NCT03068923COMPLETEDN/A'The TOP Study' is a prospective cohort study whose main objective is to develop better prognostic biomarkers and identify children at risk of adverse thrombotic outcomes very early in the course after an initial venous thromboembolic events (VTE). The study will compare biomarkers in children that develop poor VTE outcomes (such as recurrence, postthrombotic syndrome and post PE impairment ) after an initial VTE with those that do not develop such outcomes.
Inclusion Criteria: * Boys and girls age birth (0 years) to equal to or less than 21 years * A radiologically confirmed first venous thromboembolism episode (both extremity and non-extremity) who have completed anticoagulation therapy as per the 9th edition of the ACCP guidelines Exclusion Criteria: * Known malignancy * Pregnancy or immediate post-partum period (12 weeks after delivery) * Sickle cell disease * Known bleeding disorder