Establishing a Rodent Model of Venous Stent Thrombosis and In-Stent Restenosis

To establish a controlled small-animal model of venous stent placement enabling longitudinal evaluation of thrombosis, vessel wall remodeling, and in-stent restenosis (ISR). Antithrombotic treatment arms were included to assess the model's responsiveness to biologic differences.

Forty-four adult Sprague Dawley rats were randomized into saline (control), rivaroxaban, or clopidogrel groups. Self-expanding nitinol stents were deployed in the inferior vena cava (IVC). Stent patency and blood flow were assessed via high-frequency ultrasound (HFUS) at 1, 4, and 8 weeks. Histology was performed to evaluate neointimal hyperplasia and ISR.

Procedural success was 100%, with a 77.2% survival rate at 24 hours (34/44). Rivaroxaban-treated rats showed the highest stent patency and preserved flow velocities at 1 week (169 ± 54 mm/s vs. 98 ± 53 mm/s, p < 0.001). Clopidogrel-treated animals exhibited intermediate outcomes. At 8 weeks, control animals had the highest incidence of ISR and thrombosis. No significant difference in peak systolic velocities was noted in controls between 1 week (98 ± 53 mm/s) and 1 month (83 ± 24 mm/s; p = 0.327). At 4 weeks, 67% of controls, 80% of clopidogrel, and 100% of rivaroxaban-treated stents remained patent.

This study establishes a small-animal venous stent platform that integrates longitudinal imaging with structural validation of thrombosis and remodeling. The model demonstrates sensitivity to pharmacologic modulation and provides a foundation for mechanistic investigation and preclinical evaluation of venous stent therapies.