THRomboprophylaxis in Individuals Undergoing Superficial endoVEnous Treatment (THRIVE) (THRIVE)

THRomboprophylaxis in Individuals Undergoing Superficial endoVEnous Treatment (THRIVE) - a Multi-centre Assessor-blind Randomised-controlled Trial

Endovenous interventions are keyhole operations for varicose veins that are carried out from within the vein itself. Varicose veins are enlarged veins close to the surface of the skin. They are connected to the bigger deeper veins in the leg (known as deep veins). Because of this, operations to close the varicose veins can increase the chance of a blood clot forming in the deep veins. Blood clots in the deep veins happen in around 1 in 50 people after endovenous operations. A clot in the leg can cause swelling, pain, and other long-term problems. If a clot in the leg breaks off and travels to the lungs, it can cause problems with the lung' ability to move oxygen from the air into the blood and may, in rare cases, be life threatening.

Varicose vein procedures may carry a slightly higher risk of blood clot formation, and we are currently unsure if current clot reducing medicines are beneficial in preventing blood clots in people having varicose vein procedures.

This study will investigate if it is worthwhile prescribing medicines to reduce blood clots after varicose vein procedures.

Study Overview

• Status: Recruiting
• Conditions: Varicose Veins; Venous Thromboembolism
• Intervention / Treatment: Drug: Dalteparin Sodium; Drug: Tinzaparin Sodium; Drug: Enoxaparin Sodium; Drug: Rivaroxaban; Drug: Apixaban; Drug: Dabigatran Etexilate

• Study Type: Interventional
• Enrollment (Estimated): 3175
• Phase: Phase 4

Contacts and Locations

• Study Contact: Name: Sarah Whittley; Phone Number: +442033117309; Email: s.whittley@imperial.ac.uk

Study Locations

• United Kingdom
  • London, United Kingdom, W6 8RF
    • Recruiting
    • Imperial College Hospital NHS Foundation Trust
    • Contact: Alun H Davies

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Adults (>18 years)
• Scheduled to undergo endovenous intervention of truncal varicose veins under local anaesthesia
• Treatment technologies including radiofrequency, laser, mechanochemical, foam sclerotherapy and cyanoacrylate glue

Exclusion Criteria:

• Clinical indication for therapeutic anticoagulation e.g., atrial fibrillation
• Previous personal or first-degree relative history of VTE
• Thrombophilia
• Female patients of childbearing potential who have a positive pregnancy test
• A history of allergy to heparins or direct oral anticoagulants
• A history of heparin-induced thrombocytopenia
• Inherited and acquired bleeding disorders
• Evidence of active bleeding
• Concomitant major health problems such as active cancer and chronic renal and/or liver impairment

• Known thrombocytopenia (platelets known to be less than 50 x 109

  /l)

• Surgery or major trauma in the previous 90 days
• Recent ischemic stroke in the previous 90 days
• Inability to provide consent

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Compression therapy alone
Experimental: Compression therapy + single dose of low-molecular weight heparin at time of procedure; A single prophylactic dose of low molecular weight heparin (LMWH) (e.g., dalteparin sodium, tinzaparin sodium, enoxaparin sodium) will be prescribed as per standard practice and administered in accordance with the relevant Summary of Product Characteristics (SmPC), manufacturer's recommendations and instructions for use.	Drug: Dalteparin Sodium; Low molecular weight heparin; Drug: Tinzaparin Sodium; Low molecular weight heparin; Drug: Enoxaparin Sodium; Low molecular weight heparin
Experimental: Compression therapy + single dose of LMWH at time of procedure + extended course of LMWH or DOAC; An extended duration of LMWH (e.g., dalteparin sodium, tinzaparin sodium, enoxaparin sodium) or an extended duration of a direct oral anticoagulant (DOAC) (e.g., rivaroxaban, apixaban, dabigatran etexilate) will be prescribed as per current local practice and administered in accordance with the relevant SmPC, manufacturer's recommendations and instructions for use. The duration of this must be at least 7 days, but can be in line with local practice i.e., 7, 10 or 14 days.	Drug: Dalteparin Sodium; Low molecular weight heparin; Drug: Tinzaparin Sodium; Low molecular weight heparin; Drug: Enoxaparin Sodium; Low molecular weight heparin; Drug: Rivaroxaban; Direct oral anticoagulant; Drug: Apixaban; Direct oral anticoagulant; Drug: Dabigatran Etexilate; Direct oral anticoagulant

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Imaging confirmed lower limb deep vein thrombosis (DVT) with or without symptoms, or pulmonary embolism (PE) with symptoms within 90 days of varicose vein treatment.	The rate of lower limb DVT with or without symptoms, or PE with symptoms within 90 days of varicose vein treatment.	90 days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Lower limb DVT without symptoms	Duplex ultrasound scan	21 - 28 days
Lower limb DVT with symptoms	Self-reported VTE outcome questionnaire	90 days
PE with symptoms	VTE outcome questionnaire (self-reported) to determine the rate of PE	90 days
Comparisons of quality of life at 7- and 90-days post-procedure	Using EQ-5D	90-days
Cost-effectiveness of providing pharmacological thromboprophylaxis	Incremental Cost-Effectiveness Ratio (ICER)	90 days
Mortality rates in each group	Rate of mortality	90 days
Exploratory analyses to assess how well a VTE risk assessment tool predicts VTE outcome	Venous thromboembolism risk as determined by the Department of Health Risk Assessment tool	90 days
Exploratory analyses to assess how well a VTE risk assessment tool predicts VTE outcome	Venous thromboembolism risk as determined by the Caprini risk assessment model	90 days

Collaborators and Investigators

• Sponsor: Imperial College London

Study record dates

Study Major Dates

• Study Start (Actual): January 22, 2024
• Primary Completion (Estimated): June 30, 2027
• Study Completion (Estimated): December 31, 2027

Study Registration Dates

• First Submitted: January 19, 2023
• First Submitted That Met QC Criteria: February 9, 2023
• First Posted (Actual): February 21, 2023

Study Record Updates

• Last Update Posted (Actual): June 4, 2026
• Last Update Submitted That Met QC Criteria: June 3, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Embolism and Thrombosis; Thromboembolism; Venous Thromboembolism; Varicose Veins; Sulfur Compounds; Organic Chemicals; Pyridines; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Benzimidazoles; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring; Carbohydrates; Heparin, Low-Molecular-Weight; Heparin; Glycosaminoglycans; Polysaccharides; Morpholines; Oxazines; Thiophenes; Rivaroxaban; Dabigatran; Tinzaparin; Dalteparin; apixaban; enoxaparin sodium
• Other Study ID Numbers: 22CX7510; ISRCTN18501431 (Other Identifier: ISRCTN)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No