An International Survey on the Assessment of Screening and Treatment of Thrombosis Complications in Pediatrics (ASTRO-Kids): communication from the ISTH SSC Subcommittee on Pediatric and Neonatal Thrombosis and Hemostasis.

Long-term follow-up of children with venous thromboembolism (VTE) is necessary to diagnose postthrombotic sequelae, although current practice is not standardized. The ASTRO-Kids international survey investigated the current practices among pediatric thrombosis providers for extremity and nonextremity VTE following acute treatment. The International Society on Thrombosis and Haemostasis Scientific and Standardization Committee Subcommittee on Pediatric and Neonatal Thrombosis and Haemostasis created and disseminated a 24-question survey between January 2024 and July 2024. We collected information on respondent treatment centers and practices on monitoring, diagnosis, and treatment of postthrombotic sequelae following extremity and nonextremity thrombosis, stratified by the neonatal and nonneonatal age groups. One hundred fifteen pediatric thrombosis providers participated in the survey. Over half (53%; n = 61) were from North America. Overall, 35% (n = 40) and 15% (n = 5) followed nonneonates and neonates, respectively, for postthrombotic syndrome beyond 2 years from extremity thrombosis diagnosis. Long-term follow-up of nonextremity thromboses beyond 2 years from acute thrombosis was performed by less than 35% of respondents (25%-31% for nonneonates and 18%-27% for neonates). A dedicated postthrombotic syndrome clinic was present in the centers of 32% (n = 35) of respondents; physical therapy (48%, n = 62) and interventional radiology (47%, n = 60) were the most common subspecialties to participate in the long-term care of these patients. Long-term follow-up for pediatric VTE is variable. These findings underscore the imperative for globally applicable guidance that accommodates diverse practice settings, harmonize the management of thrombosis sequelae in children, and catalyze collaboration to advance research in the field.