Venous Stenting in Proximal Venous Outflow Obstruction – Lessons Learned from 500 Cases

Abstract

Introduction - Venous stenting is emerging as an important treatment strategy in venous disease. What is the real world experience with this procedure? This study reviews our experience with venous stenting in chronic venous insufficiency, highlighting patient selection, procedural considerations, outcomes, and re-interventions. Methods - This is a retrospective study of 500 patients who underwent venous stenting for chronic proximal venous outflow obstruction (PVOO) in the iliac veins from October 2013 to August 2016 at one centre. Preoperatively, we utilized venous duplex scan and magnetic resonance venogram to assist in patient selection. Intraoperative evaluation comprised of bilateral venogram and intravascular ultrasound. Wallstents were used in all cases (Boston Scientific, MA). Patients were discharged on day of procedure with rivaroxaban 10 mg initially followed by long-term Aspirin 81 mg. Wilcoxon-Mann-Whitney, Kruskal-Wallis, and logistic regressions were used in statistical analysis of variables and outcomes. Results - Of these 500 patients, follow-up was maintained in 90% of patients with a mean follow-up 320 days. Mean age of patients was 60 years old (SD 13.4 years) and 57% were female. Preoperatively, edema was present in 90.5%, and active ulceration 10.7%. 85 patients (17%) presented with persistent symptoms after a prior endovenous thermal ablation or surgery for superficial venous disease, and 69 patients (13.8) presenting with post-thrombotic syndrome. Among patients without any known DVT history, 21.5% had findings of chronic phlebitic changes (long segment diffuse disease, occlusion of vessel, intraluminal filling defects) on venogram or IVUS. Bilateral vein stents were performed in 59%. Kruskal-Wallis tests were significant for improvement (symptoms, CEAP class, and physical exam) in patients at thirty days (p=0.027), ninety days (p=0.045), six months (p=0.037), and one year (p=0.012). Ordered logistic regressions found the presence of edema (coefficient 1.59, 95% CI [0.52, 2.65], p=0.004), active ulceration (95% CI [0.022, 3.40], p=0.047), and decreased number of stents placed (coefficient -0.56, 95% CI [-1.08, -0.036], p=0.036) to predict increased improvement at thirty days, and a history of DVT (coefficient: -0.94, 95% CI [-1.79, -0.096], p=0. 029) to predict decreased improvement at one year post-operatively. Wilcoxon-Mann-Whitney tests were significant for more improvement in patients who had unilateral versus bilateral stents placed at thirty days (p=0.013) and six months (p=0.039). Major re-interventions (61.7% for recurrent symptoms, 17.6% for persistent symptoms, 6% for DVT) were performed in 7.6% of patients. Mean time to re-intervention was 191 days, and re-interventions were more prevalent (29. 4%) among patients with a known history of DVT. Conclusion - Our experience with venous stenting in chronic PVOO on an expanded scale suggested a satisfactory outcome at one year. Those patients with a prior history of DVT have poorer outcomes after venous stenting. Unilateral stents have better outcomes than bilateral stents, but the difference may reflect complexity of disease. Approximately 8% of patients will require a secondary re-intervention. Patient selection, procedural indications, and optimal pharmacologic therapy after venous stenting need further studies and clarification.