Spontaneous neonatal pulmonary arterial thrombosis - cases, mechanisms, and literature review

Spontaneous pulmonary artery thrombosis in neonates is rare and can be life-threatening. Clinical presentation may mimic pulmonary hypertension or CHD. Further, not all children present with identifiable risk factors. We report the case of two infants with pulmonary artery thromboses who underwent rapid diagnosis and therapy, one with percutaneous intervention and the other with anticoagulation. We also conducted a literature review to highlight the importance of early identification and referral to a centre capable of performing appropriate medical and interventional therapies.

The Hemostatic System in Newborns and the Risk of Neonatal Thrombosis

Newborns are the most vulnerable patients for thrombosis development among all children, with critically ill and premature infants being in the highest risk group. The upward trend in the rate of neonatal thrombosis could be attributed to progress in the treatment of severe neonatal conditions and the increased survival in premature babies. There are physiological differences in the hemostatic system between neonates and adults. Neonates differ in concentrations and rate of synthesis of most coagulation factors, turnover rates, the ability to regulate thrombin and plasmin, and in greater variability compared to adults. Natural inhibitors of coagulation (protein C, protein S, antithrombin, heparin cofactor II) and vitamin K-dependent coagulation factors (factors II, VII, IX, X) are low, but factor VIII and von Willebrand factor are elevated. Newborns have decreased fibrinolytic activity. In the healthy neonate, the balance is maintained but appears more easily converted into thrombosis. Neonatal hemostasis has less buffer capacity, and almost 95% of thrombosis is provoked. Different triggering risk factors are responsible for thrombosis in neonates, but the most important risk factors for thrombosis are central catheters, fluid fluctuations, liver dysfunction, and septic and inflammatory conditions. Low-molecular-weight heparins are the agents of choice for anticoagulation.

Prenatal and Neonatal Pulmonary Thrombosis as a Potential Complication of SARS-CoV-2 Infection in Late Pregnancy

Neonatal venous thrombosis is a rare condition that can be iatrogenic or occur due to viral infections or genetic mutations. Thromboembolic complications are also commonly observed as a result of SARS-CoV-2 infections. They can affect pediatric patients, especially the ones suffering from multisystem inflammatory syndrome in children (MIS-C) or multisystem inflammatory syndrome in neonates (MIS-N). The question remains whether the maternal SARS-CoV-2 infection during pregnancy can lead to thromboembolic complications in fetuses and neonates. We report on a patient born with an embolism in the arterial duct, left pulmonary artery, and pulmonary trunk, who presented several characteristic features of MIS-N, suspecting that the cause might have been the maternal SARS-CoV2 infection in late pregnancy. Multiple genetic and laboratory tests were performed. The neonate presented only with a positive result of IgG antibodies against SARS-CoV-2. He was treated with low molecular weight heparin. Subsequent echocardiographic tests showed that the embolism dissolved. More research is necessary to evaluate the possible neonatal complications of maternal SARS-CoV-2 infection.

"APS pregnancy - The offspring"

BACKGROUND

Antiphospholipid antibody syndrome (APS) is an autoimmune disease that affects women in childbearing age. In recent years, great improvements were achieved in the management of pregnancies in these women. Prematurity could be an issue in these pregnancies, mainly due to the direct pathogenic effect of antiphospholipid antibodies (aPL) on the placental surface. Maternal IgG aPL can cross the placenta and theoretically interact with the growing fetus; it could reach the fetal brain because of the incompleteness of the fetal blood-brain barrier: whether this can have an effect on brain development is still debated. Neonatal thrombosis episodes have been described in children positive for aPL, not always associated with maternal antibody positivity, suggesting the hypothesis of a possible aPL de novo synthesis in fetus and neonates.

METHODS

A keyword-based literature search was conducted. We also described a case of neonatal catastrophic antiphospholipid syndrome (CAPS).

RESULTS

Offspring of patients with APS are generally healthy but the occurrence of neonatal thrombosis or minor neurological disorders were reported.

CONCLUSIONS

The limited number of the available data on this sensitive issue supports the need for further studies. Clinical follow-up of children of mothers with APS seems to be important to exclude, in the neonatal period, the occurrence of aPL associated pathological events such as thrombosis, and in the long-term, impairment in learning skills or behavioral problems.

Neonatal thrombosis

Neonatal thromboembolism in pediatric patients is a rare but life-threatening condition mainly caused by combinations of at least 2 prothrombotic triggering risk factors such as the central venous lines, septic condition, and prematurity. Other risk factors include asphyxia, dehydration, liver dysfunction, inflammation, and maternal condition. Neonatal hemostatic system is different from one of the older children and adults. Coagulation proteins do not cross the placenta but are synthesized in the fetus from an early stage. In the term neonate, concentrations of several procoagulant proteins, particularly the vitamin K dependent and contact factors are reduced when compared with adults. Conversely, levels of antithrombin, heparin cofactor II and protein C and S are low at birth and fibrinolysis system is characterized by the decreased level of plasminogen and alpha-1-antiplasmin, increased tissue plasminogen activator. These features all tend to be gestational dependent and are more present in the preterm infant. Primarily in this context neonates appear to be at a higher risk of thrombosis than older children. Thrombotic complications reach their peak in the group of children born at 22-27 weeks. The role of inherited thrombophilic risk factors in neonatal VTE development is poorly defined. The presence of inherited and acquired thrombophilia in mother and newborn is also responsible for the development of thrombosis in neonates and should be considered. Thrombophilia in the mother can lead to increased coagulation potential and prethrombotic conditions during pregnancy, causing thrombotic vasculopathy at the placental level. The benefit of identifying thrombophilia in the sick preterm newborns who are in the group of risk for development of thrombotic complications may facilitate the thromboprophylaxis. Further research regarding assessment of risk factors, diagnostics and treatment strategy is required.

What is known about pediatric antiphospholipid syndrome?

INTRODUCTION

Antiphospholipid syndrome (APS) is a systemic autoimmune disease characterized by vascular thrombosis and/or pregnancy morbidity associated with the persistent presence of antiphospholipid antibodies (aPL) including lupus anticoagulant (LA), anticardiolipin antibodies (aCL), and anti-β2 glycoprotein I antibodies (aβ2GPI).

AREAS COVERED

APS is considered as the most common acquired hypercoagulation state of autoimmune origin in children. Unfortunately, data about incidence, prevalence, thrombosis risk and effective treatment in paediatric APS are limited and unmethodical. Expert commentary: This review summarizes recent clinical, laboratory and therapy characterization of paediatric APS and emphasizes the differences between paediatric and adult populations.

Neonatal Venous Thromboembolism

Neonates are the pediatric population at highest risk for development of venous thromboembolism (VTE), and the incidence of VTE in the neonatal population is increasing. This is especially true in the critically ill population. Several large studies indicate that the incidence of neonatal VTE is up almost threefold in the last two decades. Central lines, fluid fluctuations, sepsis, liver dysfunction, and inflammation contribute to the risk profile for VTE development in ill neonates. In addition, the neonatal hemostatic system is different from that of older children and adults. Platelet function, pro- and anticoagulant proteins concentrations, and fibrinolytic pathway protein concentrations are developmentally regulated and generate a hemostatic homeostasis that is unique to the neonatal time period. The clinical picture of a critically ill neonate combined with the physiologically distinct neonatal hemostatic system easily fulfills the criteria for Virchow's triad with venous stasis, hypercoagulability, and endothelial injury and puts the neonatal patient at risk for VTE development. The presentation of a VTE in a neonate is similar to that of older children or adults and is dependent upon location of the VTE. Ultrasound is the most common diagnostic tool employed in identifying neonatal VTE, but relatively small vessels of the neonate as well as frequent low pulse pressure can make ultrasound less reliable. The diagnosis of a thrombophilic disorder in the neonatal population is unlikely to change management or outcome, and the role of thrombophilia testing in this population requires further study. Treatment of neonatal VTE is aimed at reducing VTE-associated morbidity and mortality. Recommendations for treating, though, cannot be extrapolated from guidelines for older children or adults. Neonates are at risk for bleeding complications, particularly younger neonates with more fragile intracranial vessels. Developmental alterations in the coagulation proteins as well as unique pharmacokinetics must also be taken into consideration when recommending VTE treatment. In this review, epidemiology of neonatal VTE, pathophysiology of neonatal VTE with particular attention to the developmental hemostatic system, diagnostic evaluations of neonatal VTE, and treatment guidelines for neonatal VTE will be reviewed.

Neonatal haemostasis and the management of neonatal thrombosis

Two detailed reviews of the management of neonatal thrombosis were published in 2012; one was an up-dated version of guidance first issued in 2004 and the other was a comprehensive review. Both of these publications gave very similar advice regarding the practical aspects of the indications, dosage and management of antithrombotic therapy. The authors stated that the evidence supporting most of their recommendations for anti-thrombotic therapy in neonates remained weak and so the therapy for a neonate with a thrombosis has to be based on an individualized assessment of estimated risk versus potential benefit. The aim of this present review is to give the treating physician an outline of the unique physiology of neonatal coagulation and how this affects the monitoring, dosing and even the choice of therapeutic strategy for the management of thrombosis in the neonate.

Peripheral nerve blockade and neonatal limb ischemia: our experience and literature review

Considering the high frequency of bleeding complications following fibrinolytic treatment in neonates, peripheral nerve blockade (PNB) has been proposed alone or in association with lower doses of tissue plasminogen activator, as a possible new therapeutic approach in the management of neonatal limb ischemia (LI) secondary to vasospasm and/or thrombosis. The present article provides a review of the current knowledge about the topic, in order to evaluate the efficacy and safety of this therapeutic approach. According to the few case reports documented in literature and to our experience, PNB could be considered as valid procedure for the treatment of LI, especially during neonatal period, when the risk of serious bleeding associated with fibrinolytic or anticoagulant therapy is higher. Peripheral nerve blockade resulted in a safe and effective procedure for the treatment of neonatal vascular spasm and thrombosis.