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

Value of bedside echocardiography in predicting persistent patency of the ductus arteriosus during the early postnatal period in very low birth weight infants

OBJECTIVES

To study the value of bedside echocardiography in predicting persistent patency of the ductus arteriosus during the early postnatal period in very low birth weight (VLBW) infants.

METHODS

A retrospective analysis was performed for 51 VLBW infants who were admitted from March 2020 to June 2021, with an age of ≤3 days and a length of hospital stay of ≥14 days. According to the diameter of patent ductus arteriosus (PDA) on days 14 and 28 after birth, the infants were divided into three groups: large PDA group (PDA diameter ≥2 mm), small PDA group (PDA diameter <2 mm), and PDA closure group (PDA diameter =0 mm). The echocardiographic parameters measured at 72 hours after birth were compared among the three groups. The receiver operating characteristic (ROC) curve was used to evaluate the value of the echocardiographic parameters in predicting persistent patency of the ductus arteriosus (PDA≥2 mm) at the ages of 14 and 28 days.

RESULTS

On day 14 after birth, there were 17 infants in the large PDA group, 11 in the small PDA group, and 23 in the PDA closure group. On day 28 after birth, there were 14 infants in the large PDA group, 9 in the small PDA group, and 26 in the PDA closure group. There were significant differences in gestational age, birth weight, rate of pulmonary surfactant use, and incidence rate of hypotension among the three groups (P<0.05). PDA diameter, end-diastolic velocity of the left pulmonary artery, left ventricular output, and left ventricular output/superior vena cava flow ratio measured at 72 hours after birth were associated with persistent patency of the ductus arteriosus at the ages of 14 and 28 days (P<0.05), and the ratio of the left atrium to aorta diameter was associated with persistent patency of the ductus arteriosus at the age of 28 days (P<0.05). The ROC curve analysis showed that the area under the curve that the PDA diameter measured at 72 hours after birth predicting the persistent patency of the ductus arteriosus at the ages of 14 and 28 days was the largest (0.841 and 0.927 respectively), followed by end-diastolic velocity of the left pulmonary artery, with the area under the curve of 0.793 and 0.833 respectively.

CONCLUSIONS

The indicators obtained by beside echocardiography at 72 hours after birth, especially PDA diameter and end-diastolic velocity of the left pulmonary artery, can predict persistent patency of the ductus arteriosus at the ages of 14 and 28 days in VLBW infants, which provides a basis for the implementation of early targeted treatment strategy for PDA.

Comparison of Cardiac Output Measurement by Electrical Velocimetry with Echocardiography in Extremely Low Birth Weight Neonates

INTRODUCTION

Electrical velocimetry (EV) offers a noninvasive tool for continuous cardiac output (CO) measurements which might facilitate hemodynamic monitoring and targeted therapy in low birth neonates, in whom other methods of CO measurement are not practicably feasible.

METHODS

This prospective observational study compared simultaneous cardiac output measurements by electrical velocimetry (COEV) with transthoracic echocardiography (COTTE) in extremely low birth weight (ELBW) neonates in the neonatal intensive care unit (NICU). Echocardiography was performed by 1 single examiner. Data were analyzed by Bland-Altman analysis and independent-samples analysis of variance. A mean percentage error (MPE) of <30% and limits of agreement (LOA) up to ±30% were considered clinically acceptable.

RESULTS

Thirty-eight ELBW neonates were studied and yielded 85 pairs of COEV and COTTE measurements. Bland-Altman analysis showed an overall bias (the mean difference) and LOA of -126 and -305 to +52 mL min-1, respectively, and an MPE of 66%. Patients with patent ductus arteriosus had a higher bias with LOA and MPE of -166.8, -370.7 to +37 mL min-1, and 69%, respectively. The overall true precision was 58%.

CONCLUSION

This study showed high bias and lack of agreement between EV and TTE for measurement of CO in ELBW infants in NICU, limiting applicability of EV to monitor absolute values.

Spontaneous Closure of the Ductus Arteriosus in Preterm Infants: A Systematic Review

The optimal management strategy for patent ductus arteriosus in preterm infants remains a topic of debate. Available evidence for a treatment strategy might be biased by the delayed spontaneous closure of the ductus arteriosus in preterm infants, which appears to depend on patient characteristics. We performed a systematic review of all literature on PDA studies to collect patient characteristics and reported numbers of patients with a ductus arteriosus and spontaneous closure. Spontaneous closure rates showed a high variability but were lowest in studies that only included preterm infants with gestational ages below 28 weeks or birth weights below 1,000 g (34% on day 4; 41% on day 7) compared to studies that also included infants with higher gestational ages or higher birth weights (up to 55% on day 3 and 78% on day 7). The probability of spontaneous closure of the ductus arteriosus keeps increasing until at least 1 week after birth which favors delayed treatment of only those infants that do not show spontaneous closure. Better prediction of the spontaneous closure of the ductus arteriosus in the individual newborn is a key factor to find the optimal management strategy for PDA in preterm infants.

A new index of ultrasonography for estimating cerebral circulation in newborn infants

PURPOSE

To quantitatively estimate the influence of ductal shunt on cerebral blood flow and establish a new index of ultrasonography for estimating cerebral circulation without the influence of ductal shunt in newborn infants.

METHODS

We retrospectively examined the records of anterior cerebral artery (ACA) and left pulmonary artery (LPA) blood flow velocity curves recorded by pulsed Doppler ultrasonography within 6 h after birth in 123 newborn infants without asphyxia (normal group) and in 31 newborn infants with asphyxia (asphyxia group).

RESULTS

In the normal group, the resistance index (RI) of the ACA showed a positive correlation with the ratio of LPA diastolic-to-systolic flow velocities (LPAD/LPAS) (P < 0.001, r = 0.58), and the estimated RI (eRI) of the ACA was calculated using the following formula: Y = 0.47X + 0.67 (Y estimated RI; X LPAD/LPAS). In the asphyxia group, the RI of the ACA showed a weak correlation to base excess (BE) (P < 0.05, r = 0.46). The eRI of the ACA was calculated by the LPAD/PLAS in the asphyxia group, and the difference between the RI and eRI showed a better correlation to BE than RI (P < 0.001, r = 0.64).

CONCLUSION

We determined the relation between cerebral blood flow RI and ductal shunt, and (RI - eRI) may be a new useful ultrasonographic index indicating cerebral circulation without the influence of ductal shunt in newborn infants.

Baseline cardiac output and its alterations during ibuprofen treatment for patent ductus arteriosus in preterm infants

BACKGROUND

Infants with hemodynamically significant patent ductus arteriosus (PDA) may physiologically compensate with a supranormal cardiac output (CO). As such, a supranormal CO may be a surrogate marker for a significant PDA or indicate a failed response to PDA closure by ibuprofen. Electrical cardiometry (EC) is an impedance-based monitor that can continuously and non-invasively assess CO (CO_EC). We aimed to trend CO_EC through ibuprofen treatment for PDA in preterm infants.

METHODS

We reviewed our database of preterm infants receiving ibuprofen for PDA closure. Response to ibuprofen was defined as no ductal flow in echocardiography ≤24 h after treatment. Responders were compared with gestational age (GA) and postnatal age matched non-responders and their trends of CO_EC were compared. Both groups' baseline CO_EC were further compared to the reference infants without PDA.

RESULTS

Eighteen infants (9 responders and 9 non-responders) with median (interquatile range) GA 27.5 (26.6-28.6) weeks, birthweight 1038 (854-1218) g and age 3.5 (3.0-4.0) days were studied. There were positive correlations between CO_EC and ductal diameter and left atrium/ aortic root ratio (r = 0.521 and 0.374, p < 0.001, respectively). Both responders and non-responders had significantly higher baseline CO_EC than the reference. Although there was no significant within-subject alteration of CO_EC during ibuprofen treatment, there was a between-subject difference indicating non-responders had generally higher CO_EC.

CONCLUSIONS

The changes of CO_EC during pharmacological closure of PDA is less drastic compared to surgical closure. Infants with PDA had higher baseline CO_EC compared to those without PDA, and non-responders had higher CO_EC especially at baseline compared to responders.

Hemodynamics of infants with strong fluctuations of internal cerebral vein

BACKGROUND

There is a high incidence of intraventricular hemorrhage in extremely low-birthweight (ELBW) infants of low gestational age with high-grade fluctuations in the perfusion waveform of the internal cerebral vein. This study investigated changes in the hemodynamic status of ELBW infants during initial strong fluctuations in the perfusion waveform of the internal cerebral vein.

METHODS

We evaluated the perfusion waveform of the internal cerebral vein in 192 ELBW infants from birth, every 8 h for a total of 120 h. Sixty-seven infants had high-grade fluctuations. On the basis of the presence of patent ductus arteriosus (PDA), patients were subdivided into PDA(-) (n = 32) and PDA(+) (n = 35) groups.

RESULTS

During the first high-grade fluctuation, the PDA(-) group had significant increases in systolic, diastolic, and mean blood pressure (P < 0.001 for all). The PDA(+) group did not have significant changes in blood pressure but did have significant increases in the number of interruptions or regurgitations of diastolic renal arterial blood flow (P = 0.04) and end-diastolic left pulmonary arterial flow velocity (P < 0.001), indicating increased left-to-right shunt.

CONCLUSIONS

Blood pressure elevation may underlie fluctuations in the perfusion waveform of the internal cerebral vein and lead to the first high-grade increases during acute management of ELBW infants. When no elevation in blood pressure occurred, hemodynamically significant PDA was considered a potential underlying factor.

Correlation of B-type natriuretic peptide levels and echocardiographic parameters in preterm infants with patent ductus arteriosus

Purpose

This study aimed to evaluate the correlation, according to postnatal age, between plasma B-type natriuretic peptide (BNP) levels and echocardiographic parameters for the assessment of patent ductus arteriosus (PDA) in preterm infants with respiratory distress.

Methods

We enrolled 42 preterm infants with respiratory distress who underwent serial echocardiographic evaluation with simultaneous plasma BNP measurements until ductal closure. The correlations between BNP levels and the following 4 representative echocardiographic parameters were studied: diameter of the ductus arteriosus (DA), ratio of the left atrial diameter to the aortic diameter (LA/Ao), ratio of the PDA diameter to the infant's left pulmonary artery diameter (PDA/LPA), and the antegrade diastolic flow of LPA (DFLPA).

Results

BNP levels were significantly correlated to the magnitude of the ductal shunt, comprising the DA diameter, PDA/LPA ratio, LA/Ao ratio, and antegrade DFLPA for the overall study period. The earliest significant correlation, starting from postnatal day 2, was observed between the LA/Ao ratio and BNP levels. The PDA/LPA ratio and the antegrade DFLPA showed significant correlations with BNP levels postnatal day 3 onward, and with the DA diameter, postnatal day 5 onward.

Conclusion

BNP levels and echocardiographic parameters showed a positive correlation, but the significance of the correlations differed according to the postnatal age, especially during the first few days of life.

Early signs that predict later haemodynamically significant patent ductus arteriosus

OBJECTIVE

Our aim was to determine the optimal cut-off values, sensitivity, specificity, and diagnostic power of 12 echocardiographic parameters on the second day of life to predict subsequent ductal patency.

METHODS

We evaluated preterm infants, born at ⩽32 weeks of gestation, starting on their second day of life, and they were evaluated every other day until ductal closure or until there were clinical signs of re-opening. We measured transductal diameter; pulmonary arterial diastolic flow; retrograde aortic diastolic flow; pulsatility index of the left pulmonary artery and descending aorta; left atrium and ventricle/aortic root ratio; left ventricular output; left ventricular flow velocity time integral; mitral early/late diastolic flow; and superior caval vein diameter and flow as well as performed receiver operating curve analysis.

RESULTS

Transductal diameter (>1.5 mm); pulmonary arterial diastolic flow (>25.6 cm/second); presence of retrograde aortic diastolic flow; ductal diameter by body weight (>1.07 mm/kg); left pulmonary arterial pulsatility index (⩽0.71); and left ventricle to aortic root ratio (>2.2) displayed high sensitivity and specificity (p0.9). Parameters with moderate sensitivity and specificity were as follows: left atrial to aortic root ratio; left ventricular output; left ventricular flow velocity time integral; and mitral early/late diastolic flow ratio (p0.05) had low diagnostic value.

CONCLUSION

Left pulmonary arterial pulsatility index, left ventricle/aortic root ratio, and ductal diameter by body weight are useful adjuncts offering a broader outlook for predicting ductal patency.

Association of Antegrade Pulmonary Artery Diastolic Velocity with Spontaneous Closure of the Patent Ductus Arteriosus in Extremely Low-Birth-Weight Infants

OBJECTIVE

This study aims to determine echocardiographic parameters associated with spontaneous patent ductus arteriosus (PDA) closure in extremely low-birth-weight (ELBW) infants.

STUDY DESIGN

Retrospective demographic review and analysis of echocardiograms from 189 ELBW infants with suspected and confirmed hemodynamically significant PDA identified on an initial echocardiogram was performed. Comparison of echocardiographic parameters was made between infants with spontaneous closure versus those who received treatment.

RESULTS

The mean birth weight (787 ± 142 vs. 724 ± 141 g, p = 0.04) and gestational age (27.4 ± 2.8 vs. 26.2 ± 1.6 weeks, p = 0.03) were higher in the spontaneous closure versus the treatment group. Antegrade pulmonary artery (PA) diastolic velocity was lower in infants with spontaneous PDA closure versus those who received treatment (0.15 ± 0.06 vs. 0.22 ± 0.12 m/s, p = 0.009).

CONCLUSION

Heavier and more mature ELBW infants with a lower antegrade PA diastolic velocity were likely to have spontaneous closure of the PDA.

Neonatal echocardiography

Echocardiography is a technique within neonatal care increasingly used in acute management of patients because of its potential to guide care and hemodynamic management. However, its use continues to provoke controversy, as it was originally within the purview of pediatric cardiologists trained to identify structural as well as functional heart disease. This article examines some of the echocardiographic techniques available to the neonatologist, their applications, and the concerns surrounding their use on neonatal units.

Is extubation associated with changes in ductal and pulmonary blood flow in extremely preterm neonates?

AIM

Early extubation is desirable in preterm neonates to minimise the risk of complications associated with prolonged intubation. The association of significant pulmonary haemorrhage (PH) with extubation in a cluster of very preterm infants instigated an assessment of ductal and pulmonary haemodynamic effects of early extubation.

METHOD

This is a prospective observational study in 20 neonates (gestation <28 weeks) undergoing early extubation. Echocardiography was performed 5 min pre-extubation and 20 min post-extubation to continuous positive airway pressure. Normal cardiac anatomy was ascertained. Left pulmonary artery (LPA) and ductus arteriosus diameter and flows were recorded. Doppler spectral pattern of velocity was recorded over a minimum of four cycles.

RESULTS

Median (range) gestation, birthweight and age at extubation were 26.5 (24.0-28.0) weeks, 932 (595-1260) g and 18 (6-51) h, respectively. There was no significant change in pulmonary flow post-extubation: ductal size: (pre--1.2 (0-3.3) mm, post--1.0 (0-3.5) mm); ductal flow: (pre--44 (0-515), post--49 (0-441) mL/kg/min); LPA diameter: (pre--2.4 (1.9-3.8) mm, post--2.6 (1.9-3.4) mm); LPA flow: (pre--112 (59-255), post--122 (58-188) mL/kg/min. There were 3 out of 20 infants who developed PH at the post-natal age of 2, 11 and 16 days after extubation. Ductal and LPA flow did not change significantly after extubation in infants with or without PH irrespective of the ductal status.

CONCLUSIONS

Early extubation was not associated with a significant change from baseline in ductal and pulmonary flow in extremely preterm infants.

B-type natriuretic peptide for assessment of haemodynamically significant patent ductus arteriosus in premature infants

Aim: Haemodynamically significant patent ductus arteriosus (hsPDA) is frequently observed in premature infants. This study was conducted to explore whether the blood BNP can be a valuable biomarker to assess the necessity of treatment for hsPDA in premature infants.

Methods: Serial measurements of the blood BNP were performed during the first 5 days of life in premature infants with hsPDA (Group I) and those without hsPDA (Group N). The definition of the hsPDA was the PDA requiring treatment, such as indomethacin administration and/or surgical ligation.

Results: Forty-six subjects were enrolled. Compared with Group N, Group I showed significantly higher level of blood BNP at postnatal 24–96 h and demonstrated the peak value at postnatal 24–48 h. With the ROC curve using the data at postnatal 24–48 h in Group I, we deduced the predictive value of 250 pg/mL of blood BNP for indomethacin treatment. Similarly, with the ROC curve using the maximal value of blood BNP within the first 5 days of life, the predictive value of 2000 pg/mL for surgical ligation was deduced.

Conclusions: Blood BNP during early postnatal period can be a useful biomarker to assess the necessity of treatment for hsPDA in premature infants.

Functional echocardiography in staging for ductal disease severity : role in predicting outcomes

Equipoise persists as to the issue of assigning haemodynamic and clinical significance to a patent ductus arteriosus (PDA). The objective was to ascertain whether echocardiographic scoring of a PDA correlates with outcomes. Unit electronic data base was accessed to identify infants less than 32 weeks' gestation who received ibuprofen for medical closure of the PDA during the period June 2010-June 2012. Echocardiographic score was assigned on the day of therapy and the infants were prospectively followed up to ascertain the occurrence of chronic lung disease (CLD). Logistic regression analysis was used to estimate the association between composite score and occurrence of CLD. Fifty-two infants were identified out of which 27 (52 %) subsequently developed CLD. Echocardiographic parameters were of a significantly higher magnitude in infants who later developed CLD. The median composite score (inter-quartile range) was also significantly higher in this group 26 (24-26) vs. 19 (17-20), p < 0.001). Higher composite scores were associated with increased risk of developing CLD; for every one point increase in composite score, the odds of CLD increased by 78 % (odds ratio (95 % CI): 1.78 (1.35-2.34); p < 0.001).

CONCLUSIONS

Infants with a high composite score, assigned according to the staging criteria at the time of treatment, were noted to have a higher incidence of subsequent CLD. Whether disease stratification can be the basis of further RCT's needs prospective evaluation.

Can a clinical decision rule help ductus arteriosus management in preterm neonates?

AIM

Patent ductus arteriosus (DA) occurs frequently in premature neonates with respiratory distress syndrome. We assessed a combination of clinical, biological and echocardiographic parameters to derive a decision rule for selecting candidates for treatment based on the criteria in use in our unit.

METHODS

Hundred and forty neonates with a mean (SD) gestational age of 28 (2.3) weeks and a mean birth weight of 1159 (386) g, all requiring invasive ventilation with FiO(2) > 0.3 or catecholamines for severe hypotension, were assessed prospectively using echocardiography in conjunction with N-terminal pro-B-type natriuretic peptide (NTpBNP) levels within 24-72 h of birth. Independent predictors of DA treatment were identified with univariate analysis and combined in a clinical decision rule.

RESULTS

Early treatment of significant DA was adopted for 26 (18.6%) neonates. A clinical decision rule suggesting treatment in patients with NTpBNP > 8500 pg/mL, ductal diameter >1.5 mm and, for infants with a birth weight > 830 g, left pulmonary artery end-diastolic velocity >0.20 m/sec showed 88% sensitivity and 94% specificity.

CONCLUSIONS

A decision rule using realistic and/or commonly used parameters for significant patent ductus arteriosus assessment could be derived. External validation of this rule is needed before any application.

Echocardiography as a guide for patent ductus arteriosus ibuprofen treatment and efficacy prediction

OBJECTIVE

To evaluate echocardiography criteria in predicting the response to ibuprofen treatment.

DESIGN

A prospective cohort study of preterm infants untreated or treated with ibuprofen for patent ductus arteriosus.

SETTING

Three academic neonatal intensive care units.

PATIENTS

Two hundred fifty-two preterm infants of 27-31 wks gestation.

INTERVENTIONS

Ibuprofen treatment within the first 5 days of life was indicated when at least two out of four conventional echocardiography criteria were observed: ductal diameter >2 mm, left-right ductal shunt maximum velocity <2 m/sec, mean flow velocity in left pulmonary artery >0.4 m/sec, and end-diastolic flow velocity in left pulmonary artery >0.2 m/sec.

MEASUREMENTS AND MAIN RESULTS

Of the infants analyzed, 135 had a closed ductus at an average age of 1.9 ± 0.9 days, and 43 had an open ductus but <2 predefined criteria. Seventy-four infants (29%) received ibuprofen on day 2.2 ± 1.1. Sixteen infants failed ibuprofen and nine had to undergo surgical ligation. The left-right ductal shunt maximum velocity criterion had the best negative predictive value for treatment response, while the ductal diameter criterion had the best positive predictive value.

CONCLUSIONS

Echocardiography may be a useful tool to help patent ductus arteriosus management. A combined use of ductal diameter and left-right ductal shunt maximum velocity criteria allows a more accurate prediction of the response of infants with patent ductus arteriosus to ibuprofen treatment.

The methodology of Doppler-derived central blood flow measurements in newborn infants

Central blood flow (CBF) measurements are measurements in and around the heart. It incorporates cardiac output, but also measurements of cardiac input and assessment of intra- and extracardiac shunts. CBF can be measured in the central circulation as right or left ventricular output (RVO or LVO) and/or as cardiac input measured at the superior vena cava (SVC flow). Assessment of shunts incorporates evaluation of the ductus arteriosus and the foramen ovale. This paper describes the methodology of CBF measurements in newborn infants. It provides a brief overview of the evolution of Doppler ultrasound blood flow measurements, basic principles of Doppler ultrasound, and an overview of all used methodology in the literature. A general guide for interpretation and normal values with suggested cutoffs of CBFs are provided for clinical use.

Patent ductus arteriosus in the preterm infant: a survey of clinical practices in French neonatal intensive care units

Patent ductus arteriosus (PDA) is one of the most common problems in the care of premature infants, especially the extremely premature. There is no real consensus regarding the diagnostic criteria or treatment of a hemodynamically significant PDA. Its diagnosis, assessment, and treatment still remain challenges. Therefore, we investigated clinical practices in French tertiary neonatology centers regarding the management of PDA to compare their similarities and differences. We sent a questionnaire by email to the PDA specialist in every French tertiary neonatal intensive care unit. It contained 27 items regarding the unit's structure, method of diagnosing PDA, and treatment choices. The completed questionnaire were returned via email and analyzed blindly. The questionnaire response rate was 87.5%, which allowed us to draw some conclusions regarding French clinical practices in the care of neonates with PDA. Although the diagnostic criteria are quite similar, the therapeutic practices are rather different across neonatal care units. We highlight the great variability in French clinical practices when it comes to treating PDA and underscore the necessity for harmonization of these practices, which could be achieved using multicenter, randomized studies to identify the advantages of one approach compared with another.

Neonatologist-performed functional echocardiography in the neonatal intensive care unit

The use of point-of-care functional ultrasound to assess cardiovascular function is gaining interest in the neonatal intensive care unit (NICU). The modality has been in use in adult intensive care units for some time and has often guided management. Clinical signs such as heart rate, blood pressure, and capillary refill time, which physicians traditionally have relied upon, provide limited insight into the adequacy of systemic blood flow and organ perfusion. Enhanced cardiovascular imaging and hemodynamic evaluation offers novel insights regarding the contribution of the ductus arteriosus, myocardial performance and pulmonary hemodynamics to ongoing clinical instability. In addition, it allows more accurate delineation of the nature of the underlying disease process and facilitates the evaluation of response to therapeutic intervention. This review examines the potential clinical role of ultrasound methods in the NICU; specifically, its applications in different disease states, and how the technology may be introduced safely in the NICU.

How useful are B-type natriuretic peptide measurements for monitoring changes in patent ductus arteriosus shunt magnitude?

OBJECTIVE

Although B-type natriuretic peptide (BNP) concentrations seem to be useful for detecting the presence of patent ductus arteriosus, there is no information about their usefulness for monitoring changes in PDA shunt magnitude.

STUDY DESIGN

We performed a retrospective analysis of paired BNP-echocardiogram measurements (obtained from infants (24 to 32 weeks gestation) with clinical suspicion of PDA).

RESULT

Individual BNP concentrations (n=146, from 88 infants) were significantly related to shunt magnitude at the time of measurement and had good discriminating power for detecting a moderate-or-large shunt (area under receiver-operator characteristic curves (ROC-AUC)=0.85). In total, 36 infants had serial BNP-echocardiogram pairs (n=91) measured during their hospitalization. Changes (either increases or decreases) in BNP concentrations over time had only fair discriminating power (ROC-AUC=0.76) for detecting increases or decreases, respectively, in shunt magnitude.

CONCLUSION

The high degree of variability in the BNP measurements made them less useful for monitoring changes in magnitude.

Early surgical ligation versus a conservative approach for management of patent ductus arteriosus that fails to close after indomethacin treatment

OBJECTIVE

To examine whether a more conservative approach to treating patent ductus arteriosus (PDA) is associated with an increase or decrease in morbidity compared with an approach involving early PDA ligation.

STUDY DESIGN

In January 2005, we changed our approach to infants born at age

RESULTS

The 2 periods had similar rates of perinatal/neonatal risk factors and indomethacin failure (24%), as well as ventilator management and feeding advance protocols. The conservative approach (period 2) was associated with decreased rates of duct ligation (72% vs 100%; P<.05). Even though infants subjected to this approach were exposed to larger PDA shunts for longer durations, the rates of bronchopulmonary dysplasia, sepsis, retinopathy of prematurity, neurologic injury, and death were similar to those in period 1. The overall rate of necrotizing enterocolitis was significantly lower in period 2 compared with period 1.

CONCLUSIONS

These findings support the need for new controlled, randomized trials to reexamine the benefits and risks of different approaches to PDA treatment.

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Key Words

• surgery
• ductus ligation
• indomethacin
• patent ductus arteriosus

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MESH Headings

• Ductus Arteriosus, Patent/drug therapy
• Ductus Arteriosus, Patent/surgery
• Female
• Humans
• Indomethacin/therapeutic use
• Infant, Newborn
• Ligation
• Male
• Prospective Studies
• Time Factors
• Treatment Failure

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Grants

• R01 HL046691 NHLBI NIH HHS
• R01 HL046691-16 NHLBI NIH HHS
• UL1 RR024131 NCRR NIH HHS
• HL46691 NHLBI NIH HHS

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Affiliation(s)

Nami Jhaveri Department of Pediatrics, University of California, San Francisco, CA 94143-0544, USA
Anita Moon-Grady
Ronald I Clyman

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The perfusion index derived from a pulse oximeter for predicting low superior vena cava flow in very low birth weight infants

OBJECTIVE

Superior vena cava (SVC) flow is used as an index for evaluating systemic blood flow in neonates. Thus far, several reports have shown that low SVC flow is a risk factor for intraventricular hemorrhage (IVH) in the preterm infant. Therefore, it is likely to be a useful index in the management of the preterm infant. The perfusion index (PI) derived from a pulse oximeter is a marker that allows noninvasive and continuous monitoring of peripheral perfusion. The objective of this paper was to determine the accuracy of the PI for detecting low SVC flow in very low birth weight infants born before 32 weeks of gestation.

STUDY DESIGN

We studied the correlation between PI and SVC flow 0 to 72 h after birth in very low birth weight infants born before 32 weeks of gestation. The best cut-off value for low SVC flow was calculated from the respective receiver-operating characteristic curves.

RESULT

A positive correlation was found between the PI and SVC flow (r=0.509, P<0.001). The best cut-off value for the PI to detect low SVC flow was 0.44 (sensitivity 87.5%, specificity 86.3%, positive predictive value 38.9%, negative predictive value 98.6%).

CONCLUSION

This study found that the PI was associated with SVC flow, and it was a useful index for detecting low SVC flow in very low birth weight infants born before 32 weeks of gestation. Therefore, use of the PI should be evaluated in the cardiovascular management of the preterm infant.

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.

Severity of the ductal shunt: a comparison of different markers

BACKGROUND

When the ductus arteriosus (DA) is patent, the ductal shunt is proportional to the ratio of left ventricular output (LVO) to systemic blood flow. Systemic blood flow can be estimated by measuring flow in the superior vena cava (SVC).

OBJECTIVE

To re-evaluate the accuracy of standard echocardiographic markers of patent ductus arteriosus (PDA) using LVO/SVC flow ratio.

METHODS

Prospective study. Preterm infants of 24-30 weeks gestational age and postnatal age less than 48 hours. The following echocardiographic criteria were measured: left atrial to aortic root ratio (LA/Ao); DA diameter by B mode and colour Doppler; mean and end diastolic flow velocity of the left pulmonary artery (LPA); LVO; SVC flow.

RESULTS

Twenty three preterm infants were enrolled (median gestational age 28 weeks (range 24-30), median birth weight 840 g (500-1440)). The DA was closed in eight (mean (SD) LVO/SVC 2.4 (0.3)) and open in 15 (mean (SD) LVO/SVC 4.5 (0.6)). An LA/Ao ratio > or =1.4, a DA diameter > or =1.4 mm/kg, and a mean and end diastolic flow velocity of LPA respectively > or =0.42 and > or =0.20 m/s identified an LVO/SVC > or =4 with a sensitivity and a specificity above 90%.

CONCLUSION

This study indicates that LA/Ao ratio, DA diameter, and mean and end diastolic flow velocity of the LPA are accurate markers of PDA. These standard echocardiographic variables are easy to measure and need less skill and resources than direct measurements of ductal shunt.

Utility of rapid B-type natriuretic peptide assay for diagnosis of symptomatic patent ductus arteriosus in preterm infants

OBJECTIVE

In preterm infants, the rapid and accurate determination of the presence of a hemodynamically significant patent ductus arteriosus (PDA) is extremely important, but this is often difficult. Plasma B-type natriuretic peptide (BNP) measurement has been reported to be a helpful aid in the diagnosis of hemodynamically significant PDA in preterm infants. The aim of our study was to investigate the usefulness of a rapid BNP assay as a diagnostic marker of symptomatic PDA (sPDA) in preterm infants.

METHODS

Sixty-six preterm infants, ranging from 25 to 34 gestational weeks of age, underwent clinical and echocardiographic examinations for PDA every other day from the third day of life until the disappearance of ductal flow. Blood samples were collected and plasma BNP concentrations were measured simultaneously using a commercial kit, (Triage BNP test kit; Biosite Diagnositics, San Diego, CA). When > or =2 clinically significant features of PDA were noted, and a large ductal flow was confirmed by color Doppler echocardiography, sPDA was diagnosed and treated with indomethacin.

RESULTS

On the third day after birth, the mean BNP concentration in the sPDA group (n = 23) was significantly higher than in the control group (n = 43) (2896 +/- 1627 vs 208 +/- 313 pg/mL). Seventeen infants (74%) in the sPDA group became asymptomatic after an initial course of indomethacin and their BNP levels concomitantly decreased. Moreover, BNP concentrations were significantly correlated with the magnitudes of the ductal shunt, such as the ratio of left atrial to aortic root diameter and the diastolic flow velocity of the left pulmonary artery (r = 0.726 and 0.877). The area under the receiver operator characteristic curve for the detection of sPDA was high: 0.997 (95% confidence interval: 0.991-1.004). The best cutoff of BNP concentration for the diagnosis of sPDA was determined to be 1110 pg/mL (sensitivity: 100%; specificity: 95.3%).

CONCLUSION

In preterm infants, the circulating BNP levels correlated well with the clinical and echocardiographic assessments of PDA. Although not a stand-alone test, the rapid BNP assay provides valuable information for the detection of infants with sPDA that require treatment. Moreover, serial BNP measurements may be of value in determining the clinical course of PDA in preterm infants.