A high ductal flow velocity is associated with successful pharmacological closure of patent ductus arteriosus in infants 22-27 weeks gestational age

A Matched Case Control Study of Surgically and Non-surgically Treated Patent Ductus Arteriosus in Extremely Pre-term Infants

Introduction: There are still uncertainties about the timing and indication for surgical ligation of patent ductus arteriosus (PDA) in pre-term infants, where lower gestational age (GA) usually is predictive for surgical treatment. Objective: Our aim was to assess differences in clinical characteristics and outcomes between surgically treated and matched non-surgically treated PDA in extremely pre-term infants. Methods: All extremely pre-term infants born 2010-2016 with surgically treated PDA (Ligated group; n = 44) were compared to non-surgically treated infants (Control group; n = 44) matched for gestational age (+/-1 week) and time of birth (+/-1 month). Perinatal parameters, echocardiographic variables, details of pharmacological PDA treatment, morbidity, and mortality were assessed. Result: Mean GA and birthweight were similar between the Ligated group (24⁺⁵ ± 1⁺³ weeks and 668 ± 170 g) and the Control group (24⁺⁵ ± 1⁺³ weeks and 704 ± 166 g; p = 1.000 and p = 0.319, respectively). Infants in the Ligated group had larger ductal diameters prior to pharmacological treatment, and lack of diameter decrease and PDA closure after treatment (p = 0.022, p = 0.043 and 0.006, respectively). Transfusions, post-natal steroids and invasive respiratory support were more common in the Ligated group. Except for a higher incidence of severe bronchopulmonary dysplasia (BPD) in the Ligated group there were no other differences in outcomes or mortality between the groups. Conclusion: Early large ductal diameter and reduced responsiveness to pharmacological treatment predicted the need for future surgical ligation in this matched cohort study of extremely pre-term infants where the effect of GA and differences in treatment strategies were excluded. Besides an increased incidence of severe BPD in the Ligated group, no other differences in morbidity or mortality were detected.

Patent Ductus Arteriosus of the Preterm Infant

Postnatal ductal closure is stimulated by rising oxygen tension and withdrawal of vasodilatory mediators (prostaglandins, nitric oxide, adenosine) and by vasoconstrictors (endothelin-1, catecholamines, contractile prostanoids), ion channels, calcium flux, platelets, morphologic maturity, and a favorable genetic predisposition. A persistently patent ductus arteriosus (PDA) in preterm infants can have clinical consequences. Decreasing pulmonary vascular resistance, especially in extremely low gestational age newborns, increases left-to-right shunting through the ductus and increases pulmonary blood flow further, leading to interstitial pulmonary edema and volume load to the left heart. Potential consequences of left-to-right shunting via a hemodynamically significant patent ductus arteriosus (hsPDA) include increased risk for prolonged ventilation, bronchopulmonary dysplasia, necrotizing enterocolitis or focal intestinal perforation, intraventricular hemorrhage, and death. In the last decade, there has been a trend toward less aggressive treatment of PDA in preterm infants. However, there is a subgroup of infants who will likely benefit from intervention, be it pharmacologic, interventional, or surgical: (1) prophylactic intravenous indomethacin in highly selected extremely low gestational age newborns with PDA (<26 + 0/7 weeks' gestation, <750 g birth weight), (2) early targeted therapy of PDA in selected preterm infants at particular high risk for PDA-associated complications, and (3) PDA ligation, catheter intervention, or oral paracetamol may be considered as rescue options for hsPDA closure. The impact of catheter-based closure of hsPDA on clinical outcomes should be determined in future prospective studies. Finally, we provide a novel treatment algorithm for PDA in preterm infants that integrates the several treatment modalities in a staged approach.

Plasma B-type natriuretic peptide cannot predict treatment response to ibuprofen in preterm infants with patent ductus arteriosus

Plasma B-type natriuretic peptide (BNP) is a useful marker for diagnosis of hemodynamically significant PDA (hsPDA) and serial BNP measurement is also valuable for monitoring treatment response. This retrospective study was performed to evaluate whether plasma BNP level can predict treatment response to ibuprofen in preterm infants born at <30 weeks of gestation with hsPDA. Plasma BNP was measured before (baseline) and 12 to 24 h after (post-treatment) completion of the first (IBU1) and second (IBU2) course of ibuprofen. We compared the BNP levels of responders (closed or insignificant PDA) with those of non-responders (hsPDA requiring further pharmacologic or surgical closure) to each course of ibuprofen. The treatment response rates for IBU1 (n = 92) and IBU2 (n = 19) were 74% and 26%, respectively. In IBU1, non-responders had lower gestational age and birth weight than responders (both, P = 0.004), while in IBU2, non-responders had lower birth weight (P = 0.014) and platelet counts (P = 0.005) than responders; however, baseline BNP levels did not differ significantly between responders and non-responders in either IBU1 (median 1,434 vs. 1,750 pg/mL) or IBU2 (415 vs. 596 pg/mL). Post-treatment BNP was a useful marker for monitoring treatment efficacy of IBU1 and IBU2 for hsPDA with a cut-off value of 331 pg/mL (P < 0.001) and 423 pg/mL(P < 0.010), respectively. We did not identify a cut-off baseline BNP level that could predict treatment response to ibuprofen in preterm infants with hsPDA.

Exploration of potential biochemical markers for persistence of patent ductus arteriosus in preterm infants at 22-27 weeks' gestation

BACKGROUND

Early identification of infants at risk for complications from patent ductus arteriosus (PDA) may improve treatment outcomes. The aim of this study was to identify biochemical markers associated with persistence of PDA, and with failure of pharmacological treatment for PDA, in extremely preterm infants.

METHODS

Infants born at 22-27 weeks' gestation were included in this prospective study. Blood samples were collected on the second day of life. Fourteen biochemical markers associated with factors that may affect PDA closure were analyzed and related to persistent PDA and to the response of pharmacological treatment with ibuprofen.

RESULTS

High levels of B-type natriuretic peptide, interleukin-6, -8, -10, and -12, growth differentiation factor 15 and monocyte chemotactic protein 1 were associated with persistent PDA, as were low levels of platelet-derived growth factor. High levels of erythropoietin were associated with both persistent PDA and failure to close PDA within 24 h of the last dose of ibuprofen.

CONCLUSIONS

High levels of inflammatory markers were associated with the persistence of PDA. High levels of erythropoietin were associated with both the persistence of PDA and failure to respond to pharmacological treatment.

Early haemodynamically significant patent ductus arteriosus does not predict future persistence in extremely preterm infants

AIM

We assessed whether early haemodynamically significant patent ductus arteriosus (hsPDA) predicted persistent patent ductus arteriosus (PDA) in extremely preterm infants.

METHODS

This prospective observational study of 60 infants born at 22-27 weeks of gestational age (GA) without any major congenital anomalies or heart defects was conducted at Uppsala University Children's Hospital from November 2012 to May 2015. Respiratory and systemic circulatory parameters were continuously recorded, and echocardiographic examinations performed daily during the first three days of life. Pharmacological treatment was initiated if hsPDA was found on days two to seven. Persistent PDA was diagnosed if hsPDA remained after pharmacological treatment or pharmacological treatment was contraindicated.

RESULTS

The infants (56% male) had a median GA of 25 + 2 weeks and 50% received pharmacological treatment. PDA was persistent in 30% and ultimately closed or insignificant in 70%. hsPDA on days two to seven was not associated with future persistent PDA (p = 1.000). Mechanical ventilation (p = 0.025), high mean airway pressure (p = 0.020) and low ductal maximal flow velocity (V_max ) (p = 0.024) on day two were associated with future persistent PDA.

CONCLUSION

Early hsPDA did not predict persistent PDA, but the early need for assisted ventilation and low ductal V_max were associated with future persistent PDA in these extremely preterm infants.

Prediction of Therapeutic Response to Cyclooxygenase Inhibitors in Preterm Infants with Patent Ductus Arteriosus

Patent ductus arteriosus (PDA) is a morbid condition commonly seen in premature infants. Cyclooxygenase (COX) inhibitors, such as indomethacin and ibuprofen, are often used for the treatment of PDA in preterm infants, and they work by reducing the production of prostaglandin. However, as observed in clinical practice, not all PDAs in preterm infants can be closed using COX inhibitors. Some studies have demonstrated that gestational age, birth weight, B-type natriuretic peptide (BNP), and ductal diameter can predict the therapeutic responsiveness to COX inhibitors. This paper reviews the factors that can predict successful closure of the PDA in preterm infants using indomethacin or ibuprofen and presents new opinions and recent findings on this topic, including the predictive roles of intrauterine growth restriction, timing of the treatment, and the importance of platelet count and arterial pH. We also discuss the prospects for future studies to improve the individualized therapy of PDA in premature neonates.

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.