A large international Delphi consensus on the management of lower extremity venous outflow obstruction has been published, identifying “clear areas of agreement and disagreement” between experts to support future research and writing of guidelines in this field. The consensus document appeared as an Editor’s Choice paper in the February edition of the European Journal of Vascular and Endovascular Surgery (EJVES).
Authors Stephen Black (Guy’s and St Thomas’ NHS Foundation Trust, London, UK) and colleagues, on behalf of the International Venous Delphi Consensus Study Group, note that a “rapid” evolution of the treatment for lower extremity venous outflow obstruction has not been matched by a parallel proliferation of data. Instead, they write, “the pace of growth has occurred with a paucity of available evidence to support treatment”. This has been aggravated by the difficulties associated with running large randomized controlled trials. As a result, the authors state that “best practices for optimal patient outcomes are not well established”.
The purpose of the present study was to obtain consensus on management criteria for patients with lower extremity venous outflow obstruction.
Black et al detail that the study was conducted as a two-round Delphi consensus. They note that statements addressed imaging, symptoms and other baseline measures, differential diagnosis, treatment algorithm, indications for stenting, inflow and outflow assessment, successful procedural outcomes, post-procedural therapies and stent surveillance, and clinical success factors.
The authors relay that six expert physicians prepared 40 statements as part of the first round, while an expanded panel of 24 physicians prepared 80 statements for the second round. All statements were sent to a pre-identified group of venous experts who met qualifying criteria.
Black and colleagues note that a nine-point Likert scale was used and consensus was defined as ≥70% of respondents rating a statement between seven and nine (agreement) or between one and three (disagreement). Round one results were used to guide rewording and splitting compound statements for greater clarity in round two.
The authors share that 75 of 110 (68%) experts responded in round one of the Delphi consensus, and 91 of 121 (75%) responded in round two. They report that round one achieved consensus in 32/40 (80%) statements, with consensus not reached in the treatment algorithm section. Round two achieved consensus in 50/80 (62.5%) statements.
Black et al specify that statements reaching consensus were imaging (2/3, 66%), symptoms and other baseline measures (12/24, 50%), differential diagnosis (2/8, 25%), treatment algorithm (10/17, 59%), indications for stenting (10/10, 100%), inflow and outflow assessment (2/2, 100%), procedural outcomes (2/2, 100%), post-procedural therapies and stent surveillance (5/7, 71%), and clinical success factors (5/7, 71%).
“Focused and coordinated” research required
In their concluding remarks, the investigators summarize that the areas in which consensus was not achieved must be the focus of venous disease research going forward. “This study has demonstrated that while there are several areas where venous experts agree on the assessment and management of lower extremity venous outflow obstruction, there are multiple domains where consensus was not achieved,” they write. “This underlines that treating venous disease remains a controversial area and requires focused and coordinated research efforts across specialties to answer several unresolved clinical questions. The Delphi consensus has identified those areas in which these efforts should be focused.”
Black and colleagues state in the discussion section of their EJVES paper that this new Delphi consensus “represents the most widespread survey of experts to date” and “provides an important benchmark of consensus that highlights areas where further research is needed to clarify treatment for patients with venous disease”.
In their analysis, the authors underline the fact that a lack of consensus among experts was most common in statements relating to treatment. This, they write, demonstrates a “clear need” to focus future research on the treatment algorithm and clinical outcomes—including health economic outcomes—to help ensure treatments become “more robust”.
Overall, the investigators stress that consensus was achieved for most statements in both rounds of the Delphi process despite a lack of high-quality evidence guiding treatment. They reiterate, however, that a “clear lack” of consensus in several areas highlights the need for “significant efforts” to improve current evidence levels.
