THRomboprophylaxis in Individuals Undergoing Superficial endoVEnous Treatment (THRIVE)

Phase 4

Recruiting

• Conditions: Venous Thromboembolism; Varicose Veins
• Interventions: Drug: Dalteparin Sodium; Drug: Tinzaparin Sodium; Drug: Enoxaparin Sodium; Drug: Rivaroxaban; Drug: Apixaban; Drug: Dabigatran Etexilate

• Registration Number: NCT05735639
• Lead Sponsor: Imperial College London

Brief Summary

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.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2023-01-19
• Study First Submitted QC: 2023-02-09
• Study First Posted: 2023-02-21
• Study Start: 2024-01-22
• Status Verified: 2025-04
• Last Update Submitted: 2025-04-29
• Last Update Posted: 2025-05-02
• Primary Completion: 2026-06-30
• Study Completion: 2026-12-31

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 6660

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 & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Compression therapy + single dose of low-molecular weight heparin at time of procedure	Dalteparin Sodium	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.
Compression therapy + single dose of low-molecular weight heparin at time of procedure	Enoxaparin Sodium	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.
Compression therapy + single dose of LMWH at time of procedure + extended course of LMWH or DOAC	Dalteparin Sodium	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.
Compression therapy + single dose of LMWH at time of procedure + extended course of LMWH or DOAC	Rivaroxaban	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.
Compression therapy + single dose of LMWH at time of procedure + extended course of LMWH or DOAC	Enoxaparin Sodium	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.
Compression therapy + single dose of LMWH at time of procedure + extended course of LMWH or DOAC	Dabigatran Etexilate	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.
Compression therapy + single dose of LMWH at time of procedure + extended course of LMWH or DOAC	Apixaban	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.
Compression therapy + single dose of low-molecular weight heparin at time of procedure	Tinzaparin Sodium	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.
Compression therapy + single dose of LMWH at time of procedure + extended course of LMWH or DOAC	Tinzaparin Sodium	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.

Primary Outcome Measures

Name	Time	Method
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.	90 days	The rate of lower limb DVT with or without symptoms, or PE with symptoms within 90 days of varicose vein treatment.

Secondary Outcome Measures

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

Trial Locations

Locations (1)

Imperial College Hospital NHS Foundation Trust; 🇬🇧 London, United Kingdom