Betamethasone treatment-to-delivery interval, retreatment, and severe intraventricular hemorrhage in infants <28 weeks' gestation.

BACKGROUND: Antenatal corticosteroids decrease the incidence of severe intraventricular hemorrhage (grades 3, 4) in preterm infants. It is unclear whether their beneficial effects on intraventricular hemorrhage wane with time (as occurs in neonatal respiratory distress) and if repeat courses can restore this effect. Previous randomized controlled trials of betamethasone retreatment found no benefit on severe intraventricular hemorrhage rates. However, the trials may have included an insufficient number of infants at risk for intraventricular hemorrhage to be able to adequately address this question. Severe intraventricular hemorrhages occur almost exclusively in infants born at <28 weeks' gestation, whereas only 7% (0%-16%) of the retreatment trials' populations were <28 weeks' gestation. OBJECTIVE: This study aimed to determine if the risk for severe intraventricular hemorrhage in infants delivered at <28 weeks' gestation increases when the betamethasone treatment-to-delivery interval increases beyond 9 days and to determine if betamethasone retreatment before delivery decreases the rate of hemorrhage. STUDY DESIGN: This was an observational study that examined the incidence of intraventricular hemorrhage before (epoch 1) and after (epoch 2) a practice change that encouraged obstetricians to retreat pregnant women still at high risk for delivery before 28 weeks' gestation when >9 days elapsed from the first dose of betamethasone. Multivariable analyses with logistic regression using generalized estimating equation techniques were conducted to examine the rates of intraventricular hemorrhage among 410 infants <28 weeks' gestation who were either delivered between 1 to 9 days (n=290) after the first 2-dose betamethasone course or ≥10 days (and eligible for retreatment) after the first course (n=120). RESULTS: After adjusting for potential confounding variables, infants who were delivered ≥10 days after a single betamethasone course had an increased risk for either severe intraventricular hemorrhage alone or the combined outcome severe intraventricular hemorrhage or death before 4 days (odds ratio, 2.8; 95% confidence interval, 1.2-6.6) when compared with infants who were delivered between 1 and 9 days after betamethasone. Among the 120 infants who were delivered ≥10 days after the first dose of betamethasone, 64 (53%) received a second or retreatment course of antenatal betamethasone. The severe intraventricular hemorrhage rate in infants whose mothers received a second or retreatment course of betamethasone was similar to the rate among infants who delivered within 1 to 9 days and significantly lower than among those who delivered ≥10 days without retreatment (odds ratio, 0.10; 95% confidence interval, 0.02-0.65). Following the change in guidelines, the rate of retreatment in infants who were delivered ≥10 days after the first betamethasone course (and before 28 weeks) increased from epoch 1 to epoch 2 (25% to 87%; P<.001) and the rate of severe intraventricular hemorrhage decreased from 22% to 0% (P<.001). In contrast, the rate of severe intraventricular hemorrhage among infants who were delivered 1 to 9 days after the initial betamethasone dose (who were not eligible for retreatment) did not change between epochs 1 and 2 (12% and 11%, respectively). CONCLUSION: Although betamethasone's benefits on severe intraventricular hemorrhage appear to wane after the first dose, retreatment with a second course seems to restore its beneficial effects. Encouraging earlier retreatment of women at high risk for delivery before 28 weeks was associated with a lower rate of severe intraventricular hemorrhages among infants delivered at <28 weeks' gestation.

Prophylactic indomethacin and the risk of serious pulmonary hemorrhages in preterm infants less than 28 weeks' gestation.

OBJECTIVE: To determine if prophylactic indomethacin (PINDO) decreases serious pulmonary hemorrhages in infants <28 weeks. STUDY DESIGN: Intention-to-treat analysis of 615 consecutively admitted infants during four alternating protocol-driven epochs of PINDO or expectant patent ductus arteriosus (PDA) management. RESULTS: 41/615 (6.7%) developed serious pulmonary hemorrhage at 2 (1, 3) days (median (IQR)). In unadjusted and adjusted multivariable models, infants born in a PINDO epoch had significantly lower incidences of pulmonary hemorrhage and pulmonary hemorrhage or death before 7 days. There were less moderate/large PDA during PINDO epochs. The associations between PINDO and pulmonary hemorrhage and pulmonary hemorrhage/death were no longer significant when presence of a PDA was included in the analyses. There was no apparent association between PINDO epochs and the incidence of serious intraventricular hemorrhages. CONCLUSION: Even though PINDO no longer appears to affect the incidence of sIVH it still is associated with a lower incidence of pulmonary hemorrhage.

Patent ductus arteriosus (PDA) and pulmonary morbidity: can early targeted pharmacologic PDA treatment decrease the risk of bronchopulmonary dysplasia?

A persistent left-to-right shunt through a patent ductus arteriosus (PDA) increases the rate of pulmonary hydrostatic fluid filtration, impairs pulmonary mechanics, and prolongs the need for respiratory support. Infants with a moderate/large PDA shunt that persists for more than 7-14 days are at increased risk for developing bronchopulmonary dysplasia (BPD) if they also require invasive ventilation for more than 10 days. In contrast, infants who require invasive ventilation for less than 10 days have similar rates of BPD no matter how long they are exposed to a moderate/large PDA shunt. Although pharmacologic PDA closure decreases the risk of abnormal early alveolar development in preterm baboons that are ventilated for 2 weeks, the findings from recent randomized controlled trials, as well as a quality improvement project, suggest that routine early targeted pharmacologic treatments, as currently employed, do not appear to alter the incidence of BPD in human infants.

Prophylactic indomethacin, antenatal betamethasone, and the risk of intestinal perforation in infants <28 weeks' gestation.

OBJECTIVE: To determine if intestinal perforations before 14 days (either spontaneous (SIP) or necrotizing enterocolitis-induced) are increased when infants who received antenatal betamethasone shortly before birth are treated with prophylactic indomethacin (PINDO). STUDY DESIGN: Observational study of 475 infants <28 week's gestation assigned to either a PINDO-protocol (n = 231) or expectant management protocol (n = 244) during consecutive protocol epochs. RESULTS: Intestinal perforations before 14 days occurred in 33/475 (7%). In unadjusted and adjusted models, we found no associations between PINDO-protocol and intestinal perforations. PINDO-protocol did not increase intestinal perforations or SIP-alone even when given to infants who received betamethasone <7 or <2 days before delivery. 213/231 (92%) PINDO-protocol infants actually received indomethacin. The results were unchanged when examined just in those who received indomethacin. CONCLUSION: In our study, early intestinal perforations and SIP-alone were not increased when PINDO was used by protocol in infants who received antenatal betamethasone shortly before birth.

Patent ductus arteriosus and the risk of bronchopulmonary dysplasia-associated pulmonary hypertension.

BACKGROUND: The aim of the study was to determine whether prolonged exposure to a moderate/large patent ductus arteriosus left-to-right shunt (PDA) increases the risk of late (beyond 36 weeks) pulmonary hypertension (BPD-PH) and pulmonary vascular disease (BPD-PVD) during the neonatal hospitalization in preterm infants (<28 weeks' gestation) with bronchopulmonary dysplasia (BPD). METHODS: All infants requiring respiratory support ≥36 weeks had systematic echocardiographic evaluations for BPD-PH at planned intervals. Infants were classified as having either flow-associated BPD-PH (BPD-flow-PH) or BPD-PVD. RESULTS: 256 infants survived ≥36 weeks: 105 had NO BPD (were off respiratory support by 36 weeks); 151 had BPD. 22/151 had BPD-PH (12/22 had BPD-flow-PH from a PDA that persisted beyond 36 weeks; 10/22 had BPD-PVD). Moderate/large PDA shunts that persisted beyond 36 weeks were significantly associated with an increased incidence of BPD-PH due to BPD-flow-PH. We found no association between the duration of PDA exposure and the incidence of BPD-PVD. CONCLUSIONS: Moderate/large PDA shunts increase the risk of flow-associated BPD-PH when present beyond 36 weeks. Although term infants with PDA-congenital heart disease can develop pulmonary vascular remodeling and PVD after months of PDA exposure, we found no echocardiographic evidence in preterm infants that prolonged PDA exposure increases the incidence of BPD-PVD during the neonatal hospitalization. IMPACT: In our study, preterm infants (<28 weeks' gestation) with bronchopulmonary dysplasia (BPD) had a 15% incidence of pulmonary hypertension (PH) beyond 36 weeks' postmenstrual age as a comorbidity. Moderate/large patent ductus arteriosus (PDA) shunts increased the risk of flow-associated PH when present beyond 36 weeks. Although months of prolonged PDA exposure can cause pulmonary vascular remodeling and pulmonary vascular disease (PVD) in term infants with PDA-congenital heart disease, we found no echocardiographic evidence for an association between the duration of PDA exposure and the incidence of late PVD during the neonatal hospitalization in preterm infants with BPD.

Effects of prophylactic indomethacin on morbidity and mortality in infants <25 weeks' gestation: a protocol driven intention to treat analysis.

OBJECTIVE: To determine if prophylactic indomethacin (PINDO) decreases death or bronchopulmonary dysplasia-grades 2 and 3 (death/BPD) in newborns <25 weeks. STUDY DESIGN: Intention-to-treat, cohort-controlled study of 106 infants admitted during three alternating epochs of PINDO or Expectant patent ductus arteriosus (PDA) management. RESULTS: At 7-8 days 85% of Expectant Management epoch infants had a moderate/large PDA (median exposure was 23 days). Among PINDO epoch infants only 24% still had a PDA at 7-8 days. There were no significant differences in the incidence of death/BPD or of secondary outcomes (BPD, death, necrotizing enterocolitis/spontaneous perforations, or intraventricular hemorrhage (grades 3 or 4)) in either unadjusted or adjusted comparisons between infants born in a PINDO epoch and those born in the Expectant Management epoch. CONCLUSION: Despite being at high risk for PDA-related morbidities, PINDO did not appear to alter the rates of our primary and secondary outcomes in infants <25 weeks.

An Update on Patent Ductus Arteriosus and What is Coming Next.

Patent ductus arteriosus is the most common cardiovascular condition in preterm infants. There is a significant uncertainty about when and how to close ductus arteriosus in preterm infants due to a high spontaneous closure rate even in very immature preterm infants. Diagnosis and management of patent ductus arteriosus remain a challenge for both neonatologists and pediatric cardiologists. Researchers have tried to define a balance between an expectant approach and active treatment in selected infants. This review aimed to focus on the pathophysiology and management of patent ductus arteriosus and to make suggestions about approaches that might eliminate the association of morbidities with patent ductus arteriosus.

Patent ductus arteriosus, tracheal ventilation, and the risk of bronchopulmonary dysplasia.

BACKGROUND: An increased risk for bronchopulmonary dysplasia (BPD) exists when moderate-to-large patent ductus arteriosus shunts (hsPDA) persist beyond 14 days. GOAL: To examine the interaction between prolonged exposures to tracheal ventilation (≥10 days) and hsPDA on the incidence of BPD in infants <28 weeks gestation. STUDY DESIGN: Predefined definitions of prolonged ventilation (≥10 days), hsPDA (≥14 days), and BPD (room air challenge test at 36 weeks) were used to analyze deidentified data from the multicenter TRIOCAPI RCT in a secondary analysis of the trial. RESULTS: Among 307 infants who survived >14 days, 41 died before 36 weeks. Among survivors, 93/266 had BPD. The association between BPD and hsPDA depended on the length of intubation. In multivariable analyses, prolonged hsPDA shunts were associated with increased BPD (odds ratio (OR) (95% confidence interval (CI)) = 3.00 (1.58-5.71)) when infants required intubation for ≥10 days. In contrast, there was no significant association between hsPDA exposure and BPD when infants were intubated <10 days (OR (95% CI) = 1.49 (0.98-2.26)). A similar relationship between prolonged hsPDA and length of intubation was found for BPD/death (n = 307): infants intubated ≥10 days: OR (95% CI) = 2.41 (1.47-3.95)); infants intubated <10 days: OR (95% CI) = 1.37 (0.86-2.19)). CONCLUSIONS: Moderate-to-large PDAs were associated with increased risks of BPD and BPD/death-but only when infants required intubation ≥10 days. IMPACT: Infants with a moderate-to-large hsPDA that persist beyond 14 days are only at risk for developing BPD if they also receive prolonged tracheal ventilation for ≥10 days. Infants who receive less ventilatory support (intubation for <10 days) have the same incidence of BPD whether the ductus closes shortly after birth or whether it persists as a moderate-to-large shunt for several weeks. Early PDA closure may be unnecessary in infants who require short durations of intubation since the PDA does not seem to alter the incidence of BPD in infants who require intubation for <10 days.

Interactions between PDA-associated polymorphisms and genetic ancestry alter ductus arteriosus gene expression.

BACKGROUND: DNA polymorphisms in PTGIS and TFAP2B have been identified as risk factors for patent ductus arteriosus (PDA) in a population composed of preterm infants with European genetic ancestry but not in more genetically diverse populations. GOAL: To determine if the effects of TFAP2B and PTGIS polymorphisms on ductus arteriosus (DA) gene expression differ based on genetic ancestry. METHODS: DA from 273 human second trimester fetuses were genotyped for TFAP2B and PTGIS polymorphisms and for polymorphisms distributing along genetic ancestry lines. RT-PCR was used to measure the RNA expression of 49 candidate genes involved with DA closure. RESULTS: Seventeen percent of the DA analyzed were of European ancestry. In multivariable regression analyses we found consistent associations between four PDA-related TFAP2B polymorphisms (rs2817399(A), rs987237(G), rs760900(C), and rs2817416(C)) and expression of the following genes: EPAS1, CACNB2, ECE1, KCNA2, ATP2A3, EDNRA, EDNRB, BMP9, and BMP10, and between the PTGIS haplotype rs493694(G)/rs693649(A) and PTGIS and NOS3. These changes only occurred in DA with European ancestry. No consistent positive or negative associations were found among DA samples unless an interaction between the polymorphisms and genetic ancestry was taken into account. CONCLUSION: PTGIS and TFAP2B polymorphisms were associated with consistent changes in DA gene expression when present in fetuses with European ancestry. IMPACT: DNA polymorphisms in PTGIS and TFAP2B have been identified as risk factors for patent ductus arteriosus (PDA) in a population composed primarily of preterm infants with European genetic ancestry but not in more genetically diverse populations. The same PTGIS and TFAP2B polymorphisms are associated with changes in ductus gene expression when present in ductus from fetuses with European genetic ancestry. No consistent associations with gene expression can be found unless an interaction between the polymorphisms and genetic ancestry is taken into account.

Corrigendum: Platelet Counts and Patent Ductus Arteriosus in Preterm Infants: An Updated Systematic Review and Meta-Analysis.

[This corrects the article DOI: 10.3389/fped.2020.613766.].

Prolonged Tracheal Intubation and the Association Between Patent Ductus Arteriosus and Bronchopulmonary Dysplasia: A Secondary Analysis of the PDA-TOLERATE trial.

In the PDA-TOLERATE trial, persistent (even for several weeks) moderate to large patent ductus arteriosus (PDA) was not associated with an increased risk of BPD when the infant required <10 days of intubation. However, in infants requiring intubation for ≥10 days, prolonged PDA exposure (≥11 days) was associated with an increased risk of moderate/severe BPD.

The effect of prolonged tracheal intubation on the association between patent ductus arteriosus and bronchopulmonary dysplasia (grades 2 and 3).

OBJECTIVE: To determine if the need for mechanical ventilation alters the association between prolonged patent ductus arteriosus (PDA) exposure and bronchopulmonary dysplasia (grades 2 and 3) (BPD). STUDY DESIGN: Observational study of 407 infants (<28 weeks' gestation) with echocardiograms performed at planned intervals. RESULTS: Twelve percent (48/407) of study infants had BPD (grades 2 and 3). In a multivariable regression model, exposure to a moderate-to-large PDA shunt for ≥7 days was associated with an increased risk of BPD (grades 2 and 3) (from 16 to 35%: aRD = 19% (6, 32%), p < 0.005) when infants required ≥10 days of intubation (n = 170). In contrast, there was no significant association between prolonged PDA exposure and BPD when infants required ≤9 days of intubation (aRD = 4%) (-1, 10%) (n = 237). CONCLUSIONS: Moderate-to-large PDAs are associated with an increased risk of BPD-but only when infants require intubation ≥10 days.

A role for neonatal bacteremia in deaths due to intestinal perforation: spontaneous intestinal perforation compared with perforated necrotizing enterocolitis.

OBJECTIVE: To examine the relationship between intestinal perforations (caused by either spontaneous perforation (SIP) or necrotizing enterocolitis (NEC)) and the outcome "death due to intestinal perforation". METHODS: Multivariable logistic regression analyses were used to compare infants <28 weeks' gestation with SIP (n = 32) and perforated-NEC (n = 45) for the outcome perforation-related death. RESULTS: In univariate analyses the incidence of death due to perforation was higher among infants with perforated-NEC (36%) than infants with SIP (13%). However, infants with perforated-NEC were more likely to be older than 10 days and have bacteremia/fungemia with non-coagulase-negative staphylococci (non-CONS) organisms than infants with SIP. After adjusting for confounding the only variable that was significantly associated with mortality due to perforation was the presence of non-CONS bacteremia/fungemia at the onset of perforation. CONCLUSIONS: The apparent association between death and perforated-NEC could be explained by the higher incidence of non-CONS bacteremia/fungemia among infants with perforated-NEC.

Platelet Counts and Patent Ductus Arteriosus in Preterm Infants: An Updated Systematic Review and Meta-Analysis.

Background: A meta-analysis published in 2015 showed a significant association between low platelet counts in the first day(s) of life and risk of patent ductus arteriosus (PDA). The meta-analysis pooled data from 11 studies cohorts (3,479 preterm infants). Objective: To update the meta-analysis by adding new studies on the topic and including other platelet parameters different from platelet counts. Methods: PubMed/Medline and Embase databases were searched. Random-effects risk ratios (RR) and differences in means (DM) and 95% confidence intervals (CI) were calculated. Results: We included 31 studies (7,638 infants). Meta-analysis showed that the risk of developing any PDA was significantly associated with platelet counts<150 × 109/L (11 studies, RR 1.58, 95% CI 1.28 to 1.95), and <100 x 109/L (7 studies, RR 1.61, 95% CI 1.14 to 2.28), but not <50 x 109/L (4 studies, RR 1.34, 95% CI 0.77 to 2.32). Risk of developing hemodynamically significant PDA (hsPDA) was significantly associated with platelet counts<150 x 109/L (12 studies, RR 1.33, 95% CI 1.09 to 1.63), and <100 x 109/L (7 studies, RR 1.39, 95% CI 1.06 to 1.82), but not <50 x 109/L (6 studies, RR 1.24, 95% CI 0.86 to 1.79). Infants with hsPDA had significantly lower mean platelet counts (19 studies, DM 22.0 x 109, 95% CI 14.9 to 29.1) and platelet mass (11 studies, DM 214.4, 95% CI 131.2 to 297.5) and significantly higher platelet distribution width (PDW, 9 studies, DM -0.53, 95% CI -1.01 to -0.05) than infants without hsPDA. Meta-analysis could not demonstrate significant differences in mean platelet volume (MPV). Conclusion: Compared to the previous analysis, this updated meta-analysis included 21 additional studies that provide stronger evidence of the association between low platelet counts and PDA/hsPDA. Other platelet parameters such as platelet mass and PDW are also associated with hsPDA risk. However, the low number of platelets may be an epiphenomenon associated with the maturity and clinical stability of preterm infants rather than a contributing factor in the pathogenesis of PDA.

Relationship between Duration of Infant Exposure to a Moderate-to-Large Patent Ductus Arteriosus Shunt and the Risk of Developing Bronchopulmonary Dysplasia or Death Before 36 Weeks.

OBJECTIVE: This study was aimed to examine the relationship between duration of infant exposure to a moderate-to-large patent ductus arteriosus (PDA) shunt and the risk of developing bronchopulmonary dysplasia (BPD) or death before 36 weeks (BPD/death). STUDY DESIGN: Infants <28 weeks' gestation who survived ≥7 days (n = 423) had echocardiograms performed on day 7 and at planned intervals. RESULTS: In multivariable regression models, BPD/death did not appear to be increased until infants had been exposed to a moderate-to-large PDA for at least 7-13 days: OR (95%CI) (referent = closed or small PDA): moderate-to-large PDA exposure for <7 days: 0.38 (range, 0.10-1.46); for 7 to 13 days = 2.12 (range, 1.04-4.32); for ≥14 days = 3.86 (range, 2.15-6.96). Once the threshold of 7 to 13 days had been reached, additional exposure (≥14 days) did not significantly add to the increased incidence of BPD/death: (referent exposure = 7-13 days) exposure for 14 to 27 days = 1.34 (range, 0.52-3.45); for 28 to 48 days = 2.34 (range, 0.88-6.19); for ≥49 days = 1.80 (range. 0.59-5.47). A similar relationship was found for the outcome of BPD-alone. CONCLUSION: Infants < 28 weeks' gestation required at least 7 to 13 days of exposure to a moderate-to-large PDA before a significant increase in the incidence of BPD/death was apparent. Once this threshold was reached additional exposure to a moderate-to-large PDA did not significantly add to the increased incidence of BPD/death.

CYP2C9*2 is associated with indomethacin treatment failure for patent ductus arteriosus.

Aims: To identify clinical andgenetic factors associated with indomethacin treatment failure in preterm neonates with patent ductus arteriosus (PDA). Patients & Methods: This is a multicenter cohort study of 144 preterm infants (22-32 weeks gestational age) at three centers who received at least one treatment course of indomethacin for PDA. Indomethacin failure was defined as requiring subsequent surgical intervention. Results: In multivariate analysis, gestational age (AOR 0.76, 95% CI 0.60-0.96), surfactant use (AOR 9.77, 95% CI 1.15-83.26), and CYP2C9*2 (AOR 3.74; 95% CI 1.34-10.44) were each associated with indomethacin failure. Conclusion: Age, surfactant use, and CYP2C9*2 influence indomethacin treatment outcome in preterm infants with PDA. This combination of clinical and genetic factors may facilitate targeted indomethacin use for PDA.