Adopting a value-based healthcare approach to deep venous obstruction and intervention

Modern venous stents have facilitated a paradigm shift in the management of patients with deep venous pathology. Work recently published by Murphy ¹ provides surgeons and interventionalists with a comprehensive overview of the current venous stent landscape including indications for use, advantages (improved flexibility owing to an open-cell design matrix, which is present in the majority of available stents; non-braided stent design, which allows for more precise deployment with reduced fore-shortening; less overlap required in the setting of multiple stents; a broader range of available stent lengths) and potential pitfalls. The details of the VIRTUS ² (Vici stent, Boston Scientific Corporation), VIVO (Zilver Vena stent, Cook Medical), VERNACULAR ³ (Venovo stent, BD Interventional) and ABRE (Abre stent, Medtronic) investigational device exemption (IDE) trials are also provided. The main trial outcomes measures employed (in all of the above aside from VIVO) are freedom from re-intervention, in-stent stenosis >50% and stent occlusion. VIVO examined primary qualitative patency alone. Early summary trial data are currently available for VIRTUS (one-year) and VERNACULAR (two-years).^2–4

While these trials may add to the body of evidence available on indications for and advantages of dedicated venous stents in an arena where non-venous stents have been used to date, the drawbacks are numerous. Firstly, these studies were industry sponsored, a feature that leads to an inherent degree of bias. ⁵ Furthermore, the aforementioned trials feature a single-arm, non-randomized design, making it difficult to draw firm conclusions regarding either stent efficacy or safety. While initial results of these trials may be encouraging, caution must be observed while longer-term outcomes are awaited. One must only look to the endovascular aneurysm repair (EVAR) setting to be reminded of the changes in outcome data that may be observed over time (erosion of the early survival benefit of elective EVAR when compared to open abdominal aortic aneurysm repair beyond 5 years ⁶ ). Ideally, a head-to-head stent comparison would be performed in a randomized, controlled setting similar to that of the IMPERIAL trial. ⁷ This approach has the potential to reduce bias and provide more meaningful results.

In terms of non-industry sponsored data on deep venous stenting, the STEVECO randomized controlled trial ⁸ set out to compare stenting with conservative measures (analgesia, compression hosiery, anticoagulation and manual lymphatic drainage). The primary outcome measure is the change in quality of life at 12 months compared with baseline. While results of this trial are awaited, we must select patients for stenting with caution.

The definitions used to categorize subgroups within iliac occlusive disease are a subject of much debate. These issues are seen within the venous stent trials where different symptom durations were used to define acute deep venous thrombosis (DVT) in VERNACULAR, VIVO and ABRE. Similarly, chronic disease management also varied across the trials. Such heterogeneity in subgroup definitions makes comparison of outcomes across studies difficult, a point previously been highlighted by Jalaie et al. In their review of interventions available to treat patients with post-thrombotic syndrome the authors identified heterogeneous patient populations that cannot be directly compared. ⁹

While re-intervention rates, patency and other outcomes such as stent fractures are undoubtedly relevant from a safety and efficacy standpoint, one must question how much impact they actually have on the wellbeing of patients. Limited quality of life data is being collated over the course of modern venous stent trials. VIRTUS, for example, reported a Venous Clinical Severity Score (VCSS) decrease of 4.4 points at 12 months. ² In VERNACULAR, the VCSS pain score at 12 months showed a significant improvement, with a mean reduction of 1.7. CIVIQ-20 scores also improved significantly at 12 months follow-up, with a mean improvement of −15.7. ³ However, we question if it is sufficient to measure VCSS and CIVIQ-20 alone. Indeed, the shortcomings of several quality of life scores that are commonly used to assess patients with venous disease have been underscored in the literature.^10,11 In 2015 Catarinella et al., advocated the development of a novel tool combining quality of life and clinical assessment in order to adequately assess outcomes related to treatment for venous disease. ¹⁰

To this end we may consider the venous stenting arena from a value-based healthcare perspective and the work which is being undertaken by the International Consortium for Health Outcomes Measurement (ICHOM). ¹² Based on the framework proposed by Porter and Teisberg ¹³ the ICHOM mission statement is to “to unlock the potential of value-based healthcare by defining global Standard Sets of outcome measures that matter most to patients and driving adoption and reporting of these measures worldwide to create better value for all stakeholders”. The desired result of this approach is to create “a world where patients ask their doctors about meaningful outcomes, and doctors can respond with data-driven answers”. By adopting this approach to healthcare, it is envisaged that patients will be able to make more informed decisions regarding their health and potential treatments. Furthermore, quality improvement opportunities will be enhanced and costs may also be reduced.

In order to achieve their aims, ICHOM have formulated Standard Sets consisting of standardized outcomes, measurement tools and factors for risk adjustment for 28 distinct diseases and patient cohorts. A multidisciplinary panel consisting of physicians, experts and patients has defined individual Standard Sets. This approach aims to ensure that outcomes of interest to the patient remain at the forefront. Standard Sets are now available for a variety of conditions including atrial fibrillation, inflammatory arthritis, colorectal cancer, breast cancer and cataracts. Nano et al. recently published the results of an international, ICHOM-led study aiming to report the outcomes that matter most to patients with diabetes. ¹⁴ A total of 27 measures were divided into the following categories: diabetes control; acute events; chronic complications; health services; and survival. This standard set included 3 patient-reported outcome measures (PROMs) related to well-being, depression and diabetes-related emotional distress. The results of an online survey pertaining to the final outcome list ranked highly among diabetic patients. Similarly, the majority of outcomes were approved by a group of surveyed healthcare professionals. ¹⁴

Therefore, we propose the development of a Standard Set for deep venous disease to include subcategories of patients with acute and subacute DVT, and post-thrombotic luminal and mural changes, in addition to non-thrombotic occlusive disease. To our knowledge, this work has yet to be undertaken in the field of deep venous disease. We envisage the inclusion of the following outcome domains (Figure 1):

Clinician reported scores: Clinical, Etiologic, Anatomic, and Pathologic (CEAP) classification, ¹⁵ Villalta scale, ¹⁶ and Venous Clinical Severity Score (VCSS) ¹⁷

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Figure 1.

Proposed standard set for deep venous disease.

The development of a Standard Set for deep venous disease would not only force us to define patient cohorts with greater clarity but would facilitate our decision-making processes with regard to treatment. Aligned with this, more patient-centric outcomes, if incorporated into the clinical trial setting, will allow for the generation of more meaningful results whereby the true impact of our endeavors may be fully elucidated.

The development of a dedicated Standard Set in conjunction with interventional radiologists, vascular surgeons and patients may lead to rapid improvement in how we measure success following deep venous interventions. It may also generate data, which leads to the development of even better devices than those currently available.