Factors Associated with Contralateral Deep Venous Thrombosis after Iliocaval Venous Stenting

Background: The majority of iliac venous obstructions occur on the left side, and endovascular therapy has become the first line treatment for this condition. A left common iliac venous stent will protrude into the inferior vena cava (IVC) to some extent, thereby covering the contralateral common iliac vein (CIV) outflow. This may increase the risk of thrombosis of the contralateral iliac vein. The aim of this paper was to determine the rate of, and factors associated with, contralateral lower limb venous thrombosis after stenting, and to evaluate the results of salvage revascularisation. Methods: A total of 376 patients (102 from UCH, Galway, Ireland, 2008-16, and 274 from, CHU Nord, Marseille, France, 2000-15) with symptomatic acute or chronic left iliocaval venous obstruction were retrospectively evaluated. Either duplex ultrasound scanning (DUS) or computed tomographic venography (CTV) was used for pre- and post-operative imaging. Data were collected from the PACS system (IMPAX, Agfa, BE) of the Radiology Department, UCH, Galway, and from the electronic medical records of Vascular Surgery department, CHU Nord, Marseille. Results: The median age of stented patients was 46 (range 15-86 years), 80% were female (301/376). Following left CIV stent placement, 10 patients later presented with a right (contralateral) iliac deep venous thrombosis (DVT) resulting in a cumulative incidence of contralateral DVT of 4% according to Kaplan-Meier analysis. Acute DVT (p=.001), non-compliance with the prescribed 6 months anticoagulation (p = 0.05), pre- operative contralateral internal iliac vein (IIV) thrombosis (p = 0.001), and pre- existing IVC filter placement (p = 0.003) were all statistically significantly associated with contralateral DVT. All patients with symptomatic contralateral iliac DVT underwent clot removal in the acute phase. The primary patency of these limbs was 100% at 3 years. Conclusion: Stent placement across the iliocaval confluence from the left CIV is associated with a low but definite rate of contralateral iliac vein thrombosis. Acute DVT, pre- operative contralateral IIV thrombosis, pre- existing IVC filters, and anticoagulation non-compliance are significant risk factors. (C) 2017 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.