International pediatric thrombosis network to advance pediatric thrombosis research: Communication from the ISTH SSC subcommittee on pediatric and neonatal thrombosis and hemostasis

The Use of DOACs in Pediatrics: Current Therapeutic and Prophylactic Indications, Cardiac Indications, and Real-World Evidence-A Review

Based on clinical trials that have been conducted and published in the past decade, direct oral anticoagulants (DOACs) are increasingly being used as an antithrombotic treatment in children with venous thrombotic events and to prevent thrombotic events in children at risk. In this review, current indications and standards for the initiation of DOACs in children are summarized for the treatment of venous thrombotic events and for the primary and secondary prevention in children at risk of developing thromboses based on the published randomized controlled trials (RCT). Similarly, indications for DOACs in children with underlying cardiac disease are portrayed based on RCT findings. Lastly, available real-world data are reviewed for the use of DOACs in pediatric patients with a focus on patients at higher risk of both thrombosis and bleeding who were primarily excluded from the RCTs. DOACs contribute largely to the evolving individualization of care of thrombotic events in children, but at-risk patient populations remain underrepresented regarding DOAC experience, such as preterm infants, and children with severe renal or hepatic disease. Real-world data from observational studies and registries will continue to be necessary to establish DOACs' effectiveness and safety in children in everyday clinical use.

Results of a multinational survey on the diagnostic and management practices of catheter-related arterial thrombosis in children and neonates: communication from the ISTH SSC Subcommittee on Pediatric and Neonatal Thrombosis and Hemostasis

BACKGROUND

Arterial thrombosis is increasingly recognized in children and is most commonly related to the presence of an arterial catheter. Diagnosis and treatment of arterial thrombosis in children varies widely and consists of commonly available anticoagulants and antiplatelet drugs. No evidence-based guidelines exist for management strategies for catheter-related arterial thrombosis (CAT).

OBJECTIVES

To understand pediatric hematologists' current practices and opinions in the management of CAT in children and neonates.

METHODS

A multinational survey on diagnostic and management practices from experts and practitioners in the field was conducted by means of a questionnaire with general questions and specific clinical CAT scenarios in regard to umbilical arterial catheters, extremity indwelling arterial catheters, and cardiac catheterization.

RESULTS

Of 54 complete survey responses, there was agreement that Doppler ultrasound is the preferred diagnostic modality to identify CAT and unfractionated heparin and low-molecular-weight heparin are the preferred antithrombotic treatments, while thrombolysis/thrombectomy is used in life-/limb-threatening CAT, long-term follow-up is necessary to detect adverse outcomes, and generally no thrombophilia testing is indicated. There was considerable heterogeneity in treatment indications on when to start antithrombotic treatment, treatment duration, timepoint of catheter removal, and length of follow-up.

CONCLUSION

These results highlight some congruency, but also considerable heterogeneity, in the management practices of CAT. Based on these findings, an international guidance document is necessary to harmonize management practices and further clinical investigations of CAT.

Update on Cancer-Associated Venous Thromboembolism in Children

Children with cancer have an increased risk for venous thromboembolic events (VTEs) compared to the healthy pediatric population. VTE rates in children with cancer vary among cancer types. Other VTE risk factors include central venous catheters and cancer therapies. VTE diagnosis relies on objective radiological imaging, and management to this date typically involves anticoagulant therapy. Low-molecular-weight heparins (LMWHs) are the most common choice. Evidence for primary VTE prevention is conflicting, and antithrombin replacement, LMWH, or apixaban have been studied. Recently, direct oral anticoagulants such as rivaroxaban or dabigatran were investigated for VTE treatment, showing promise in efficacy and safety. However, bleeding risks in this population need careful consideration, especially periprocedurally or with treatment-related thrombocytopenia. Prediction tools for VTE require adaptation for pediatric cancer patients. Progress in understanding and managing VTE in children with cancer is significant, with ongoing trials and real-world data contributing to improved strategies.

Non-criteria antiphospholipid antibodies and calprotectin as potential biomarkers in pediatric antiphospholipid syndrome

Our study aimed to evaluate the presence, clinical associations, and potential mechanistic roles of non-criteria antiphospholipid antibodies (aPL) and circulating calprotectin, a highly stable marker of neutrophil extracellular trap release (NETosis), in pediatric APS patients. We found that 79% of pediatric APS patients had at least one non-criteria aPL at moderate-to-high titer. Univariate logistic regression demonstrated that positive anti-beta-2 glycoprotein I domain 1 (anti-D1) IgG (p = 0.008), anti-phosphatidylserine/prothrombin (aPS/PT) IgG (p < 0.001), and aPS/PT IgM (p < 0.001) were significantly associated with venous thrombosis. Positive anti-D1 IgG (p < 0.001), aPS/PT IgG (p < 0.001), and aPS/PT IgM (p = 0.001) were also associated with non-thrombotic manifestations of APS, such as thrombocytopenia. Increased levels of calprotectin were detected in children with APS. Calprotectin correlated positively with absolute neutrophil count (r = 0.63, p = 0.008) and negatively with platelet count (r = -0.59, p = 0.015). Mechanistically, plasma from pediatric APS patients with high calprotectin levels impaired platelet viability in a dose-dependent manner.

The role of coagulation factors VIII, IX and XI in the prediction and mediation of recurrent thrombotic events in children with non-central venous catheter deep vein thrombosis

BACKGROUND

The role of elevated coagulation factors VIII (FVIII), FIX, FXI for the prediction of recurrent thrombotic events in children after an index non-central venous catheter (non-CVC) related deep vein thrombosis (DVT) remains unclear.

OBJECTIVE

This study investigates the predictive role of FVIII, FIX, and FXI for recurrent thrombosis in children with index non-CVC DVTs, and the mediation effect of FVIII on chronic inflammation and recurrent thrombosis.

METHODS

Children aged 0-18 years diagnosed with an index non-CVC related DVT (1993-2020) were included in this single-center retrospective cohort study. Plasma levels of FVIII, FIX, FXI were measured cross-sectionally ≥30 days after the acute DVT. The association between the continuous variables FVIII, FIX, FXI and thrombosis recurrence was investigated using uni- and multivariable logistic regression, adjusting for age, sex, and chronic inflammation. Mediation analysis assessed the role of FVIII as a mediator between chronic inflammation and recurrent thrombosis. Ethics approval was obtained.

RESULTS

A total of 139 children with an index non-CVC related DVT were included. Thirty-eight (27 %) had a recurrent thrombosis at a median of 237 days (P25-P75 65-657 days) after the index DVT. In uni- and multivariable-analysis, FVIII, FIX or FXI did not predict thrombosis recurrence; However, chronic inflammation was an independent predictor. There was no evidence that FVIII mediated the effect of chronic inflammation on thrombosis recurrence.

CONCLUSION

We found no evidence that elevated FVIII, FIX or FXI predicted thrombosis recurrence, or evidence of a mediating role of FVIII. Underlying chronic inflammation predicted venous recurrent thrombotic events in this cohort.

Anticoagulation of pediatric patients with venous thromboembolism in 2023

Venous thromboembolism (VTE) is a rare and heterozygous disease in children. Management of VTE in children is complicated by age-related differences in epidemiology, recurrent VTE and bleeding risk, hemostatic proteins and pharmacokinetics of anticoagulants. Recently, the choice of anticoagulation has expanded to oral factor IIa and Xa inhibitors, which have been authorized for children for treatment of acute VTE and extended secondary prevention. These drugs have several properties that make them extremely suitable for use in children, including oral administration, antithrombin independence, less interactions with food and drugs and no need for monitoring. Unfortunately, the phase 3 studies had many exclusion criteria, and only a few term neonates and infants were included in these studies. Additional real-world data is needed to make evidence-based recommendations in these age and patient groups, as well.

How I treat pediatric venous thromboembolism in the DOAC era

ABSTRACT

The direct oral anticoagulants (DOACs) rivaroxaban and dabigatran are newly licensed for the treatment and prevention of venous thromboembolism (VTE) in children and mark a renaissance in pediatric anticoagulation management. They provide a convenient option over standard-of-care anticoagulants (heparins, fondaparinux, and vitamin K antagonists) because of their oral route of administration, child-friendly formulations, and significant reduction in monitoring. However, limitations related to therapeutic monitoring when needed and the lack of approved reversal agents for DOACs in children raise some safety concerns. There is accumulating experience of safety and efficacy of DOACs in adults for a broad scope of indications; however, the cumulative experience of using DOACs in pediatrics, specifically for those with coexisting chronic illnesses, is sparse. Consequently, clinicians must often rely on their experience for treating VTE and extrapolate from data in adults while using DOACs in children. In this article, the authors share their experience of managing 4 scenarios that hematologists are likely to encounter in their day-to-day practice. Topics addressed include (1) appropriateness of indication; (2) use for special populations of children; (3) considerations for laboratory monitoring; (4) transition between anticoagulants; (5) major drug interactions; (6) perioperative management; and (7) anticoagulation reversal.

Pediatric arterial thrombosis: A single-institution cohort study of patient characteristics and thrombosis outcomes

BACKGROUND

Arterial thrombosis (AT) is an increasingly recognized complication in pediatrics. Consensus clinical practice guidelines suggest immediate removal of the indwelling arterial catheter and a short course (5-7 days) of anticoagulation. The optimal duration and modality of antithrombotic therapy in children are yet to be determined.

AIMS

Describe treatment patterns and outcomes in pediatric patients with AT and explore predictors for complete thrombus resolution or long-term complications.

METHODS

Single-institution retrospective study. Patients were identified by ICD-9 and ICD-10 codes for the diagnosis of AT or reports of AT on ultrasound from January 1, 2012, to October 1, 2022. Descriptive and logistic regression analyses were used.

RESULTS

101 patients were included. The median age was 2.2 months. The most common underlying diagnoses were congenital heart disease (39.6%) and infection (22.8%). A majority of patients had symptomatic thrombosis in an extremity, and 78% were catheter-associated. 81% of patients received anticoagulation with a median duration of 35 days. Out of the 70 patients who were treated with anticoagulation alone and had a follow-up imaging, 70% had complete resolution after 90 days of anticoagulation. No clear predictors of complete resolution were identified. Eighteen patients had long-term sequelae secondary to arterial insufficiency. Those with infection-associated AT were more likely to have long-term complications. The major and clinically relevant non-major bleeding rate was 11%.

CONCLUSION

Duration of anticoagulation was widely variable, and 70% of patients achieved complete resolution by 90 days of anticoagulation. A significant proportion of patients developed long-term sequelae secondary to arterial insufficiency. Sepsis/infection at the time of diagnosis with AT was more likely to be associated with long-term complications.

Spontaneously disappearing right atrial mass in a preterm infant: a case report

Background

There is currently a lack of evidence-based guidelines regarding ideal management of a neonate, specifically a preterm, with thrombo-embolus. There are no clear guidelines as to the time-frame of spontaneous resolution of a thrombo-embolus.

Case summary

A large pedunculated right atrial mass was identified on a clinician-performed cardiac ultrasound in a preterm neonate. The mass was smaller than half of the atrial size and was not causing obstruction. The mass disappeared spontaneously within 6 days and was retrospectively presumed to have been a thrombus. The neonate remained asymptomatic with no signs suggesting that the mass may have embolized.

Discussion

In this case of an incidentally identified asymptomatic intracardiac mass in a preterm infant, presumed to be a thrombus, our conservative 'wait and watch' approach was not associated with any adverse pulmonary or systemic effects.

The new Italian registry of infantile thrombosis (RITI): A reflection on its journey, challenges and pitfalls

Introduction

Thrombotic events in neonates and children represent a rare although severe occurrence in view of the associated risk of mortality and sequelae. Quality evidence is limited in this field, and registry studies provide an essential base for research. The aim of this paper is to present the new Italian Registry of Infantile Thrombosis (RITI), set it into the scene of international thrombosis and stroke registries, and provide some insight on the challenges associated with registry management.

Methods

We present the detailed structure and content of the new RITI registry, a brief overview of its main data, and a reflection on its features, pitfalls and the main challenges related to its management.

Results

The RITI, initially started in 2007 and officially re-launched in 2017 after structural modifications, is a non-interventional retrospective and prospective registry study collecting data on neonatal and pediatric patients (0-18 years) who experienced a systemic or cerebral thrombotic event in Italy. The RITI is managed by a multidisciplinary team with expertise in pediatric thrombosis, and participation is open to all Italian physicians, on a voluntary basis. The overall aim of the registry is to acquire new evidence to better characterize the population of children with thrombotic events and improve their management and outcome. 48 Italian pediatric and intensive care units are actively involved in the RITI, including 85 medical doctors from 16 Italian regions. A total of 1,001 neonates and children affected by cerebral or systemic thrombosis have been enrolled.

Discussion

The RITI is one of the largest available European registries of neonatal and pediatric thrombosis. National registries like the RITI represent a model for the study of rare conditions based on multidisciplinary and multicenter collaboration, aimed at overcoming the limitations due to small populations of patients, and creating a network of experts for patient referral and continuous education. Moreover, registry studies have a pivotal role in the research on pediatric thrombosis, due to the limited feasibility of high-quality studies. In our experience, the main critical stages, pitfalls and challenges in registry management include adequate registry designing, diffusion, data completeness and quality control.

The Incidence of Thromboembolic Events During Hospitalizations Following Surgical Resection of Lower Extremity Sarcomas in Children: Utilizing the Pediatric Health Information System Database

BACKGROUND

Venous thromboembolism (VTE) is a frequent occurrence during treatment for adults with sarcoma. The incidence and underlying risk factors of postsurgical VTE in children and adolescents undergoing resection of sarcoma are unknown.

METHODS

Using International Classification of Disease revision-9 diagnostic and procedure codes, the Pediatric Health Information System database was queried for patients aged 18 years and younger, discharged from 2004 to 2015 with a diagnosis of lower extremity malignant neoplasm who had a tumor resection or amputation performed during the encounter. Malignant neoplasms of the pelvic bones and soft tissues were categorized as "pelvis tumors", whereas malignant neoplasms of bone and soft tissues of the lower limbs were categorized as "lower limb tumors". Hospitalizations were evaluated for the occurrence of VTE. Demographic characteristics (age at admission, sex, race, and race/ethnicity) and incidence of VTE were reported.

RESULTS

There were 2400 patients identified. Of these, 19 experienced VTE (0.79%) during their surgical hospitalization encounter. By anatomic group, the rate of VTE was 1.4% (CI: 0.5%-3.2%) for tumors in the pelvis and 0.6% (CI: 0.3%-1.0%) in lower limb tumors. Categorizing by age, the incidence of VTE was 1.2% in patients aged zero to 5, 0.3% in patients 6 to 13, and 1.2% in patients 14 to 18 years old. (Table 1). The extremely low rate of VTE occurrence precluded further analysis of risk factors.

CONCLUSIONS

In this analysis, postsurgical VTE during hospitalization after pelvic and lower extremity sarcoma resection was an uncommon event in children and adolescents. There seemed to be an increased incidence of postsurgical VTE in pelvic tumors when compared with lower limb tumors, however, the rarity of all events precluded formal statistical analysis. A more robust data set would be required to determine if there are subsets of children and adolescents with sarcoma at higher risk of VTE that could benefit from thromboprophylaxis in the postoperative setting.

LEVEL OF EVIDENCE

Level II.

Just DOAC: Use of direct-acting oral anticoagulants in pediatrics

PURPOSE

The aim of this article is to provide an overview of the current literature for direct-acting oral anticoagulant (DOAC) use in pediatric patients and summarize ongoing trials.

SUMMARY

In treatment of venous thromboembolism (VTE) in pediatric patients, evidence supports use of both dabigatran and rivaroxaban. Dabigatran has been shown to be noninferior to standard of care (SOC) in terms of efficacy, with similar bleeding rates. Similarly, treatment with rivaroxaban in children with acute VTE resulted in a low recurrence risk and reduced thrombotic burden, without increased risk of bleeding, compared to SOC. Treatment of pediatric cerebral venous thrombosis as well as central venous catheter-related VTE with rivaroxaban appeared to be both safe and efficacious and similar to that with SOC. Dabigatran also has a favorable safety profile for prevention of VTE, and rivaroxaban has a favorable safety profile for VTE prevention in children with congenital heart disease. Many studies with several different DOACs are ongoing to evaluate both safety and efficacy in unique patient populations, as well as VTE prevention.

CONCLUSION

The literature regarding pediatric VTE treatment and prophylaxis is growing, but the need for evidence-based pediatric guidelines remains. Additional long-term, postauthorization studies are warranted to further elucidate safety and efficacy in clinical scenarios excluded in clinical trials. Additional data on safety, efficacy, and dosing strategies for reversal agents are also necessary, especially as the use of DOACs becomes more common in the pediatric population.

Real world experience of efficacy and safety of rivaroxaban in paediatric venous thromboembolism

INTRODUCTION

Paediatric clinical practice for treatment of venous thromboembolism (VTE) is based on extrapolation from adult trials with minimal data on anticoagulation efficacy and safety in children. Based on EINSTEIN-Jr clinical trial data, rivaroxaban was approved to treat VTE and prevent its recurrence in children of all ages.

AIM

To report the safety and efficacy of rivaroxaban use in paediatric VTE and to present real-world data, specifically about very young children.

METHODS

We conducted a retrospective observational study at Birmingham Children's Hospital. Data were collected from patients <16 years old who received rivaroxaban after its licensure in the period between March 2021 and June 2022.

RESULTS

Rivaroxaban was used for treatment of acute VTE in 64 patients. Thrombosis was CVC-related in 26 patients, unprovoked in 3, while the rest had one or more risk factors for VTE. Safety and efficacy of rivaroxaban were assessed in 52 patients after excluding patients who were on current rivaroxaban treatment and those who were lost to follow up or stopped rivaroxaban due to intolerance. No bleeding events were reported, and recurrence of thrombosis occurred in only 3.6 %. About 35 % had normalised re-imaging, 40.3 % improved, 9.6 % were unchanged and 11.5 % stopped rivaroxaban without re-imaging. Rivaroxaban was used for secondary VTE prophylaxis in 6 patients in our cohort with no recurrence of thrombosis or bleeding reports.

CONCLUSIONS

Our real-world experience confirmed that rivaroxaban was well tolerated, effective and safe. Further real-world data and observational studies are essential to investigate the use of rivaroxaban among different risk groups.

Recommendations for standardized definitions, clinical assessment, and future research in pediatric clinically unsuspected venous thromboembolism: Communication from the ISTH SSC subcommittee on pediatric and neonatal thrombosis and hemostasis

Clinically unsuspected venous thromboembolism (VTE) in children is defined as a VTE diagnosed via imaging test performed for surveillance (i.e., with an intent to identify clinically silent VTEs) or incidentally found (most often via imaging performed for evaluation of regional pathology unrelated to VTE) in the absence of any VTE-associated signs or symptoms. Our understanding of the clinical significance of these events in children is limited by a paucity of data on the epidemiology and outcomes of this complication. There is an urgent need for further research in this area to inform optimal management. Recognizing this knowledge gap, this Task Force has previously published a systematic review of the literature in this topic. We now provide guidance recommendations for standardization of definitions and identify future research needs on clinically unsuspected VTE in children. These recommendations will serve to enhance the quantity and quality of evidence on the topic and facilitate the design and execution of cooperative observational studies, and interventional trials of risk-stratified management approaches aimed at preventing and optimizing long-term outcomes of clinically unsuspected VTE in children.

Results of an international survey on adherence with anticoagulation in children, adolescents, and young adults: Communication from the ISTH SSC Subcommittee on Pediatric and Neonatal Thrombosis and Hemostasis

BACKGROUND

The ISTH Scientific and Standardization Committee (SSC) Subcommittee on Pediatric/Neonatal Thrombosis and Hemostasis convened a working group on medication adherence to begin to understand the current state of clinical practice to inform priority areas for efforts to improve adherence for children, and adolescents and young adults (AYA) prescribed anticoagulants.

OBJECTIVES

We sought to survey an international group of clinicians involved in anticoagulation management in children and/or AYA about perceptions of medication on health outcomes, clinical practice related to medication adherence, and barriers to assessing and improving medication adherence.

METHODS

Clinicians involved in anticoagulation management in children and/or AYA were surveyed via REDCap® . Descriptive statistics were used to summarize demographic and clinical characteristics and responses to multiple choice and Likert-type questions. Free-text answers were coded based on the Behaviour Change Technique Taxonomy and the Expert Recommendations for Implement Change project.

RESULTS AND CONCLUSIONS

There were 200 participants, 90% of whom were pediatric hematology/oncology physicians. Based on the results, which demonstrate that clinicians are concerned about impact of poor medication adherence and have limited resources to identify and improve adherence, the working group has identified next steps to further understand impact of medication adherence on anticoagulation-related health outcomes, address the need for validated measures to assess medication adherence for all anticoagulants prescribed to this population, and develop an intervention and implementation research agenda to improve outcomes.

Clinical Efficacy of Soluble Thrombomodulin, Tissue Plasminogen Activator Inhibitor complex, Thrombin-Antithrombin complex,α2-Plasmininhibitor-Plasmin complex in Pediatric Sepsis

Objective

To investigated the clinical efficacy of Soluble thrombomodulin (sTM), tissue plasminogen activator inhibitor complex (t-PAI·C),thrombin-antithrombin complex (TAT),α2-plasmininhibitor-plasmin complex (PIC) in pediatric sepsis and pediatrics sepsis-induced coagulopathy (pSIC).

Methods

We prospectively collected patient data with sepsis diagnosed in the PICU of Shanghai Children's Medical Center from June 2019 to June 2021. sTM,t-PAI·C, TAT,PIC and classical coagulation laboratory tests (CCTs) were evaluated on the day of sepsis diagnosis.

Results

Fifty-nine children were enrolled, There were significant differences in t-PAI·C (P = 0.001), Plt (P < 0.001), PT (P < 0.001), INR (P < 0.001), aPTT (P < 0.001), and TT (P = 0.048) between the pSIC and non-pSIC groups, logistic regression analysis showed that Plt (P = 0.032) was an independent risk factor for pSIC. Logistic regression analysis showed that sTM (P = 0.007) and Plt (P = 0.016) were independent risk factors for the outcome in pediatrics sepsis following discharge. The AUC of sTM combined with Plt on the mortality outcome of children with sepsis at discharge was 0.889 (95%CI: 0.781,0.956). which was better than that for PRISM III (AUC, 0.723), pSOFA (AUC, 0.764), and blood Lac (AUC, 0.717) when sepsis was diagnosed in the PICU.

Conclusions

The t-PAI·C increased in children with pSIC. The prediction of sepsis outcome using sTM combined with Plt was better than with PRISM III, pSOFA, or Lac.Further research is still needed in the future to explore the clinical value of sTM, TAT, PIC, and t-PAI·C in diagnosis and outcome of pediatrics sepsis and pSIC.

Clinical value of pediatric sepsis-induced coagulopathy score in diagnosis of sepsis-induced coagulopathy and prognosis in children

BACKGROUND

In adults, sepsis-induced coagulopathy (SIC) is diagnosed by the SIC score, known as sepsis-3. There is no pediatric SIC (pSIC) score at present.

OBJECTIVES

We proposed a pSIC scoring method and evaluated the diagnostic efficacy of the score in the diagnosis of SIC in children.

PATIENTS/METHODS

Patient data were retrospectively analyzed from Shanghai Children's Medical Center between February 2014 and January 2015. The pSIC score was modified from the SIC score. The area under ROC curve (AU-ROC) was used to compare the prognostic values of pSIC with other scores for pediatric sepsis-induced disseminated intravascular coagulation (DIC) to arrive at a 28-day outcome.

RESULTS AND CONCLUSIONS

There were 54 patients in the pSIC group and 37 in the non-pSIC group. The Kaplan-Meier survival curve analysis showed that the 28-day prognosis was better in the non-pSIC than in the pSIC group (p < .001). The AU-ROC of the pSIC score in predicting 28-day mortality in sepsis was 0.716, with the optimal cutoff value of >3 inferior to that of pediatric sequential organ failure (0.716 vs. 0.921, p < .001). The AU-ROC of pSIC in predicting nonovert DIC was 0.845 and the optimal cutoff value was >3. The AU-ROC of pSIC in predicting overt DIC was 0.901, with the best optimal cutoff value of >4. The pSIC score can be used to diagnose SIC in children, screen potential nonovert DIC, and assess the severity of sepsis, organ dysfunction, and 28-day outcome in children.