Table 1 Details of study visits and telephone calls

Enrollment visit

• The nurse completes the baseline form (inclusion/exclusion criteria, demographic and clinical variables, results of objective tests for DVT), PTS scale and pain scale

• The patient self-completes the QOL form

• The nurse performs the leg measurements to size the stockings

• The nurse teaches patients how to apply (using a plastic leg model) and care for stockings (handling, washing), and reinforces the importance of daily use

• Study stockings are supplied to the patient (within a few days after enrollment)

• A venous blood sample is taken for markers of inflammation

2-week telephone call

• The nurse reinforces the importance of wearing stockings daily

• Bleeding/Other Adverse Event form and pain scale are completed

For the following visits, the patient does not wear study stocking to prevent unblinding of study nurse:

1-month visit

• The nurse completes the follow-up form (includes data on symptoms and signs of PTS, suspected recurrent VTE, compliance with stockings, pain scale)

• The patient self-completes the QOL form

• Bleeding/Other Serious Adverse Event form is completed

• A venous blood sample is taken for markers of inflammation and genetic thrombophilia

• The nurse reinforces the importance of wearing stockings daily

2-month telephone call

• Same as the 2-week telephone call

6-month visit

• The nurse completes the follow-up form

• The patient self-completes the QOL form

• Bleeding/Other Serious Adverse Event form is completed

• Leg measurements are taken, and a new pair of stockings is supplied

• A venous blood sample is taken for markers of inflammation, d-dimer and coagulation-based assays

• The nurse reinforces the importance of wearing stockings daily

1-year visit

• Same as 6-month visit except no blood sampling

• A venous ultrasound is performed to assess reflux

18-month visit

• Same as 6-month visit except no blood sampling

2-year visit

• The nurse completes the follow-up form

• The patient self-completes the QOL form

• Bleeding/Other Serious Adverse Event form is completed

• The success of blinding (patient, nurse, and investigator) is assessed (or at Study Termination if earlier than 2 years).