Pharmacological thromboprophylaxis in superficial endovenous intervention
File(s)
Author(s)
Whittley, Sarah
Type
Thesis
Abstract
Background: Varicose veins affect up to 45% of the United Kingdom (UK) population. Endovenous intervention is now the recommended first-line treatment for symptomatic cases. Despite being common outpatient procedures, superficial endovenous interventions carry a higher risk of venous thromboembolism (VTE) than many other day-case surgeries, with rates reported up to 3.4%. Current guidelines on pharmacological thromboprophylaxis for this patient population are conflicting and lack clarity. Additionally, no validated VTE risk assessment tool exists to appropriately stratify patients before intervention.
Aims: This thesis aims to: 1) Investigate current global practices for pharmacological thromboprophylaxis in superficial endovenous intervention. 2) Assess the impact of pharmacological thromboprophylaxis on VTE risk in superficial endovenous procedures.
Methods: To address Aim 1, three clinician surveys were conducted in the UK, internationally and in the United States of America (USA). Clinical practice guidelines were also identified and critically appraised using the Appraisal of Guidelines for Research and Evaluation II (AGREE II) framework. To address Aim 2, a multicentre randomised controlled trial (RCT), the THRIVE study, was setup and is ongoing. This ongoing trial evaluates whether pharmacological thromboprophylaxis plus compression offers benefit over compression alone in reducing post-operative VTE risk.
Results: There is considerable international variation in practice. Pharmacological thromboprophylaxis is less commonly prescribed in the UK, Ireland and parts of Europe compared to the USA. Guidelines are inconsistent, generally of low methodological quality and based on limited evidence. The THRIVE trial continues to recruit but has faced challenges including operational constrains, staffing limitations and broader systemic pressures.
Conclusion: Robust, high-quality evidence is urgently needed to inform clear, consistent guidelines. The ongoing THRIVE trial is designed to address this gap. If thromboprophylaxis is shown to offer no additional benefit over compression alone, routine anticoagulant use could be safely reduced, minimising costs and patient exposure to unnecessary side effects.
Aims: This thesis aims to: 1) Investigate current global practices for pharmacological thromboprophylaxis in superficial endovenous intervention. 2) Assess the impact of pharmacological thromboprophylaxis on VTE risk in superficial endovenous procedures.
Methods: To address Aim 1, three clinician surveys were conducted in the UK, internationally and in the United States of America (USA). Clinical practice guidelines were also identified and critically appraised using the Appraisal of Guidelines for Research and Evaluation II (AGREE II) framework. To address Aim 2, a multicentre randomised controlled trial (RCT), the THRIVE study, was setup and is ongoing. This ongoing trial evaluates whether pharmacological thromboprophylaxis plus compression offers benefit over compression alone in reducing post-operative VTE risk.
Results: There is considerable international variation in practice. Pharmacological thromboprophylaxis is less commonly prescribed in the UK, Ireland and parts of Europe compared to the USA. Guidelines are inconsistent, generally of low methodological quality and based on limited evidence. The THRIVE trial continues to recruit but has faced challenges including operational constrains, staffing limitations and broader systemic pressures.
Conclusion: Robust, high-quality evidence is urgently needed to inform clear, consistent guidelines. The ongoing THRIVE trial is designed to address this gap. If thromboprophylaxis is shown to offer no additional benefit over compression alone, routine anticoagulant use could be safely reduced, minimising costs and patient exposure to unnecessary side effects.
Version
Open Access
Date Issued
2025-10-28
Date Awarded
2026-02-01
Copyright Statement
Attribution-NonCommercial 4.0 International Licence (CC BY-NC)
License URL
Advisor
Davies, Alun
Onida, Sarah
Carradice, Daniel
Publisher Department
Department of Surgery & Cancer
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)