Venovo Venous Stent in Treating Iliac Vein Compression: A Single-Center Experience

Background. The Venovo venous stent (BD/Bard Peripheral Vascular) is indicated to treat iliofemoral veno-occlusive disease. We present our own experience with the Venovo venous stent in treating iliac vein compression (ILVC). Methods. In this retrospective cohort, we included consecutive patients treated with the Venovo venous stent for ILVC at our center. Stent deployment and sizing were guided by intravascular ultrasound (IVUS). Minimal luminal areas at the compression before and after treatment were measured by IVUS. Clinical improvement was determined by symptoms reported by patients and the Clinical Etiologic Anatomic and Pathophysiologic (CEAP) score. The primary safety endpoint was freedom from acute venothromboembolic disease, stent migration, perforation, acute/subacute closure, and vascular complications. The primary safety endpoint was target-lesion revascularization at 1 year. Results. A total of 50 consecutive patients (57 Venovo stents, 36 women, mean age, 59.8 ± 16.3 years) were included. IVUS-measured mean percent stenosis at the compression site was 64.8% ± 12.8%. Mean total stent length and diameter were 78.0 ± 54.0 mm and 17.1 ± 1.9 mm, respectively. The primary safety endpoint was met in all subjects. Procedural technical success was 100% (successful deployment with no complications). At 1 year, 83.8% of patients reported improvement in their symptoms. Freedom from total occlusion at 1 year was 100% (data available for n = 30 patients). Target-lesion revascularization (TLR) was 2% at 1 year due to 1 patient who had stent explantation from worsening ipsilateral left leg and back pain. Conclusion. In this single-center experience, the Venovo venous stent was safe and effective in treating ILVC with 98% freedom from TLR at a follow-up of 1 year. Improvement in symptoms was reported in the majority of patients.

Key words: iliac vein compression, iliac vein stent, May-Thurner syndrome, nitinol venous stent, Venovo stent

Iliac vein stenting is now recognized as an important treatment for patients with symptomatic iliac vein compression (ILVC). Traditionally, ILVC stenting was carried out with an off-label application of the Wallstent (Boston Scientific).^1-3 Newly dedicated venous stents were recently approved (Venovo [BD/Bard Peripheral Vascular] and Vici [Boston Scientific]) by the United States Food and Drug Administration and offer precise deployment and stronger radial force than the Wallstent.⁴ Furthermore, intravascular ultrasound (IVUS) is now considered the gold standard in sizing venous stents by most operators since venography underestimates vessel size and lesion severity.⁵ ILVC stenting is reserved for symptomatic patients and appears to significantly improve symptoms and quality of life, and reduces lower-extremity swelling.

We present our experience with the first 50 patients with ILVC treated with the Venovo venous stents with a focus on acute procedural results, symptom improvement, and long-term outcomes of target-lesion revascularization and patency.

In this retrospective cohort, we included consecutive patients treated with the Venovo venous stent for ILVC by 2 operators at our center. The study was approved by the ethics committee at the Genesis Health System. Demographic, clinical, angiographic, and IVUS variables were collected. Stent deployment and sizing were guided by IVUS. Minimal luminal area (MLA) at the compression and reference sites before and after treatment were measured by IVUS and percent stenosis severity was calculated. Clinical improvement was determined by symptoms reported by patients and the clinical, etiological, anatomical, and pathophysiological (CEAP) score. The primary safety endpoint was freedom from acute venothromboembolic disease, stent migration, perforation, acute/subacute closure, and vascular complications. The primary effectiveness endpoint was freedom from target-lesion revascularization. Secondary endpoints included patency as evaluated by duplex ultrasound (defined as freedom from total occlusion). Patency was defined as lack of total occlusion on duplex ultrasound at 1-year follow-up.

Statistical methods. Continuous variables are presented as mean ± standard deviation and dichotomous variables as count/sample (percentage). Analyses were performed using Minitab, version 17 (Minitab, LLC).

A total of 50 consecutive patients (57 Venovo stents) were included. Table 1 shows demographic and clinical variables. The mean age was 59.8 ± 16.3 years. Of the 50 patients, 72% were women, 24% had history of deep vein thrombosis, and 14% had history of pulmonary embolus. All patients were symptomatic with either lower-extremity edema (86%) or pain (78%) in the affected leg. Table 2 illustrates IVUS-measured mean percent stenosis at the compression site before treatment (64.8 ± 12.8%) and post stenting (25.4 ± 12.8%). Mean stent length and diameter were 78.0 ± 54.0 mm and 17.1 ± 1.9 mm, respectively. The common iliac vein was the main site of ILVC and stenting. The majority of patients (88.0%) received 1 stent.

The primary safety endpoint was met in all subjects (Table 3). Procedural success was 100% (successful deployment with no complications). At 1 year, 83.8% of patients reported improvement in their symptoms. Freedom from total occlusion at 1 year was 100% (data available in 30 patients who underwent duplex ultrasonography). Target-lesion revascularization was 2% at 1 year due to stent explantation in 1 patient secondary to worsening ipsilateral left leg and back pain. This case of stent extraction was recently reported in a case report and analysis that evaluated the role of stent size and the occurrence of chronic back and leg pain post nitinol venous stent implantation.⁶ The majority of patients were asymptomatic with healed ulcerations at 1 year. There were no device-related major or serious adverse events at the index procedure.

Iliac vein stenting is now the standard to treat symptomatic iliac vein compression. Previously, Wallstents were used to treat iliac vein compression. The Wallstent is off-label for venous applications, but overall, it has good procedural and long-term data when sizing is done appropriately.^1-5,7 Raju et al generally upsize the Wallstent by 2 mm above the measured diameter of the iliac vein and recommend post-stent dilation with a minimum of 16 mm, 14 mm, and 12 mm diameter balloons for the common iliac vein, external iliac vein, and common femoral vein, respectively.^1,2 Recently, venous dedicated stents, including the Venovo venous stent and the Vici venous stent, have been approved in the United States. Based on our experience in the investigational device exemption (IDE) clinical trials of these stents, we have advocated the use of the compression-spared segment of the ipsilateral common iliac vein to obtain a reference luminal area or diameter by IVUS and size the stent 1-2 mm above the measured size.⁶ Post-balloon dilation followed the recommended guidelines by Raju et al described above.

In our study, the majority of the stents used were 16 mm or larger. The common iliac vein was the most treated segment of the iliac veins. Despite a history of deep vein thrombosis in 24% of patients, the freedom from target-lesion revascularization at 1 year was 48/49 patients (98%). Patency was 100% in 30 patients who had duplex ultrasound at 1 year. Overall, this seems to be consistent with the high patency rate seen in the VERNACULAR trial (IDE Venovo study). In this prospective, multicenter study, 156 patients (219 stents) were successfully treated. Of these, 84 had post-thrombotic syndrome and 72 patients had non-thrombotic presentation. The primary patency at 1 year was 88.3% and reintervention rate was 7.4%.⁸ We believe that accurate sizing is critical to achieve long-term patency and freedom from target-lesion revascularization. The patient who had target-lesion revascularization in our series was due to worsening back and leg pain that persisted despite no objective findings of neurologic impairment and eventually required stent explantation. Details on this case were recently reported separately.⁶

CEAP classifications in the affected leg were class 2 (6%), class 3 (58%), class 4 (22%), healed ulcer (4%), and active ulceration (10%). Following treatment, all active ulcerations have healed at 1 year (Table 3). Also, when patients who died or lost to follow-up were censored, 83.8% of patients had either resolution or improvement in symptoms.

Iliac vein stenting with the Venovo venous stent is very effective, with excellent procedural and long-term follow-up, and with symptom improvement in the majority of patients. Surgical intervention is rarely needed in these cases and the endovascular approach is now a widely accepted standard.