Optimal thromboprophylaxis following superficial endovenous treatment: What is it?

Chronic venous disease (CVD) is significantly detrimental to the comfort, mobility and mental wellbeing of the patients it afflicts. The estimated burden of CVD in the UK is vast and can be expected to increase imminently in conjunction with population age and obesity. ¹ Minimally invasive procedures permitted by technological advancement have become the mainstay of surgical CVD management, with over 60% of superficial venous interventions conducted in recent years implementing an endovenous approach. ² Such modalities of varicose vein treatment comprise radiofrequency, laser, mechanochemical, sclerotherapy and cyanoacrylate glue. They are predominantly carried out under local anaesthesia, with occasional requirement for sedation due to degree of patient tolerance or disease extent. Despite minimal hospital admission time and prompt post-operative ambulation, venous thromboembolism (VTE) continues to present as a considerable and potentially fatal complication of these procedures. ³ Characteristics associated with the development of VTE are frequently observed within the patient cohort and varicose veins are identified as additional contributors to VTE risk by the validated Caprini score. ⁴ Furthermore, the aetiological phenomena of endovenous heat-induced thrombosis (EHIT), glue-induced thrombosis and foam-induced thrombosis (EFIT) are minimally understood.

Thromboprophylaxis, both pharmacological and mechanical, can reduce the risk of perioperative VTE occurrence. Mechanical thromboprophylaxis (compression) without contra-indication is relatively minimal in adverse effect and its potential benefit following varicose vein surgery has been reported. ⁵ Decisions surrounding the use of pharmacological thromboprophylaxis in the perioperative period balance the risk of VTE against that of significant bleeding. Historically, preceding the establishment of accredited guidance, a variety of anticoagulant regimes have been implemented by surgeons without consensus on optimal choice of agent or duration of treatment. This variability in practice was recognised by the vascular academic community as an area in need of further research to promote health and economic outcomes. ⁶

In 2020 The Venous Forum of the Royal Society of Medicine (RSMVF) published prevailing guidance on thromboprophylaxis following varicose vein procedures in patients without pre-existing clinical indication for anticoagulation or significant contra-indication to it. ⁷ The guidance recognised contemporary variability in practice and provided an acclaimed evidence-based standard for clinicians to reference. It advised the pragmatic stratification of patients into three discrete categories based on their VTE risk profile, with each category corresponding to a recommended duration of pharmacological thromboprophylaxis; a precise formula for risk stratification is not provided, instead risk factors to be considered are simply listed. The guidance proposed that individuals ‘at additional risk’ should receive prophylaxis for 7 to 14 days while those ‘at high risk’ should receive prophylaxis for 4 to 6 weeks. For patients deemed to be ‘at low risk’, the guidance acknowledged a state of clinical equipoise, listing a variety of practicable options for thromboprophylaxis ranging from none at all to 3 days of medicinal treatment. Low molecular weight heparin or a direct oral anticoagulant were both presented as equally suitable agents, with ultimate selection determined by clinical factors and personal preference. The lack of specification in the guidance regarding optimal prophylaxis in the ‘low risk’ group reflected the extreme paucity of quality studies addressing this pertinent issue. Since 2019, NICE have similarly recommended that VTE prophylaxis is ‘generally not needed’ if patients are ‘at low risk’ and with total anaesthesia time below 90 min. ⁸ However, if these criteria are not met, a 7-day thromboprophylaxis regime is advised. Most recently in 2022, the European Society for Vascular Surgery promoted the consideration of ‘individualised thromboprophylaxis strategies’ without detailed elaboration. ⁹ A national survey in 2019 suggested that the majority of clinicians defaulted to prescribing pharmacological thromboprophylaxis for all patients following superficial venous intervention, despite there being no peer-reviewed evidence to support this practice. ¹⁰

Novel level I evidence is required to resolve the current state of clinical equipoise regarding optimal thromboprophylaxis following superficial endovenous treatment. A randomised controlled trial comparing commonly implemented thromboprophylaxis regimes, with respect to VTE risk reduction and adverse events, would directly address the aforementioned gap in literature. Resultant understanding of the efficacy, cost effectiveness and implications on quality of life associated with various treatment approaches would inform stakeholders in this proliferating field. We believe that original research in this area represents a pressing opportunity to improve outcomes on a population scale for patients undergoing varicose vein treatment.