Physical Activity in Children at Risk of Post-thrombotic Sequelae (PACT) (PACT)

Feasibility criteria for rate of study eligibility met when assessed to be ≥ 30% INCLUSION CRITERIA: 1.) Age 7-21 years 2.)2. A radiologically confirmed, acute, proximal (iliofemoral and femoropopliteal) first lower extremity DVT and/or confirmed, acute pulmonary embolism (unilateral or bilateral) 3.) 12 weeks (±2 weeks) after starting anticoagulation 4.) Out-patient ambulatory status

Feasibility criteria for rate of consent was assessed to be ≥ 30% at baseline INCLUSION CRITERIA: 1.) Age 7-21 years 2.)2. A radiologically confirmed, acute, proximal (iliofemoral and femoropopliteal) first lower extremity DVT and/or confirmed, acute pulmonary embolism (unilateral or bilateral) 3.) 12 weeks (±2 weeks) after starting anticoagulation 4.) Out-patient ambulatory status

Adherence in the physical activity group is calculated based on the number of participants who complied with the target weekly goal or activity prescription during the "active" 8-week period.

The Godin-Shephard Leisure-Time Physical Activity Questionnaire was used to quantify physical activity levels. Individuals reporting moderate-to-strenuous activity levels ≥24 were classified as active (better outcome), whereas individuals reporting moderate-to-strenuous activity levels ≤23 were classified were insufficiently active (worse outcome).

The Godin-Shephard Leisure-Time Physical Activity Questionnaire was used to quantify physical activity levels. Individuals reporting moderate-to-strenuous activity levels ≥24 were classified as active (better outcome), whereas individuals reporting moderate-to-strenuous activity levels ≤23 were classified were insufficiently active (worse outcome).

The Godin-Shephard Leisure-Time Physical Activity Questionnaire was used to quantify physical activity levels. Individuals reporting moderate-to-strenuous activity levels ≥24 were classified as active (better outcome), whereas individuals reporting moderate-to-strenuous activity levels ≤23 were classified were insufficiently active (worse outcome).

Feasibility criteria is met when assessed to be ≥ 80%. This includes the number of subjects who successfully completed the trial.

Change in PTS biomarkers from baseline to post intervention of increased physical activity measured by coagulation activation marker D-dimer.

Change in PTS biomarkers from baseline to post intervention of increased physical activity measured by the coagulation activation marker FVIII

Change in PTS biomarkers from baseline to post intervention of increased physical activity measured by inflammation marker C-reactive protein (CRP) using a latex-enhanced immunoturbidimetric assay.

Change in PTS biomarkers from baseline to post intervention of increased physical activity measured by endogenous thrombin potential using calibrated automated thrombogram (CAT). CAT is a routine test that measures hyper- and hypocoagulability.

Change in PTS biomarkers from baseline to post intervention of increased physical activity measured by thrombin generation assay using calibrated automated thrombogram (CAT). CAT is a routine test that measures hyper- and hypocoagulability.

Percent Change in Fibrinolysis Biomarker from baseline to post intervention of increased physical activity is measured by thromboelastography (TEG). TEG is often used to predict bleeding and diagnose various bleeding disorders. Lysis 30% and Lysis 60% are measurements of percent amplitude reduction 30 and 60 minutes after maximum amplitude, respectively, on thromboelastography. Decreased clotting ability (negative value) = better outcome Increased clotting ability (positive value)= worse outcome

Change in Quality of Life from baseline to post intervention of increased physical activity assessed by PedsQL instrument. It consists of structured interview with the parents and the child with 23 items divided among 4 sub-scales to assess function in 4 domains: Physical; Emotional; social; and School. Each item is a statement of a problem, which the subject rates in severity from 0-4, indicating a problem never occurs (score of 0) to almost always occurs (score of 4). Items are reversed scored and linearly transformed to a 0-100 scale as follows: 0=100, 1=75, 2=50,3=25,4=0, with higher scores indicating better health related QoL. The positive change from baseline to 6 months correspond to better quality of life.