International Survey of Secondary Thromboprophylaxis Practice Patterns in Pediatrics
Authors: Wilson Hope P , Capio Rosebella , Aban Inmaculada , Lebensburger Jeffrey D. , Goldenberg Neil 
Published: November 2021

Abstract
Background/Aims: Despite the increase in clinicians identifying venous thromboembolism (VTE), we lack robust research to support clinical care guidelines. Although most children are at low risk for VTE recurrence, some have higher risks due to persistent prothrombotic risk factors. However, pediatric-specific guidance and expert consensus to recommend long-term anticoagulation in children is lacking. Understanding provider practices is a vital first step to addressing current limitations in pediatric guidelines for secondary thromboprophylaxis among such high-risk children.
Methods: We performed an international survey of pediatric thrombosis physicians to approximate the number of children with persistent prothrombotic risk factors and characterize the contemporary practice patterns for the use of secondary thromboprophylaxis. Potential participants were identified using the membership registries of three of the primary pediatric thrombosis networks: Duration of Therapy for Thrombosis in children investigators, Children's Hospital Acquired Thrombosis consortium and the VENUS pediatric thrombosis subgroup. Surveys were disseminated December 2020 through January 2021 using Qualtrics (Provo, UT).
Results: The survey was distributed electronically to 124 potential participants with 80 respondents. After exclusions, 61 complete surveys were evaluable. The majority of responders were from the United States, practicing more than 10 years at freestanding, academic pediatric hospitals with dedicated pediatric thrombosis programs. Providers were more likely to prescribe secondary thromboprophylaxis to adolescents and teenage patients as compared to infants and children. Respondents reported they were most likely to initiate chronic secondary thromboprophylaxis (therapeutic or low dose) in children with a potent thrombophilia (homozygous prothrombin or factor V Leiden mutations, protein C/S levels &lt;20%, Antithrombin levels &lt;30%), recurrent unprovoked VTE and in those with underlying inflammatory disorders (i.e., inflammatory bowel disease, systemic lupus erythematosus, sickle cell disease) and/or chronic indwelling central venous catheters.
Conclusion: Our results show variation in practice patterns but less so in areas where we have more definitive guidelines. These findings highlight the need for a multi-center prospective cohort study to determine the impact of various risk factors on recurrence rates. This will inform the design of ultimate interventional studies aimed at safely decreasing the risk of recurrent VTE in children who have persistent prothrombotic risk factors upon completion of a conventional course of anticoagulation for provoked VTE.

Disclosures
Lebensburger: Novartis: Consultancy; Bio Products Laboratory: Consultancy. Goldenberg: Novartis: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Daiici: Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Anthos: Membership on an entity's Board of Directors or advisory committees.