Neonatal Venous Thromboembolism

Retrospective study evaluating safety, clinical effect, and dosing of dalteparin for the treatment of venous thromboembolism in term neonates

BACKGROUND

There is an increased risk of venous thromboembolism (VTE) among neonates due to their unique hemostatic system. However, there is lack of approved treatment options for VTE in neonatal population. Importantly, dalteparin, a low molecular weight heparin approved for pediatric VTE in children ≥1 month of age, has also been used for the treatment of neonatal VTE. Based on the request from the Food and Drug Administration, this retrospective study aimed to characterize the safety, clinical effects, and dosing of dalteparin for treatment of VTE among neonates.

PROCEDURE

Data from electronic medical records for neonates (born ≥35 weeks of gestation) treated with dalteparin for VTE between January 2010 and December 2021 were collected. The data assessed included bleeding and deterioration in hematological biomarkers among other adverse events, changes in relevant factor antifactor Xa (anti-Xa) levels and VTE status, and dosing of dalteparin and corresponding anti-Xa assay levels.

RESULTS

Sixteen neonates from five participating sites in the United Kingdom were included. There were no bleeding events or deaths. Only one serious adverse event of hypoglycemic brain injury (unrelated to dalteparin) was documented in a patient with a history of hyperinsulinism. Median (range) daily dose of dalteparin at initiation was 309 (297-314) IU/kg. Eight of 16 neonates achieved therapeutic anti-Xa level, including two patients who did so after the first dose.

CONCLUSIONS

Dalteparin treatment in neonates raised no major safety concerns. Larger cohort studies may help provide further insights on clinical effects of dalteparin for neonatal VTE.

An unusual cause of renal vein thrombosis in a newborn: COVID-19

There is no information on renal vein thrombosis induced by COVID-19 infection in a neonate. Few cases of renal vein thrombosis caused by COVID-19 infection have been reported in predominantly adult patients. On day 25 after birth, a newborn whose mother was infected with COVID-19 had renal vein thrombosis. We believed that our patient's renal vein thrombosis was caused by postnatal transmission of the COVID-19 infection that the mother had acquired during birth. The clinical and radiologic findings of these unusual renal complications in a neonate, as well as treatment options, are presented.

Central Lines and Their Complications in Neonates: A Case Report and Literature Review

Central lines are essential devices in NICUs, used primarily in preterm neonates and critically ill term neonates. They are typically divided into non-tunnelled, tunnelled and totally implanted. In light of the increasing use of central lines in the NICU setting, monitoring of the risk factors associated with complications has to be an important part of neonatal care quality management. Presented here is a case of a preterm neonate with cardiac tamponade caused by UVC tip migration. Among complications of central lines are CLABSI, with an incidence of 3 to 21 per 1000 catheter days, and portal vein thrombosis, which is common but probably under-recognised, whereas other mechanical complications such as pericardial and pleural effusions are rare, with an incidence of less than 1%. Complications can cause injury to the neonates, as well as increase the costs of health services because of increases in the length of stay in the NICU. It is recommended that the catheter tip location is confirmed either by X-ray or ultrasonography. In order to minimise the risk of CLABSI, the use of bundles is recommended. Certain recommendations need to be followed when using different types of catheters. Future research is aimed at novel ways of central line securement to minimise mechanical complications and the use of antimicrobial catheters to reduce the rate of CLABSI.

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.

Outcomes in infants with unprovoked venous thromboembolism: A retrospective cohort study

Background

Although children aged <1 year have a relatively high rate of venous thromboembolism (VTE) compared to older children, most have additional prothrombotic risk factors. Unprovoked VTE is rare, and little is known about this population, particularly the risk of recurrent VTE.

Objectives

We aimed to determine the rate of recurrent VTE in infants with prior unprovoked VTE and evaluate long-term, end-organ outcomes for infants with renal and intracranial vein thrombosis.

Methods

Infants <1 year of age with an unprovoked VTE between 2003 and 2021 at a single institution were included. Time to recurrent event and anticoagulation duration were summarized using the Kaplan-Meier estimator. Neurologic outcomes were summarized with the pediatric stroke outcome measure for infants with cerebral sinovenous, medullary, or cortical vein thrombosis. Kidney outcomes were summarized with estimated glomerular filtration rates for infants with renal vein thrombosis. Anticoagulation was summarized.

Results

Forty infants with intracranial, renal, portal, and extremity VTE met the inclusion criteria and were followed for a median of 4.7 years (IQR, 2.1-8.5). Most VTE events occurred during the first month of life. There was 1 recurrent event in 237 person-years of follow-up (incidence rate, 4 per 1000 [95% CI, 0.6-29.9] person-years). In outpatient follow-up, 40% of infants with intracranial thrombosis met criteria for moderate or severe neurologic outcomes and two-thirds of infants with a prior renal vein thrombosis had abnormal kidney function (estimated glomerular filtration rate < 90 mL/min/1.73 m2).

Conclusion

There is a low rate of recurrent VTE but significant end-organ morbidity in infants with unprovoked VTE.

Assessment of the Particularities of Thrombophilia in the Management of Pregnant Women in the Western Part of Romania

Background and objectives: Thrombophilia in pregnant women is a condition whose incidence is constantly increasing worldwide, and, under these conditions, the development of preventive procedures is becoming essential. In this study, we aimed to evaluate thrombophilia in pregnant women in the western part of Romania and to establish anthropometric characteristics, socioeconomic features, and genetic and risk factors. Material and Methods: 178 pregnant women were divided into three study groups, according to the type of thrombophilia, aiming to carry out the genetic profile and the acquired one. Anthropometric measures and biological tests were performed. Results: The mixed type of thrombophilia predominates. The particularities of pregnant women diagnosed with thrombophilia are higher age, living in an urban environment, with normal BMI, approximately 36 weeks of gestational period, and having at least one miscarriage. Regarding the most frequent thrombophilic genetic markers, we obtained the MTFHR gene mutation C677T and A1298C, followed by the PAI-1 4G/5G gene mutation. Smoking represents an aggravating factor in the evolution of this pathology, manifested through the increase of D-dimers and the decrease in antithrombin values, simultaneously with the increase in therapeutic need. Conclusions: The predominance of MTHFR and PAI-1 4G/5G gene polymorphism is a particularity of pregnant women with thrombophilia from the western part of Romania. Smoking is confirmed as an important risk factor in spontaneous abortion.

Case Report of a Massive Life-threatening Neonatal Thrombosis Treated With a Targeted, Goal-oriented Scheme of Urokinase

BACKGROUND

Thrombotic events are severe, often under-diagnosed, complications occurring in newborn infants during their hospital stay. Currently, there is no consensus regarding the optimal treatment scheme for thrombolysis in neonates.

OBSERVATIONS

We present the case of a newborn suffering from a life-threatening thrombosis. Diagnosis was suggested by a gradual increase of C-reactive protein, with repeatedly normal procalcitonin. Thrombosis was successfully and safely treated with a long scheme of 21 days of urokinase, supported by vascular ultrasound and d-dimer trend.

CONCLUSIONS

Laboratory and ultrasound results may help in adjusting the duration of the thrombolytic treatment, allowing for longer therapeutic schemes that could optimize treatment success. In addition, our case may suggest a possible combined role of C-reactive protein and procalcitonin as an early diagnostic aid in neonatal thrombosis.

Successful Treatment of Saddle Pulmonary Thromboembolism in 23-Week Preterm Infant

Saddle pulmonary thromboembolism (PTE) is defined as a thromboembolism straddling the bifurcation of the main pulmonary artery trunk and it is rarely seen in extremely low birth weight infants (ELBWI). Saddle PTE is a critical disease that requires urgent treatment. However, the treatment guidelines for ELBWI are not established. We present the case of a 1-day-old preterm infant (gestational age 23 weeks) who showed sudden desaturation and pulmonary hypertension due to saddle PTE. A thrombus was observed in the bifurcation of the pulmonary artery. The blood flow to the pulmonary artery on the left side was interrupted, and the right side showed severe stenosis. Since the patient was an ELBWI in the acute phase, we decided to use recombinant tissue plasminogen activator (rt-PA) and administered a maintenance dose (0.08 mg/kg/hour), instead of the loading dose. After using rt-PA, the thrombus dissolved in 8 hours without adverse events. This case suggests that starting with a maintenance dose of rt-PA may be an effective treatment option for saddle PTE in ELBWI in the acute phase under the high risk of bleeding.

Vena Cava Thrombosis after Congenital Diaphragmatic Hernia Repair: Multivariate Analysis of Potential Risk Factors

INTRODUCTION

 The treatment of newborns with congenital diaphragmatic hernia (CDH) is associated with a significant complication rate. Information on major thrombotic complications and their incidence in newborns with CDH is lacking. The aims of our analysis were to evaluate the frequency of vena cava thrombosis and to determine its predictors within a consecutive series of patients with CDH.

MATERIALS AND METHODS

 We retrospectively analyzed charts of all neonates of our department that underwent CDH repair from 2007 to 2021, focusing on vena cava thrombosis. Vena cava thrombosis was diagnosed sonographically and classified as complete or partial venous occlusion. Complete occlusion was confirmed by cavography. Variables evaluated were CDH side, liver position, central vein line, surgical approach, and extracorporeal membrane oxygenation (ECMO). Univariate and multivariate tests were utilized.

RESULTS

 Among 57 neonates who underwent CDH repair, vena cava thrombosis was diagnosed in 14 (24.6%), seven of whom had complete occlusion of the vena cava. Factors associated with vena cava thrombosis were femoral or saphenous venous catheter (p = 0.044), right sided CDH (p = 0.027) and chylothorax (p < 0.0001). ECMO was not associated with vena cava thrombosis. Seven patients (50%) with vena cava thrombosis were treated interventionally with angioplasty and seven (50%) conservatively with anticoagulation only. Mortality was not higher in patients with compared with patients without vena cava thrombosis.

CONCLUSION

 The incidence of vena cava thrombosis in newborns with CDH in our series is high. Routine postoperative abdominal sonography focusing on vena cava thrombosis is mandatory in all patients with CDH. Patients who developed vena cava thrombosis were more likely to develop chylothorax after CDH repair. Considering the good outcome of medical therapy of partial vena cava thrombosis, it may be discussed whether low dose anticoagulation may be provided to all newborns with CDH.

The role of the calibrated automated thrombogram in neonates: describing mechanisms of neonatal haemostasis and evaluating haemostatic drugs

Premature infants are at high risk of haemorrhage and thrombosis. Our understanding of the differences between the neonatal and adult haemostatic system is evolving. There are several limitations to the standard coagulation tests used in clinical practice, and there is currently a lack of evidence to support many of the transfusion practices in neonatal medicine. The evaluation of haemostasis is particularly challenging in neonates due to their limited blood volume. The calibrated automated thrombogram (CAT) is a global coagulation assay, first described in 2002, which evaluates both pro- and anti-coagulant pathways in platelet-rich or platelet-poor plasma. In this review, the current applications and limitations of CAT in the neonatal population are discussed.Conclusion: CAT has successfully elucidated several differences between haemostatic mechanisms in premature and term neonates compared with adults. Moreover, it has been used to evaluate the effect of a number of haemostatic drugs in a pre-clinical model. However, the lack of evidence of CAT as an accurate predictor of neonatal bleeding, blood volume required and the absence of an evidence-based treatment algorithm for abnormal CAT results limit its current application as a bedside clinical tool for the evaluation of sick neonates. What is Known: • The Calibrated automated thrombogram (CAT) is a global coagulation assay which evaluates pro- and anti-coagulant pathways. • CAT provides greater information than standard clotting tests and has been used in adults to evaluate bleeding risk. What is New: • This review summarises the physiological differences in haemostasis between neonates and adults described using CAT. • The haemostatic effect of several drugs has been evaluated in neonatal plasma using CAT.

Cavitary lung lesions in a neonate: Potential manifestation of COVID-19 related multisystem inflammatory syndrome

BACKGROUND

The hyperinflammatory state of multisystem inflammatory syndrome in children (MIS-C) predisposes to thromboembolic complications. We report a neonate with multiple cavitary lesions in lung, which we suspect could be a manifestation of multisystem inflammatory syndrome in neonate (MIS-N) following maternal COVID-19 infection during pregnancy.

CASE REPORT

Eight-day-old neonate was referred with fever and fast breathing. Mother was positive for COVID-19 in 29th week. COVID-19 reverse-transcription polymerase chain reaction was negative, however, antibodies were positive. He had increased leucocyte count, and elevated levels of C-reactive protein (CRP), procalcitonin, ferritin, lactate dehydrogenase, and d-dimer along with bilateral reticulonodular opacities on chest radiograph and multiple nodules with evidence of cavitation in both lungs on chest tomography. All cultures were negative. A possible diagnosis of MIS was made. Infant was treated with intravenous immunoglobulin (IVIG) which he responded to with resolution of symptoms.

CONCLUSION

Neonates exposed to COVID-19 should be evaluated for thromboembolic complications and IVIG can be one of the treatment modalities.

Real-World Anticoagulant Use and Incidence of Venous Thromboembolism and Major Bleeding in Children

PURPOSE

Children generally have a lower risk of venous thromboembolism (VTE) than adults, but those with acute and chronic conditions requiring hospitalization and surgical procedures are at increased risk. Anticoagulant use in children has not been systematically studied, and limited data exist. This study aimed to provide data on the conditions associated with use of anticoagulants, the type of anticoagulant used in children, and the incidence of thromboembolism and major bleeding events reported in this population.

METHODS

To increase understanding of the use of anticoagulant therapies in children with at-risk conditions, 3 health claims databases in the United States were analyzed to describe the characteristics of use of heparins, warfarin, and direct oral anticoagulants (DOACs). Cumulative drug exposure was determined for continuous exposure, defined as >30 days. Unadjusted event rates of VTE and major bleeding after exposure to these therapies were reported. The data were presented descriptively and are not intended for comparison or to imply any causation.

FINDINGS

Anticoagulants were infrequently used in the pediatric population, including at any time point after Fontan surgery for congenital heart disease. Heparins were used most frequently in the population overall and especially for patients aged <12 years. DOACs were used least often and primarily for patients ages 12 to <18 years. Among pediatric patients exposed to anticoagulants, unadjusted incidence rates of VTE per 1000 person-years of exposure ranged from 30.8 to 34.0 for all DOACs, 21.6 to 46.2 for warfarin, and 6.0 to 7.3 for heparins. Rates per 1000 person-years for major bleeding ranged from 0 to 4.9 for all DOACs, 4.3 to 6.7 for warfarin, and 3.7 to 4.6 for heparins.

IMPLICATIONS

With results from clinical trials evaluating DOACs in the pediatric population expected in the next 2 years, these descriptive real-world data may provide a baseline understanding of current prescribing patterns and outcomes associated with the use of DOACs and other anticoagulants in routine pediatric clinical practice. This information represents the use of real-world evidence and may function as the benchmark for evaluating changes in prescription practices and potential outcomes in the future.

How to use low-molecular-weight heparin to treat neonatal thrombosis in clinical practice

Among children, neonates have the highest incidence of thrombosis due to risk factors such as catheter instrumentation, an evolving coagulation system and congenital heart disease. Low-molecular-weight heparins (LMWHs) are the most commonly used anticoagulants in neonates. Published guidelines delineate dosing and monitoring protocols for LMWH therapy in newborns. However, challenging clinical situations frequently present that warrant healthcare providers to think critically beyond the range of guidelines, and judiciously resolve specific problems. This review describes the use of LMWH in the neonatal population, including practical aspects such as route and site of administration, preparation from concentrated formulations and methods to minimize pain of subcutaneous injection. It is followed by a discussion on dosing, monitoring and outcomes of LMWH therapy in neonates. The risk of recurrence of thrombosis in neonates after LMWH therapy is approximately 3% based on a pooled analysis of studies reporting this outcome over the last 24 years. The article concludes with an overview of the side-effects of LMWH, including the risk of bleeding which is around 4% based on pooled analyses of more than 30 studies.

Neonatal thrombosis: risk factors and principles of prophylaxis

Data analysis on the pathogenesis and risk factors of neonatal thrombosis was carried out. The main risk factor of any neonatal thrombosis is central catheter installment, but other maternal, fetal and neonatal factors should be taken into consideration. We discuss the epidemiology of neonatal thrombosis and the main features of the hemostasis system in newborns, the most significant risk factors, including genetic and acquired thrombophilia. We consider the von Willebrand factor activity and ADAMTS-13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) level in the development of neonatal thrombotic microangiopathy. Finally, we discuss the basic principles of prevented neonatal thrombosis by using low molecular weight heparins.

Risk Factors of Thrombotic Complications and Antithrombotic Therapy in Paediatric Cardiosurgical Patients

The development of cardiosurgical care for paediatric and neonatal patients is undergoing the rapid growth. Complex, multi-stage reconstructive operations and the use of invasive monitoring are associated with high risk of venous and arterial thrombosis.

The cardiac surgery patient is inherently unique, since it requires controlled anticoagulation during cardiopulmonary bypass. Moreover, the most cardiovascular pediatric patients require antithrombotic measures over the perioperative period. In addition to medication support with the use of various groups of antithrombotic agents, vascular access management is justified in order to minimize the risk of thromboembolic complications, which can affect both the functional status, and common and inter-stage mortality.

The purpose of this review was to systematize the available data on risk factors contributing to the development of thrombotic complications in patients with congenital heart disease.

An information search was carried out using Internet resources (PubMed, Web of Science, eLibrary.ru); literature sources for period 2015–2020 were analysed. As a result of the analysis of the literature data age-dependent features of the haemostatic system, and associated with the defect pathophysiology, and undergone reconstructive interventions were described. The issues of pathophysiology of univentricular heart defects and risk factors associated with thrombosis were also covered.

Moreover, aspects of intraoperative anti-thrombotic support are discussed, as well as measures to prevent thromboembolic complications in this population.

Coordinated actions of haematologists, cardiologists, anaesthesiologists, intensivists, and cardiac surgeons will allow achieving a fine balance between risks of bleeding and thrombosis in the population of paediatric patients undergoing cardiovascular surgery. 

Adult Donor Blood Products as Risk Factors for Central Venous Catheter-associated Thromboembolism in Neonates: A Retrospective Case-Control Study

This study aimed to examine whether the transfusion of donor blood products, abnormal coagulation or inflammation increase the risk of venous thromboembolism (VTE) associated with central venous catheters (CVC) in neonates. A retrospective case-control study including 25 neonates with CVC-associated VTE and tightly matched controls with CVC, but without VTE was performed. The frequency of (i) abnormal coagulation screens, (ii) increased inflammatory marker proteins before catheter insertion, or (iii) catheter-associated blood stream infection did not differ between cases and controls. No difference was found in the number or type of transfusions within the last day before VTE. However, the total number of transfusions in the time period between catheter placement and VTE diagnosis (median 6.5 d) was significantly higher (P<0.001) in cases (44 red blood cell, 61 plasma, and 18 platelet transfusions) compared with an equal median time period of 7 days postcatheter insertion in controls (26/24/11). In conclusion, intensive transfusion treatment (through a peripheral line) after CVC insertion was associated with a higher risk of VTE (odds ratio 7.58; 95% confidence interval, 0.84-68.46), suggesting that transfusion of adult donor blood products into the cellular and plasmatic hemostatic system of the neonate increases the risk for CVC-associated VTE.

Thrombosis in infants in the neonatal intensive care unit: Analysis of a large national database

BACKGROUND

Thrombosis in the neonatal population is rare, but increasing. Its incidence and management are not well understood.

OBJECTIVES

To investigate the incidence, associated factors, and management of thrombosis in the neonatal intensive care unit (NICU) population.

PATIENTS/METHODS

We performed a retrospective cohort study of infants admitted to a Pediatrix Medical Group-affiliated NICU from 1997 through 2015. We determined the prevalence of venous and arterial thrombosis, and assessed demographic characteristics and known risk factors. Categorical variables were compared with the Pearson χ2 test and continuous variables with Wilcoxon rank-sum tests. Stepwise logistic regression was used to identify associated factors. The primary outcome was incidence of thrombosis. Secondary analyses investigated correlations between clinical and demographic characteristics and thrombosis.

RESULTS

Among 1 158 755 infants, we identified 2367 (0.20%) diagnosed with thrombosis. In a multivariable regression analysis, prematurity, male sex, congenital heart disease, sepsis, ventilator support, vasopressor receipt, central venous catheter, invasive procedures, and receipt of erythropoietin were associated with increased risk of thrombosis, while Black race and Hispanic ethnicity were associated with reduced risk. The majority of infants diagnosed with thrombosis (73%) received no anticoagulation, but anticoagulant use in infants with thrombosis was higher than those without (27% versus 0.2%, P < .001). Thrombosis in infants was associated with higher mortality (11% versus 2%, P < .001) and longer hospital stays (57 days, [interquartile range (IQR) 28--100] versus 10 days, [IQR 6--22], P < .001).

CONCLUSIONS

In the largest national study to date, we found that thrombosis in NICU patients is associated with prematurity, low birth weight, sepsis, and invasive procedures.

Portal vein thrombosis and food protein-induced allergic proctocolitis in a premature newborn with hypereosinophilia: a case report

Background

Peripheral blood eosinophilia is identified in numerous medical conditions associated with allergic, infectious, and inflammatory processes mostly as reactive eosinophilia with or without tissue eosinophilia. In hospitalized neonates, eosinophilia is common with an inverse relationship with gestational age and occurs solely as mild eosinophilia in the majority of cases. In the literature, eosinophilia has been proposed as a possible risk factor for venous thromboembolism. However, few reports are found on thromboembolic events including portal vein thrombosis (PVT) associated with eosinophilia in the newborn period.

Neonates, particularly preterm infants, are vulnerable to thrombosis due to the immature and developing hemostatic system with little reserve capacity, which occurs as catheter-related thrombosis in most cases.

Case presentation

A male newborn at 34^+ 5 weeks’ gestation presented with a left portal venous thrombus and hematochezia after initial cow’s milk feeding in the setting of blood hypereosinophilia for a prolonged period of time without central venous catheterization. The infant was diagnosed with PVT and food protein-induced allergic proctocolitis (FPIAP) and showed complete resolution of the conditions with expectant management with food avoidance, including the normalized eosinophil count.

Conclusions

Our experience suggests that in the setting of hypereosinophilia with a prolonged duration in premature neonates, FPIAP should be suspected in case of hematochezia in otherwise healthy infants, and considering the increased thrombotic risk by the hypereosinophilia and premature newborn status, evaluation for neonatal thrombosis may be needed, including PVT with the potential risk for the more serious, but uncommon, late complications encompassing portal hypertension.

Evaluation and Management of Coagulopathies and Thrombophilias in Pediatric Patients

The diagnosis of coagulopathy or thrombophilia in pediatric patients can be challenging. Congenital coagulopathies often present in the pediatric period and require appropriate work-up for diagnosis and ongoing management. Acquired coagulopathies of childhood are frequently encountered in hospitalized children and warrant appropriate coagulation testing for goal-directed therapy. The incidence of thrombosis is increasing in pediatric patients. After identifying the presence of thrombus, acute management includes initiating therapeutic anticoagulation. Choice of anticoagulant depends on patient's clinical status, along with availability of the anticoagulant. Thrombophilia evaluation is performed when children present with spontaneous thrombosis. Thrombophilia tests are inaccurate during acute illness.

FDA approval summary: Dalteparin for the treatment of symptomatic venous thromboembolism in pediatric patients

On May 16, 2019, the U.S. Food and Drug Administration (FDA) approved dalteparin sodium for the treatment of symptomatic venous thromboembolism (VTE) to reduce the risk of recurrence in pediatric patients 1 month of age and older. Approval was primarily based on FDA review of a single-arm trial evaluating dalteparin administered subcutaneous twice daily in 38 pediatric patients with symptomatic VTE. Efficacy was based on the achievement of therapeutic plasma anti-Xa levels. The FDA concluded that dalteparin has efficacy and acceptable safety for pediatric patients.

Thrombolytic therapy in preterm infants: Fifteen-year experience

OBJECTIVE

To report a single-center experience with thrombolytic therapy using recombinant tissue plasminogen activator (rt-PA) in preterm neonates with severe thrombotic events, in terms of thrombus resolution and bleeding complications.

STUDY DESIGN

This retrospective study included 21 preterm neonates with severe venous thrombotic events admitted to the neonatal intensive care unit, identified in our pharmacy database from January 2001 to December 2016, and treated with rt-PA until complete or partial clot lysis, no-response or bleeding complications. Our primary outcome was thrombus resolution.

RESULTS

Twenty-one preterm neonates were treated with rt-PA for an average of 2.9 cycles. Seventeen patients (80.9%) had superior vena cava thrombosis and superior vena cava syndrome. All patients had a central venous catheter, parenteral nutrition, mechanical ventilation, and sepsis. Fifteen patients (71.4%) were extremely preterm, 11 (52.4%) were extremely low birth weight, and seven (33.3%) were very low birth weight. The patency rate was 85.7%, complete lysis occurred in 11 (52.4%) patients, and partial lysis in seven (33.3%). Minor bleeding occurred in five (23.8%) patients, three patients (14.2%) had clinically relevant nonmajor bleeding events, and major bleeding occurred in six (28%) patients.

CONCLUSION

In this study, the rate of thrombus resolution in preterm neonates treated with rt-PA were similar to the percentages reported in children and adolescents, with a high rate of bleeding. Therefore, rt-PA thrombolytic therapy should only be considered as a treatment option for severe life-threatening thrombosis in premature neonates for whom the benefits of the thrombolytic treatment outweigh the risks of bleeding.

Thrombosis after umbilical venous catheterisation: prospective study with serial ultrasound

BACKGROUND

Umbilical venous catheters (UVCs) are associated with thrombus formation. Most studies on thrombosis in infants with UVCs focus on only one part of the route, and none assessed a control group of infants without UVCs.

OBJECTIVE

To determine the incidence and location of thrombi in infants after umbilical catheterisation and compare this with a control group of infants without umbilical catheters.

DESIGN

Prospective observational study with serial ultrasonography of the UVC route from the umbilico-portal confluence to the heart. Ultrasonography was performed until day 14 after catheterisation in cases and day 14 after birth in controls.

RESULTS

Thrombi in the UVC route were detected in 75% (30/40) of infants with UVCs in the study group, whereas no thrombi were detected in the control group of infants without UVCs (0/20) (p<0.001). Six thrombi (20%) were located in the right atrium. Most of these were also partly present in the ductus venosus. Six thrombi (20%) were located in the ductus venosus only, and in 12 infants (40%), the thrombus was at least partly located in the umbilico-portal confluence. Thrombi persisted after UVC removal in 25/30 cases. Two infants with thrombotic events were treated with low-molecular-weight heparin and resolution was found. In the other 23 infants managed expectantly, 2 died due to necrotising enterocolitis, 1 was lost to follow-up and in 20 spontaneous regression was seen.

CONCLUSIONS

Thrombotic events occur frequently in infants after umbilical catheterisation. Most thrombi were asymptomatic and regressed spontaneously with expectant management. Routine screening for thrombi in UVCs is therefore not advised.

Inferior vena cava syndrome in neonates: An evidence-based systematic review of the literature

Neonatal inferior vena cava syndrome (IVCS), though uncommon, is associated with significant morbidity and mortality. Information on risk factors, diagnosis, treatment, and outcomes is limited. This review comprised 61 neonates across 33 reports. Thrombosis occurred in 98% and 42% involved a central venous catheter. Diagnosis was mainly established by ultrasound in 82%. Therapeutically, heparin was employed in 36% and thrombolysis in 18% of the cases. The overall mortality was 23%. An algorithm of clinical signs, investigation, and management is presented. Well-designed prospective studies are needed to establish a concrete investigational approach to neonatal IVCS and institute safe, evidence-based treatment.

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.

Pediatric APS: State of the Art

PURPOSE OF REVIEW

The purpose of this report is to review recent research findings on APS in children and neonates.

RECENT FINDINGS

European evidence-based recommendations for diagnosis and treatment of pediatric APS has recently been published by the SHARE Initiative. Recent studies have shown a high prevalence of non-thrombotic manifestations in children with aPL, domains 4/5 specificity of 'innocent' anti-β2GPI antibodies in infants, and a higher risk for developmental delays and learning disabilities, hence, the need for neurodevelopmental monitoring in children born to mothers with APS. An International effort on creating a new diagnostic criteria for APS is underway. Pediatric APS is a rare disease with significant differences from the APS in adults. Majority of the children with persistently positive aPL do not develop thrombotic events; however, relatively higher proportion of thrombosis in children is related to aPL positivity compared to adults; this may partly be due to the absence of common pro-thrombotic "second-hit" risk factors of adults such as atherosclerosis and cigarette smoking. Diagnosis of APS in children may be delayed or missed when adult APS criteria are used, because in pediatric APS, non-thrombotic clinical manifestations such as thrombocytopenia, hemolytic anemia, and neurological disorders such as migraine, epilepsy, and chorea may precede thrombotic manifestations. Around 20% of the children initially diagnosed with primary APS eventually develop SLE. Neonatal APS is rare; however, the offspring of mothers with APS are at a higher risk for developmental delays and learning disabilities; prematurity and IUGR may increase this risk. Regular assessment of neurodevelopmental status of these children should be performed. Thrombosis is a rare event in the offspring of mothers with APS; anticoagulation of such infants is not recommended. An international effort to create a new diagnostic criteria for APS is underway.

Procoagulant imbalance in preterm neonates detected by thrombin generation procedures

Preterm newborns are considered at risk of acquired coagulopathy and are often prophylactically infused with fresh frozen plasma (FFP) even in the absence of bleeding. To assess the coagulation asset of preterm neonates and the biological plausibility of such infusions, we investigated at birth 87 very low birth weight (≤1500 g) preterm (gestational age <35 weeks) newborns and 64 full-term newborns. Preterm neonates were also investigated at different time-points up to 30 days after birth. Plasma from preterm and full-term neonates were subjected to the measurement of prothrombin and activated partial thromboplastin time (PT, APTT), pro- and anticoagulant factors as well as to thrombin-generation procedures both with and without thrombomodulin. PT and APTT of preterm newborns were longer than those of full-term neonates [PT: 15.9 s (11.7-51.2)-vs-13.8 (11.0-25.4), p < 0.001. APTT: 59.0 (37.8-97.5)-vs- 47.3 (28.1-71.9), p < 0.001] and tended to shortening after 30 days from birth. Thrombin-generation defined as endogenous thrombin potential (ETP) was increased in preterm as compared to full-term neonates at birth [1322 nM·min (474-2384)-vs-1006 (697-1612), p < 0.001] and did not change appreciably over time up to 30 days from birth. In conclusion, plasma from preterm neonates displays a procoagulant imbalance at birth as shown by increasing ETP, despite the prolongation of PT and APTT. The results define preterm newborns as having hyper- rather than hypo-coagulability and argue against the infusion of FFP when given prophylactically and/or based solely on prolongation of PT or APTT.

Development of venous thrombi in a pediatric population of intestinal failure

BACKGROUND/PURPOSE

Although pediatric intestinal failure (IF) is now a survivable diagnosis, children are still at risk for complications. Loss of venous access persists as a leading indication for intestinal transplantation. The goal of this study was to identify risk factors for loss of venous access in a pediatric intestinal failure population on long-term PN.

METHODS

We identified all patients who were PN dependent.

RESULTS

Patients that developed venous thrombosis had significantly more lines placed in the first 2 years of life compared to those who did not develop thrombosis. Multivariate regression analysis revealed that diagnosis (NEC and gastroschisis) and parental education were significant predictors of venous thrombosis.

CONCLUSION

By identifying potential risk factors for thrombus development, interventions can be developed to improve the overall outcome in pediatric IF patients.

TYPE OF STUDY

Diagnostic LEVEL OF EVIDENCE: III.

Neonatal thrombocytopenia: Thrombin generation in presence of reduced platelet counts and effects of rFVIIa in cord blood

Healthy neonates exhibit a well-functioning haemostatic system despite peculiarities regarding composition of clotting factors and inhibitors as well as impaired platelet aggregation. Thrombocytopenia and severe bleeding events are feared in sick infants. Recombinant factor VIIa (rFVIIa) is a haemostatic agent used as a last resort in neonates with refractory bleedings. Aim of this study was to investigate in-vitro (i) changes in thrombin generation with different platelet counts, (ii) effects of rFVIIa under conditions of thrombocytopenia and (iii) potentially differing dose-response of rFVIIa in cord blood as a surrogate for neonatal blood compared to adult blood. Thrombin generation parameters were observed in cord blood plasma and adult plasma with various platelet counts, with or without addition of rFVIIa, respectively. Low platelet counts did not influence thrombin generation in cord blood in contrast to adult blood. RFVIIa primarily affected lag time throughout all platelet concentrations. Interestingly, peak height was reduced exclusively in cord blood plasma after addition of rFVIIa. No significant differences regarding dose-response were observed between cord blood and adult blood. In contrast to adult blood, thrombocytopenia in cord blood does not significantly influence thrombin generation. Even at very low platelet counts there is enough negatively charged surface to support rFVIIa action in plasma from cord blood and adult blood in-vitro.

Effectiveness and Safety of 4-factor Prothrombin Complex Concentrate (4PCC) in Neonates With Intractable Bleeding or Severe Coagulation Disturbances: A Retrospective Study of 37 Cases

BACKGROUND

To date, clinical experience with prothrombin complex concentrate (PCC) in the neonatal population has been limited.

AIM

The objective of this study was to describe our experience regarding the effectiveness and safety of PCC administration in newborns with severe bleeding or coagulopathy resistant to conventional therapy.

METHODOLOGY

We retrospectively analyzed data from 37 neonates with intractable bleeding or severe coagulation disturbances. All patients received intravenous bolus administration of 20 or 30 u/kg of PCC per dose, as a rescue procedure.

RESULTS

Hemostasis was achieved in the majority of neonates and we observed statistically significant improvement in prothrombin time, international normalized ratio, and activated partial thromboplastin time (P<0.001, P=0.044, P<0.001, respectively). Thirteen neonates survived, whereas 24 did not survive. In those who survived, PCC had been administered earlier (<24 h) in the disease process compared with those who died (P=0.043). Neither acute adverse events nor thromboembolic complications were observed in all neonates.

CONCLUSIONS

In our study, PCC seemed to be a safe and effective intervention for hemostasis and early intervention was more effective as a rescue therapy, without any adverse event. Further prospective controlled trials are required to determine optimal dose and timing of PCC administration in neonates.

Diagnostic challenge of the newborn patients with heritable protein C deficiency

ABSTARCT

OBJECTIVE: The diagnosis of neonatal-onset protein C (PC) deficiency is challenging. This study aimed to establish the neonatal screening of heritable PC deficiency in Japan.

STUDY DESIGN

We determined the changes in plasma activity levels of PC and protein S (PS) in healthy neonates, and studied newborn patients with PROC mutation in the Japanese registry.

RESULT

Physiological PC and PS levels increased with wide range. The PC/PS-activity ratios converged after birth. The PC/PS-activity ratios of 19 patients with biallelic mutations, but not, 9 with monoallelic mutation, were lower than those of 13 without mutation. The logistic regression analyses established a formula including two significant variables of PC activity (cut-off < 10%, odds ratio = 30.0) and PC/PS-activity ratio (cut-off < 0.35, odds ratio = 22.7), with 93% sensitivity and 44% specificity for determining patients with mutation(s).

CONCLUSION

The PC/PS-activity ratio is an effective parameter for the genetic screening of neonatal-onset PC-deficiency in Japanese population.

Management of Extremity Venous Thrombosis in Neonates and Infants: An Experience From a Resource Challenged Setting

We aimed to evaluate the outcome of different treatment modalities for extremity venous thrombosis (VT) in neonates and infants, highlighting the current debate on their best tool of management. This retrospective study took place over a 9-year period from January 2009 to December 2017. All treated patients were referred to the vascular and pediatric surgery departments from the neonatal intensive care unit. All patients underwent a thorough history-taking as well as general clinical and local examination of the affected limb. Patients were divided into 2 groups: group I included those who underwent a conservative treated with the sole administration of unfractionated heparin (UFH), whereas group II included those who were treated with UFH plus warfarin. Sixty-three patients were included in this study. They were 36 males and 27 females. Their age ranged from 3 to 302 days. Forty-one (65%) patients had VT in the upper limb, whereas the remaining 22 (35%) had lower extremity VT. The success rate of the nonsurgical treatment was accomplished in 81% of patients. The remaining 19% underwent limb severing, due to established gangrene. The Kaplan-Meier survival method revealed a highly significant increase in both mean and median survival times in those groups treated with heparin and warfarin compared to heparin-only group ( P < .001). Nonoperative treatment with anticoagulation or observation (ie, wait-and-see policy) alone may be an easily applicable, effective, and a safe modality for management of VT in neonates and infants, especially in developing countries with poor or highly challenged resource settings.