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Sponsor: Imperial College London (ref: 19CX5434); IRAS: 263041; Approved by London Bloomsbury REC 14/01/2020


CHAPS Trial Co-ordinating Centre

Section of Vascular Surgery
Room 14, 4th Floor East Wing
Charing Cross Hospital
Fulham Palace Road
London W6 8RF

Tel: 0203 311 5204


To measure the difference in incidence of post-thrombotic syndrome at a median of 18 months follow up after first, acute DVT between standard clinical care (anticoagulation) and the intervention arm (a graduated compression stocking and the standard clinical care (anticoagulation)).


Multi-centre, pragmatic, blinded outcome assessment, randomised controlled trial. The trial will follow patients up for a median of 18 months (range 6 – 30 months) and will be conducted in approximately 11 secondary care Trusts in the United Kingdom.

Sample size

A total of 864 patients will be recruited, in 1:1 allocation between the two randomised arms.

Eligibility criteria 

Inclusion Criteria

  • Symptomatic presentation of first deep vein thrombosis, <3 weeks from diagnosis
  • Imaging confirmed, lower limb deep vein thrombosis (popliteal, femoral, iliac or combination)
  • Ability to give informed consent
  • Age 18 or over

Exclusion Criteria

  • Life expectancy < 2 years
  • Contraindication to wearing graduated compression stockings
  • Previously intolerant of or already wearing graduated compression stockings for more than 1 month.
  • Ankle brachial pressure index (ABPI) <0.8 or pedal pulses absent
  • Bilateral deep vein thrombosis
  • Previous chronic venous insufficiency (patients with existing chronic skin changes or ulceration, defined as C5 and C6 by CEAP classification)
  • Pre-existing post thrombotic syndrome, significant leg pain (e.g. knee arthritis, spinal claudication) or oedema (e.g. lymphoedema).
  • Newly diagnosed cancer, metastatic cancer, or cancer undergoing active treatment or palliation
  • Contraindication to anticoagulation
  • Known allergy to fabric in compression stockings

Primary endpoint

The primary outcome is any incidence of Post Thrombotic Syndrome (PTS) using the validated Villalta criteria (Appendix 1) over a median 18 month follow up (range 6 to 30 months). The primary outcome will be assessed on up to three occasions (6 and 12 months post randomisation, and at study end) depending on an individual participant’s length of follow up (minimum 6 and maximum 30 months)

Secondary endpoints

  • Venous ulceration incidence as measured by the validated Villalta criteria
  • Employment status-(change in number of days working from baseline)
  • Change in disease-specific and generic quality of life- VEINES-QoL and EuroQoL EQ5D scales from baseline over 6m, 12m and end of study visit
  • Adherence to stockings and anticoagulants- patient self-report
  • Cost-effectiveness of stocking prescription- Incremental cost-effectiveness ratio (ICER) from the EQ-5D questionnaire, with appropriate sensitivity analysis

Randomisation (performed through RedCap)

Consenting eligible patients will be randomised through RedCap.

If you have any problems logging on to RedCap please contact the team via

Study documents


Trial co-ordinating centre staff

Ms Rebecca Lawton

Ms Rebecca Lawton

Ms Rebecca Lawton
Clinical Trial Manager