From December 7 to 10, 2024, the 66th Annual Meeting of the American Society of Hematology (ASH) took place in San Diego, bringing together hematology experts from around the globe to discuss and exchange insights on the latest advancements in the field. During the conference, Dr. Paul Monagle from the Royal Children’s Hospital, University of Melbourne, chaired a specialized session titled "ASH ISTH Clinical Practice Guidelines on Treatment of Venous Thromboembolism (VTE) in Pediatric Patients." This session explored the epidemiology, updated guidelines, and treatment recommendations for pediatric VTE. To provide a comprehensive overview, Hematology Frontier conducted an exclusive interview with Prof. Monagle. Below is a summary of the key points discussed.1. Epidemiology and Mechanisms of Pediatric VTE
Hematology Frontier: Pediatric deep vein thrombosis (VTE) is relatively rare but shows an increasing trend. Could you elaborate on the epidemiology and underlying mechanisms of pediatric VTE?
Dr. Paul Monagle: Pediatric VTE significantly differs from adult VTE. The majority of pediatric VTE cases occur in hospitalized children, with central venous catheter placement being the leading cause. Additionally, children with malignancies or those undergoing major surgeries are also at heightened risk of developing VTE. These factors induce two major changes: they alter the child’s anticoagulant capacity and influence the outcomes of thrombosis treatment. This distinction is critical and must be thoroughly understood.
Another key difference lies in treatment goals. While adult VTE treatment primarily focuses on repairing the damage and restoring the patient to their pre-disease state, pediatric treatment aims to ensure the child reaches their full potential in adulthood. This necessitates an entirely different treatment approach.
2. Updates to the Pediatric VTE Guidelines
Hematology Frontier: The guidelines for pediatric VTE have recently been updated. Could you explain the key changes?
Dr. Paul Monagle: The first set of ASH guidelines for VTE treatment was published in 2018. Since then, there has been a significant increase in clinical trial data on pediatric VTE, largely due to industry-sponsored studies on direct oral anticoagulants (DOACs), including rivaroxaban, dabigatran, and more recently, apixaban. These large-scale studies have dramatically expanded the dataset for pediatric VTE, increasing available data tenfold or more compared to 2018.
This surge in evidence necessitated updating the guidelines. Two primary reasons drove this update: the availability of more robust research data and the significant changes in the medications now available for pediatric VTE. The guidelines needed to reflect the latest research and align with current clinical practices.
3. Anticoagulation Indications and Duration for Provoked and Unprovoked Pediatric VTE
Hematology Frontier: Could you discuss the indications and duration of anticoagulant therapy for provoked and unprovoked pediatric VTE?
Dr. Paul Monagle: First, it’s essential to distinguish between symptomatic and asymptomatic deep vein thrombosis (DVT). Symptomatic DVT typically requires treatment, while the necessity of treating asymptomatic DVT is less clear.
For provoked DVT, the recent KIDS clinical trial provides valuable insights. It suggests that after six weeks of anticoagulant therapy, DVT either resolves or becomes non-obstructive, making it safe to discontinue treatment. This approach has shown similar efficacy to extended treatment in pediatric VTE cases without other risk factors—specifically, children without underlying malignancies, thrombophilia, or antiphospholipid antibodies. However, for other provoked DVT cases, treatment should extend to three months.
For unprovoked VTE in children, we recommend anticoagulation for at least 6 to 12 months. In adults, unprovoked VTE often necessitates indefinite anticoagulation. However, for children, prolonged anticoagulant therapy poses significant challenges, impacting their quality of life and mental health. Therefore, after 6 to 12 months of treatment, we advise discussing the priorities and preferences of the family to guide further decisions.
