Inhaled iloprost as a rescue therapy for transposition of the great arteries with persistent pulmonary hypertension of the newborn

Successful Weaning From Veno-Venous Extracorporeal Membrane Oxygenation (VV-ECMO) After Initiation of Inhaled Epoprostenol in a Neonate With Refractory Persistent Pulmonary Hypertension of the Newborn (PPHN)

Despite improvements in the medical management of persistent pulmonary hypertension of the newborn (PPHN), a significant number of patients persist with inadequate gas exchange and are treated with extracorporeal membrane oxygenation (ECMO). Prolonged time to weaning ECMO can increase mortality risk. Therefore, multiple therapies are utilized for pulmonary hypertension treatment, including pharmacotherapy with pulmonary vasodilators, to improve the prognosis of these critical patients. We report a case of a 37 2/7-week neonate with severe PPHN refractory to triple pulmonary vasodilator therapy (inhaled nitric oxide (iNO), sildenafil, and milrinone) and required veno-venous (VV)-ECMO support to improve oxygenation. Our patient was successfully weaned from ECMO after the addition of inhaled epoprostenol (iEPO) therapy. This report indicates that inhaled prostacyclin therapy effectively helps refractory PPHN patients off extracorporeal life support (ECLS) and should be considered a valuable treatment.

Inhaled iloprost is an effective alternative therapy for persistent pulmonary hypertension in newborns

Persistent pulmonary hypertension of the newborn (PPHN) is one of the diseases of the neonate with severe potential morbidity and mortality. Inhaled iloprost, a stable prostacyclin analog, has been suggested as an alternative treatment for inhaled nitric oxide (iNO). However, more data on neonates' dosing, setting, and effectiveness still needs to be solved. This study suggests using inhaled iloprost as rescue therapy for PPHN based on our experience. This was a retrospective study. The data from medical records of six newborns diagnosed with PPHN and had received inhaled iloprost from December 2019 to April 2022 were collected. Demographic and clinical features, dosing regimen, changes in oxygenation index, echocardiographic findings, and mortality were evaluated. The inhalation dose was 2-4 mcg/dose, and 3-48 inhalations per day were applied over 2-7 days. Inhaled iloprost was effective in all patients. No side effects were attributable to inhaled iloprost, and no mortality was recorded. Our experience suggests that inhaled iloprost can be used as a first-line therapy in newborn infants with PPHN when iNO is unavailable. However, there are large fluctuations in the oxygenation index due to the setting.

Effects of Inhaled Iloprost for the Management of Persistent Pulmonary Hypertension of the Newborn

OBJECTIVE

The study aimed to evaluate the effects of inhaled iloprost on oxygenation indices in neonates with persistent pulmonary hypertension of the newborn (PPHN).

STUDY DESIGN

We conducted a retrospective chart review of 30 patients with PPHN from January 2014 to November 2018, who did not respond to inhaled nitric oxide (iNO) alone and received inhaled iloprost. Twenty-two patients met the inclusion criteria and eight patients were excluded from the study (complex cardiac disease and extreme prematurity). Patients were categorized as responders or nonresponders (patients who required extracorporeal membrane oxygenation or died). Oxygenation index, mean airway pressure (MAP), and arterial partial pressure of oxygen (PaO₂) were recorded.

RESULTS

Among a total of 22 patients who were included in the study, 10 were classified as nonresponders as they required either extracorporeal membrane oxygenation or died. Gestational age and gender did not differ between responders and nonresponders. The median PaO₂ was lower (37 vs. 42 mm Hg; p < 0.05) and median MAP was higher (20 vs. 17 cm H₂O; p < 0.02) in nonresponders compared with responders just prior to initiating iloprost. Iloprost responders had a significant increase in median PaO₂ and decrease in median oxygenation index in the 24 hours after initiating treatment (p < 0.05), with no significant change in required mean airway pressure over that same period. There was no change in vasopressor use or clinically significant worsening of platelets count, liver, and kidney functions after initiating iloprost.

CONCLUSION

Inhaled iloprost is well tolerated and seems to have beneficial effects in improving oxygenation indices in neonates with PPHN who do not respond to iNO. There is a need of well-designed prospective trials to further ascertain the benefits of using inhaled iloprost as an adjunct treatment in neonates with PPHN who do not respond to iNO alone.

KEY POINTS

· Inhaled iloprost seems to have beneficial effects in improving oxygenation indices in PPHN.. · Inhaled iloprost is generally well tolerated in newborns with PPHN.. · There is a need for prospective randomized controlled trials to further ascertain the benefits of using inhaled iloprost..

Life-threatening PPHN refractory to nitric oxide: proposal for a rational therapeutic algorithm

Persistent pulmonary hypertension of the neonate (PPHN) refractory to inhaled nitric oxide still represents a frequent clinical challenge with negative outcomes in neonatal critical care. Several pulmonary vasodilators have become available thanks to improved understanding of pulmonary hypertension pathobiology. These drugs are commonly used in adults and there are numerous case series and small studies describing their potential usefulness in neonates, as well. New vasodilators act on different pathways, some of them can have additive effects and all have different pharmacology features. This information has never been summarized so far and no comprehensive pathobiology-driven algorithm is available to guide the treatment of refractory PPHN.Conclusion: We offer a rational clinical algorithm to guide the treatment of refractory PPHN based on expert advice and the more recent pathobiology and pharmacology knowledge. What is Known: • Refractory PPHN occurs in 30-40% of iNO-treated neonates and represents a significant clinical problem. Several pulmonary vasodilators have become available thanks to a better understanding of pulmonary hypertension pathobiology. What is New: • Available vasodilators have different pharmacology, mechanisms of action and may provide additive effect. We provide a rational clinical algorithm to guide the treatment of refractory PPHN based on expert advice and the more recent pathobiology and pharmacology knowledge.

Relationship between interatrial communication, ductus arteriosus, and pulmonary flow patterns in fetuses with transposition of the great arteries: prediction of neonatal desaturation

BACKGROUND

The relationship between interatrial communication, ductus arteriosus, and pulmonary flow in transposition of the great arteries and intact ventricular septum may help predict postnatal desaturation.

METHODS

Echocardiographic data of 45 fetuses with transposition of the great arteries and intact ventricular septum and 50 age-matched controls were retrospectively reviewed. Interatrial communication, left and right ventricular output, flow in the ductus arteriosus, as well as effective pulmonary flow were measured. Patients were divided into two groups on the basis of postnatal saturations: group 1 had saturations ⩽50% and group 2 >50%.

RESULTS

Of 45 fetuses, 13 (26.7%) were classified into group 1. Compared with fetuses in group 2, they had a smaller interatrial communication (2.9 versus 4.0 mm, p=0.004) and more retrograde diastolic flow in the ductus arteriosus (92 versus 23%, p=0.002). Both groups showed a significant decrease in ductal flow compared with controls. Patients in group 2 had a higher effective pulmonary flow compared with controls. There was a mild correlation between left ventricular output and size of the interatrial communication (Spearman's rank correlation 0.44).

CONCLUSION

A retrograde diastolic flow is present in most of the fetuses with postnatal desaturation. Fetuses with transposition of the great arteries have a lower flow through the ductus arteriosus compared with controls. Fetuses without restrictive foramen ovale have higher effective pulmonary flow. Peripheral pulmonary vasodilatation due to higher oxygen saturation in pulmonary arteries in the case of transposition of the great arteries could be one possible cause.

Transposition of the great arteries: Rationale for tailored preoperative management

As preoperative morbi-mortality remains significant, care of newborns with transposition of the great arteries is still challenging. In this review of the literature, we discuss the different treatments that could improve the patient's condition into the preoperative period. Instead of a standardized management, we advocate personalized care of these neonates. Considering the deleterious effects of hypoxia, special attention is given to the use of non-invasive technologies to assess oxygenation of the tissues. As a prolonged preoperative time with low cerebral oxygenation is associated with cerebral injuries, distinguishing neonates who should undergo early surgery from those who could wait longer is crucial and requires full expertise in the management of neonatal congenital heart disease. Finally, to treat these newborns as soon as possible, we support a planned delivery policy for foetuses with transposition of the great arteries.

Preoperative Intubation and Lack of Enteral Nutrition are Associated with Prolonged Stay After Arterial Switch Operation

Mortality for the arterial switch operation (ASO) has diminished significantly over the past few decades. Some patients do, however, continue to have protracted and complicated courses after surgery. We attempted to determine which preoperative factors were best associated with prolonged hospital stay after ASO. We retrospectively reviewed all patients that underwent an ASO over a 10-year period. Outcomes of patients with postoperative stays (POS) >14 days (long stay group-LS) were compared with those patients with POS < 7 days (short stay group-SS). The following variables were evaluated: age at surgery, weight, septostomy performed (BAS) and management the day prior to surgery including use of prostaglandin E1 (PGE1), inotropes, intubation status and the establishment of enteral feeds. The SS group had 25 patients and the LS group had 32 patients. Both groups (SS vs. LS) were similar in PGE1 use (48 vs. 69 %), BAS (76 vs. 59 %), age at surgery (6 vs. 7 days) and preoperative inotropes (12 vs. 38 %). The SS group had significantly higher incidence of preoperative feeding (80 vs. 31 %, p < 0.001) and less frequent intubation (12 vs. 47 %, p < 0.001). Patients who are intubated and have not yet begun to receive enteral feeds at the time of their ASO are more likely to have prolonged POS. It is unclear if prolonged stays were a result of operating on patients with worse preoperative hemodynamics or a consequence of a preoperative management strategy that did not allow for extubation and establishment of feeds prior to surgery.

Pulmonary Arterial Hypertension and Neonatal Arterial Switch Surgery for Correction of Transposition of the Great Arteries

INTRODUCTION AND OBJECTIVES

There are few reports of the appearance of pulmonary arterial hypertension following arterial switch surgery in the neonatal period to correct transposition of the great arteries. We assessed the frequency and clinical pattern of this complication in our series of patients.

METHODS

Our database was reviewed to select patients with transposition of the great arteries corrected by neonatal arterial switch at our hospital and who developed pulmonary hypertension over time.

RESULTS

We identified 2 (1.3%) patients with transposition of the great arteries successfully repaired in the first week of life who later experienced pulmonary arterial hypertension. The first patient was a 7-year-old girl diagnosed with severe pulmonary hypertension at age 8 months who did not respond to medical treatment and required lung transplantation. The anatomic pathology findings were consistent with severe pulmonary arterial hypertension. The second patient was a 24-month-old boy diagnosed with severe pulmonary hypertension at age 13 months who did not respond to medical therapy.

CONCLUSIONS

Pulmonary hypertension is a rare but very severe complication that should be investigated in all patients with transposition of the great arteries who have undergone neonatal arterial switch, in order to start early aggressive therapy for affected patients, given the poor therapeutic response and poor prognosis involved.

Inhaled pulmonary vasodilators for persistent pulmonary hypertension of the newborn: safety issues relating to drug administration and delivery devices

Treatment for persistent pulmonary hypertension of the newborn (PPHN) aims to reduce pulmonary vascular resistance while maintaining systemic vascular resistance. Selective pulmonary vasodilation may be achieved by targeting pulmonary-specific pathways or by delivering vasodilators directly to the lungs. Abrupt withdrawal of a pulmonary vasodilator can cause rebound pulmonary hypertension. Therefore, use of consistent delivery systems that allow for careful monitoring of drug delivery is important. This manuscript reviews published studies of inhaled vasodilators used for treatment of PPHN and provides an overview of safety issues associated with drug delivery and delivery devices as they relate to the risk of rebound pulmonary hypertension. Off-label use of aerosolized prostacyclins and an aerosolized prostaglandin in neonates with PPHN has been reported; however, evidence from large randomized clinical trials is lacking. The amount of a given dose of aerosolized drug that is actually delivered to the lungs is often unknown, and the actual amount of drug deposited in the lungs can be affected by several factors, including patient size, nebulizer used, and placement of the nebulizer within the breathing circuit. Inhaled nitric oxide (iNO) is the only pulmonary vasodilator approved by the US Food and Drug Administration for the treatment of PPHN. The iNO delivery device, INOmax DS_IR®IR, is designed to constantly monitor NO, NO₂, and O₂ deliveries and is equipped with audible and visual alarms to alert providers of abrupt discontinuation and incorrect drug concentration. Other safety features of this device include two independent backup delivery systems, a backup drug cylinder, a battery that provides up to 6 hours of uninterrupted medication delivery, and 27 alarms that monitor delivery, dosage, and system functions. The ability of the drug delivery device to provide safe, consistent dosing is important to consider when selecting a pulmonary vasodilator.

Pulmonary Interstitial Glycogenosis: A Reversible Underlying Condition Associated With D-Transposition of the Great Arteries and Severe Persistent Pulmonary Hypertension

Transposition of the great arteries with intact ventricular septum and persistent pulmonary hypertension (TGA-IVS PPHN) is a rare association with a poor prognosis. We report the case of a term newborn with TGA-IVS PPHN successfully managed with perioperative extracorporeal membrane oxygenation (ECMO) and aggressive pulmonary vasodilation therapy that underwent successful arterial switch procedure. A lung biopsy obtained during the surgical procedure showed pulmonary interstitial glycogenosis, a reversible condition. Concerns over left ventricle deconditioning after ECMO could be minimized with appropriate management and monitoring of the ductus arteriosus and appropriate timing of surgery.

Persistent Pulmonary Hypertension of the Newborn with D-transposition of the Great Arteries: Management and Prognosis

OBJECTIVE

There is a paucity of data on clinical correlates and outcomes of pulmonary hypertension (PH) in patients with D-transposition of the great arteries (D-TGA) in the era of inhaled nitric oxide (iNO) and extracorporeal membrane oxygenation (ECMO). Our objective was to compare clinical characteristics and outcomes of infants with D-TGA with and without PH, defined as hypoxemia that required iNO and/or ECMO.

METHODS

We undertook a single-center retrospective chart review involving infants with gestational age ≥32 weeks with D-TGA who, underwent arterial switch operation over a 12-year period. Demographic and clinical data, details of the repair and postoperative complications were abstracted.

RESULTS

Our cohort (n = 93), 61 (66%) of whom were males, had a mean (SD) gestational age and birth weight of 38.7 (1.8) weeks and 3.2 (0.6) kg, respectively. PH requiring iNO and/or ECMO was noted in 20 (21.5%) infants. Infants with PH had significantly lower birth weight [2.8 (0.56) vs. 3.33 (0.61)] and gestational age [37.7 (2.1) vs. 38.9 (1.7)] than those without PH. Rates of postoperative complications (duration of pressors, sedative medicaiton and duration of hospital stay, and mechanical ventilation were higher in the group with PH. Of the five (5.4%) infants who died, four received iNO and ECMO. Death or postoperative complications tended to be associated with lower gestational age [OR 0.689; 95% CI: 0.469-1.012, P = 0.058] but not with D-TGA category or bypass duration.

CONCLUSIONS

Despite aggressive treatment with iNO and ECMO, the coexistence of PH in this population is associated with higher rates of mortality and postoperative complications. Our results also suggest that an early term birth may be associated with PH in infants with D-TGA.