Is antithrombotic therapy necessary after stenting of nonthrombotic iliac vein lesions?

Presented herein is a literature review considering the problems of using antithrombotic therapy after venous stenting. Described herein are the literature data according to which the authors give preference to anticoagulant therapy (low-molecular-weight heparins, vitamin K antagonists, direct oral anticoagulants). This is followed by considering the problems of duration of treatment depending on various clinical situations. According to the presented data, the problem of prescribing disaggregants in a combination with anticoagulants after stenting of veins remains disputable, finding however many supporters. Analysed in the article are the results of the first International Delphi Consensus dedicated to antithrombotic therapy after venous stenting. Participating in the study were 106 independent experts practicing stenting in 78 centres of 28 countries of the world. Nonthrombotic iliac vein lesions, having appeared as May-Thurner syndrome due to extravasal compression and residual obstruction after thrombolysis, as well as the presence of postthrombotic syndrome were the main 'scenarios' for our study. The study resulted in working out provisions considering the policy of antithrombotic therapy in various obstructive lesions of deep veins. According to the presented data, anticoagulant therapy is preferable during 6-12 months after stenting in nonthrombotic iliac vein lesions. Low-molecular-weight heparins appear to be a method of choice in treatment during the first 2-6 weeks. Life-long administration of anticoagulants is recommended after multiple deep vein thromboses. Discontinuation of anticoagulants after 6-12 months is indicated after venous stenting in one episode of deep vein thrombosis. No consensus was achieved regarding the role of prolonged disaggregant therapy. Underlined in the article is the importance of a meticulous individual approach to choosing optimal policy of antithrombotic therapy and determining therapeutic policy together with a haematologist.

Principles of Optimal Antithrombotic Therapy for Iliac VEnous Stenting (POATIVES): A national expert-based Delphi consensus study

Objective: May-Thurner syndrome typically refers to symptoms and signs arising from the compression of the left common iliac vein by the right common iliac artery. However, such clinical manifestations can occur in the setting of compression of the right common iliac vein and/or either external iliac vein. Given this scenario, the more appropriate term for the condition would be non-thrombotic iliac vein lesion(s) [NIVL]. The goal of this review of large sample size studies is to evaluate outcomes following stenting for chronic iliofemoral venous obstruction (CIVO) due to NIVL, including clinical, quality-of-life, and stent-related outcomes. Additionally, where evidence gaps or controversies exist, expert opinion has been offered for guidance. Methods: A review of the literature was undertaken to determine the role of stenting for NIVL. Appropriate search terms were used to search PubMed, Cochrane Central Register of Controlled Trials, and EMBASE. Studies were only included if they had a sample size of at least 100 limbs that underwent stenting for NIVL and had at least 12 months of follow-up. Additionally, every study needed to have at least one metric of objective clinical evaluation [Venous clinical severity score (VCSS)] and/or a quality-of-life (QoL) measure (generic or venous disease-specific). Results: A total of six studies met the eligibility criteria and included 1404 limbs that underwent stenting for NIVL. All except three studies had a combination of PTS and NIVL limbs, with all six studies having at least 100 limbs that underwent stenting for NIVL. Follow-up varied from 12 to 50 months post-stenting. Improvements in VCSS and quality-of-life measures were noted post-stenting. Additional outcome measures, like grade of swelling or visual analog scale pain score, when utilized, also demonstrated improvement. Recurrence-free ulcer healing rates of 63% to 82% were observed. Good long-term stent primary stent patencies (74-98%) were also reported, irrespective of stent type. Conclusions: This review notes that good outcomes can be expected following stenting for CIVO due to NIVL. Gaps, however, exist with regard to patient selection, peri/post-procedural antithrombotic strategies, and long-term follow-up in this context. A CEAP clinical class-based algorithm is provided to help with patient selection in addition to guidance on antithrombotic therapy and follow-up. Further study of these areas is merited.

In patients receiving stents for symptomatic non-thrombotic iliac vein lesions, many clinicians prescribe anti-thrombotic medications. Whether or not anti-coagulation post-venous stenting improves stent patency is unknown. The aim of this investigation is to determine whether prophylactic post-operative anti-thrombotic therapy improves stent patency and/or prevents in-stent restenosis. The medical records and venous ultrasounds for 389 patients stented for non-thrombotic iliac vein lesions were retrospectively reviewed. Patients were categorized into three anti-thrombotic regimens: Clopidogrel, Aspirin and Clopidogrel, and Apixaban or Rivaroxaban. Patients were routinely assessed for restenosis and stent patency at 6, 26, and 52 weeks and treated with anti-thrombotics for 90 days. Freedom from in-stent restenosis at 6, 26, and 52 weeks were Clopidogrel (91.50, 82.91, 80.95%), Aspirin and Clopidogrel (88.68, 80.03, 80.03%), and Apixaban or Rivaroxaban (91.03, 85.11, 83.18%). Primary patencies were Clopidogrel (98.77, 98.77, 98.10%), Aspirin and Clopidogrel (100, 95.74, 95.74%), and Apixaban or Rivaroxaban (98.70, 98.70, 96.71%). There were no statistically significant differences. The type of post-operative anti-thrombotic therapy for non-thrombotic iliac vein lesions does not appear to improve stent patency or prevent the development of in-stent restenosis.

Stent implantation is the common treatment method for iliac vein (IV) occlusion. IV stents usually enter into the inferior vena cava (IVC) to partially or completely cover the contralateral IV, but it is still uncertain whether this can increase the risk of thrombosis in the contralateral IV. The purpose of this study was to investigate the effect of the stent position on the bilateral IVs patency. A total of 261 patients with symptomatic IV lesions, including 177 patients with non-thrombotic iliac vein lesions (NIVLs) and 84 patients with thrombotic iliac vein lesions (TIVLs), were implanted with IV stents between July 2007 and June 2017. The data of these patients were retrospectively studied. The follow-up time was 6-114 months, and the median time was 62 months. A total of 183 cases had stenting into the IVC for more than 5mm. The incidence of thrombosis in the contralateral IV was only 0.55% (1/183). A total of 17 short- and long-term cumulative cases had ipsilateral thrombosis on the stent side. There was no significant difference between the incidence of patients (8.79%, 7/78) with stenting into the IVC for less than 5mm and those with more than 5mm (5.46%, 10/183, P = 0.287). However, in the TIVLs group, the incidence of ipsilateral thrombosis between stenting positions less than 5mm (29.6%, 8/27) and those more than 5mm (8.77%, 5/57) was significantly different (P = 0.022). Stent implantation for NIVLs had an excellent long-term patency rate; the primary patency rate and the assisted primary patency rate were 97.7% and 100%, respectively. The entry of IV stents into the IVC was safe and had a very low incidence of thrombosis in the contralateral vein. Stenting less into the IVC increased the incidence of thrombosis in the ipsilateral vein, especially among thrombotic cases. Treatment of NIVLs using stent implantation had a better long-term patency rate. This principle plays an important guiding role in the endovascular therapy of IV lesions.

High prevalence of nonthrombotic iliac vein lesions in chronic venous disease: A permissive role in pathogenicity

Stenting for iliac vein stenosis or compression has become a common therapeutic approach in recent years. The antithrombotic therapy after the stent deployment, however, reaches no consensus. Medications strategies and patients' prognoses differ in non-thrombotic, acute thrombotic and chronic thrombotic these three circumstances. Non-thrombotic patients usually possess satisfactory stent patency whatever antithrombotic therapy is used. Anticoagulant is the basic medication for acute thrombotic patients, benefits from additional antiplatelet drug remains to be clarified. In terms of chronic thrombotic patients, their prognoses are unsatisfactory under all antithrombotic therapies. In this review, we outlined the recent progress of antithrombotic therapy after iliac vein stenting, aiming to provide feasible medication plans for each circumstance.

Antithrombotic Therapy Following Venous Stenting: International Delphi Consensus

Objective To investigate the value of computed tomography venography (CTV) in the evaluation of post-thrombolic syndrome (PTS) and nonthrombotic iliac vein lesions (NIVL). Methods Clinical data of patients with PTS or NIVL experienced both CTV and digital subtraction angiography (DSA) examination in our department from January 2014 to February 2016 were analyzed retrospectively. The differences of two methods in the diagnosis of PTS and NIVL were compared. Results One hunderd and fifty-eight consecutive patients, 96 for PTS and 32 for NIVL, were presented. Compared with DSA in diagnosis of PTS and NIVL, CTV's sensitivity, specificity, Youden index, positive likelihood ratio and negative likelihood ratio was 94.8% and 93.8%, 87.1% and 96.0%, 0.819 and 0.898, 7.35 and 23.45, 0.06 and 0.06, respectively. Both Kappa values were> 0.7 and there was no significant difference (P>0.05, McNemar test) between the two groups. Both area under curves (AUC) were > 0.9 showed by receiver operating characteristic (ROC) curve. Conclusions CTV is remarkable in sensitivity and specificity for PTS and NIVL, which is consistent with DSA. There are no significant differences between CTV and DSA in the diagnosis of PTS and NIVL. CTV is important for the diagnosis and preoperative assessment of PTS and NIVL. Key words: Post-thrombolic syndrome; Nonthrombotic iliac vein lesions; Computed tomography venography; Digital subtraction angiography

Objective To assess the safety and influence of the stents extended into inferior vena cava in patients with non-thrombotic iliac vein lesions (NIVLs) on the bilateral iliac vein blood flow. Methods We retrospectively reviewed data from July 2008 to June 2017 in 197 patients with NIVLs who underwent iliac vein stenting and complete follow-up was obtained at our institution.Of these patients, stents extended into IVC more than 10 mm in 141 cases, less than 5 mm in 22 cases, and 34 cases were between 5 and 10 mm.Restenosis and thrombosis of bilateral iliac vein and patency of these stents were assessed in the follow-up.The count data were expressed by percentage (%), and the sample comparison rate was analyzed by Fisher exact test formula.The measurement data were first tested for normal distribution and homogeneity of variance, and then corrected t test. Results The two hundred and five iliac vein stents were placed in 197 patients. During a mean follow-up of 58.7 months (6 to 98 months), there were no thrombosis occurred in the contralateral iliac vein, 6 patients suffered restenosis or new thrombosis in the stents, the incidence between stenting positions less than 5 mm (13.6%, 3/22) and those more than 5 mm (3.43%, 6/175) was sighificantly different (P<0.001), and 5 of 6 patients had a good patency after endovascular therapy. During the fllow-up, the primary and assisted-primary patency rates were 97.0% and 99.5%. Conclusions From these data, it appears that there is a very high patency rates of the stenting treatment for the NIVLs, and it is safe for the stents extended into the IVC, stenting across the iliocaval confluence can result in a small number of new contralateral thromboses. Moreover, the risk of stents restenosis or occlusion is high when stents are not extended into IVC. Key words: Iliac vein; Stent; Vein thrombosis; Interventional therapy

10:30 AM Abstract No. 1 ■ ABSTRACT OF THE YEAR A prospective, multicenter evaluation of the Venovo self-expanding vascular stent used to treat obstructive lesions of the iliac and femoral veins: 12-month results from the VERNACULAR trial

Timing of outpatient stenting is associated with stent size in nonthrombotic iliac vein lesions

Contemporary Outcomes of Elective Iliac Vein Stenting in Chronic Venous Occlusive Disease

To determine the diagnostic accuracy of preinterventional imaging modalities in patients being evaluated for iliocaval venous recanalization and stent placement. Consecutive patients with iliocaval postthrombotic obstructions or nonthrombotic iliac vein lesions (NIVL), who were scheduled for recanalization, underwent duplex ultrasound (DUS), magnetic resonance venography (MRV), multiplanar venography (MPV), and intravascular ultrasound (IVUS). The diagnostic accuracies of DUS, MRV, and MPV were analyzed using IVUS as reference. A total of 216 limbs in 108 patients (80 patients with postthrombotic obstructions, 28 patients with NIVL) were examined. In patients with postthrombotic obstructions, the diagnostic sensitivities for the detection of lesions of the common femoral vein were 81% (95% CI 71-89%) for DUS, 76% (95% CI 65-85%) for MRV, and 86% (95% CI 76-93%) for MPV. The sensitivities for detecting lesions of the iliac veins were 96% (95% CI 89-99%) for DUS, 99% (95% CI 92-100%) for MRV, and 100% (95% CI 94-100%) for MPV. Regarding the inferior vena cava, the sensitivities were 44% (95% CI 24-65%) for DUS, 52% (95% CI 31-73%) for MRV, and 70% (95% CI 47-86%) for MPV. The sensitivities for detecting NIVL were 58% (95% CI 34-79%) for DUS, 90% (95% CI 68-97%) for MRV, and 95% (95% CI 73-99%) for MPV. In patients scheduled for recanalization of iliocaval postthrombotic obstructions, the sensitivities of DUS, MRV, and MPV were similar. In patients with suspected inferior vena cava involvement and in patients with NIVL, additional imaging with MR or conventional venography is required.

Treatment of Acute Iliofemoral Deep Venous Thrombosis by Thrombus Removal