Pulmonary hypertension of the newborn

Evaluation of cardiovascular morphology and associated anomalies in patients with crossed pulmonary arteries on multidetector computed tomography angiography

AIM

The present study sought to study the morphology and associated cardiovascular anomalies in patients with crossed pulmonary arteries on multidetector CT angiography.

MATERIALS AND METHODS

We retrospectively evaluated all CT angiography studies performed at a tertiary medical centre from January, 2014 to December, 2021 to identify patients with crossed pulmonary arteries. The associated cardiovascular anomalies as identified on CT angiography were evaluated.

RESULTS

Out of 4773 patients who had undergone CT angiography for evaluation of congenital heart diseases, we identified 24 (0.5%) patients (18 males; mean age: 7.7 years) with crossed pulmonary arteries. Tetralogy of Fallot was associated in 7 (29.17%) patients, double outlet right ventricle in 1 (4.17%) patient, and common arterial trunk in 4 (16.67%) patients. An aorto-pulmonary window was seen in 3 (12.5%) patients while atrial septal defect and ventricular septal defect were seen in 2 (8.33%) and 16 (66.67%) patients respectively. Aortic arch anomalies were present in 16 (66.67%) patients including interrupted aortic arch and coarctation of aorta with hypoplastic aortic arch seen in 2 (8.33%) patients each. A double aortic arch with atretic left arch was seen in 1 (4.17%) patient. Coronary artery anomalies were seen in 3 (12.5%) patients.

CONCLUSION

Crossed pulmonary arteries is a rare anomaly and its presence suggests coexistence of a variety of cardiovascular anomalies, including aortic arch anomalies and outflow tract malformations. Comprehensive CT angiography-based evaluation of cardiovascular morphology is imperative in the presence of crossed pulmonary arteries to facilitate pre-surgical planning. This article is protected by copyright. All rights reserved.

Hypoxia in utero increases the risk of pulmonary hypertension in rat offspring and is associated with vasopressin type‑2 receptor upregulation

Pulmonary hypertension (PH) in newborns and adults is a disease that can lead to right heart failure and result in a shorter lifespan. PH was induced by maintaining pregnant rats in a hypoxic chamber for 4 h twice a day, from days 7–21 of pregnancy. Hypoxia was confirmed by a decrease in the partial pressure of oxygen (PaO₂) and the oxygen saturation (SaO₂) of arterial blood in the aorta. The body weight of newborns from hypoxic rats was ~20% decreased compared with the control newborns of normoxic rats. The vascular wall thickness/vascular diameter values of hypoxia treated pubs were increased compared with that of control newborns 7 days after birth; however, it decreased to similar levels than in the control group after 3 months, and then further decreased to significantly lower levels than in the control group at 6 months after birth. At birth, the lung tissues of newborns from hypoxic rats exhibited an increase in the levels of mRNA and proteins associated with PH such as HIF-1α, HIF-2α, V2R, TGF-β, TNF-α, Ang-2 and α-SMA. At 3 and 6 months after birth, the levels of both V2R mRNA and protein in offspring from hypoxic rats were at least 2-fold higher, whereas the expression of all other factors decreased compared with the control offspring. By contrast, HIF-2α and Ang-2 expression levels were significantly increased in the 6-month-old control offspring from normoxic rats. V2R overexpression in pups induced by hypoxia in maternal rats was sustained until their adulthood. V2R may be a marker for detecting PH.

Glucocorticoids negatively regulates chaperone mediated autophagy and microautophagy

Glucocorticoids are released from the adrenal cortex and are important for regulating various physiological functions. However, a persistent increase in glucocorticoids due to chronic stress causes various dysfunctions in the central nervous system which can lead to mental disorders such as depression. Macroautophagy, one of the pathways of the autophagy-lysosome protein degradation system, is dysregulated in psychiatric disorders, implicating a disturbance of protein degradation in the pathogenesis of psychiatric disorders. In the present study, we investigated whether glucocorticoids affect the activity of chaperone-mediated autophagy (CMA) and microautophagy (mA), the other two pathways of the autophagy-lysosome system. Treatment of human-derived AD293 cells and primary cultured rat cortical neurons with dexamethasone, a potent glucocorticoid receptor agonist, and endogenous glucocorticoids decreased both CMA and mA activities. However, this decrease was significantly suppressed by treatment with RU-486, a glucocorticoid receptor antagonist. In addition, dexamethasone significantly decreased lysosomal Hsc70. These findings suggest that glucocorticoids negatively regulate CMA and mA in a glucocorticoid receptor-dependent manner, and provide evidence for CMA and mA as novel therapeutic targets for depression.

Management of Multi Organ Dysfunction in Neonatal Encephalopathy

Neonatal Encephalopathy (NE) describes neonates with disturbed neurological function in the first post-natal days of life. NE is an overall term that does not specify the etiology of the encephalopathy although it often involves hypoxia-ischaemia. In NE, although neurological dysfunction is part of the injury and is most predictive of long-term outcome, these infants may also have multiorgan injury and compromise, which further contribute to neurological impairment and long-term morbidities. Therapeutic hypothermia (TH) is the standard of care for moderate to severe NE. Infants with NE may have co-existing immune, respiratory, endocrine, renal, hepatic, and cardiac dysfunction that require individualized management and can be impacted by TH. Non-neurological organ dysfunction not only has a negative effect on long term outcome but may also influence the efficacy of treatments in the acute phase. Post resuscitative care involves stabilization and decisions regarding TH and management of multi-organ dysfunction. This management includes detailed neurological assessment, cardio-respiratory stabilization, glycaemic and fluid control, sepsis evaluation and antibiotics, seizure identification, and monitoring and responding to biochemical and coagulation derangements. The emergence of new biomarkers of specific organ injury may have predictive value and improve the definition of organ injury and prognosis. Further evidence-based research is needed to optimize management of NE, prevent further organ dysfunction and reduce neurodevelopmental impairment.

Effects of intravenous phosphodiesterase inhibitors and corticosteroids on severe meconium aspiration syndrome

BACKGROUND

Meconium aspiration syndrome (MAS) is a major cause of severe respiratory failure in near- and full-term neonates. Alleviating inflammation is key to successfully treating severe MAS. Phosphodiesterase (PDE) inhibitors are known to play a role in airway smooth muscle relaxation and alveolar inflammation inhibition. This study aimed to investigate the effects of various intravenous (IV) PDE inhibitors and corticosteroids on MAS.

METHODS

MAS was induced in newborn piglets by instilling human meconium in them. The piglets were randomly divided into five groups (n = 5 in each group): (1) control (sham treatment); (2) dexamethasone (Dex) (IV 0.6 mg/kg of dexamethasone); (3) aminophylline (Ami) (IV 6 mg/kg of aminophylline, followed by continuous infusion of 0.5 mg/kg/h of aminophylline; (4) milrinone (Mil) (IV 50 μg/kg of milrinone, followed by continuous infusion of 0.75 μg/kg/h of milrinone); and (5) rolipram (Rol) (IV 0.8 mg/kg of rolipram). The duration of the experimental period was 4 hours.

RESULTS

Compared to the control group, all the four treatment groups revealed better oxygenation 3 hours and more after the start of treatment. The Rol group had a significantly elevated heart beat (p < 0.05) and relatively lower blood pressure compared to the other groups during the first 2 hours of the experiment. The Dex group had significantly lower interleukin (IL)-1β levels in the lung tissue compared to the other groups (p < 0.05) and significantly lower IL-6 levels compared to the Ami and Mil groups (p < 0.05). Lung histology showed slightly less inflammation and atelectasis in the Dex group compared to the other groups, but lung injury scores showed no significant between-group differences.

CONCLUSION

Using IV corticosteroids or any type of PDE inhibitors has some beneficial effects in improving oxygenation in MAS. PDE inhibitors are not superior to IV corticosteroids; in fact, adverse cardiovascular effects occur with the phosphodiesterase type 4 (PDE4) inhibitor. Further investigations are required before using IV corticosteroids and PDE inhibitors in future clinical application.

The role of nitric oxide signaling in pulmonary circulation of high- and low-altitude newborn sheep under basal and acute hypoxic conditions

Nitric oxide (NO) is the main vasodilator agent that drives the rapid decrease of pulmonary vascular resistance for the respiratory onset during the fetal to neonatal transition. Nevertheless, the enhanced NO generation by the neonatal pulmonary arterial endothelium does not prevent development of hypoxic pulmonary hypertension in species without an evolutionary story at high altitude. Therefore, this study aims to describe the limits of the NO function at high-altitude during neonatal life in the sheep as an animal model without tolerance to perinatal hypoxia. We studied the effect of blockade of NO synthesis with l-NAME in the cardiopulmonary response of lowland (580 m) and highland (3600 m) newborn lambs basally and under an episode of acute hypoxia. We also determined the pulmonary expression of proteins that mediate the actions of the NO vasodilator pathway in the pulmonary vasoactive tone and remodeling. We observed an enhanced nitrergic function in highland lambs under basal conditions, evidenced as a markedly greater increase in basal mean pulmonary arterial pressure (mPAP) and resistance (PVR) under blockade of NO synthesis. Further, acute hypoxic challenge in lowland lambs infused with l-NAME markedly increased their mPAP and PVR to values greater than baseline, whilst in highland animals under NO synthesis blockade, these variables did not show additional increase in response to low PO₂. Highland animals showed increased pulmonary RhoA expression, decreased PSer188-RhoA fraction, increased PSer311-p65-NFқβ fraction and up-regulated smooth muscle α-actin, relative to lowland controls. Taken together our data suggest that NO-mediated vasodilation is important to keep a low pulmonary vascular resistance under basal conditions and acute hypoxia at low-altitude. At high-altitude, the enhanced nitrergic signaling partially prevents excessive pulmonary hypertension but does not protect against acute hypoxia. The decreased vasodilator efficacy of nitrergic tone in high altitude lambs could be in part due to increased RhoA signaling that opposes to NO action in the hypoxic pulmonary circulation.

Impact of Objective Echocardiographic Criteria for Timing of Congenital Diaphragmatic Hernia Repair

OBJECTIVE

To assess the impact of specific echocardiographic criteria for timing of congenital diaphragmatic hernia repair on the incidence of acute postoperative clinical decompensation from pulmonary hypertensive crisis and/or acute respiratory decompensation, with secondary outcomes including survival to discharge, duration of ventilator support, and length of hospitalization.

STUDY DESIGN

The multidisciplinary congenital diaphragmatic hernia management team instituted a protocol in 2012 requiring the specific criterion of echocardiogram-estimated pulmonary artery pressure ≤80% systemic blood pressure before repairing congenital diaphragmatic hernias. A retrospective review of 77 neonatal patients with Bochdalek hernias repaired between 2008 and 2015 were reviewed: group 1 included patients repaired before protocol implementation (n = 25) and group 2 included patients repaired after implementation (n = 52).

RESULTS

The groups had similar baseline characteristics. Postoperative decompensation occurred less often in group 2 compared with group 1 (17% vs 48%, P = .01). Adjusted analysis accounting for repair type, liver herniation, and prematurity yielded similar results (15% vs 37%, P = .04). Group 2 displayed a trend toward improved survival to 30 days postoperatively, though this did not reach statistical significance (94% vs 80%, P = .06). Patient survival to discharge, duration of ventilator support, and length of hospitalization were not different between groups.

CONCLUSIONS

The implementation of a protocol requiring echocardiogram-estimated pulmonary arterial pressure ≤80% of systemic pressure before congenital diaphragmatic hernia repair may reduce the incidence of acute postoperative decompensation, although there was no difference in longer-term secondary outcomes, including survival to discharge.

Altered expression of PPAR‑γ and TRPC in neonatal rats with persistent pulmonary hypertension

Persistent pulmonary hypertension of the newborn (PPHN) is a life-threatening disease that is commonly observed in the neonatal intensive care unit. PPHN is pathologically characterized by pulmonary vascular remodeling and, in particular, pulmonary artery smooth muscle cell (PASMC) proliferation. Decreased expression levels of peroxisome proliferator-activated receptor γ (PPAR-γ), which is a member of the nuclear receptor hormone superfamily, in combination with elevated expressions of transient receptor potential cation channel, subfamily C, member 1 (TRPC1) and TRPC6 contributes to the PASMC proliferation and excessive pulmonary vascular remodeling in adult pulmonary hypertension (PH). Whether PPAR-γ, TRPC1 and TRPC6 affect the development of vascular remodeling in PPHN model rats remains unknown. The aim of the present study was to investigate the roles of PPAR-γ, TRPC1 and TRP6 on the pathogenesis of PPHN in rats. The rat model of PPHN was established by exposure to hypoxic conditions and indomethacin treatment. Lung tissues, hearts and blood from PPHN model and Control rats were collected and examined. Parameters, including the percentage of medial wall thickness (WT %), the percentage of medial wall area (WA %), right ventricular hypertrophy (RVH) and the plasma concentration of B-type natriuretic peptide (BNP) were used to estimate the development of PPHN. The expression levels of PPAR-γ, TRPC1 and TRPC6 in lung tissues were detected by immunohistochemistry, western blotting and reverse transcription-quantitative polymerase chain reaction. Significant increases were observed in the WT %, WA %, RVH and plasma BNP in the PPHN group compare with the Control group (P<0.01). In addition, the mRNA and protein expression levels of PPAR-γ were markedly downregulated (P<0.05 vs. Control). In the PPHN group, the protein expression levels of TRPC1 and TRPC6 were higher compared to the control group; however, there was no difference in the mRNA expression levels (P>0.05). In conclusion, the present study successfully established a PPHN rat model, and the altered expressions of PPAR-γ, TRPC1 and TRPC6 in the pulmonary artery located in the lungs of newborn rats with PPHN suggested that these proteins may be important mediators of PPHN.

Endothelin receptor antagonists for persistent pulmonary hypertension in term and late preterm infants

BACKGROUND

Endothelin, a powerful vasoconstrictor, is one of the mediators in the causation of persistent pulmonary hypertension of the newborn (PPHN). Theoretically, endothelin receptor antagonists (ETRA) have the potential to improve the outcomes of infants with PPHN.

OBJECTIVES

To assess the efficacy and safety of ETRA in the treatment of PPHN in full-term, post-term and late preterm infants.To assess the efficacy and safety of selective ETRAs (which block only the ETA receptors) and non-selective ETRAs (which block both ETA and ETB receptors) separately.

SEARCH METHODS

CENTRAL (Cochrane Central Register of Controlled Trials), MEDLINE, EMBASE and CINAHL databases were searched until December 2015.

SELECTION CRITERIA

Randomised, cluster-randomised or quasi-randomised controlled trials were eligible.

DATA COLLECTION AND ANALYSIS

Two review authors independently searched the literature, selected the studies, assessed the risk of bias and extracted the data. A fixed-effect model was used for meta-analysis. We used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to assess the quality of evidence.

MAIN RESULTS

Two randomised controlled trials of ETRA met the inclusion criteria. Both studies utilized oral Bosentan. The first study was done in a setting where inhaled nitric oxide (iNO) therapy was not available. Forty-seven infants (≥ 34 weeks' gestation) were randomised to receive either Bosentan or placebo. The second study was a multicentre study where iNO therapy was the standard of care for PPHN. Twenty-one infants were randomised to receive either 'iNO plus Bosentan' or 'iNO plus placebo'.In the first study, there was no significant difference in the incidence of death before hospital discharge between the Bosentan and placebo groups (1/23 vs 3/14; RR 0.20, 95% CI 0.02 to 1.77; RD -0.17, 95% CI -0.40 to 0.06). A higher proportion of infants in the Bosentan group showed improvement in oxygenation index (OI) at the end of therapy (21/24 vs 3/15; RR 4.38, 95% CI 1.57 to 12.17; RD 0.68, 95% CI 0.43 to 0.92; number needed to treat for a beneficial outcome (NNTB) 1.5). The duration of mechanical ventilation was lower in the Bosentan group (4.3 ± 0.9 vs 11.5 ± 0.6 days; MD -7.20, 95% CI -7.64 to -6.76). There was no significant difference in adverse neurological outcomes at six months (0/23 vs 4/14; RR 0.07, 95% CI 0.00 to 1.20; RD -0.29, 95% CI -0.52 to -0.05). The study suffered from a high risk of attrition bias since 8/23 infants in the placebo group were excluded from various analyses. Since the protocol for the study could not be accessed, the study suffered from unclear risk of reporting bias.In the second study, there was no significant difference in the incidence of treatment failure needing extracorporeal membrane oxygenation (ECMO) between the 'iNO plus Bosentan' vs 'iNO plus placebo' groups (1/13 vs 0/8; RR 1.93, 95% CI 0.09 to 42.35; RD 0.08, 95% CI -0.14 to 0.30). There was no significant difference in the median time to wean from iNO ('iNO plus Bosentan': 3.7 days (95% CI 1.17 to 6.95); 'iNO plus placebo': 2.9 days (95% CI 1.26 to 4.23); P = 0.34). There were no significant differences in the OI 0, 3, 5, 12, 24, 48 and 72 hours of treatment between the groups. There were no significant differences in the time to complete weaning from mechanical ventilation (median 10.8 days (CI 3.21 to 12.21) versus 8.6 days (CI 3.71 to 9.66); P = 0.24). The study had unequal distribution to the Bosentan group (N = 13) and the placebo group (N = 8). The methods used for generating random sequence numbers and allocation concealment were unclear, resulting in unclear risk of selection bias.Both studies reported that Bosentan was well tolerated and no major adverse effects were noted. Data from the two studies was not pooled given the heterogenous nature of the clinical settings and the modalities used for the treatment of PPHN.Overall, the quality of evidence was considered low, given the small sample size of the included studies, the numerical imbalance between the groups due to randomisation and attrition, and unclear risk of bias on some of the important domains.

AUTHORS' CONCLUSIONS

There is inadequate evidence to support the use of ETRAs either as stand-alone therapy or as adjuvant to inhaled nitric oxide in PPHN. Adequately powered RCTs are needed.

The myocardial architecture changes in persistent pulmonary hypertension of the newborn in an ovine animal model

BACKGROUND

Persistent pulmonary hypertension in the newborn remains a syndrome with high mortality. Knowledge of changes in myocardial architecture in the setting of heart failure in persistent pulmonary hypertension is lacking, and could aid in the explanation of the prevailing high mortality.

METHODS

Persistent pulmonary hypertension was induced by antenatal ligation of the arterial duct in six ovine fetuses. The hearts were compared ex vivo with five matched control hearts, using diffusion tensor imaging to provide the overall anatomical arrangement, and assessment of the angulations and course of the cardiomyocytes. Fibrosis was assessed with histology.

RESULTS

We found an overall increase in heart size in pulmonary hypertension, with myocardial thickening confined to the interventricular septum. An increase of 3.5° in angulation of myocyte aggregations was found in hypertensive hearts. In addition, we observed a 2.2% increase in collagen content in the right ventricular free wall. Finally, we found a previously undescribed subepicardial layer of strictly longitudinally oriented cardiomyocytes confined to the right ventricle in all hearts.

CONCLUSION

Myocardial fibrosis and possibly changes in angulations of myocytes seem to play a part in the etiology of persistent pulmonary hypertension. Moreover, a new anatomical arrangement of right ventricular mural architecture is described.

Common respiratory conditions of the newborn

KEY POINTS

Respiratory distress is a common presenting feature among newborn infants.Prompt investigation to ascertain the underlying diagnosis and appropriate subsequent management is important to improve outcomes.Many of the underlying causes of respiratory distress in a newborn are unique to this age group.A chest radiograph is crucial to assist in diagnosis of an underlying cause.

EDUCATIONAL AIMS

To inform readers of the common respiratory problems encountered in neonatology and the evidence-based management of these conditions.To enable readers to develop a framework for diagnosis of an infant with respiratory distress. The first hours and days of life are of crucial importance for the newborn infant as the infant adapts to the extra-uterine environment. The newborn infant is vulnerable to a range of respiratory diseases, many unique to this period of early life as the developing fluid-filled fetal lungs adapt to the extrauterine environment. The clinical signs of respiratory distress are important to recognise and further investigate, to identify the underlying cause. The epidemiology, diagnostic features and management of common neonatal respiratory conditions are covered in this review article aimed at all healthcare professionals who come into contact with newborn infants.

Biocompatibility Assessment of the CentriMag-Novalung Adult ECMO Circuit in a Model of Acute Pulmonary Hypertension

Extracorporeal membrane oxygenation (ECMO) is rarely used in patients with severe pulmonary hypertension (PH) as a bridge to lung transplantation. In this study, we assess the blood biocompatibility of the integrated CentriMag-Novalung ECMO system (venoarterial) in an acute model of PH. Severe PH (≥2/3 systemic) was induced in eight sheep through progressive ligation of the main pulmonary artery. System performance, platelet activation, thromboelastography (TEG) parameters, fibrinogen, plasma-free hemoglobin, and total plasma protein were measured at initiation, 3, and 6 hr of support in the ECMO (N = 4) and sham (N = 4) groups. A stable ECMO flow (2.2 ± 0.1 L/min), low transmembrane pressure gradient, and steady blood O2 and CO2 levels were maintained. Platelet activation was low (<4%) in both the groups, whereas platelet responsiveness to agonist (platelet activating factor) was reduced in the sham group when compared with the ECMO group. There were no differences in the TEG parameters, fibrinogen concentration, plasma-free hemoglobin (<10 mg/dl), and plasma total protein between the two groups. The findings of low levels of platelet activation and plfHb suggest adequate blood biocompatibility of the integrated CentriMag-Novalung circuit use for short-term support in a model of PH.

A Rare Cause of Persistent Pulmonary Hypertension Resistant to Therapy in The Newborn: Short-Rib Polydactyly Syndrome

Short-rib polydactyly syndrome is an autosomal recessively inherited lethal skeletal dysplasia. The syndrome is characterized by marked narrow fetal thorax, short extremities, micromelia, cleft palate/lip, polydactyly, cardiac and renal abnormalities, and genital malformations. In cases with pulmonary hypoplasia, persistent pulmonary hypertension of the newborn can develop. In this paper, we present a term newborn with persistent pulmonary hypertension of the newborn, which has developed secondary to short-rib polydactyly syndrome and was resistant to therapy with inhaled nitric oxide and oral sildenafil.

Molecular physiopathogenetic mechanisms and development of new potential therapeutic strategies in persistent pulmonary hypertension of the newborn

Persistent pulmonary hypertension of the newborn (PPHN) is a cyanogenic plurifactorial disorder characterized by failed postnatal drop of pulmonary vascular resistance and maintenance of right-to-left shunt across ductus arteriosus and foramen ovale typical of intrauterine life. The pathogenesis of PPHN is very complex and can result from functional (vasoconstriction) or structural (arteriolar remodeling, reduced pulmonary vessels density) anomalies of pulmonary circulation. Etiopathogenetic factors heterogeneity can strongly condition therapeutical results and prognosis of PPHN that is particularly severe in organic forms that are usually refractory to selective pulmonary vasodilator therapy with inhaled nitric oxide. This paper reports the more recent acquisitions on molecular physiopathogenetic mechanisms underlying functional and structural forms of PPHN and illustrates the bases for adoption of new potential treatment strategies for organic PPHN. These strategies aim to reverse pulmonary vascular remodeling in PPHN with arteriolar smooth muscle hypertrophy and stimulate pulmonary vascular and alveolar growth in PPHN associated with lung hypoplasia.In order to restore lung growth in this severe form of PPHN, attention is focused on the results of studies of mesenchymal stem cells and their therapeutical paracrine effects on bronchopulmonry dysplasia, a chronic neonatal lung disease characterized by arrested vascular and alveolar growth and development of pulmonary hypertension.

A rare case of crossed pulmonary arteries in an infant - case report

Crossed pulmonary arteries are a quite rare form of pulmonary arterial malposition. In this anomaly, the left pulmonary artery originates from the pulmonary trunk to the right and usually above the origin of the right pulmonary artery. Both pulmonary arteries cross each other on their course to each respective lung. We presented a case of a Chinese infant with crossed pulmonary arteries. Physical examination showed a mild cyanosis and continuous machine-like heart murmur in the 2 intercostal space at the left sternal border. An echocardiogram revealed pulmonary hypertension, atrial septal defect, patent ductus arteriosus and ostial stenosis in the inferior left pulmonary vein. Dual-source CT angiography was performed for further evaluation of pulmonary trunk and its branches. Dual-source CT angiography showed origin of left pulmonary artery from the pulmonary trunk in a plane superior to that of the right pulmonary artery. The branch pulmonary arteries then crisscrossed as they coursed to their respective lungs. In summary, we report an infant with crossed pulmonary arteries who was diagnosed during dual-source CT angiography. Three-dimensional reconstruction is useful for visualizing this condition. Knowledge of this rare anomaly will help in the differential diagnosis of pulmonary artery abnormalities.

Classification of pulmonary hypertension

Pulmonary hypertension (PH) can develop in association with many different diseases and risk factors, and its presence is nearly always associated with reduced survival. The prognosis and management of PH is largely dependent upon its underlying etiology and severity of disease. The combination of clinical and hemodynamic classifications of PH provides a framework for the diagnostic evaluation of PH to establish a final clinical diagnosis that guides therapy. As our understanding of the different pathologic mechanisms that underlie the syndrome of PH evolves, so too will the classification and treatment of PH.

Persistent pulmonary hypertension of non cardiac cause in a neonatal intensive care unit

Parenchymal lung diseases are the main cause of persistent pulmonary hypertension of the newborn (PPHN). We aimed to assess the non cardiac conditions associated to PPHN in the newborn and the survival rate over the last 15 years, at our center. A retrospective chart review of the neonates admitted for PPHN from 1996 to 2010 was performed. New therapies were introduced in 2003, and the survival rates between two periods (1996–2002 and 2003–2010) were compared. Out of 6750 newborns, 78 (1.1%) had the diagnosis of PPHN of non cardiac cause. The most prevalent causes were associated to pulmonary hypoplasia (30.7%), infection (24.3%), and aspiration syndromes (15.3%). Many other causes were identified in 33.3%. The overall survival rate was 68%. There was a significant difference on survival rates between the two periods (1996–2002 = 63.8% and 2003–2010 = 71.4%, P = 0.04). Our study showed a myriad of non cardiac aetiologies for PPHN of the newborn, most of them related to lung disease or lung hypoplasia. We observed an improvement in survival rate since 2003, which was associated to the use of new therapies.

Heart Failure Treated with Low-dose Milrinone in a Full-term Newborn

A term newborn with a hypocontractile myocardium complicating persistent pulmonary hypertension of the newborn was successfully treated with a low-dose phosphodiesterase III inhibitor milrinone. Echocardiography diagnosed heart failure with a left ventricular ejection fraction of 35% and a left ventricular shortening fraction of 18% and severe persistent pulmonary hypertension of the newborn with oxygenation index of 28. Milrinone was started at an initial dose of 50 mcg/kg, followed by continuous infusion of 0.20 mcg/kg/min. With lowdose milrinone oxygenation index decreased to 3 within 6 hours, left ventricular ejection fraction and left ventricular shortening fraction increased to 57%, and 30%, respectively. Low doses of milrinone might be promising in the treatment of heart failure and persistent pulmonary hypertension of the newborn in term newborns.