DESCRIPTION (provided by applicant): There has been a dramatic increase in the rate of pediatric venous thromboembolism (VTE). The concept of VTE in children has now evolved from that of an acute event to one of chronic disease. VTE leads to tremendous burdens, especially on physical functioning, due either to antithrombotic therapy or the development of poor outcomes over time. The major poor outcomes after VTE include a chronic, life-long syndrome of pain, cramping and swelling of the affected extremity called the postthrombotic syndrome (PTS), recurrent VTE and other debilitating post thrombotic sequelae including, but not limited to pulmonary hypertension. Although early diagnosis of VTE complications can improve health outcomes, it is not known currently how to identify children at risk of these outcomes. The capacity of a given individual to generate thrombin called thrombin generation potential (TGP) and, dissolve the clot called fibrinolysis can be measured in plasma by global coagulation assays. Global coagulation assays capture coagulation in its entirety and provide information from clot initiation through clot dissolution. These assays may help identify children at risk of poor outcomes after VTE. Even if global coagulation assessment is more likely to identify those at risk of poor outcomes, it is unlikely that biomarker profiling or pharmacology alone will be sufficient to eradicate post VTE disease. Indeed, decreased exercise and activity levels are already known to contribute to the risk for PTS in adults. Maintaining adherence to a post VTE-activity regimen is likely to be a problem, though. Emerging technological tools might be leveraged to more carefully track activity and increase incentive for such activity in children. The paucity of data and the poor understanding of the biology behind these outcomes holds several important implications: 1) providers caring for pediatric patients with VTE (pediatric hematologists/oncologists) and those following them after diagnosis (pediatricians and family physicians) are poorly informed about the gravity of these complications; 2) standardized approaches to testing and long term follow-up are missing; and 3) expertise and/or resources to carry out well-conceived prospective studies to define robust, predictive biomarkers and effective treatment strategies are rare. This proposal describes a career development plan that will prepare the candidate to become a successful independent investigator and attain her long-term career goal of becoming a national leader in pediatric thrombosis. Her immediate goals include testing the conceptual innovation of looking at coagulation globally to predict poor VTE outcomes in children. She will also investigate the feasibility of using a fitness tracker to facilitate adherence to an activity regimen in children with deep venous thrombosis (DVT. To meet these goals, she has proposed a career development plan that integrates didactic coursework, parti...