Pivotal Study Evaluating the Safety and Effectiveness of the Abre Venous Self-Expanding Stent System in Patients With Symptomatic Iliofemoral Venous Outflow Obstruction

Abstract

Background: Iliofemoral venous obstruction is recognized with increasing frequency as the underlying cause of lower extremity symptoms including edema, pain, skin changes, and, in advanced cases, ulceration. This study sought to evaluate the safety and effectiveness of the Abre venous self-expanding stent system for the treatment of symptomatic iliofemoral venous outflow obstruction.

Methods: The ABRE Study (A Multi-Center, Non-Randomized Study to Evaluate the Safety and Effectiveness of the Abre Venous Self-Expanding Stent System in Patients With Symptomatic Iliofemoral Venous Outflow Obstruction) is a single-arm, multicenter, prospective study that included 200 subjects from 24 global sites. The primary end points were 12-month primary patency and major adverse events within 30 days. Secondary end points included lesion and procedure success, primary-assisted and secondary patency, major adverse events, stent migration, stent fracture, and quality of life changes. End point-related adverse events and imaging studies were adjudicated by independent clinical events committee and core laboratories, respectively.

Results: Venous obstruction cause was classified as acute deep vein thrombosis (16.5%, 33/200), post-thrombotic syndrome (47.5%, 95/200), or nonthrombotic iliac vein lesion (36.0%, 72/200). The common iliac and external iliac veins were stented in 96.0% (192/200), 80.5% (161/200) of subjects, respectively. Stent implant into the common femoral vein was required in 44.0% (88/200). Primary patency at 12 months was 88.0% (162/184). Four (2.0%) major adverse events occurred within 30 days. Twelve-month primary-assisted and secondary patency were 91.8% (169/184) and 92.9% (171/184), respectively. No stent fractures or migrations were reported. Mean target limb Villalta score decreased from 11.2±5.6 at baseline to 4.1±4.8 at 12 months, and the mean target limb revised Venous Clinical Severity Score decreased from 8.8±4.7 at baseline to 4.3±3.6 at 12 months. Clinically meaningful improvements in quality of life and venous functional assessment scores from baseline were demonstrated through 12 months in all measures.

Conclusions: Symptomatic iliofemoral venous obstruction can be successfully treated with an Abre venous stent. Study outcomes demonstrated a high patency rate with a good safety profile. Patients demonstrated a significant reduction in clinical symptoms and improvement in quality of life that was maintained through 12-month follow-up. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03038438.

Keywords: iliac vein; quality of life; stent; thromboembolism; thrombosis.

Figure 1.

Abre venous stent design. The width and thickness of the struts on the Abre venous stent were altered for each stent diameter to achieve strength uniformity of all stent sizes, and the strut radii were opened selectively to achieve maximal fracture resistance. The stent has connection points that spiral down the stent (A, green circles). The stent cells are connected at 3 points around the circumference for maximum flexibility and kink resistance (A, blue squares). The Abre venous stent is easily seen under fluoroscopy (B, C) with 3 radiopaque markers on the cranial and caudal stent ends (see arrows on A, B, and C).

Figure 2.

Subject compliance flowchart. The ABRE Study (A Multi-Center, Non-Randomized Study to Evaluate the Safety and Effectiveness of the Abre Venous Self-Expanding Stent System in Patients With Symptomatic Iliofemoral Venous Outflow Obstruction) included 200 subjects with 191 (95.5%) subjects completing the 12-mo follow-up.

Figure 3.

Kaplan-Meier estimates of patency. A, Primary patency rates through 12 mo across subgroups. B, Patency estimates by Kaplan-Meir estimate through 12 mo. aDVT indicates acute deep vein thrombosis; NIVL, nonthrombotic iliac vein lesion; PAP, primary assisted patency; PP, primary patency; PTS, post-thrombotic syndrome; and SP, secondary patency.

Figure 4.

Summary of quality of life and functional assessments. Quality of life and functional assessments were taken at baseline (0 d), 6 mo, and 12 mo. Sustained and clinically meaningful improvement were demonstrated for all measures at 12 mo compared with baseline, despite a high proportion of stents crossing the inguinal ligament. A, Venous Insufficiency Epidemiological and Economics Study Quality of Life (VEINES-QoL). B, VEINES-Symptoms. C, Villalta score. D, Revised Venous Clinical Severity Score (VCSS). E, EuroQoL Five Dimensions (EQ-5D). aDVT indicates acute deep vein thrombosis; NIVL, nonthrombotic iliac vein lesion; and PTS, post-thrombotic syndrome.