Prevention of heart failure in the management of congenital diaphragmatic hernia by maintaining ductal patency. A case report

Prenatal predictors of mortality in fetuses with congenital diaphragmatic hernia: a systematic review and meta-analysis

PURPOSE

This study aimed to evaluate prenatal predictors of mortality in fetuses with congenital diaphragmatic hernia (CDH).

METHODS

A systematic literature search was performed to identify relevant observational studies that evaluated the ability of lung-to-head ratio (LHR), observed-to-expected LHR (o/e-LHR), observed-to-expected total fetal lung volume (o/e-TFLV), lung-to-thorax transverse area ratio (L/T ratio), intrathoracic herniation of the liver and the stomach, and side of diaphragmatic hernia, using a threshold for the prediction of mortality in fetuses with CDH. Study quality was assessed using the QUADAS-2 tool. Hierarchical summary receiver operating characteristic curves were constructed.

RESULTS

A total of 50 articles were included in this meta-analysis. The QUADAS-2 tool identified a high risk of bias in more than one domain scored in all parameters. Among those parameters, the diagnostic odds ratio of mortality with o/e-LHR < 25%, o/e-TFLV < 25%, and L/T ratio < 0.08 were 11.98 [95% confidence interval (CI) 4.65-30.89], 11.14 (95% CI 5.19-23.89), and 10.28 (95% CI 3.38-31.31), respectively. The predictive values for mortality were similar between the presence of liver herniation and retrocardiac fetal stomach position.

CONCLUSIONS

This systematic review suggests that o/e-LHR, o/e-TFLV, and L/T ratio are equally good predictors of neonatal mortality in fetuses with isolated CDH.

Use of prostaglandin E1 to treat pulmonary hypertension in congenital diaphragmatic hernia

BACKGROUND/PURPOSE

Prostaglandin E1 (PGE) has been used to maintain ductus arteriosus patency and unload the suprasystemic right ventricle (RV) in neonates with congenital diaphragmatic hernia (CDH) and severe pulmonary hypertension (PH). Here we evaluate the PH response in neonates with CDH and severe PH treated with PGE.

METHODS

We performed a retrospective chart review of CDH infants treated at our center between 2011 and 2016. In a subset, PGE was initiated for echocardiographic evidence of severe PH, metabolic acidosis, or hypoxemia. To assess PH response, we evaluated laboratory data, including B-type natriuretic peptide (BNP) and echocardiograms before and after PGE treatment. Categorical and continuous data were analyzed with Fisher's exact tests and Mann-Whitney t-tests, respectively.

RESULTS

Fifty-seven infants were treated with PGE a mean 17 ± 2 days. BNP levels declined after 1.4 ± 0.2 days of treatment and again after 5.2 ± 0.6 days. After 6 ± 0.8 days of treatment, echocardiographic estimates of severe PH by tricuspid regurgitation jet velocity, ductus arteriosus direction, and ventricular septum position also improved significantly. Treatment was not associated with postductal hypoxemia or systemic hypoperfusion.

CONCLUSIONS

In patients with CDH and severe PH, PGE is well tolerated and associated with improved BNP and echocardiographic indices of PH, suggesting successful unloading of the RV.

TYPE OF STUDY

Treatment study.

LEVEL OF EVIDENCE

Level III.

Variable role of patent ductus arteriosus

Although patent ductus arteriosus is essential in fetal life, interventions to close or minimize the adverse hemodynamic effects associated with the left-to-right shunt are often needed after birth, especially in extremely premature infants. However, there are clinical conditions where maintaining patency of the ductus is essential for survival. In this article we discuss use of prostaglandin E₁ in the management of congenital heart defects, pulmonary hypertension and left ventricular failure in early neonatal period.

Lung size and liver herniation predict need for extracorporeal membrane oxygenation but not pulmonary hypertension in isolated congenital diaphragmatic hernia: systematic review and meta-analysis

OBJECTIVES

To identify antenatal predictors of persistent pulmonary hypertension (PPH) and the need for extracorporeal membrane oxygenation (ECMO) in fetuses with congenital diaphragmatic hernia (CDH).

METHODS

We performed a systematic literature review on antenatal diagnostic tests in fetuses with isolated CDH. The primary outcomes assessed were PPH within 28 days of age and the need for ECMO. Quality of studies was assessed with the QUADAS-2 tool. Meta-analysis was performed when at least three studies reported on the same test. Sensitivity analysis was performed according to prenatal management of CDH (tracheal occlusion vs expectant management).

RESULTS

Thirty-eight studies met the inclusion criteria. Fifteen reported on the incidence of PPH only, 19 on the need for ECMO only and four reported on both outcomes. The general quality of the studies was moderate; most studies were retrospective (61%) and single-center series (92%). One study included only fetuses undergoing tracheal occlusion, 22 included only fetuses managed expectantly in utero and 15 included both populations. We could not identify antenatal predictors of PPH. The need for ECMO was predicted by parameters indicative of lung size: lung-to-head ratio (LHR) (relative risk (RR) for LHR < 1, 1.65 (95% CI, 1.27-2.14)) and observed/expected LHR (standardized mean difference (SMD), -0.70 (95% CI, -0.98 to -0.42)) measured by ultrasound and observed/expected total lung volume (SMD, -1.00 (95% CI, -1.52 to -0.48)) measured by magnetic resonance imaging. Liver herniation was also associated with an increased risk of need for ECMO (RR, 3.04 (95% CI, 2.23-4.14)). These results were confirmed by a sensitivity analysis of studies that included only expectantly managed cases. Data on vascular assessment for the prediction of PPH could not be pooled as most of the parameters were evaluated in a single series or in different series by the same principal investigator.

CONCLUSIONS

In fetuses with CDH, lung size and liver herniation predict the need for ECMO, however a predictor for PPH is still lacking. Further studies aimed at diagnosing impaired vascular development in utero should therefore be undertaken. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Current Concepts in the Management of Congenital Diaphragmatic Hernia in Infants

The therapeutic approach to congenital diaphragmatic hernia (CDH) has shifted from one of immediate repair to management of pulmonary hypertension, physiologic stabilization, and delayed surgical repair. Lung hypoplasia, remodeled pulmonary vasculature, and ventricular dysfunction all contribute to the high morbidity and mortality associated with CDH. In addition, genetic syndromes associated with CDH can increase the incidence of serious anomalies and hence impact survival. Prenatal and postnatal management of infants with CDH is challenging in the best of circumstances and need multidisciplinary teams for optimal outcomes. However, advances using ultrasound and fetal MRI can predict prognosis and survival and plan for postnatal management. Survival rates for patients with CDH have increased for the past decade with better management at resuscitation; implementation of gentle ventilation strategies; and medical management of pulmonary hypertension, physiologic stabilization, and extracorporeal membrane oxygenation. However, follow-up of these infants for long-term morbidities is essential for optimal outcomes after discharge.

Early neonatal echocardiographic findings in an experimental rabbit model of congenital diaphragmatic hernia

This study aimed to demonstrate that congenital diaphragmatic hernia (CDH) results in vascular abnormalities that are directly associated with the severity of pulmonary hypoplasia and hypertension. These events increase right ventricle (RV) afterload and may adversely affect disease management and patient survival. Our objective was to investigate cardiac function, specifically right ventricular changes, immediately after birth and relate them to myocardial histological findings in a CDH model. Pregnant New Zealand rabbits underwent the surgical procedure at 25 days of gestation (n=14). CDH was created in one fetus per horn (n=16), and the other fetuses were used as controls (n=20). At term (30 days), fetuses were removed, immediately dried and weighed before undergoing four-parameter echocardiography. The lungs and the heart were removed, weighed, and histologically analyzed. CDH animals had smaller total lung weight (P<0.005), left lung weight (P<0.005), and lung-to-body ratio (P<0.005). Echocardiography revealed a smaller left-to-right ventricle ratio (LV/RV, P<0.005) and larger diastolic right ventricle size (DRVS, P<0.007). Histologic analysis revealed a larger number of myocytes undergoing mitotic division (186 vs 132, P<0.05) in CDH hearts. Immediate RV dilation of CDH hearts is related to myocyte mitosis increase. This information may aid the design of future strategies to address pulmonary hypertension in CDH.

Acute Neonatal Respiratory Failure

Acute respiratory failure requiring assisted ventilation is one of the most common reasons for admission to the neonatal intensive care unit. Respiratory failure is the inability to maintain either normal delivery of oxygen to the tissues or normal removal of carbon dioxide from the tissues. It occurs when there is an imbalance between the respiratory workload and ventilatory strength and endurance. Definitions are somewhat arbitrary but suggested laboratory criteria for respiratory failure include two or more of the following: PaCO₂ > 60 mmHg, PaO₂ < 50 mmHg or O₂ saturation <80 % with an FiO₂ of 1.0 and pH < 7.25 (Wen et al. 2004).

Right ventricular diastolic function measured by tissue Doppler imaging predicts early outcome in congenital diaphragmatic hernia

OBJECTIVE

To investigate the relationship between early right ventricular function measured by tissue Doppler imaging and early outcome measures in newborn infants with congenital diaphragmatic hernia.

DESIGN

Retrospective cohort study.

SETTING

Surgical neonatal ICU within a regional pediatric center.

PATIENTS

Twenty newborn infants with congenital diaphragmatic hernia.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Analysis of serial echocardiograms in a cohort of 20 infants with congenital diaphragmatic hernia was done. Tissue Doppler early diastolic and systolic myocardial velocities were measured to assess diastolic and systolic function, respectively, in the basal right ventricle. Pulmonary:systemic peak pressure ratio was estimated using velocity of tricuspid regurgitation. Physiologic, treatment, and early outcome data (duration of respiratory support and length of stay) were recorded. For analysis, duration of respiratory support was selected as the main outcome measure, and infants were divided into two groups based on median duration of respiratory support of 21 days: duration of respiratory support more than 21 days and duration of respiratory support less than 21 days. In 16 surviving infants, mean right ventricular early diastolic myocardial velocity on days 1 and 2 of life correlated with length of stay and duration of respiratory support (r = -0.75, p = 0.002 and r = -0.84, p = 0.0001, respectively). Mean pulmonary:systemic peak pressure ratio on days 1 and 2 of life did not significantly correlate with outcome measures. At receiver-operating characteristics analysis, averaged right ventricular early diastolic myocardial velocity on days 1 and 2 of life of less than 4.6 cm/s predicted duration of respiratory support more than 21 days, with 100% sensitivity and 88% specificity (area under the curve = 0.96, p = 0.002). Right ventricular early diastolic myocardial velocity was significantly lower in the first week of life in the duration of respiratory support more than 21-day group on days 1 and 2 and days 7 and 8. After surgery, right ventricular early diastolic myocardial velocity decreased in the duration of respiratory support more than 21-day group and was significantly lower at days 3 and 4 postoperative.

CONCLUSIONS

Tissue Doppler imaging mean right ventricular early diastolic myocardial velocity on days 1 and 2 of life predicted early outcome in surviving infants with congenital diaphragmatic hernia. Right ventricular diastolic dysfunction is associated with disease severity in congenital diaphragmatic hernia. Right ventricular function may be optimized by delaying surgical repair in infants with severe congenital diaphragmatic hernia.

Cardiovascular hybrid procedure in severe congenital diaphragmatic hernia with significant left heart hypoplasia

The authors discuss an early hybrid cardiovascular intervention in a neonate with left-sided congenital diaphragmatic hernia and significant left heart hypoplasia. The operation included persistent ductus arteriosus stenting and right pulmonary artery calibrated banding (3.5 mm) to increase blood flow in the aorta and to decrease right ventricle overload and decrease blood pressure and overflow in pulmonary circulation. The operation improved the child's general condition and gained time for left ventricle growth and restoration of its function.

Congenital diaphragmatic hernia

Congenital Diaphragmatic Hernia (CDH) is defined by the presence of an orifice in the diaphragm, more often left and posterolateral that permits the herniation of abdominal contents into the thorax. The lungs are hypoplastic and have abnormal vessels that cause respiratory insufficiency and persistent pulmonary hypertension with high mortality. About one third of cases have cardiovascular malformations and lesser proportions have skeletal, neural, genitourinary, gastrointestinal or other defects. CDH can be a component of Pallister-Killian, Fryns, Ghersoni-Baruch, WAGR, Denys-Drash, Brachman-De Lange, Donnai-Barrow or Wolf-Hirschhorn syndromes. Some chromosomal anomalies involve CDH as well. The incidence is < 5 in 10,000 live-births. The etiology is unknown although clinical, genetic and experimental evidence points to disturbances in the retinoid-signaling pathway during organogenesis. Antenatal diagnosis is often made and this allows prenatal management (open correction of the hernia in the past and reversible fetoscopic tracheal obstruction nowadays) that may be indicated in cases with severe lung hypoplasia and grim prognosis. Treatment after birth requires all the refinements of critical care including extracorporeal membrane oxygenation prior to surgical correction. The best hospital series report 80% survival but it remains around 50% in population-based studies. Chronic respiratory tract disease, neurodevelopmental problems, neurosensorial hearing loss and gastroesophageal reflux are common problems in survivors. Much more research on several aspects of this severe condition is warranted.

Pulmonary artery size has prognostic value in low birth weight infants with congenital diaphragmatic hernia

AIM

The aim of this study was to examine the relationship between birth weight, pulmonary artery (PA) size, and outcome in congenital diaphragmatic hernia (CDH) to establish if PA size has prognostic value.

METHODS

The subjects for this study were 39 consecutive left-sided CDH patients treated at our institution according to the same protocol from 2002 to 2009. Other CDH patients with concurrent anomalies that eventually caused death or who became symptomatic more than 6 h after birth were excluded. Birth weight was used to create two groups; low birth weight (LBW; birth weight ≤ 2,500 g; n = 15) and normal birth weight (NBW; birth weight >2,500 g; n = 24). Right PA (RPA) and left PA (LPA) were measured by echocardiography (EC) during late pregnancy (fetal; gestational age (GA): 32-34 weeks), and on days 0, and 2 of life and compared.

RESULTS

Mean birth weights were significantly different between the two groups; however, gender, mean GA, and outcome were similar. In LBW survivors, RPA was significantly larger than in non-survivors. PA size was not related to outcome in NBW.

CONCLUSION

We are the first to show that RPA size has prognostic value in low birth weight infants with left-sided CDH.

CONTEMPORARY NEONATAL INTENSIVE CARE MANAGEMENT IN CONGENITAL DIAPHRAGMATIC HERNIA: DOES THIS OBVIATE THE NEED FOR FETAL THERAPY?

The management of congenital diaphragmatic hernia (CDH) in the newborn infant has changed radically since the first successful outcomes were reported 60 years ago. Then it seemed a surgical problem with a surgical solution – do an operation, remove the intestines and solid viscera from the thoracic cavity, repair the defect and allow the lung to expand. CDH in that era was regarded as the quintessential neonatal surgical emergency. The expectation was that urgent surgery would result in improvement in lung function and oxygenation. That approach persisted up to the 1980s when it was realized that the problem was far more complex and involved both an abnormal pulmonary vascular bed as well as pulmonary hypoplasia. The use of systemically delivered pulmonary vasodilator therapy, principally tolazoline, became a focus of interest in the 1980s with small case reports and case series suggesting improved survival. In the 1990s, based on studies that showed worsening thoracic compliance and gas exchange following surgical repair, deferred surgery and pre-operative stabilization became the standard of care. At the same time extracorporeal membrane oxygenation (ECMO) was increasingly used either as part of pre-operative stabilization or as a rescue therapy after repair. Other centres chose to use high frequency oscillatory ventilation (HFOV). Despite all these innovations the survival in live born infants with CDH did not improve to more than 50% in large series published from high volume centres. However, in the past 10 years there has been an appreciable improvement in survival to the extent that many centres are now reporting survival rates of greater than 80%. Probably the biggest impact on this improvement has been the recognition of the role that ventilation induced lung injury plays in mortality and the need for ECMO rescue. This has ushered in an era of a lung protective or “gentle ventilation” strategy which has been widely adopted as a standard approach. While there have been these radical changes in postnatal management attempts have been made to improve outcome with prenatal interventions, starting with prenatal repair, which was abandoned because of preterm labour. More recently there has been increasing experience in the use of balloon occlusion of the trachea as a prenatal intervention strategy with patients being selected based on prenatal predictors of poor outcome. This approach can only be justified if those predictors can be validated and the outcomes (death or serious long term morbidity) can be shown to be better than those currently achievable, namely 80% survival in high volume CDH centres rather than the 50–60% survival frequently quoted in historical papers.

Significance of pulmonary artery size and blood flow as a predictor of outcome in congenital diaphragmatic hernia

AIM

To determine if pulmonary artery size and blood flow have prognostic value in congenital diaphragmatic hernia (CDH).

METHODS

Twenty-eight consecutive left-sided CDH patients treated according to a standard protocol with high frequency oscillatory ventilation (HFOV) + nitric oxide (NO) had right and left pulmonary artery (RPA, LPA) diameters, LPA/RPA diameter (L/R) ratios, and PA blood flows examined by echocardiography (EC) on days 0, 2, and 5 after birth and compared prospectively.

RESULTS

Twenty-two patients (78.6%) survived. Of these, 15 required NO (NO-s), and seven did not (non-NO-s). All six patients that died required NO (NO-d). RPA in the NO-d group was significantly smaller than in the NO-s or non-NO-s groups on day 0 (2.90 +/- 0.41 vs. 3.40 +/- 0.49 or 4.01 +/- 0.43; P < 0.01, respectively). LPA in the NO-d group was significantly smaller than in the non-NO-s on day 0 (2.13 +/- 0.45 vs. 3.39 +/- 0.34; P < 0.01). L/R ratios in NO subjects were significantly smaller (NO-s 0.74 +/- 0.11; NO-d 0.73 +/- 0.11) than in non-NO-s subjects (0.84 +/- 0.03) on day 0 (P < 0.01). PA diameters and L/R ratios did not change significantly from day 0 to day 5 in all three groups. There was LPA flow on day 0 in all non-NO-s subjects, but none in all NO subjects. In the NO-s group, LPA flow was confirmed in 87% (13/15) on day 2 and in 100% on day 5, however, there was no LPA flow from day 0 to day 5 in any of the NO-d group.

CONCLUSION

Our data indicate that PA diameters on day 0 and LPA flow are strongly prognostic in left-sided CDH and L/R ratio would appear to be a simple highly reliable indicator of the necessity for NO therapy.

Management of pulmonary hypertension in congenital diaphragmatic hernia: nitric oxide with prostaglandin-E1 versus nitric oxide alone

AIM

Prostaglandin-E1 (PGE1) is used at most centers for treating pulmonary hypertension (PH) in congenital diaphragmatic hernia (CDH) because it has been regarded as effective. The aim of this study was to investigate the role of PGE1 for treating PH in CDH.

METHODS

We reviewed 49 CDH cases with echocardiography-proven PH. PH was treated with PGE1 and nitric oxide (NO) and high frequency oscillatory ventilation (HFOV) from 1997 to 2001 (PG + NO; n = 19) and with NO and HFOV from 2002 to 2007 (NO; n = 30).

RESULTS

Subject demographics, severity of PH, and presence of other anomalies were not significantly different between the two groups. In the PG + NO group, 12/19 (63.2%) survived (PG + NO-s) and 7/19 (36.8%) died (PG + NO-d). In the NO group, 21/30 (70.0%) survived (NO-s) and 9/30 (30.0%) died (NO-d). Survival rates were not significantly different. In the NO-s group, spontaneous closure of the ductus arteriosus (DA) was significantly earlier compared with the PG + NO-s group (P < 0.01; 4.0 +/- 0.9 vs. 9.5 +/- 2.2 days after birth). DA diameters were significantly larger in groups that died compared with groups that survived (P < 0.01), and PH persisted in groups that died. In the NO-s group, surgery was possible significantly earlier compared with the PG + NO-s group (P < 0.01; 3.75 +/- 0.67 vs. 6.12 +/- 0.78 days after birth). No NO-s case developed a PH crisis even though PGE1 was not used. Hospital stay was significantly shorter in the NO-s group compared with the PG + NO-s group (P < 0.05; 39.9 +/- 19 vs. 53.2 +/- 23 days).

CONCLUSION

Nitric oxide alone would appear to simplify the management of CDH with PH and provide better outcome.

Congenital diaphragmatic hernia: a systematic review and summary of best-evidence practice strategies

OBJECTIVES

Recent reports suggest that specific care strategies improve survival of infants with congenital diaphragmatic hernia (CDH). This review presents details of care from centers reporting high rates of survival among CDH infants.

STUDY DESIGN

We conducted a MEDLINE search (1995 to 2006) and searched all citations in the Cochrane Central Register of Controlled Trials. Studies were included if they contained reports of >20 infants with symptomatic CDH, and >75% survival of isolated CDH.

RESULT

Thirteen reports from 11 centers met inclusion criteria. Overall survival, including infants with multiple anomalies, was 603/763 (79%; range: 69 to 93%). Survival for isolated CDH was 560/661 (85%; range: 78 to 96%). The frequency of extracorporeal membrane oxygenation (ECMO) use for isolated CDH varied widely among reporting centers 251/622 (40%; range: 11 to 61%), as did survival for infants with isolated CDH placed on ECMO: 149/206 (73%; range: 33 to 86%). There was no suggestion of benefit from use of antenatal glucocorticoids given after 34 weeks gestation or use of postnatal surfactant. Low mortality was frequently attributed to minimizing lung injury and adhering to center-specific criteria for ECMO.

CONCLUSION

Use of strategies aimed at minimizing lung injury, tolerance of postductal acidosis and hypoxemia, and adhering to center-specific criteria for ECMO were strategies most consistently reported by successful centers. The literature lacks randomized clinical trials of these or other care strategies in this complex patient population; prospective studies of safety and long-term outcome are needed.

Congenital diaphragmatic hernia and associated cardiovascular malformations: type, frequency, and impact on management

The co-occurrence of congenital diaphragmatic hernia (CDH) and cardiovascular malformations (CVMs) has important clinical, genetic, and developmental implications. Previous examinations of this topic often included patients with genetic syndromes. To correct this potential bias, we undertook an extensive review of the literature and obtained new data. The frequency of CVMs associated with isolated CDH was 11-15%. A careful analysis of CVMs indicates that atrial and ventricular septal defects, conotruncal defects, and left ventricular outflow tract obstructive defects were the most common type of CVMs, but proportional to the frequency of occurrence in the general population. The combination of CVM and CDH results in a poorer prognosis than would be expected with either malformation alone. However, the impact on survival from patients with a genetic syndrome has not been consistently evaluated. We encourage researchers to re-analyze existing series and recommend that future studies distinguish isolated CDH from that which is associated with other malformations, especially as part of genetic syndromes. Therapies should be tailored to maximize cardiac output and systemic oxygen delivery rather than systemic oxygen saturation alone. Although there is speculation about the frequency with which isolated left ventricular "hypoplasia" occurs in patients with CDH, we suggest it results from compression of a pre-load deficient left ventricle by the hypertensive right ventricle, and unlike true hypoplasia, is reversible. Irrespective of the type of severity of CVMs in patients with CDH, the degree of pulmonary hypoplasia and pulmonary vascular disease predicts outcome.

Systemic haemodynamics in infants with vein of Galen malformation: assessment and basis for therapy

Systemic haemodynamics in three infants with severe cardiac failure secondary to vein of Galen malformation (VGAM) were studied using two-dimensional and Doppler echocardiography. In all cases, ventricular outputs were over two times normal and superior vena caval flows up to 10 times normal reflecting high flow through the low-resistance fistula. Severe pulmonary hypertension, right heart dilatation and retrograde flow in the descending aorta were uniformly present. Systemic blood flow below the head and neck was reduced resulting in metabolic acidosis at presentation. Two infants had patent arterial ducts, in which flow was entirely right to left and on entering the aorta passed predominantly retrogradely towards the VGAM. These findings provide a basis for understanding the pathophysiology of cardiac failure in VGAM and support treatment with pulmonary and systemic vasodilating agents.

Pulmonary hypertension in congenital diaphragmatic hernia

Clinically significant pulmonary hypertension (PHTN) is a common finding in newborn infants with congenital diaphragmatic hernia (CDH) resulting in right to left shunting at pre- and postductal level, hypoxemia, and acute right heart failure in those most severely affected. Even in those without clinical manifestations of ductal shunting, cardiac echo studies would suggest that increased pulmonary vascular resistance and right ventricular pressures are almost a universal finding in this disease, and in some instances, may persist well into the postnatal period. The lung is small and structurally abnormal, and the pulmonary vascular bed is not only reduced in size, but responds abnormally to vasodilators. During the last 20 years, "gentle" ventilation, delayed surgery, and improved peri-operative care have made the greatest impact in decreasing mortality in this condition. Use of PGE1 should be considered early if there is hemodynamically significant PHTN, right ventricular dysfunction, and the patent ductus arteriosus (PDA) is becoming restrictive. In individual patients, inhaled nitric oxide (iNO) might be helpful, but the response to iNO should be confirmed using echocardiography. In patients who survive operation and leave the hospital, there are chronic causes of morbidity that need to be looked for and managed in a multi-disciplinary follow-up clinic.