Acute hemodynamic decompensation following patent ductus arteriosus ligation in premature infants

Near-infrared spectroscopy for perioperative assessment and neonatal interventions

Perioperative applications of near-infrared spectroscopy (NIRS) to monitor regional tissue oxygenation and perfusion in cardiac and noncardiac surgery are of increasing interest in neonatal care. Complex neonatal surgery can impair adequate oxygen delivery and tissue oxygen consumption and increase the risk of neurodevelopmental delay. Coupled with conventional techniques, NIRS monitoring may enable targeted hemodynamic management of the circulation in both cardiac and noncardiac surgical procedures. In this narrative review, we discuss the application of perioperative NIRS in specific neonatal interventions, including surgical intervention for congenital heart defects, definitive closure of the patent ductus arteriosus, neurological and gastrointestinal disorders, and use of extracorporeal membrane oxygenation. We identified areas for future research within disease-specific indications and offer a roadmap to aid in developing evidence-based targeted diagnostic and management strategies in neonates. IMPACT: There is growing recognition that perioperative NIRS monitoring, used in conjunction with conventional monitoring, may provide critical hemodynamic information that either complements clinical impressions or delivers novel physiologic insight into the neonatal circulatory and perfusion pathways.

Post-ligation cardiac syndrome after surgical versus transcatheter closure of patent ductus arteriosus in low body weight premature infants: a multicenter retrospective cohort study

Transcatheter patent ductus arteriosus (PDA) closure is a safe and effective alternative to surgical ligation in low-body-weight infants. Post-ligation cardiac syndrome (PLCS) is defined as severe hemodynamic and respiratory collapse within 24 h of PDA closure, requiring initiation or an increase of an inotropic agent by > 20% of preligation dosing and an absolute increase of at least 20% in ventilation parameters compared with the preoperative value. Whilst PLCS is routinely observed after surgery, its incidence remains poorly described following transcatheter closure. This study aimed to compare the incidence of PLCS after surgical versus transcatheter closure of PDA in low-body-weight premature infants. Propensity scores were used to compare surgical (N = 78) and transcatheter (N = 76) groups of preterm infants who underwent PDA closure at a procedural weight less than 2000 g in two tertiary institutions between 2009 and 2021. The primary outcome was the incidence of PLCS. Secondary outcomes included overall mortality before discharge, risk factors for PLCS, and post-procedural complications. Procedural success was 100% in both groups. After matching, transcatheter group experienced no PLCS vs 15% in the surgical group (p = 0.012). Furthermore, overall mortality (2% vs 17%; p = 0.03) and major complications (2% vs 23%; p = 0.002) were higher in the surgical group. Surgery (100% vs 47%; p < 0.01), gestation age (25 ± 1 vs 26 ± 2 weeks, p < 0.05) and inotropic support before closure (90% vs 29%; p < 0.001) were associated with PLCS occurrence.          Conclusion: Transcatheter PDA closure may be equally effective but safer than surgical PDA closure in low-body-weight premature infants. What is Known: • Post-ligation cardiac syndrome is a serious and common complication of surgical closure of the ductus arteriosus in preterm infants. • Transcatheter closure of preterm ductus arteriosus is a safe and effective technique that is becoming more and more common worldwide. What is New: • Device closure is safer than surgical ligation for patent ductus arteriosus closure in preterm infants and may be the first-line non-pharmacological therapeutic option in this indication in experienced teams. • Our findings should encourage neonatologists and pediatric cardiologists to start and/or strengthen a durable interventional program for transcatheter PDA closure in premature infants.

Effects of Milrinone on Neonates after Patent Ductus Arteriosus Ligation: A Retrospective Nationwide Database Study

INTRODUCTION

Milrinone is administered after patent ductus arteriosus (PDA) ligation to prevent and treat postoperative hemodynamic instability (i.e., postligation cardiac syndrome). We aimed to explore the effectiveness of milrinone on in-hospital outcomes in infants who underwent PDA ligation using a nationwide inpatient database in Japan.

METHODS

Using the Japanese Diagnosis Procedure Combination database, we identified patients who received milrinone after PDA ligation (n = 428) in neonatal intensive care units between July 2010 and March 2021 and those who did not (n = 3,392). We conducted a 1:4 propensity score-matched analysis with adjustment for background characteristics (e.g., gestational age, birth weight, comorbidities, preoperative treatments, and hospital background) to compare morbidities (bronchopulmonary dysplasia, intraventricular hemorrhage, necrotizing enterocolitis, and retinopathy of prematurity), mortality, total hospitalization costs, and other outcomes. For sensitivity analysis, we performed an overlap propensity score-weighted analysis.

RESULTS

In-hospital morbidity, bronchopulmonary dysplasia, intraventricular hemorrhage, and necrotizing enterocolitis occurred in 58%, 48%, 9.5%, and 7.1% of patients, respectively; the in-hospital mortality was 5.4%. After 1:4 propensity score matching, no significant difference was observed regarding mortality (7.1 vs. 5.7%), in-hospital morbidity (55 vs. 50%), bronchopulmonary dysplasia (44 vs. 41%), intraventricular hemorrhage (7.8 vs. 9.1%), necrotizing enterocolitis (8.5 vs. 8.9%), retinopathy of prematurity (21 vs. 22%), or total hospitalization costs (median: approximately 86,000 vs. 82,000 US dollars) between milrinone users (n = 425) and nonusers (n = 1,698). Sensitivity analyses yielded consistent results.

CONCLUSIONS

Milrinone use after PDA ligation was not associated with improved in-hospital outcomes, such as mortality and morbidity.

Left ventricular function before and after percutaneous patent ductus arteriosus closure in preterm infants

BACKGROUND

Definitive closure of the patent ductus arteriosus (PDA) is associated with significant changes in the loading conditions of the left ventricle (LV), which may lead to cardiovascular and respiratory instability. The objective of the study was to evaluate targeted neonatal echocardiography (TnECHO) characteristics and the clinical course of preterm infants ≤2 kg undergoing percutaneous PDA closure.

METHODS

Retrospective cohort study of prospectively acquired pre- and post-closure TnECHOs to assess hemodynamic changes. Cardiorespiratory parameters in the first 24 h following PDA closure were also evaluated.

RESULTS

Fifty patients were included with a mean age of 30.6 ± 9.6 days and weight of 1188 ± 280 g. LV global longitudinal strain decreased from -20.6 ± 2.6 to -14.9 ± 2.9% (p < 0.001) after 1 h. There was a decrease in LV volume loading, left ventricular output, LV systolic and diastolic parameters. Cardiorespiratory instability occurred in 24 (48%) [oxygenation failure in 44%] but systolic hypotension and/or need for cardiovascular medications was only seen in 6 (12%). Patients with instability had worse baseline respiratory severity score and lower post-closure early diastolic strain rates.

CONCLUSIONS

Percutaneous PDA closure leads to a reduction in echocardiography markers of LV systolic/diastolic function. Post-closure cardiorespiratory instability is characterized primarily by oxygenation failure and may relate to impaired diastolic performance.

IMPACT

Percutaneous patent ductus arteriosus closure leads to a reduction in echocardiography markers of left ventricular volume loading, cardiac output, and left ventricular systolic/diastolic function. Post-procedural cardiorespiratory instability is characterized primarily by oxygenation failure. Post-procedural cardiorespiratory instability may relate to impaired diastolic performance.

Electrical cardiometry in monitoring percutaneous closure of ductus arteriosus in preterm infants: a case study on five patients

Patent ductus arteriosus closure by catheter-based interventions has become the preferred therapeutic choice. However, hemodynamic perturbances associated to this procedure have not yet been investigated. This study sought to examine the on-site hemodynamic impact caused by the procedure in preterm neonates. In this study, hemodynamic monitoring was obtained in a non-invasive way using electrical cardiometry in five preterm infants who underwent percutaneous patent ductus arteriosus closing at ASST Grande Ospedale Metropolitano Niguarda of Milan. All five infants underwent successful transcatheter closures. All patients experienced immediate hemodynamic changes upon ductal closing. Significative modifications occurred mainly in heart contractility, cardiac output, and stroke volume. In three cases, there was also a significative increase of systemic vascular resistance which persisted for 4 h after closing. While in two cases they spontaneously reduced with an amelioration of cardiac output and contractility, in the other case they were persistently high, associated with an hypertensive crisis and a progressive reduction of cardiac functions. For these reasons, milrinone was started and hemodynamic parameters returned normal in about 3 h, so therapy was discontinued.   Conclusions: Our single-center, prospective, consecutive, case series demonstrated hemodynamic aberrations due to sudden closure of a patent ductus arteriosus. Moreover, post procedural hemodynamic monitoring is important to precociously detect possible cardiac impairment and start an adequate therapy. What is Known: • It has previously suggested a temporarily impairment in cardiac output following patent ductus arteriosus closing. • Little is known about the other hemodynamic parameters during the procedure and how they change in the next hours according to the new hemodynamic status. What is New: • The persistence of increased systemic vascular resistance after percutaneous closure of ductus arteriosus could suggest the occurrence of hemodynamic complications. • Electrical cardiometry was useful to early detect postoperative hemodynamic changes.

[Timing of surgical ligation of patent ductus arteriosus in very low birth weight infants]

OBJECTIVES

To study the effect of timing of surgical ligation of patent ductus arteriosus (PDA) on the prognosis of very low birth weight infants (VLBWI).

METHODS

The medical data of VLBWI who underwent transthoracic ligation for PDA from June 2018 to May 2021 were reviewed retrospectively. The infants were divided into early ligation group (≤21 days of age) and late ligation group (>21 days of age) based on the age of ligation. The two groups were compared in terms of perioperative clinical features, complications, and mortality. The risk factors for early surgical ligation were analyzed.

RESULTS

A total of 72 VLBWI were enrolled, with 19 infants (26%) in the early ligation group and 53 infants (74%) in the late ligation group. There were significant differences in birth weight, gestational age, weight at operation, days of age at operation, rates of preoperative invasive and noninvasive mechanical ventilation, incidence rate of pulmonary hemorrhage, incidence rate of hypotension, preoperative PDA internal diameter (mm/kg), intraoperative PDA external diameter (mm/kg), incidence rate of post-ligation cardiac syndrome, and duration of postoperative invasive mechanical ventilation between the two groups (P<0.05). A binary logistic regression analysis showed that pulmonary hemorrhage was an indication of early surgical ligation of PDA (P<0.05). There were no significant differences in the incidence rates of post-operative complications and the mortality rate between the early ligation and late ligation groups.

CONCLUSIONS

Early surgical ligation may be performed for VLBWI who are experiencing pulmonary hemorrhage and hemodynamically significant PDA confirmed by cardiac ultrasound after birth. However, post-ligation cardiac syndrome should attract enough attention. In addition, early surgical ligation of PDA does not increase the risk of surgery-related and long-term complications or death, indicating that it is a safe and feasible treatment option.

Phenotyping respiratory decompensation following definitive closure of the patent ductus arteriosus in preterm infants

OBJECTIVE

To identify risk factors associated with high-frequency ventilation (HFV) following definitive closure of the patent ductus arteriosus (PDA).

METHODS

We performed a retrospective study of premature infants (<37 weeks) who were mechanically ventilated before and after surgical or transcatheter PDA closure. Primary outcome was HFV requirement within 24 h of procedure. Logistic regression was used to estimate clinical associations with post procedure HFV requirement.

RESULTS

We identified 110 infants who were mechanically ventilated before PDA closure, of which 48 (44%) escalated to HFV within 24 h after closure. In the multivariable model, surgical ligation (OR 21.5, 95% CI 1.6-284), elevated Respiratory Severity Score (RSS) 1 h post-procedure (OR 1.78, 95% CI 1.07-2.99) and 12 h post-procedure (OR 2.12, 95% CI 1.37-3.26) were independent predictors of HFV.

CONCLUSION

Surgical ligation and elevated RSS values over the first 12 h after PDA closure are risk factors for HFV.

Percutaneous Closure of Patent Ductus Arteriosus

Percutaneous-based patent ductus arteriosus closure is technically feasible among infants less than 1.5 kg. However, marked heterogeneity in the type and nature of adverse events obscures current safety profile assessments. Although data on the risks of postdevice closure syndrome remain promising, a lack of comparative trials of surgical ductal ligation and inconsistent surveillance across published studies obscure confidence in present estimates of safety and efficacy. To minimize risk and yield the greatest benefits, clinical studies of patent ductus arteriosus treatment should consider incorporating more robust assessments to ensure that infants at greatest risk for adverse ductal consequences are included.

The clinical value of ultrasonic cardiac output monitor in very-low birth-weight and extremely-low-birth-weight infants undergoing PDA ligation

BACKGROUND

Cardiorespiratory instability occurs very often in very-low-birth-weight (VLBW) and extremely-low-birth-weight (ELBW) infants undergoing patent ductus arteriosus (PDA) ligation during the early postoperative period. This study aimed to investigate ultrasonic cardiac output monitor (USCOM) as a bedside tool by evaluating the hemodynamic changes in preterm infants following PDA ligation and assessing factors that may influence these changes.

METHODS

This was a single-center prospective observational study at a third-level neonatal intensive care unit. A total of 33 infants, including 21 VLBW and 12 ELBW infants, were involved. Hemodynamic measurements were performed in these infants using a USCOM preoperatively as well as 0-1 h, 8-10 h, and 24 h postoperatively.

RESULTS

The PDA ligation was associated with reductions of the left ventricular cardiac output (LVCO) (P < 0.001), cardiac index (P < 0.001), flow time corrected (FTC) (P < 0.001), Smith-Madigan inotropy index (SMII) (P < 0.001), oxygen delivery (DO₂) (P < 0.001), and oxygen delivery index (DO₂I) (P < 0.001) and an increase of the systemic vascular resistance index (SVRI) (P < 0.001) at 0-1 h, 8-10 h, and 24 h post-ligation compared with the respective preoperative values. Compared with the respective values at 0-1 h post-ligation, there was no significant difference in the CI, SMII, or FTC at 8-10 h and 24 h post-ligation. However, the SVRI decreased at 8-10 h and 24 h post-ligation. Moreover, the DO₂I increased at 8-10 h and 24 h post-ligation, and the LVCO and DO₂ increased at 24 h post-ligation.

CONCLUSION

Our study confirmed that the hemodynamic changes measured by the USCOM were similar to those measured by echocardiography in previous reports. Thus, USCOM is a useful and convenient bedside tool for assessing hemodynamic changes to guide the use of fluids, inotropic agents, and vasopressors and help modify the post-ligation course, and they may be a surrogate for repeated echocardiography during the early post-ligation period in preterm infants or a preliminary screening method.

Which Inotropic Drug, Dobutamine or Milrinone, Is Clinically More Effective in the Treatment of Postligation Cardiac Syndrome in Preterm Infants?

OBJECTIVE

This study aimed to detect which of the two main medicines suggested in the treatment of postligation cardiac syndrome (PLCS)-dobutamine or mirinone-possesses a more therapeutic effect. While doing this, clinicians are provided with a broader perspective on the treatment and follow-up of cases. The desire was to increase the treatability and monitor ability of the cases in question and hence their survivability.

STUDY DESIGN

A retrospective review of a cohort of infants with PLCS was conducted between March 2012 and December 2018. In the treatment of infants with PLCS, dobutamine (dobutamine study group-DSG) or milrinone (milrinone study group-MSG) was used. The respiration, cardiac, echocardiography, and perfusion parameters of the cases were assessed both before and after ligation. Based on the data obtained, both the effects of the medicines on PLCS and the difference between their therapeutic effects were studied. The accuracy of prognostication was assessed with receiver operating characteristic analyses.

RESULTS

PLCS was detected in 29 (34.1%) of 85 patent ductus arteriosus ligation cases in total. Of all the PLCS cases, 13 (44.8%) were treated with dobutamine and 16 (55.2%) with milrinone. It was observed that the effects of the medicines on the respiratory system and cardiovascular system manifested in the third and 6th hour, respectively. It was detected that both medicines had more effect on the systolic blood pressure (SBP) (area under the curve [AUC]: 0.997/0.996, p = 0.001/0.002) than on the diastolic blood pressure (AUC: 0.911/0.843, p = 0.032/0.046).

CONCLUSION

Dobutamine and milrinone, two primary medicines that can be used in the treatment of cases with PLCS, possess similar therapeutic effects on this pathology. In addition, their postoperative therapeutic effects on the SBP are more in the foreground.

Anesthesia protocols for "bedside" preterm patent ductus arteriosus ligation: A single-institutional experience

Background :

Hemodynamically significant patent ductus arteriosus (PDA) is frequently encountered in preterm infants sometimes requiring surgical attention. Although PDA ligation is regularly performed in the operating room, conducting it at the bedside in a neonatal intensive care unit (NICU) and its anesthetic management remains challenging.

Aim :

We aim to discuss the anesthetic considerations in patients undergoing bedside PDA ligation and describe our experience highlighting the feasibility and safety of this procedure.

Setting and Design :

The study was conducted in the NICU in a tertiary care hospital; This was a retrospective, observational study.

Methods :

Preterm infants scheduled for bedside PDA ligation using a predefined anesthesia protocol between August 2005 and October 2020 were included.

Statistical Analysis Used:

Quantitative data were presented as median with interquartile range and categorical data were presented as numbers and percentage thereof.

Results :

Sixty-six premature infants underwent bedside PDA ligation. Thirty-day mortality was 4.5% (3 infants), but there were no procedural deaths. One (1.5%) patient had intraoperative endotracheal tube dislodgement. Three (4.5%) infants had postoperative pneumothorax requiring an additional chest tube insertion. Twenty-one (32%) patients required initiation of postoperative inotrope/vasodilator therapy within 6 h. Three postligation cardiac syndromes (≥ Grade-III mitral regurgitation with left ventricular dysfunction and hypotension) occurred.

Conclusions :

Although anesthesia for preterm neonates undergoing bedside PDA ligation poses unique challenges, it can be safely conducted by following a predetermined standardized anesthesia protocol. Its successful conduct requires utmost vigilance and pristine understanding of the principles of neonatal and cardiac care.

Short-Term Complications Associated with Surgical Ligation of Patent Ductus Arteriosus in ELBW Infants: A 25-Year Cohort Study

OBJECTIVE

This article aims to determine the incidence of short-term complications of surgical patent ductus arteriosus (PDA) ligations, the factors associated with those complications, and whether complications are associated with poor long-term outcomes.

STUDY DESIGN

Retrospective cohort study of all extremely low birth weight (ELBW, < 1,000 g) infants who underwent surgical PDA ligation at a single-center neonatal intensive care unit from 1989 to 2015. Demographic, clinical, and laboratory data were reviewed. The primary outcome was development of a short-term (< 2 weeks from ligation) surgical complication. Secondary outcomes include bronchopulmonary dysplasia (BPD), length of stay, and mortality.

RESULTS

A total of 180 ELBW infants were included; median gestational age and birth weight was 24 weeks and 683 g, respectively, and 44% of infants had at least one short-term complication. Need for vasopressors (33%) was the most common medical complication and vocal cord paralysis (9%) was the most common surgical complication. Younger corrected gestational age at time of repair was associated with increased risk for complications. Mortality, length of stay, and BPD rates were similar between infants with and without complications.

CONCLUSION

Serious complications were seen in a minority of infants. Additional research is needed to determine if short-term complications are associated with long-term adverse outcomes.

Patent ductus arteriosus in preterm infants: is early transcatheter closure a paradigm shift?

The optimal management approach of the patent ductus arteriosus (PDA) in premature infants remains uncertain owing the lack of evidence for long-term benefits and the limited analyses of the complications of medical and surgical interventions to date. In recent years, devices suitable to plug the PDA of premature infants (including extremely low birthweight, <1000 g) have become available and several trials have demonstrated successful and safe transcatheter PDA closure (TCPC) in this population. Whether TCPC represents a paradigm shift in PDA management that will result in improved short- and long-term outcomes, less bronchopulmonary dysplasia, improved neurodevelopment, or better long term renal function remains to be seen. Careful rigorous study of the potential benefits of TCPC in this highly vulnerable population in the context of well-designed adequately powered trials is needed prior to widespread adoption of this approach.

Childhood Neurodevelopmental Outcome in Low Birth Weight Infants With Post-ligation Cardiac Syndrome After Ductus Arteriosus Closure

Background

Post-ligation cardiac syndrome (PLCS) is a common complication of patent ductus arteriosus (PDA) surgical closure in low birth weight infants. It has been associated with mortality, but there is a lack of information about the neurodevelopmental outcome of the survivors. We aimed to explore the prevalence of PLCS and to assess whether this clinical condition is a risk factor for adverse outcome, (moderate or severe neurodevelopmental disabilities).

Methods

We retrospectively reviewed the medical charts of all the infants < 30 weeks of gestation who underwent ductus arteriosus ligation at our unit between 2005 and 2009.

Results

During the study period, 39 preterm infants [mean gestational age 26.4 (2) weeks] underwent surgical closure of the PDA at a mean postnatal age of 25.3 (2.3) days. Twenty six percent of the study population developed PLCS. Five infants died and the follow-up was accomplished in 24 infants (70% of the survivors) at a mean age of 5.3 (1.5) years (range 2–9 years). Neurodevelopmental impairment was observed in 6 in the PLCS group (75%) and in 6 infants in the no PLCS group (37%), p = 0.08]. Multiple regression analyses showed that the best fitting model for predicting adverse outcome included PLCS and low birth weight, p = 0.018.

Conclusion

Preterm infants undergoing surgical closure of PDA who fulfill the criteria of PLCS according to this study seem to have a tendency toward higher risk of long-term neurodevelopmental impairment. Prospective clinical trials reporting long-term follow-up data should be designed to confirm the hypotheses generated in this pilot study.

Post-ligation cardiac syndrome is associated with increased morbidity in preterm infants

OBJECTIVE

The influence of post-ligation cardiac syndrome (PLCS), a complication of patent ductus arteriosus (PDA) ligations, on neonatal outcomes is unknown. The purpose of this study was to determine the risks of PLCS on severe pulmonary morbidity and severe retinopathy of prematurity (ROP).

STUDY DESIGN

Retrospective cohort study of infants who underwent a PDA ligation between 2006 and 2015. Data were collected on patients with and without PLCS. The primary outcome was the difference in severe bronchopulmonary dysplasia (BPD) between groups. Secondary outcomes included discharge with home oxygen and severe ROP.

RESULT

A total of 100 infants that underwent PDA ligation during the study period were included in the study; 31 (31%) neonates developed PLCS. In adjusted analysis, PLCS was associated with increased risk for severe BPD (RR 1.67, 95% CI: 1.15-2.42) and home oxygen therapy (RR: 1.47, 95% CI: 1.09-1.99) only. No association with severe ROP was seen (RR: 1.48; 95% CI: 0.87-2.52).

CONCLUSION

PLCS is associated with severe neonatal pulmonary morbidity, but not with severe ROP. Further investigation is warranted to validate these results.

Terlipressin-induced modifications of Doppler ultrasound signals of systemic arteries in preterm infants with vasoactive-resistant patent ductus arteriosus: A pilot study

PURPOSE

To study the effects of terlipressin (TP) infusion on systemic perfusion, estimated with pulsed-wave Doppler ultrasonography of systemic arteries, in a population of extremely low birth-weight (ELBW) preterm infants with vasoactive-resistant ductus arteriosus.

METHODS

This prospective, observational cohort included, during five years, 12 ELBW infants with hemodynamically significant patent ductus arteriosus and absent or reversed diastolic flow at Doppler ultrasonography of systemic arteries, despite treatment and high-dose vasoactive support. We measured flow velocity of the anterior cerebral, right renal, and superior mesenteric arteries before and after TP infusion. Changes were evaluated by Spearman's rho coefficient analysis, Wilcoxon signed-rank, and Friedman test.

RESULTS

Time-averaged mean velocity of the renal artery (P = .028) increased, while renal pulsatility (P = .010) and resistance (P = .004) indexes, and cerebral artery resistance index (P = .021) decreased after TP infusion. Time-averaged mean velocity of the anterior cerebral artery proportionately increased with dopamine dose (rho = 0.678; P = .015), but showed opposite shifts after TP (rho = -0.662; P = .024).

CONCLUSIONS

These changes suggest that TP may improve systemic perfusion in the ELBW infants with vasoactive-resistant ductus arteriosus.

Neurodevelopmental Outcome at 2 Years of Age according to Patent Ductus Arteriosus Management in Very Preterm Infants

BACKGROUND

Patent ductus arteriosus (PDA) is a condition frequently found in very preterm infants, and its treatment remains a subject of debate. Furthermore, there are only a few studies available that have examined the impact of these treatments on the neurological outcome of the patient.

OBJECTIVE

To evaluate the neurodevelopmental outcome of PDA treatment on preterm infants born between 24+0 and 28+6 weeks of gestation.

METHODS

We conducted an observational multicentric cohort study (LIFT Cohort). We compared three groups of patients according to their PDA treatment strategy: medical treatment with ibuprofen, surgical ligation, and no treatment. The neurodevelopmental outcome was assessed with a physical examination and cognitive function evaluation at 2 years of age. A propensity score was used to reduce bias in the analysis.

RESULTS

Between 2003 and 2011, 857 infants (91.3%) were evaluated at 2 years of corrected age and included in the analysis: 248 received ibuprofen treatment (29%), 104 had PDA surgical ligation (12%), and 505 did not receive any PDA treatment (59%). Surgical ligation of PDA was significantly associated with neurodevelopmental impairment at 2 years of age (adjusted odds ratio = 2.2; 95% confidence interval: 1.4-3.4).

CONCLUSION

We found an association between PDA surgical ligation and a nonoptimal neurodevelopmental outcome at 2 years of age for preterm infants born before 29 weeks of gestation. These results suggest that if surgical ligation is unavoidable, particular attention should be given to the patient's neurodevelopmental follow-up.

Hemodynamic alterations recorded by electrical cardiometry during ligation of ductus arteriosus in preterm infants

This is a prospective study using non-invasive electrical cardiometry to measure hemodynamic changes during surgical ligation of patent ductus arteriosus (PDA) in very low birth weight (VLBW, ≤1500 g) infants. The aims of this study were to examine hemodynamic aberration caused by abrupt closure of a ductal shunting and to define factors that affect hemodynamic changes. Simultaneous measurements of heart rate (HR), stroke volume (SV), cardiac output (CO), and systemic vascular resistance (SVR) were collected at ten time points: 1 h prior to anesthesia, at the beginning of anesthesia, starting of surgery, immediately after PDA being ligated, and 1 h followed by 6, 12, 18, 24, and 48 h after the surgery. Thirty infants with gestational age of 27.7 ± 2.0 weeks and birth weight of 929 ± 280 g were studied. Upon sudden termination of ductal shunting, there was a significant decline in CO to 73 % of presurgery baseline. The deterioration in CO was associated with a decreased SV rather than HR. At the same time, there was an increase of SVR following ductal ligation. Magnitude of CO and SV reduction were higher in smaller infants (≤1 kg), and recovery was to a lesser degree in infants with more severe PDA.

CONCLUSION

Reduced stroke volume and elevated vascular resistance contribute to the major hemodynamic aberrations in VLBW infants receiving PDA ligation surgery.

Catecholamine-resistant hypotension and myocardial performance following patent ductus arteriosus ligation

OBJECTIVE

We performed a multicenter study of preterm infants, who were about to undergo patent ductus arteriosus ligation, to determine whether echocardiographic indices of impaired myocardial performance were associated with subsequent development of catecholamine-resistant hypotension following ligation.

STUDY DESIGN

A standardized treatment approach for hypotension was followed at each center. Infants were considered to have catecholamine-resistant hypotension if their dopamine infusion was > 15 μg kg(-1)min(-1). Echocardiograms and cortisol measurements were obtained between 6 and 14 h after the ligation (prior to the presence of catecholamine-resistant hypotension).

RESULT

Forty-five infants were enrolled, 10 received catecholamines (6 were catecholamine-responsive and 4 developed catecholamine-resistant hypotension). Catecholamine-resistant hypotension was not associated with decreased preload, shortening fraction or ventricular output. Infants with catecholamine-resistant hypotension had significantly lower levels of systemic vascular resistance and postoperative cortisol concentration.

CONCLUSION

We speculate that low cortisol levels and impaired vascular tone may have a more important role than impaired cardiac performance in post-ligation catecholamine-resistant hypotension.

Hypotension following patent ductus arteriosus ligation: the role of adrenal hormones

OBJECTIVE

To test the hypothesis that an impaired adrenal response to stress might play a role in the hypotension that follows patent ductus arteriosus (PDA) ligation.

STUDY DESIGN

We performed a multicenter study of infants born at <32 weeks' gestation who were about to undergo PDA ligation. Serum adrenal steroids were measured 3 times: before and after a cosyntropin (1.0 μg/kg) stimulation test (performed before the ligation), and at 10-12 hours after the ligation. A standardized approach for diagnosis and treatment of postoperative hypotension was followed at each site. A modified inotrope score (1 × dopamine [μg/kg/min] + 1 × dobutamine) was used to monitor the catecholamine support an infant received. Infants were considered to have catecholamine-resistant hypotension if their greatest inotrope score was >15.

RESULTS

Of 95 infants enrolled, 43 (45%) developed hypotension and 14 (15%) developed catecholamine-resistant hypotension. Low postoperative cortisol levels were not associated with the overall incidence of hypotension after ligation. However, low cortisol levels were associated with the refractoriness of the hypotension to catecholamine treatment. In a multivariate analysis: the OR for developing catecholamine-resistant hypotension was OR 36.6, 95% CI 2.8-476, P = .006. Low cortisol levels (in infants with catecholamine-resistant hypotension) were not attributable to adrenal immaturity or impairment; their cortisol precursor concentrations were either low or unchanged, and their response to cosyntropin was similar to infants without catecholamine-resistant hypotension.

CONCLUSION

Infants with low cortisol concentrations after PDA ligation are likely to develop postoperative catecholamine-resistant hypotension. We speculate that decreased adrenal stimulation, rather than an impaired adrenal response to stimulation, may account for the decreased production.

Adrenal function in preterm infants undergoing patent ductus arteriosus ligation

BACKGROUND

Targeted milrinone treatment for low left ventricular output (LVO) reduces the incidence of acute cardiorespiratory instability following ligation of patent ductus arteriosus (PDA) in preterm infants. Despite this, some infants continue to experience postoperative deterioration. Adrenal insufficiency related to prematurity has been postulated as a possible mechanism.

OBJECTIVES

To describe adrenal function in premature infants undergoing PDA ligation and to investigate its association with pre- and postoperative clinical and echocardiography-derived indices of disease severity.

METHODS

A retrospective cohort study was conducted over a 2-year period on infants who underwent PDA ligation and had preoperative adrenocorticotropic hormone (ACTH) stimulation. All infants were screened by echocardiography for low LVO at 1 h after surgery and treated with intravenous milrinone if LVO <200 ml/kg/min. The primary outcome evaluated was low LVO at 1 h after surgery. Secondary outcomes included hypotension and oxygenation and ventilation failure occurring within 24 h.

RESULTS

A total of 35 infants at a median gestation of 25.4 (24.5-26.4) weeks and weight at birth of 700 (600-810) g were included. Baseline median cortisol measured preoperatively was 202 (137-403) nmol/l. Following the ACTH stimulation test, 3 infants had cortisol ≤500 nmol/l while 15 had ≤750 nmol/l. There was no association seen between any cortisol value and low LVO postoperatively. Post-ACTH cortisol ≤750 nmol/l was significantly associated with hypotension (p = 0.03) and oxygenation (p = 0.04) and ventilation (p = 0.008) failure. Receiver-operator characteristic curve showed a high predictive value of post-ACTH cortisol for all clinical outcomes.

CONCLUSIONS

Post-ACTH cortisol (≤750 nmol/l) may be associated with clinical indices of postoperative cardiorespiratory instability. Relative adrenal insufficiency may play a role in the etiology of post-PDA ligation hemodynamic and respiratory instability.

Cardiovascular instability after patent ductus arteriosus ligation in preterm infants: the role of hydrocortisone

OBJECTIVE

Following patent ductus arteriosus (PDA) ligation, preterm infants may develop profound hypotension and respiratory failure. Prophylactic stress hydrocortisone (HC) has emerged as a therapy to prevent complications, postulating these infants do not synthesize steroids because of an immature hypothalamic-pituitary-adrenal axis. The purpose of this study was to compare outcomes in infants who received stress HC before their PDA ligations to those who did not.

STUDY DESIGN

A retrospective chart review was performed of infants who underwent PDA ligations at our institution's neonatal intensive care unit. Data were collected on treatment with HC, and respiratory and cardiovascular support.

RESULT

Gestational age (GA) and birth weight were lower in the HC group (24 vs 25 weeks, 632 vs 790 g), but age at time of surgery was similar (26 vs 21 days). Cardiorespiratory support was comparable between the groups pre- and post-operatively. In regression models that adjusted for GA, HC treatment was not independently related to respiratory support postoperatively, but was associated with a decrease in postoperative dopamine (2.2 mcg kg(-1)  min(-1); P=0.03). Respiratory support postoperatively was predicted by preoperative respiratory support. GA and age at surgery were not independently associated with outcome.

CONCLUSION

Preoperative stress HC was not associated with improved cardiorespiratory stability, regardless of GA. Further investigation is needed to identify infants who may benefit from this therapy.

Pros and cons of patent ductus arteriosus ligation: hemodynamic changes and other morbidities after patent ductus arteriosus ligation

Although surgical ligation of a persistent patent ductus arteriosus resolves the adverse hemodynamic consequences of the systemic-to-pulmonary shunt and may confer some long-term benefits, it is also associated with both immediate and long-term negative effects. The population that benefits from or is harmed by the procedure is not clearly defined. Although indiscriminate ligation of the patent ductus arteriosus in all patients is not supported by the available information, the recent suggestion declaring the ductus harmless is not supported either. As we await the results of appropriately designed randomized control studies to define the indications for ligation, we must use clinical and echocardiographic indicators of a hemodynamically significant ductus arteriosus and thoughtful assessment of each individual patient to help guide us in addressing this complex problem.

Use of targeted neonatal echocardiography to prevent postoperative cardiorespiratory instability after patent ductus arteriosus ligation

OBJECTIVES

To investigate the value of targeted neonatal echocardiography (TnECHO) in predicting cardiorespiratory instability after patent ductus arteriosus (PDA) ligation, and to evaluate the impact of TnECHO-directed care.

STUDY DESIGN

We reviewed serial echocardiography evaluations of 62 preterm infants after PDA ligation to investigate the relationship between indices of myocardial performance and postoperative cardiorespiratory instability. A predictive model was developed based on TnECHO criteria, with targeted initiation of intravenous milrinone. A comparative evaluation was performed between matched infants in the previous era (epoch 1; n=25) and current era (epoch 2; n=27) of TnECHO-guided treatment.

RESULTS

Left ventricular output <200 mL/kg/min at 1 hour after PDA ligation was a sensitive predictor of systemic hypotension and the need for inotropes, and was used for initiation of i.v. milrinone infusion in epoch 2. Infants treated with milrinone had a lower incidence of ventilation failure (15% vs 48%; P=.02) and less need for inotropes (19% vs 56%; P=.01), and showed a trend toward improved oxygenation (P=.08).

CONCLUSION

TnECHO facilitates early detection of infants at greatest risk for subsequent cardiorespiratory deterioration. Administration of milrinone to neonates with low cardiac output may lead to improved postoperative stability.

Use of milrinone in the management of haemodynamic instability following duct ligation

Haemodynamic instability affects 22% to 29% of very low birth weight infants in the acute period following ligation of the ductus arteriosus and contributes to the mortality seen in this group. Since the sudden elevation of systemic vascular resistance has been recognised to be one of the factors contributing to this instability, milrinone, an afterload reducing agent, might potentially be of significant therapeutic benefit. This report presents the clinical course of an infant born at 26 weeks gestation who required surgical ligation of a haemodynamically significant patent ductus arteriosus after two unsuccessful 6-day courses of intravenous indomethacin. The post-operative period was characterized by oxygenation failure, rising blood pressure and echocardiographic signs indicative of diastolic dysfunction. The infant was successfully managed with milrinone, a phosphodiesterase inhibitor, which acts both as an "inodilator" and has lusitropy properties. Post-duct ligation haemodynamic instability in a preterm infant was successfully managed with milrinone. The role of afterload-reducing agents such as milrinone in this setting should, therefore, be systematically analyzed.

Adrenal function in newborns undergoing surgery

OBJECTIVE

To measure cortisol, adrenocorticotropic hormone (ACTH)-stimulated cortisol and ACTH values in the newborn intensive care unit-admitted newborn infants within 48 h before surgery and to describe the relationship of these values to measures of clinical illness before and after surgery.

STUDY DESIGN

In this prospective observational study, we measured baseline and ACTH-stimulated cortisol concentrations within 48 h before surgery in newborn infants <44 weeks postmenstrual age and examined the relationship of these values to measures of illness severity both before and after surgery, including the score for neonatal acute physiology (SNAP) and use of vasopressors. ACTH concentrations were measured in a subset of the infants.

RESULT

Twenty-five infants were enrolled and had median (25th to 75th percentile) baseline and ACTH-stimulated cortisol values of 7.1 (3.5 to 11.1) and 40.4 mcg per 100 ml (22.6 to 50.6). Preterm infants had significantly lower ACTH-stimulated cortisol values (median 21.6 vs 44.7 mcg per 100 ml). There was no correlation between any of these values and either the presurgical or postsurgical measures of illness severity, nor the increase in SNAP after surgery. Infants receiving vasopressors perioperatively had lower median ACTH-stimulated cortisol values (22.6 vs 44.7 mcg per 100 ml).

CONCLUSION

Presurgical cortisol values do not predict clinical response to surgical stress as measured by severity of illness scores but lower values were associated with vasopressor therapy. Further investigation would be required to determine how cortisol values are related to outcome and whether perioperative glucocorticoid supplementation would be beneficial in this population.