373 - Preprocedural Lower Extremity Inflow Status Correlates with Early Re-Occlusion After Thrombectomy for Deep Vein Thrombosis

Purpose: To determine whether pre-procedural inflow status predicts outflow tract re-occlusion after thrombectomy in iliofemoral or femoropopliteal deep vein thrombosis (DVT).

Materials and Methods: A single-center retrospective analysis of patients undergoing thrombectomy with multiple devices from 2018 to mid-2023 was conducted. First-time unilateral iliofemoral or femoropopliteal DVTs without evidence of extensive collateralization constituted the outflow conduit. Pre-procedural duplex within 72 hours was used to assess profunda femoris (PF) and tibioperoneal trunk (TPT) inflow, while follow-up duplex within 90 days evaluated re-occlusion within the outflow conduit. Demographic and presenting characteristics were collected, excluding patients with underlying malignant obstruction or strictures and those for whom treatment was aimed at inflow vessels. Group differences were tested using Chi-square tests, and the odds of re-occlusion were analyzed using logistic regression.

Results: Among 64 patients without prior intervention, outflow patency at 90 days was achieved in 26 of 29 patients with an open PF. Similarly, 26 out of 33 with an open TPT achieved outflow patency. Inflow status achieved significantly different outflow re-occlusion rates, with 10% versus 54% re-occlusions observed when the PF was respectively open versus occluded (χ², p = 0.0006). Similar differences were observed for TPT status (χ², p = 0.043). Single inflow vessel occlusion proved to have limited discrimination for short-term re-occlusion, with half of the outflow vessels remaining patent at 90 days (n=16/35 for PF; n=16/31 for TPT). Composite inflow occlusion results in a stepwise increase in 90-day re-occlusion rates: 6% when neither was occluded, 29% if one was occluded, and 68% if both were. Each additional occluded inflow vessel increased the odds of re-occlusion by six times (OR 5.7, 95% CI 2.4–16.3, p < 0.0001). Limitations include the operator’s dependency on ultrasound and the lack of formal assessment for confounders.

Conclusion: Irrespective of procedural details, pre-procedural inflow status correlated with short-term re-occlusion in this lower extremity DVT thrombectomy cohort. Systematic assessment of inflow patency during the procedure is challenging in a retrospective manner, and whether the treatment of PF and TPT occlusion alters short- and long-term patency remains to be determined.