Pivotal Evaluation of Novel Dedicated Venous Stent for Iliofemoral Venous Obstruction: A Prospective Cohort Study

Purpose: The purpose was to evaluate the clinical outcomes of a dedicated venous stent with the tripartite composite segments for the treatment of iliofemoral venous obstruction (IVO) in a mixed cohort of nonthrombotic iliac vein lesion (NIVL) and post-thrombotic syndrome (PTS) over a period of 12 months. Methods: The Grency Trial is a prospective, multicenter, single-arm, open-label, pivotal study, which was conducted at 18 large tertiary hospitals in China from August 2019 to October 2020. A total of 133 hospitalized patients were screened and 110 patients with clinical, etiology, anatomical, and pathophysiology clinical class (CEAP) clinical grade C>3 and iliac vein stenosis >50% or occlusion, including 72 patients with NIVL and 38 patients with PTS, were implanted with Grency venous stents. Primary endpoint was stent patency at 12 months follow-up, and secondary outcomes were technical success; improvement in venous clinical severity score (VCSS) at 3, 6, and 12 month follow-up; and rates of clinical adverse events. Results: Among 110 patients who were implanted with Grency venous stents, 107 patients completed the 12 month follow-up. All 129 stents were successfully implanted in 110 limbs. Twelve-month primary patency rate was 94.39% [95% confidence interval [CI]=88.19%-97.91%] overall, and 100% [94.94%-100%] and 83.33% [67.19%-93.63%] in the NIVL and PTS subgroups, respectively. Venous clinical severity score after iliac vein stenting improved significantly up to 12 months follow-up. There were 3 early major adverse events (1 intracerebral hemorrhage and 2 stent thrombosis events related to anticoagulation therapy), and 7 late major adverse events (1 cardiovascular death, 1 intracranial hemorrhage with uncontrolled hypertension, and 5 in-stent restenosis cases without stent fractures or migration). Conclusions: The Grency venous stent system appeared excellent preliminary safe and effective for IVO treatment. Further large-scale studies with longer-term follow-up are needed to evaluate long-term patency and durability of stent. Clinical impact The design of venous stents for iliofemoral venous obstruction (IVO) must address engineering challenges distinct from those encountered in arterial stenting. The Grency venous stent, a nitinol self-expanding stent specifically tailored for IVO, features a composite structure designed to meet the stent requirements of various iliac vein segments. The Grency Trial is a prospective, multicenter, single-arm, open-label pivotal study aimed at evaluating the efficacy and safety of the Grency stent system. Following a 12-month follow-up period, the Grency venous stent system has demonstrated both safety and efficacy in treating iliofemoral venous outflow obstruction.