in circulatory transition; (2) prematurity did not affect ductal closure times significantly; and (3) RDS was associated with prolonged ductal patency and delayed postnatal circulatory adaptation characterized by pulmonary hypertension.

Longitudinal changes in the diameter of the ductus arteriosus in ventilated preterm infants: correlation with respiratory outcomes

This study aimed to examine the early natural history of ductal shunting in ventilated preterm infants (< 1500 g) and to document the association between this shunting and respiratory outcomes. The size of the ductal shunt was assessed in 48 infants using serial echocardiographic measurement of colour Doppler internal ductal diameter and pulsed Doppler postductal aortic diastolic flow (PADF). At all postnatal ages, normal antegrade PADF was invariably seen when the ductal diameter was 1.5 mm or less, and was usually abnormal (absent or retrograde) when more than 1.5 mm. Longitudinal progress of ductal diameter fell into three groups: (i) asymptomatic spontaneous closure (n = 31)--in 20 of these infants closure occurred within 48 hours; (ii) symptomatic PDA which enlarged after a postnatal constriction (n = 9); and (iii) symptomatic PDA that showed minimal postnatal constriction (n = 8). Infants in group 2 were significantly less mature and had PDAs which became symptomatic significantly later than those in group 3. Logistic regression showed that ductal shunting had a significant correlation with mean oxygenation index over the first five days but not with ventilator or oxygen days. Gestation had the most significant association with the latter two variables, with atrial shunting also being related to days in oxygen. The preterm duct displays a wide spectrum of postnatal constrictive activity. Symptomatic PDAs usually showed slower early postnatal constriction. Ductal shunting independently related to short term but not long term respiratory outcomes.

Effect of ductal patency on organ blood flow and pulmonary function in the preterm baboon with hyaline membrane disease

OBJECTIVE

To examine the effect of early ductal ligation vs. maintenance of ductal patency on vital organ perfusion and pulmonary function in premature baboons with hyaline membrane disease.

DESIGN

Randomized, controlled interventional study to compare early ligation with formalin infiltration of the ductus arteriosus.

SETTING

Animal care facility at a dedicated research foundation.

SUBJECTS

Eighteen premature baboons delivered by hysterotomy at 140 +/- 2 day gestation.

INTERVENTION

Nine premature baboons underwent formalin infiltration of the ductus arteriosus (group 1), and nine underwent ductal ligation (group 2). Surgical ligation or formalin infiltration was performed at 2 to 4 hrs of age. Animals were maintained on mechanical ventilation and ventilator parameters were adjusted to maintain PaO2 and PaCO2 within the physiologic range.

MAIN OUTCOME MEASURES

Left ventricular output indexed to body weight and vital organ perfusion were measured at 24 hrs of age by the radiolabeled microsphere method. Lung mechanics, including lung wet/dry weight ratio, total lung water, static compliance and functional residual capacity were measured immediately following euthanasia.

RESULTS

Total pulmonary blood flow was significantly lower (p = .0001) in group 2 (mean = 94 mL/min/kg), compared with group 1 (mean = 287 mL/min/kg). Systemic blood flow and effective pulmonary blood flow were higher in group 1 (p = .07). No significant difference between groups in absolute organ blood flow was noted, although flow as a percent of left ventricular index was significantly higher in all organs except the kidney in group 2. There was no difference in arterial blood gas values, parameters of mechanical ventilation, percent lung water, or postmortem measurement of lung mechanics between groups.

CONCLUSION

Early ductal ligation did not result in improved cardiac output, increased organ blood flow, or improved pulmonary function. We postulate that gradual constriction of the ductus arteriosus may play an important role in successful cardiovascular adaptation in the premature infant. While it is clear that premature infants with symptomatic patent ductus arteriosus often benefit from ductal closure, we question the practice of prophylactic early ductal closure.

A blinded comparison of clinical and echocardiographic evaluation of the preterm infant for patent ductus arteriosus

The accuracy of the characteristic physical signs of a patent ductus arteriosus (PDA), that is, a systolic murmur, increased volume of pulses and increased praecordial activity, in diagnosing a haemodynamically significant PDA in ventilated premature infants was prospectively evaluated. Fifty-five ventilated preterm infants (birthweight < 1500 g) had daily echocardiographic and clinical evaluation for a PDA for the first 7 days of life. The examiners were blinded to each other's findings. Probability analysis was performed for the accuracy of each clinical sign in detecting a haemodynamically significant PDA as defined by echocardiographic criteria. Clinical signs were poor at detecting a significant PDA in the first 4 days of life. On day 1, none of the 10 infants with a significant PDA had a murmur. By day 4, clinical signs were better at detecting a significant PDA, but specificity remained poor with many false positive signs. Six infants had murmurs with a closed duct. The development of echocardiographic haemodynamic significance preceded the development of physical signs by a mean of 1.8 days. Significant ductal shunts often occurred silently, but the development of a murmur often marked an increase in the velocity of the flow through the duct rather than an increase in the size of a shunt. This study confirms that echocardiography is required for the reliable early diagnosis of a PDA in ventilated preterm infants.

Color Doppler flow mapping of the patent ductus arteriosus in very low birthweight neonates: echocardiographic and clinical findings

Forty-eight preterm infants (mean birthweight 1.0 +/- 0.3 kg; mean gestational age 28 +/- 3 weeks) underwent serial echocardiograms and physical examinations in order to determine the correlation between color Doppler flow mapping (CDFM) results and physical findings of a patent ductus arteriosus (PDA), the predictive value of early CDFM as an indicator of subsequent requirement for treatment of a PDA, and to determine the direction and duration of ductal shunting and the rate of ductal closure and opening. CDFM analysis and cardiac physical examination of left-to-right ductal shunting were usually concordant in infants with a large PDA shunt, the most reliable physical finding being increased precordial activity. CDFM studies on day 2 or 3 of postnatal life had prognostic value with regard to subsequent need for closing the PDA. Additional findings included the absence of right-to-left PDA shunting in infants < 1 kg and < 28 weeks gestation and the absence of ductal reopening in infants in whom it had closed spontaneously. After complete PDA closure using indomethacin, subsequent ductal reopening is uncommon, except in infants < 25 weeks gestation and < 700 g bodyweight.

Pharmacokinetics of mefenamic acid in preterm infants with patent ductus arteriosus

The pharmacokinetics of mefenamic acid (MA), 2 mg/kg, were studied in 17 preterm infants with symptomatic patent ductus arteriosus. They were given this dosage orally at 24 h intervals. There were marked inter-individual differences in some of the pharmacokinetic parameters after the first dose; peak plasma concentration (Cmax) varied from 1.2 to 6.1 micrograms/mL with a mean of 3.8 micrograms/mL, time to reach Cmax (tmax) varied from 2 to 18 h with a mean of 7.7 h and plasma half-life (t1/2) varied from 3.8 to 43.6 h with a mean of 18.7 h. The group of infants (10/17) who had ductus closure after the first dose had significantly lower clearance (P < 0.01), longer t1/2 (P < 0.01) and higher 24 h plasma concentration (P < 0.001) compared to the group of infants (7/17) who had no ductus closure after the first dose. It appeared that the plasma concentration of MA had to be above 2.0 micrograms/mL and maintained at this concentration for at least 12 h for MA associated with ductus closure in preterm infants to take effect. In view of the inter-individual variation of plasma MA concentration and the effective plasma concentration, we suggest that measurement of the plasma concentration should be done 24 h after the first dose. This might be useful for safe and effective therapy for infants with ductus closure failure after the first dose.

Re-evaluation of the left atrial to aortic root ratio as a marker of patent ductus arteriosus

The aim of this study was to re-examine the accuracy of the left atrial aortic root ratio (LA:Ao) as a marker of significant patent ductus arteriosus (PDA) in the preterm infant by comparison with direct Doppler echocardiographic assessment. Fifty six infants (< 1500 g) had 463 serial echocardiograms. Firstly the LA:Ao was measured, then the duct was imaged and classified as wide open, restricting, or closed according to two dimensional and Doppler criteria. Probability analysis was performed to test the ability of the LA:Ao to discriminate between a wide open PDA and a restricting or closed duct. Mean LA:Ao was 1.17 and 1.21 when the duct was respectively closed or restricting compared with 1.61 when wide open. Using a LA:Ao of 1.5 as a cut off gives a sensitivity of 79% and specificity of 95% and increases the accuracy over the recommended levels of 1.3 and 1.4. With this cut off there were 20/94 false negatives, these were associated with scans on day 1 and large interatrial shunts. The sensitivity of the LA:Ao increased to 88% if only scans performed after day 1 were analysed. For diagnosing a PDA after day 1, the positive likelihood ratio of an LA:Ao of 1.5 or more was 17.5, and the negative likelihood ratio of an LA:Ao < 1.5 was 0.13. The LA:Ao is still a useful tool in the diagnosis of PDA. It is a simple method which needs less skill and resources than direct PDA imaging and is feasible on neonatal units without direct access to echocardiographic expertise. Its use on the first postnatal day is not recommended.

Effect of patent ductus arteriosus on Doppler-derived right ventricular systolic time intervals

Right ventricular systolic time intervals (RVSTI) and noninvasive Doppler-derived pulmonary blood flow were measured before and after surgical ductus ligation in 18 otherwise healthy infants and children who were older than 3 months of age. Right ventricular preejection period (PEP) and the ratio of preejection period and right ventricular ejection time (PEP/RVET), both corrected or uncorrected for heart rate, decreased significantly following surgery (PEP 71 +/- 14 vs. 50 +/- 13, p < 0.001 and PEP/RVET 0.29 +/- 0.06 vs. 0.21 +/- 0.05, p < 0.001). The volume of pulmonary blood flow correlated with PEP/RVET (r = 0.48, p = 0.003). The magnitude of the change in pulmonary blood flow correlated with the change in PEP/RVET (r divided by 0.56, p = 0.016). The velocity of circumferential fiber shortening (VCFc) increased after surgery, but not significantly. We speculate that patent ductus arteriosus has a similar effect on right ventricular performance when other congenital heart defects are present.

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.

Effect of low intravaginal doses of prostaglandin E2 on the closure time of the ductus arteriosus in term newborn infants

Seventeen term newborn infants (control subjects) and 17 whose mothers had been given intravaginal doses of prostaglandin E2 (PGE2) were examined serially by color Doppler echocardiography to determine whether maternal PGE2 prolonged ductal patency. No clinically relevant differences in closure times were found. Low-dose intravaginal PGE2 therapy was not associated with prolonged ductal patency in term infants.

Diagnosis of patent ductus arteriosus in the preterm newborn

Images

Intermittent ductal patency in healthy newborn infants: demonstration by colour Doppler flow mapping

Colour Doppler flow mapping was used to determine the time of closure of the arterial duct in 51 healthy newborn infants. Initial time of closure corresponded with previous reports: 20% on the first day, 82% by the second day, 96% by the third day, and 100% by the fourth day. Twenty infants were delivered by caesarean section and followed up for seven days even if the duct had apparently closed; in six intermittent patency was demonstrated with flow in the third, fourth or fifth day, although earlier functional closure had been observed. All were found to be closed on the sixth and seventh days. It is necessary to be aware of the phenomenon of intermittent closure in any study determining or assessing the effect of any intervention on ductal patency.

The neonatal transitional circulation: a combined noninvasive assessment

Dramatic changes occur in the circulation of the newborn during the transition from fetal to neonatal life. Closure of the foramen ovale and ductus arteriosus, decrease in pulmonary vascular resistance, and improvement in right ventricular compliance are among these changes. These physiological-anatomical events were characterized by means of two-dimensional, Doppler and color flow echocardiography. Forty-five full-term infants (22 male, 23 female) were studied at a mean age of 4.2 hours (T1), 25.5 hours (T2), 49.8 hours (T3), and 73.8 hours (T4) by two-dimensional, Doppler and color flow echocardiography. At T1, T2, T3, and T4, the ductus arteriosus was patent by color flow echocardiography in 100%, 34%, 22%, and 11%, respectively. Conversely, patency of the ductus by Doppler alone was detected in 100% (T1), 13% (T2, T3), and 11% (T4). Reversal of flow in the descending aorta, reflective of diastolic ductal filling, was not sensitive in detecting ductal patency (T1 50%, T2 3%, T3 and T4 0%). The patency of the foramen ovale was noted to decrease over the course of the study. Right ventricular compliance was quantitatively assessed by pulsed-Doppler diastolic properties (E-to-A ratio). This changed significantly from T1 to T4 (0.90 to 0.97) reflecting improving compliance of the right ventricle. The ratio of acceleration to ejection time, a Doppler estimation measure of pulmonary vascular resistance, increased from 0.28 to 0.33 (T1 to T4) reflecting a decrease in pulmonary vascular resistance.(ABSTRACT TRUNCATED AT 250 WORDS)

Intravenous indomethacin therapy in preterm neonates with patent ductus arteriosus

This study examined the response of the patent ductus arteriosus (PDA) to intravenous Indomethacin using serial two dimensional and Doppler echocardiography and documented the complications associated with therapy. Thirty-six preterm neonates who were oxygen and ventilator dependent were studied when they were aged 3-7 days. The PDA initially closed in 22 (61%) and constricted in seven (19%) of the infants. It was non-responsive in five (14%) and the treatment was stopped because of complications in two (6%). Only three (43%) of seven neonates given a second course had PDA closure. In the 25 instances where there was PDA closure following Indomethacin, re-opening was documented echocardiographically on three (12%) occasions. Overall, Indomethacin therapy was successful in 29 (81%) neonates, PDA ligation was required in four (11%) and three died from unrelated causes. Three (8%) neonates developed major complications: multiple gastric perforations in the first, focal ileal perforation in the second, and necrotizing enterocolitis in the third. Treatment failure, PDA ligation and major complications occurred exclusively in neonates less than 28 weeks gestation. In view of the relatively low efficacy and high major complication rate in these extremely preterm infants, a randomized clinical trial needs to be conducted using two dimensional and Doppler echocardiography to allow accurate assessment of the PDA response to intravenous Indomethacin.