Twelve-month clinical outcomes of a hybrid oblique self-expanding nitinol stent used for the treatment of post-thrombotic syndrome with common iliac vein compression: The TOPOS study

Abstract

The majority of patients with iliofemoral deep vein thrombosis (DVT) have an underlying iliac vein compression.1 Approximately 50% develop the post-thrombotic syndrome (PTS) if treated conservatively.2 As in May–Thurner syndrome, common iliac vein lesions are typically located close to the iliocaval confluence and are caused by iliac vein compression from overriding iliac arteries against the spine. Conventional non-oblique stents had been used for many years to treat iliac vein compression syndromes by extending the stent across the iliocaval confluence into the inferior vena cava, thereby jailing the contralateral outflow. The risk of contralateral DVT with a conventional stent was 10% after 5 years.3 A self-expandable nitinol stent with a 35° obliqueshaped proximal end (sinus-Obliquus; Optimed, Ettlingen, Germany) was designed for the treatment of common iliac vein compression to minimize contralateral outflow obstruction (figure in the online supplemental material). In the prospective, international, monitored, single-arm TOPOS (Treatment Of Post-thrombotic syndrome with the Oblique Stent) study, we included 60 consecutive PTS patients who required endovascular therapy and who were treated with the self-expandable oblique stent for unilateral common iliac vein obstruction. TOPOS recruited from experienced centers that performed at least 30 deep venous interventions per year. We have described the study specifics and methodology previously.4 All participants provided written informed consent and the study was approved by local research ethics committees. In brief, stent extension of the oblique stent in or below the external iliac vein was permitted using the sinus-XL Flex or sinus-Venous stents (both from Optimed) in the case of insufficient stent inflow. TOPOS did not mandate the use of intravascular ultrasound (IVUS). Follow-up visits were scheduled for 3, 6, 12, and 24 months following the procedure, each of which included a duplex ultrasound exam for stent patency evaluation. The course of clinical signs and symptoms was estimated with the Villalta score and revised venous clinical severity score (rVCSS), as well as the patient based visual analog scale for pain (VAS) and the chronic lower limb venous insufficiency questionnaire (CIVIQ-20).5–7 Recently, all remaining study participants had completed the 12-month follow-up visit. The primary outcome was the primary patency rate at 12 months. The secondary outcomes were primary assisted patency, secondary patency, and changes in signs and symptoms at 12 months relative to baseline using the aforementioned clinical scores. Stent patency rates have been outlined in accordance with the reporting standards of the Society for Vascular Surgery.8 In case of an inconclusive ultrasound exam, it was adjudicated for the worst-case scenario (nonpatency). We calculated 12-month incidences for the primary Twelve-month clinical outcomes of a hybrid oblique self-expanding nitinol stent used for the treatment of post-thrombotic syndrome with common iliac vein compression: The TOPOS study