Defining optimal poststent medical therapy in deep venous obstruction remains elusive

In this article, the authors report the results of a Delphi consensus study in which vascular experts from China and Taiwan experienced in venous stenting participated to produce recommendations on preferred antithrombotic therapy in patients after venous stenting.1Guo B. Chen C. Li Y. et al.Principles of optimal antithrombotic therapy for iliac Venous stenting (POATIVES): Anational expert based Delphi consensus study.J Vasc Surg Venous Lymphat Disord. 2024; 12101739Google Scholar The Delphi process has been validated to assist in defining best practices, particularly when the evidence base is insufficient to define these practices clearly. A review of the published database concerning venous stenting suggests that little is well-defined by the evidence to date. No prospective randomized studies exist comparing anticoagulant types, durations, doses, or anticoagulation vs no anticoagulation. Similarly, the role of antiplatelet agents, either alone or in combination with anticoagulants, is poorly defined. Complicating the analysis is the variability of venous obstructive etiology and severity, such that different situations may be best treated with specific anticoagulation strategies. The scenarios considered in this article are similar to those considered in a previous Delphi consensus study reported in 2018 by Milinis et al.2Milinis K. Thapar A. Shalhoub J. Davies A.H. Antithrombotic therapy following venous stenting: International Delphi consensus.Eur J Vasc Endovasc Surg. 2018; 55: 537-544Google Scholar In both, the scenarios requested expert opinion on the best anticoagulant/antiplatelet management after venous stenting for nonthrombotic, compressive iliac lesions, after acute deep vein thrombosis with iliac obstruction, and after stenting for chronic post-thrombotic obstruction. In Milinis' study, the variety of recommended anticoagulant/antiplatelet regimens was astonishing. Although the panel of experts might have agreed that anticoagulation was necessary, there was little agreement on which type of anticoagulation, dosage, duration, or whether antiplatelet agents were beneficial. In the current report, the panel of experts from China and Taiwan also reached consensus on the need for anticoagulation for all venous stenting situations, but it is difficult to determine what type of anticoagulation was preferred. For nonthrombotic lesions, it is reported that 89% of the experts preferred a direct oral anticoagulant or low-molecular-eight heparin for initial phase therapy but the numbers for each type of preferred anticoagulation are not provided. Conversely, for patients undergoing stenting for post-thrombotic syndrome, anticoagulation was recommended using a direct oral anticoagulant. These details highlight the limitations of the Delphi process, particularly in an area in which there is significantly variability in the condition under study. Determination of the optimal poststent therapy to maintain patency and prevent thrombosis requires assessment of the factors placing each individual patient at risk, including their prior thrombotic history, risk factors for recurrent thrombosis, disease type, severity, inflow, and success in reestablishing a fully patent outflow tract with no residual obstruction. Based on this finding, the treatment of a patient with a history of one prior provoked DVT who has a nonocclusive stenosis of the iliac vein, and no femoral vein obstruction is very different from a post-thrombotic patient with a history of multiple DVTs, a hypercoagulable state and a completely occluded iliac outflow tract requiring recanalization and extensive stenting. Although both patients would be lumped into the category of post-thrombotic, their risk of rethrombosis and loss of patency over time are significantly different. Although the Delphi method is useful in providing an assessment of the current thinking of specialists in an area, it is highly susceptible to change when new information is available, and it depends on the way that the experts involved consider the available evidence. As an example, Guo et al's article reports that the experts recommended anticoagulation for patients stented for nonthrombotic compressive lesions with a high degree of consistency. However, the largest reported study on the benefit of anticoagulation in this group, by Pappas et al,3Pappas P.J. Lakhanpal G. Lakhanpal S. et al.Immediate postprocedure anticoagulation with factor Xa inhibitors of venous stents for nonthrombotic venous lesions does not increase stent patency.J Vasc Surg Venous Lymphat Disord. 2022; 10: 633-639Google Scholar identified no benefit to anticoagulation in nonthrombotic iliac vein lesions. We cannot determine whether the participants in the Delphi consensus document were unaware of Pappas' study or whether they considered a retrospective study to be insufficient to change their opinion on optimal therapy for their patients. Despite two recent Delphi consensus documents in this area, defining the optimal poststent medical therapy remains challenging owing to the lack of high-quality clinical data. The only way forward will be to develop well-powered prospective studies to address all aspects of poststent venous stent therapy, hopefully tailored to specific patient groups, such that the results accurately reflect best therapy for each individual patient. The opinions or views expressed in this commentary are those of the authors and do not necessarily reflect the opinions or recommendations of the Journal of Vascular Surgery: Venous and Lymphatic Disorders or the Society for Vascular Surgery. None. Principles of Optimal Antithrombotic Therapy for Iliac VEnous Stenting (POATIVES): A national expert-based Delphi consensus studyJournal of Vascular Surgery: Venous and Lymphatic DisordersVol. 12Issue 2PreviewManagement of antithrombotic therapy in patients undergoing venous stents has not yet reached consensus, and there are not any recommendations from published guidelines. We undertook a Delphi consensus from Chinese experts to develop recommendations regarding the preferred antithrombotic therapy in patients following venous stenting.