Midterm and Long-Term Outcomes following Dedicated Endovenous Nitinol Stent Placement for Symptomatic Iliofemoral Venous Obstruction: Three- to 5-Year Results of the VIRTUS Study

Final 3-Year Study Outcomes from the Evaluation of the Zilver Vena Venous Stent for the Treatment of Symptomatic Iliofemoral Venous Outflow Obstruction (The VIVO Clinical Study)

PURPOSE

To report 3-year outcomes from a prospective, multicenter, nonrandomized, single-arm study designed to assess the safety and effectiveness of the Zilver Vena Venous Stent for the treatment of symptomatic iliofemoral venous outflow obstruction.

MATERIALS AND METHODS

The VIVO study included patients with symptomatic obstruction of 1 iliofemoral venous segment (ie, 1 limb), characterized by a Clinical, Etiological, Anatomic, Pathophysiology (CEAP) clinical classification of ≥3 or a Venous Clinical Severity Score (VCSS) for pain of ≥2. Patients were retrospectively grouped based on baseline clinical presentation as postthrombotic syndrome (PTS), nonthrombotic iliac vein (NIVL) obstruction, or acute deep vein thrombosis (aDVT). Clinical improvement was assessed by change in VCSS, Venous Disability Score, Chronic Venous Disease Quality of Life Questionnaire (CIVIQ-20) scores, and CEAP C classification. Stent performance was evaluated by rates of patency by ultrasound (US), freedom from clinically driven reintervention, and freedom from stent fracture.

RESULTS

The 3-year results for the 243 patients in the VIVO cohort included a 90.3% rate of patency by US and a 92.6% rate of freedom from clinically driven reintervention. The 3-year rates of patency by US for the NIVL, aDVT, and PTS groups were 100%, 84.0%, and 86.1%, respectively. Sustained clinical improvement through 3 years was demonstrated by changes in VCSS, Venous Disability Score, CIVIQ-20, and CEAP C classification. No stent fractures were observed.

CONCLUSIONS

The VIVO study demonstrated sustained high rates of patency and freedom from clinically driven reintervention and improvements in venous clinical symptoms through 3 years. Each patient group (NIVL, aDVT, and PTS) showed clinical improvement and sustained patency through 3 years; some variation existed among groups (eg, only the NIVL group had a 100% patency rate).

Appropriateness of care: Deep venous procedures

In the past decade, technologies to treat venous pathologies have increased dramatically, to the benefit of an often underserved and overlooked population of patients with venous disease. However, given the rapid release of various technologies, including venous-dedicated stents and thrombectomy devices across varied venous pathologies, evidence-based guidelines have been slow to develop. When discussing appropriateness of care, one needs to consider optimal patient selection, technical approach, medical management, and surveillance protocols, to name a few. All of which, in the venous space, are currently widely varied in practice. The future of deep venous work is limitless, but multicenter, randomized controlled trials are needed to optimally treat patients with venous disease.

The TOPOS study

Background: We aimed to study the long-term safety and efficacy of oblique venous stents for post-thrombotic syndrome (PTS) with iliac vein compression. Patients and methods: In the multinational, prospective, single-arm TOPOS study, PTS patients scheduled for endovascular therapy with the sinus-Obliquus® stent and optional distal extension with the sinus-Venous® or sinus-XL Flex® stent were enrolled at eight European vascular centres between October 2016 and December 2020. The primary outcome was primary stent patency at 24 months, and secondary outcomes included the clinical course of PTS (Villalta score, revised Venous Clinical Severity Score [rVCSS], Visual Analog Scale [VAS] of pain), quality of life changes (Chronic Venous Insufficiency Quality of Life Questionnaire, CIVIQ-20), and device-related complications. Results: We enrolled 60 patients (mean age 46±15 years, 68% women, 13% active ulcers): 80% required stent extension (70% below the inguinal ligament). The primary patency rate at 24 months was 80.7% (95%CI 68.1-90.0%); it was higher in patients without vs. those with stent extension (90.9% vs. 78.3%, p=.01). Compared to baseline, the Villalta, rVCSS, pain VAS, and CIVIQ-20 decreased by a median of 8 (interquartile range (IQR): 4-11), 5 (IQR: 3-7), 3 (IQR: 2-5), and 17 (IQR: 6-22) points, respectively; p<.001 for all parameters. Overall, 9 events of acute stent occlusion, 4 symptomatic stent stenosis, and 1 pulmonary embolism occurred. We did not observe major bleeding events or contralateral thrombosis. Conclusions: Endovascular treatment with the oblique stent and optional stent extension was safe and resulted in high patency rates at 24 months. The reduction in PTS severity was substantial and persisted over 2-year follow-up.

A meta-analysis of the medium- to long-term outcomes in patients with chronic deep venous disease treated with dedicated venous stents

OBJECTIVE

This review summarizes the safety profile, stent patency, and clinical effectiveness of dedicated venous stents for the treatment of chronic deep venous disease. The approaches to stenting and post-procedural management of different vascular units are also explored.

METHODS

The MEDLINE and Embase databases were searched for pertinent literature published from January 2010 to January 2023. Outcomes related to post-stenting symptoms and health-related quality of life were described narratively. A meta analysis was conducted to evaluate stent patency, ulcer healing, bleeding, and 30-day stent thrombosis, and these outcomes were presented as proportion event rates.

RESULTS

Seventeen studies were identified comprising of 2218 patients. 62.7% of individuals had post-thrombotic stenosis or occlusion. The majority of patients (78.6%) were noted to have complete occlusions of their deep veins before stenting. Eleven different dedicated venous stents were deployed. At 12 months, the primary patency rate was 83% (95% confidence interval [CI]: 76%-90%), the primary-assisted patency rate was 90% (95% CI: 85%-96%), and the secondary patency rate was 95% (95% CI: 92%-98%). A significant improvement in health-related quality of life was demonstrated after intervention. In total, 68.8% (95% CI: 52.0%-83.7%) of ulcers healed at the last follow-up. The remaining symptomatic changes were described narratively; improvements in pain, venous claudication, and edema after stenting were observed. Seventeen deaths occurred, but none were linked to the stenting procedures. A total of 159 cases (7.2% of patients) of in-stent stenosis were observed, whereas 110 stents (5.0% of patients) were occluded. The incidence of major and minor bleeding was 1.7% (95% CI: 1.0%-2.5%) and 3.2% (95% CI: 1.3%-5.6%), respectively, more commonly seen in patients undergoing hybrid intervention.

CONCLUSIONS

Deep venous stenting using dedicated venous stents is a safe technique to treat chronic deep venous stenosis and/or occlusion. Within the limitations of this study, deep venous stenting is associated with good patency rates and symptomatic improvement.

Three-Year Outcomes of the Abre Venous Self-Expanding Stent System in Patients with Symptomatic Iliofemoral Venous Outflow Obstruction

PURPOSE

To report 36-month outcomes and subgroup analysis of the ABRE study evaluating the safety and effectiveness of the Abre venous self-expanding stent system for the treatment of symptomatic iliofemoral venous outflow obstruction disease.

METHODS

The ABRE study was a prospective, multicenter, nonrandomized study that enrolled and implanted Abre venous stents in 200 participants (mean age 51.5 years [SD ± 15.9], 66.5% women) with symptomatic iliofemoral venous outflow obstruction at 24 global sites. Outcomes assessed through 36 months included patency, major adverse events, stent migration, stent fracture, and quality-of-life changes. Adverse events and imaging studies were adjudicated by independent clinical events committee and core laboratories, respectively.

RESULTS

Primary, primary-assisted, and secondary patency through 36 months by Kaplan-Meier estimates were 81.6%, 84.8%, and 86.3%, respectively. The cumulative incidence of major adverse events through 36 months was 10.2%, mainly driven by 12 thrombosis events. Subgroup analyses demonstrated a primary patency of 76.5% in the acute deep vein thrombosis group, 70.4% in the postthrombotic syndrome group, and 97.1% in the nonthrombotic iliac vein lesion group through 36 months. The overall mean lesion length was 112.4 mm (SD ± 66.1). There were no stent fractures or migrations in this study. Quality of life and venous functional assessments demonstrated significant improvements from baseline to 36 months across all patient subsets.

CONCLUSIONS

Results from the ABRE study demonstrated sustained patency with a good safety profile after implantation of a dedicated venous stent in patients with symptomatic iliofemoral venous outflow obstruction disease.

Novel venous balloon for compliance measurement and stent sizing in a post-thrombotic swine model

Objective: Real-time accurate venous lesion characterization is needed during endovenous interventions for stent deployment. The goal of this study is to validate a novel device for venoplasty sizing and compliance measurements. Methods: A compliance measuring sizing balloon (CMSB) uses real-time electrical conductance measurements based on Ohm's Law to measure the venous size and compliance in conjunction with pressure measurement. The sizing accuracy and repeatability of the CMSB system were performed with phantoms on the bench and in a swine model with an induced post thrombotic (PT) stenosis in the common femoral vein of swine. Results: The accuracy and repeatability of the CMSB system were validated with phantom bench studies of known dimensions in the range of venous diameters. In 9 swine (6 experimental and 3 control animals), the luminal cross-sectional areas (CSA) increased heterogeneously along the PT stenosis when the CMSB system was inflated by stepwise pressures. The PT stenosis showed lower compliance compared to the non-PT vein segments (5 mm2 vs. 10 mm2 and 13 mm2 at a pressure change of 40 cm H2O). Compliance had no statistical difference between venous hypertension (VHT) and Control. Compliance at PT stenosis, however, was significantly smaller than that at Control and VHT (p < 0.05, ANOVA). Conclusion: The CMSB system provides accurate, repeatable, real-time measurements of CSA and compliance for assessment of venous lesions to guide interventions. These findings provide the impetus for future first-in-human studies.