Post-Stent Vein Lumen Shape and Clinical Response in Patients Treated for Iliofemoral Venous Occlusive Disease

Objective Interventionalists have noted significant venous luminal gain with nitinol venous stents although post-placement lumen shape differed from the circular shape observed with elgiloy stents. The goal of this study was to determine the characteristics of a stented vein lumen that correspond with clinical outcomes, and to identify metrics that might be relevant for stent design by assessing aspect ratio (AR), lumen diameter (LD), lumen area (LA), and stent shape (symmetry and eccentricity) post-implant. Methods This post-hoc analysis evaluated patients from the VIVO US Study (NCT01970007) with pre- and post-stent intravascular ultrasound (IVUS) imaging. Patient characteristics, Venous Clinical Severity Score (VCSS) and Venous Disability Score (VDS) were collected in the study. LD, LA, and stent geometry were measured by the core laboratory. Data were analyzed for linear association between core-laboratory assessed pre and post stent LD, LA, AR, stent eccentricity and symmetry index, and VCSS and VDS change. Results IVUS imaging was available for 29 patients (2 sites) enrolled in the VIVO US Study (55.2% women; mean age: 59.8 ± 17 years). The cohort had post-thrombotic (48.3%), nonthrombotic iliac vein lesion (44.8%) or acute deep vein thrombotic (6.9%) disease. Mean lesion length was 111.8 ± 60.9 mm. Eleven stents extended below the inguinal ligament. Median minimum LD and LA significantly increased after stent placement ( P < 0.001); median lumen AR changed from 2.0 pre-stent to 1.4 post-stent ( P < 0.001). Mean VCSS improved from baseline to 12 months (7.6 ± 4.3 to 3.7 ± 2.6). No statistically significant linear relationships were identified between VCSS / VDS change and a specific characteristic of LA, LD, or AR. Conclusions Measures of lumen change pre and post iliofemoral vein nitinol stent placement reflect disease and stent characteristics. After stent placement, minimum LD and LA increased and AR decreased. Stented lumen shape or size with Zilver Vena did not impact 1-year clinical improvement by VCSS.