Vflower Stent System for Iliofemoral Vein Stenosis and Occlusion: A Multicenter Real-World Study

This is a prospective, multicenter, real-world observational study conducted at five hospitals in China. The study aims to evaluate the effectiveness and safety of the Vflower venous stent system in adult patients with symptomatic iliofemoral vein stenosis or occlusion.

Study Design: This is an observational (non-randomized) study. Treatment decisions, including the choice of stent type and procedural technique, will be made by the treating physicians based on each patient's clinical condition. The research team will collect prospective data from routine clinical visits, imaging examinations, and laboratory tests performed as part of standard patient care.

Study Population: Approximately 310 adult patients (aged 18 years or older) with symptomatic iliofemoral vein stenosis or occlusion will be enrolled. Inclusion criteria require symptomatic disease (e.g., leg swelling, pain, varicose veins, or skin changes) and angiographic evidence of iliofemoral vein stenosis of 75% or greater, or complete occlusion. Patients with contraindications to anticoagulation, active infection, or other conditions that would preclude standard endovascular treatment will be excluded.

Procedure: Eligible patients will undergo standard endovascular intervention, which includes balloon angioplasty followed by placement of the Vflower venous stent. The Vflower stent is a self-expanding nitinol stent specifically designed for venous application, with a unique flower-shaped geometry that provides radial force while accommodating venous pulsatility and movement. The stent has been approved by the China National Medical Products Administration for use in iliofemoral venous lesions.

Follow-up and Assessments: Patients will be followed at 1 month, 6 months, 12 months, and 24 months after the procedure. At each follow-up visit, patients will undergo clinical evaluation, venous duplex ultrasonography to assess vein patency, and completion of validated patient-reported outcome questionnaires, including the Clinical, Etiology, Anatomy, and Pathophysiology (CEAP) classification and the Venous Clinical Severity Score (VCSS).

Primary Outcome: The primary outcome is the technical and clinical success rate, defined as the patency rate of the treated vein segment at 12 months post-procedure, as assessed by venous duplex ultrasonography.

Secondary Outcomes: Secondary outcomes include: (1) the change in VCSS from baseline to each follow-up visit; (2) the rate of freedom from target lesion revascularization at 12 and 24 months; (3) the incidence of device-related and procedure-related adverse events, including stent thrombosis, restenosis, stent migration, and bleeding complications; (4) health-related quality of life assessed by validated instruments; and (5) the rate of vein patency at 6, 12, and 24 months.

Data Collection: Study data will be collected using electronic case report forms (eCRFs). Data sources include medical records, imaging reports, laboratory results, and patient-reported outcomes. A centralized data management system will be used for data storage, with regular monitoring for data quality and completeness.

Statistical Analysis: Continuous variables will be summarized using means and standard deviations or medians and interquartile ranges, as appropriate. Categorical variables will be presented as frequencies and percentages. Vein patency rates will be estimated using the Kaplan-Meier method, with 95% confidence intervals. Adverse events will be coded using standardized terminology and summarized by severity and relationship to the device/procedure.

Ethical Considerations: The study protocol has been approved by the institutional review boards of all participating centers. Written informed consent will be obtained from all participants prior to enrollment. The study will be conducted in accordance with the Declaration of Helsinki and Good Clinical Practice guidelines.