Early thrombosis after iliac stenting for venous outflow occlusion is related to disease severity and type of anticoagulation.

Abstract Background Stenting of the iliac venous system is often performed for symptomatic obstruction, with high patency rates reported. However, patients with post-thrombotic disease and those with more extensive obstruction have experienced poorer outcomes, including a higher rate of early post-stent thrombosis. In the present study, we examined the outcomes of patients with complete venous outflow occlusion. We focused on the variables associated with early post-stenting thrombosis to identify opportunities to reduce its incidence. Methods From 2010 to 2020, the patients who had undergone stenting for chronic obstruction of the common femoral vein, iliac veins, and/or inferior vena cava were retrospectively reviewed. The pre- and intraoperative imaging studies were examined to identify those who had had total occlusion of one venous outflow segment (type III disease) or multiple venous outflow segments (type IV disease). The patient characteristics and procedural and post-stent variables were recorded. The post-procedure follow-up visits and imaging studies were reviewed to determine stent patency and thrombotic complications. Key variables were studied to determine their association with early stent reocclusion. Results A total of 106 patients were identified, including 43 with type III (40.6%) and 63 with type IV (59.4%) disease. The mean patient age was 49.8 ± 13.7 years, and the mean stented length was 177.3 ± 63 mm. Stainless steel Wallstents were used solely in 44% of the cases, with a variety of nitinol stents used in the remainder. Femoral vein inflow was minimally diseased in 50% of the cases, moderately diseased in 26%, and severely diseased or occluded in 24%. Antiplatelet medications were prescribed after intervention for 52.8% and anticoagulation medication for 95.3% of the patients. Occlusion of the stented segment occurred within 3 months in 25.5%. Primary patency was 74.5% at 3 months, 63.9% at 12 months, and 58.5% at 3 years. Secondary patency was 93.4% at 3 months and 76.1% at 3 and 5 years. Univariate analysis of variables related to early stent thrombosis identified the presence of a hypercoagulable state, type IV obstruction, and the type of anticoagulation used after stenting were associated with early stent thrombosis. On multivariate analysis, each of these variables was independently associated with early stent thrombosis. The presence of type IV obstruction (odds ratio [OR], 4.596; 95% confidence interval [CI], 1.424-18.109) or a hypercoagulable state (OR, 3.835; 95% CI, 1.207-12.871) was associated with significantly greater odds of reocclusion than was class III obstruction and no hypercoagulable state. Treatment with low-molecular-weight heparin for >10 days was associated with significantly lower odds (OR, 0.012; 95% CI, 0.001-0.130) of reocclusion. Conclusions Patients who require recanalization of a completely occluded venous outflow tract before stenting have a high rate of early reocclusion. Patients with more extensive occlusion and a hypercoagulable state have greater odds of reocclusion. Treatment with low-molecular-weight heparin for >10 days reduced the odds of early reocclusion.