Risk factors of moderate-severe Post-thrombotic syndrome within 2 years in patients with subacute thrombosis: A case-control study

OBJECTIVE

To study the risk factors influencing the occurrence of moderate-severe post-thrombotic syndrome (PTS) within 2 years in patients with subacute lower extremity deep vein thrombosis (DVT).

METHODS

Seventy patients who developed moderate-severe PTS within 2 years after subacute lower extremity DVT from June 2018 to June 2022 were retrospectively selected as the case group. They were matched 1:1 by sex and age (±5 years) with 70 patients who did not develop moderate- severe PTS during the same follow-up period as the control group. Multiple logistic regression, stratified analysis, and interaction analyses were used to explore the risk factors for moderate-severe PTS.

RESULTS

The multiple logistic regression model showed that patients with iliofemoral vein thrombosis had a significantly increased risk of developing moderate-severe PTS within 2 years. Patients who underwent intraluminal intervention treatment during hospitalization had a significantly reduced risk. The odds ratios (ORs) were 4.000 (95%CI 1.597∼10.016) for the femoral-popliteal vein thrombosis and 0.262 (95%CI 0.106∼0.647) for the anticoagulation treatment group. The stratified analysis showed that intraluminal intervention treatment was a protective factor against moderate-severe PTS within 2 years across different strata of hypertension, thrombus type, BMI, duration of anticoagulation, and wearing compression stockings. Additionally, there was an interaction between thrombus type and treatment method, with intraluminal intervention treatment having a more pronounced effect on preventing moderate-severe PTS in patients with iliofemoral vein thrombosis.

CONCLUSION

Iliofemoral vein thrombosis is a risk factor for the development of moderate-severe PTS within 2 years in patients with subacute lower extremity DVT. Intraluminal intervention treatment can reduce the risk of moderate-severe PTS, especially in patients with iliofemoral vein thrombosis.

Antithrombotic Therapy after Deep Venous Intervention

Chronic deep venous disease (CVD) can result in significant morbidity and impact on quality of life due to a spectrum of symptoms, including lower extremity edema, venous claudication, and venous ulcers. CVD can be secondary to both thrombotic and nonthrombotic disease processes, including postthrombotic syndrome from prior deep vein thrombosis (DVT) or iliac vein compression syndrome. Endovascular therapy has become a mainstay therapy for CVD patients, with venous stent placement frequently performed. However, the management of anticoagulation following venous stent placement is not well-studied, with no large trials or consensus guidelines establishing an optimal regimen. The current knowledge gap in antithrombotic therapy is magnified by heterogeneity in practice and data collection, along with incomplete reporting in available studies. Furthermore, most published datasets are antiquated in the setting of rapid evolution in technique and technology available for deep venous intervention. Herein, we summarize the current available literature and offer an approach to anticoagulation and antiplatelet management following deep venous intervention for CVD.

A Systematic Review and Meta-Analysis of 12-Month Patency After Intervention for Iliofemoral Obstruction Using Dedicated or Non-Dedicated Venous Stents

BACKGROUND

Endovascular stenting of the deep venous system has been proposed as a method to treat patients with symptomatic iliofemoral outflow obstruction. The purpose of this systematic review and meta-analysis was to compare the effectiveness of this treatment at 1-year following the development of dedicated venous stents.

METHOD AND RESULTS

We searched MEDLINE and EMBASE for studies evaluating the effectiveness of venous stent placement. Data were extracted by disease pathogenesis: non-thrombotic iliac vein lesions (NIVL), acute thrombotic (DVT), or post-thrombotic syndrome (PTS). Main outcomes included technical success, stent patency at 1 year and symptom relief. A total of 49 studies reporting outcomes in 5154 patients (NIVL, 1431; DVT, 950; PTS, 2773) were included in the meta-analysis. Technical success rates were comparable among groups (97%-100%). There were no periprocedural deaths. Minor bleeding was reported in up to 5% of patients and major bleeding in 0.5% upon intervention. Transient back pain was noted in 55% of PTS patients following intervention. There was significant heterogeneity between studies reporting outcomes in PTS patients. Primary and cumulative patency at 1 year was: NIVL-96% and 100%; DVT-91% and 97%; PTS (stents above the ligament)-77% and 94%, and; PTS (stents across the ligament)-78% and 94%. There were insufficient data to compare patency outcomes of dedicated and nondedicated venous stents in patients with acute DVT. In NIVL and PTS patients, stent patency was comparable at 1 year. There was inconsistency in the use of validated tools for the measurement of symptoms before and after intervention. When reported, venous claudication, improved in 83% of PTS patients and 90% of NIVL patients, and ulcer healing occurred in 80% of PTS patients and 32% of NIVL patients.

CONCLUSIONS

The first generation of dedicated venous stents perform comparably in terms of patency and clinical outcomes to non-dedicated technologies at 1 year for the treatment of patients with NIVL and PTS. However, significant heterogeneity exists between studies and standardized criteria are urgently needed to report outcomes in patients undergoing deep venous stenting.

Three-Year Results from the Venovo Venous Stent Study for the Treatment of Iliac and Femoral Vein Obstruction

Purpose

To assess safety and patency of the Venovo venous stent for the treatment of iliofemoral vein obstruction.

Materials and Methods

Twenty-two international centers enrolled 170 patients in the VERNACULAR study (93 post-thrombotic syndrome; 77 non-thrombotic iliac vein lesions). Primary outcome measures were major adverse events at 30 days and 12-month primary patency (freedom from target vessel revascularization, thrombotic occlusion, or stenosis > 50%). Secondary outcomes included the Venous Clinical Severity Score Pain Assessment and Chronic Venous Quality-of-Life Questionnaire assessments (hypothesis tested). Secondary observations included primary patency, target vessel and lesion revascularization (TVR/TLR), and assessment of stent integrity through 36 months.

Results

Freedom from major adverse events through 30 days was 93.5%, statistically higher than a pre-specified performance goal of 89% (p = 0.032) while primary patency at 12 months was 88.6%, also statistically higher than a performance goal of 74% (p < 0.0001). Mean quality-of-life measures were statistically improved compared to baseline values at 12 months (p < 0.0001). Primary patency at 36 months was 84% (Kaplan–Meier analysis) while freedom from TVR/TLR was 88.1%. There was no stent embolization/migration, and no core laboratory assessed stent fractures reported through 36 months. Six deaths were reported; none adjudicated as device or procedure related.

Conclusion

The Venovo venous stent was successfully deployed in obstructive iliofemoral vein lesions and met the pre-specified primary outcome measures through 12 months. At 3 years, primary patency was 84%, reintervention rates were low, standardized quality-of-life and pain measures improved from baseline, and there was no stent migration or fractures.

Level of Evidence

Level 2—prospective, multicenter, controlled clinical study without a concurrent control or randomization. Pre-specified endpoints were hypothesis-tested to performance goals derived from peer-reviewed clinical literature.

Registration clinicaltrials.gov

Unique Identifier NCT02655887.

Endovascular and medical therapy of May-Thurner syndrome: Case series and scoping literature review

INTRODUCTION

May-Thurner syndrome has been recognized as a cause of chronic venous insufficiency and a trigger for venous thromboembolism. There is no consensus about the definition, diagnosis, and therapeutic approach. We are aiming to describe its characteristics and a scoping literature review.

METHODS

A retrospective review of patients with May-Thurner syndrome from March 2010 to May 2018 and scoping literature review were made.

RESULTS

Seven patients were identified. All patients were female with a median age of 36 (20-60) years. The median time from the first symptom to diagnosis was 3.41 (0.01-9) years. The primary clinical presentation was post-thrombotic syndrome (4 patients). Six patients had at least one risk factor for deep venous thrombosis. All patients underwent angioplasty with stent; patients with acute deep venous thrombosis, furthermore mechanic thrombectomy with or without catheter-directed thrombolysis were done. There were three complications (one patient, lymphedema, and two venous stent thrombosis). Scoping review results were descriptively summarized.

CONCLUSION

May-Thurner syndrome has a varied spectrum of clinical presentation, and clinical awareness is paramount for diagnosis. Its principal complication is the post-thrombotic syndrome, which is associated with high morbidity. There is no consensus on the antithrombotic treatment approach.

Post-thrombotic Syndrome: Preventative and Risk Reduction Strategies Following Deep Vein Thrombosis

Venous disease is common in the general population, with chronic venous disorders affecting 50–85% of the western population and consuming 2–3% of healthcare funding. It, therefore, represents a significant socioeconomic, physical and psychological burden. Acute deep vein thrombosis, although a well-recognised cause of death through pulmonary embolism, can more commonly lead to post-thrombotic syndrome (PTS). This article summarises the pathophysiology and risk factor profile of PTS, and highlights various strategies that may reduce the risk of PTS, and the endovenous management of iliofemoral deep vein thrombosis. The authors summarise the advances in PTS risk reduction strategies and present the latest evidence for discussion.

Antithrombotic Therapy after Venous Stent Placement

Chronic deep venous disease (CVD) affects millions of Americans and can result in significant morbidity, such as debilitating lower extremity oedema, venous claudication, and in severe cases, venous ulcers. CVD can be caused by thrombotic and non-thrombotic disease processes, such as deep venous thrombosis and iliac compression syndrome. Recently, endovascular intervention with percutaneous transluminal angioplasty and venous stent placement has become the mainstay therapy for these patients, with several studies demonstrating its safety and efficacy. However, anticoagulation management following venous stent placement is largely unstudied, and there are no large randomised controlled trials or official guidelines establishing an optimal regimen. Most published studies are plagued with data heterogeneity and incomplete reporting. This is further complicated by rapidly evolving improvements in technique and dedicated devices in endovenous intervention. In this article, the authors discuss the current literature to date and offer an approach to anticoagulation and antiplatelet management following venous stent placement in CVD.

An efficacy and safety study of rivaroxaban for the prevention of deep vein thrombosis in patients with left iliac vein compression treated with stent implantation (PLICTS): study protocol for a prospective randomized controlled trial

BACKGROUND

Balloon dilatation with stent implantation has been proved to be an effective option for left iliac vein compression syndrome (LIVCS), but thrombosis may still occur after the operation. Currently, warfarin is used for anticoagulant therapy, but long-term monitoring is required, while rivaroxaban does not need laboratory monitoring, which can simplify treatment. Therefore, this study aimed to compare the efficacy and safety of rivaroxaban and warfarin in anticoagulation.

METHODS

This study is a multicenter, randomized controlled trial. We will recruit 224 patients with thrombotic LIVCS from 9 hospitals. Moreover, these patients will be randomized to either the experimental group (rivaroxaban) or the control group (warfarin plus nadroparin). The primary outcome is stent occlusion rate. Secondary outcomes are quality of life scale survey results, all-cause mortality, anticoagulation-related mortality, and the proportion of participants with stent displacement/fracture, thrombosis, hemorrhage, and other vascular events.

DISCUSSION

This study will provide reliable, evidence-based clinical evidence for the efficacy and safety of rivaroxaban antithrombotic therapy after stent implantation.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04067505 . Registered on August 26, 2019.

Modified one-session endovascular treatment for deep venous thrombosis with high risk of pulmonary embolism: Short-term outcomes

OBJECTIVES

To evaluate the safety and short-term outcomes of the modified one-session endovascular treatment with inferior vena cava filter placement and retrieval in one stage for the treatment of acute lower extremity deep vein thrombosis.

METHOD

Twenty-three patients with unilateral acute lower extremity deep vein thrombosis underwent modified one-session endovascular treatments, which were performed in one stage. Inferior vena cava filter placement without detachment, thrombectomy, and inferior vena cava filter retrieval were performed in one stage. Angioplasty and stent implantation were performed for patients with iliac vein stenosis. Venography was performed to identify the clearance of the thrombus. Color Doppler ultrasound and/or venography were conducted during the follow-up.

RESULTS

A total of 20/23 (87%) patients with thrombus removal rate >90% successfully underwent modified one-session endovascular treatment. inferior vena cava filters were detached in 3/23 (13%) patients achieving 50%-90% thrombus removal rate. Twenty-one iliac vein stents were implanted in 21/23 (91%) patients with iliac vein stenosis. After treatment, the differences in the circumferences of the affected limb and the healthy limb both significantly decreased. No procedure-related death, symptomatic pulmonary embolism, or major bleeding occurred. During the 12-25 months of follow-up, iliac vein stents and lower extremity veins maintained patent.

CONCLUSIONS

The modified one-session endovascular treatment with one-stage inferior vena cava filter placement and retrieval might be safe for the treatment of acute lower extremity deep vein thrombosis, and the early clinical outcomes are satisfactory. Placing and retrieving an inferior vena cava filter in one session could safeguard the endovascular interventions as well as reduce the filter-related complications associated with long dwelling times.

Strategies for the diagnosis and treatment of the iliac vein compression syndrome

Aim

To evaluate the diagnosis and treatment strategies for the iliac vein compression syndrome (IVCS) and the factors that affect the treatment outcome.

Methods

In total, 69 patients with IVCS were enrolled in the study. The patients underwent computed tomography (CT) venography before treatment. CT observations included assessment of the iliac venous channel sagittal diameter (IVCD) before the lower lumbar vertebra, causes of oppression, thrombus density, and embolization range. The patients with IVCS were divided into the simple IVCS (sIVCS, n = 22), lumbar degeneration-related type IVCS (dIVCS, n = 33), and IVCS of other causes (oIVCS, n = 14) including lumbar fracture, hematoma of infection, and abscess wraping around and compressing the iliac vein, groups. The treatment methods included target venous catheter-directed thrombolysis (CDT), a mechanical breaking and sucking treatment for the thrombi, followed by balloon dilatation and iliac vein stent implantation. The factors that may possibly affect the treatment outcomes included IVCS type, duration of disease, thrombus hardness, embolization length, and treatment regimen. Logistic regression was used to analyze the factors that affected the therapeutic efficacy.

Results

At the first stage, CDT was only effective in 15 cases (5 dIVCSs and 10 oIVCSs) and was ineffective in the remaining 54 cases, which required further mechanical breaking and sucking of the thrombi and intravenous balloon dilatation. In the second stage, combination of thrombi breaking and suction and balloon dilatation was preliminarily effective in 26 cases (6 sIVCSs, 16 dIVCSs and 4 oIVCSs), but during follow-up from 1 to 6 months, treatment was considered futile for 9 recurrent cases (3 sIVCSs and 6 dIVCSs). So, 28 cases of preliminary ineffective treatment and 9 relapse in the second stage were arranged to the third stage of treatment by iliac vein stent implantation. All 37 cases were treated effectively and achieved a satisfactory iliac vein patency, and were followed-up for 24 months without recurrence. Logistic regression analysis showed that IVCS type (β = 4.14; Wald test, P < 0.01), duration of illness (β = -5.33; Wald test, P = 0.02), thrombus density (β = -6.46; Wald test, P = 0.01), embolization length (β = 2.74; Wald test, P = 0.03), and treatment regimens (β = 11.92; Wald test, P = 0.01) all had a significant effect on the treatment outcomes.

Conclusion

The selection of a suitable intervention treatment regimen for different types of IVCS may aid in improving the curative effect.

Guidance of Venous Stent Implantation after Catheter-directed Thrombosis in Patients with Acute Left Lower Extremity Deep Venous Thrombosis based on Pressure Gradient Differences between the Iliac Vein and Inferior Vena Cava: A Single-center Retrospective Study

BACKGROUND

Iliac vein compression syndrome (IVCS) can lead to acute deep venous thrombosis (DVT) and post-thrombotic syndrome (PTS). Endovascular venous stenting has become a preferred treatment for IVCS. In this article, we guide stent implantation by the pressure gradient of iliac vein and inferior vena cava. To evaluate the feasibility of guidance of venous stent implantation based on venous pressure gradient difference.

METHODS

A retrospective analysis was performed on patients with acute left lower extremity DVT who were treated in our center from March 2012 to December 2017. The patients were divided into 2 groups: group 1: from January 2015 to December 2017, patients were treated with catheter-directed thrombolysis (CDT) and stent implantation was guided by the pressure gradient of iliac vein and inferior vena cava after thrombectomy; group 2: from May 2012 to December 2014, patients underwent CDT treatment without stent implantation. In group 1, the patients were divided into 2 groups according to the difference in pressure gradient after CDT: the stent group (>2 mm Hg) and the control group (≤2 mm Hg). All patients were evaluated by color Doppler ultrasound at 1, 3, and 6 months after the operation to evaluate the patency of the iliofemoral vein. The Villalta score was used to evaluate the incidence of PTS.

RESULTS

The primary and secondary patency rate of group 1 at 1, 3, and 6 months after operation were higher than that in group 2 (P < 0.05). In group 1, there was no significant difference in the primary and secondary patency rate between the stent group and the control group at 1, 3, and 6 months after the operation. The incidence of PTS in group 1 at 6 months after the operation was lower than that in group 2 (P < 0.05). In group 1, there was no significant difference in the incidence of PTS between the stent group and the control group at 6 months after the operation.

CONCLUSIONS

Practice proves that it is simple and effective to guide stent implantation according to differences in pressure gradients. Two millimeter of mercury is the traditional standard for venous pressure interference in the pelvic area, and the effectiveness of this method was proved.

May-Thurner syndrome and thrombosis: A systematic review of antithrombotic use after endovascular stent placement

BACKGROUND

May-Thurner Syndrome (MTS) is caused by compression of the left common iliac vein between the right common iliac artery and the pelvis. It likely predisposes an individual to lower extremity deep vein thrombosis (DVT) as well as symptoms of unilateral lower extremity swelling and discomfort in the absence of a known history of thrombosis. In the case of MTS-associated acute thrombosis, there is low-quality evidence to suggest that endovascular intervention including thrombolysis and endovascular stent placement reduces the risk of recurrent thrombosis. However, the optimal type and duration of antithrombotic therapy after stent placement for left iliofemoral vein stenosis is not known.

METHODS

A systematic literature search including studies that evaluated the outcome of endovascular stent occlusion and systemic anticoagulant use in patients with MTS associated DVT was performed. The primary outcome of interest was 12-month risk of endovascular stent occlusion or recurrent DVT.

RESULTS

A total of five studies encompassing 61 patients were included in our study. All studies were retrospective without a comparator group. A variety of anticoagulants and durations were prescribed. Of the 55 patients evaluable, the 12-month rate of endovascular stent occlusion or recurrent DVT ranged from 0% to 40%. The 12-month stent patency rate ranged from 60% to 100%.

CONCLUSIONS

The published evidence regarding antithrombotic treatment for patients with MTS who have undergone stent placement for a DVT is limited. Further high-quality, prospective studies are needed in this setting to inform clinical decision making.

Beneficial Effect of Endovascular Treatment on Villalta Score in Japanese Patients With Chronic Iliofemoral Venous Thrombosis and Post-Thrombotic Syndrome

BACKGROUND

Post-thrombotic syndrome (PTS), the most common complication of deep venous thrombosis (DVT), develops in ≥50% of patients with iliofemoral DVT. However, the benefit of endovascular treatment in Japanese patients with chronic DVT and PTS remains unclear. Methods and Results: Between June 2014 and May 2016, endovascular treatment was performed in 11 consecutive Japanese patients with chronic iliofemoral DVT and PTS refractory to anticoagulant therapy and elastic compression stockings. We evaluated the technical success rate, complications, patency, Villalta score, calf circumference, and popliteal vein reflux in both the acute stage (the day following endovascular treatment) and chronic stage (after 6 months). Imaging follow-up included venous duplex scanning and/or magnetic resonance venography. The technical success rate was 81.8%, without complications. In patients with successful intervention, the Villalta score improved significantly, from 9.0±3.7 preoperatively to 3.6±2.5 in the acute phase (P<0.01) and 2.9±2.1 in the chronic phase (P<0.001). The bilateral difference in lower thigh circumference also improved significantly, from 2.6±1.0 cm preoperatively to 1.4±1.0 cm in the chronic phase (P<0.001). However, popliteal vein reflux did not improve. In patients with successful intervention, venous patency rate was 100% at 6 months post-intervention.

CONCLUSIONS

Endovascular treatment is safe and effective in Japanese patients with chronic iliofemoral DVT and PTS.

Results of catheter-directed thrombolysis for acute ilio-femoral deep venous thrombosis - A retrospective cohort study

Background

Catheter-directed thrombolysis may prevent post-thrombotic syndrome in patients with ilio-femoral deep venous thrombosis. We performed a retrospective review of prospectively collected follow-up data to evaluate the results of catheter-directed thrombolysis at our institution.

Method

Patients admitted for venous thrombolysis were included in the study and their files screened for information regarding results and technical aspects of treatment and patient status on follow-up. A catheter was inserted under imaging guidance into the thrombosed vein. Through the catheter tissue plasminogen activator was administered. Daily catheter-based venographies were performed to monitor progression in thrombus resolution. After thrombolysis flow-limiting stenosis was stented. Patients started wearing compression stockings and were started on oral anticoagulant therapy. Follow-up visits with ultrasound, magnetic resonance venography and clinical assessment were scheduled at six weeks and three, six, 12 and 24 months.

Results

A total of 48 patients underwent catheter-directed thrombolysis, including 36 female patients. Median age was 28 years. Complete lysis of the thrombus was achieved in 43 cases and partial lysis in two cases and 26 stents were placed. No deaths or life-threatening bleeding events occurred. Thirty-two of the patients who achieved full lysis and were followed up remained patent at follow-up. At 12 months seven patients had symptoms of post-thrombotic syndrome.

Conclusion

Catheter-directed thrombolysis represents a safe and effective alternative to systemic anticoagulative treatment of deep venous thrombosis with rapid resolution of the thrombus and few complications. Long-term patency shows good validity and this study suggests that catheter-directed thrombolysis is effective in preventing post-thrombotic syndrome.

[Recurrent pain and swelling of the left leg in a 49-year-old male patient]

A 49-year-old male patient presented due to recurrent pain and swelling in the left leg. The patient had had deep venous thrombosis with pulmonary embolism 5 years previously. Since then, he had been treated with Vit-k-antagonists. Pronounced paraumbilical collateral circulation of unknown origin was striking. Doppler sonographic evaluation pointed to May-Thurner syndrome. This was confirmed by phlebography. Venous stenting of the stenosis in the left iliac vein achieved long-term symptom improvement. This case report is intended to draw attention to the rare May-Thurner syndrome as an important differential diagnosis of deep vein thrombosis and, at the same time, identify diagnostic and therapeutic treatment strategies.

Feasibility of continuous, catheter-directed thrombolysis using low-dose urokinase in combination with low molecular-weight heparin for acute iliofemoral venous thrombosis in patients at risk of bleeding

The present study aimed to examine the feasibility of catheter-directed thrombolysis (CDT) using continuous infusion of low-dose urokinase in combination with low molecular weight heparin (LMWH) for acute iliofemoral venous thrombosis. This retrospective analysis included patients with symptomatic acute iliofemoral venous thrombosis who received CDT using continuous infusion of low-dose urokinase in combination with LMWH within the past four years. Urokinase was administered at 1×10⁴ U/h and 2×10⁴ U/h in patients at high-risk and low-risk of bleeding, respectively. Measurements included urokinase dosage, duration, clinical outcomes and CDT-related complications. A total of 46 patients were included (high-risk, n=17; low-risk, n=29). In the high-risk patients, 64.7% experienced dissolution of ≥50% thrombi after a median CDT duration of 8 days (range, 6-10 days) and median total urokinase dose of 1.92×10⁶ units (range, 1.44-2.4×10⁶ units). In the low-risk patients, 82.8% achieved dissolution of ≥50% thrombi after a median CDT duration of 7 days (range, 4-10 days) and a median total urokinase dose of 3.36×10⁶ units (range, 1.92-4.80×10⁶ units). Remission of clinical symptoms after CDT was achieved in 15 (88.2%) and 28 (96.6%) cases in high-risk and low-risk patients, respectively. No treatment-associated pulmonary embolism or major bleeding was observed. Three (6.5%) subjects (high-risk, n=1; low-risk, n=2) experienced minor bleeding. In conclusion, continuous infusion of low-dose urokinase via CDT in combination with LMWH is effective and safe for acute iliofemoral venous thrombosis in patients with one or more risk factor for bleeding.

Underlying Anatomy and Typing Diagnosis of May-Thurner Syndrome and Clinical Significance: An Observation Based on CT

STUDY DESIGN

Cross-sectional study.

OBJECTIVE

To explore the underlying anatomy of May-Thurner syndrome (MTS) using computed tomography (CT) and discuss its clinical significance for typing diagnosis.

SUMMARY OF BACKGROUND DATA

Because the anatomical position of the corpse cannot fully illustrate the actual clinical situation in vivo, the diversity of MTS has not been fully elucidated yet.

METHODS

We retrospectively analyzed the data of 69 patients with MTS. By CT showing, patients were categorized to simple MTS (sMTS, 22 patients), lumbar degeneration-related MTS (dMTS, 33 patients) and other causes MTS (oMTS, 14 patients); meanwhile, a healthy control group were set. Evaluated indexes were onset age, course of disease, diameter of the iliac vein tunnel (IVTD), lumbar degeneration-related iliac vein compression (IVC), therapeutic effect, and diagnostic cutoff of risk IVTD prone to MTS.

RESULTS

The onset age of sMTS, dMTS, and oMTS were respectively 42.3 ± 6.5 years, 61.5 ± 10.6 years, and 53.1 ± 16.8 years (P < 0.001); courses were respectively 12.1 ± 9.2 days, 22.5 ± 7.6 days, and 6.8 ± 6.7 days (P = 0.002). IVTDs of sMTS, dMTS, oMTS, and the control were respectively 2.52 ± 0.50 mm, 2.29 ± 0.30 mm, 5.93 ± 2.21 mm, and 4.34 ± 1.61 mm (P < 0.001). Lumbar degeneration-related IVC in dMTS occurred at 41 places, including forward bulging or protruding intervertebral discs (51%,17/33), osteophytes (50%,16/33), and spondylolisthesis (19%, 8/33), but none happened in sMTS, oMTS, and the control. Eighty-six percent of sMTSs, 55% dMTSs, and none oMTSs needed intravenous stent-implanted operation to obtain effective treatment. MTS type (Waldχ = 6.092, P = 0.009), course (Waldχ = 4.618, P = 0.032), and treatment plan (Waldχ = 14.748, P < 0.001) markedly influence the therapeutic result. The cutoff of risk IVTD for sMTS and dMTS was 2.98 mm, which diagnostic sensitivity was 90% and specificity 100%.

CONCLUSION

Owing to the distinct pathoanatomy and causes, diagnosis in classification of MTS by CT is helpful in accurate treatment program.

LEVEL OF EVIDENCE

3.

Diagnosis and Treatment of Lower Extremity Deep Vein Thrombosis: Korean Practice Guidelines

Lower extremity deep vein thrombosis is a serious medical condition that can result in death or major disability due to pulmonary embolism or post-thrombotic syndrome. Appropriate diagnosis and treatment are required to improve symptoms and salvage the affected limb. Early thrombus clearance rapidly resolves symptoms related to venous obstruction, restores valve function and reduces the incidence of post-thrombotic syndrome. Recently, endovascular treatment has been established as a standard method for early thrombus removal. However, there are a variety of views regarding the indications and procedures among medical institutions and operators. Therefore, we intend to provide evidence-based guidelines for diagnosis and treatment of lower extremity deep vein thrombosis by multidisciplinary consensus. These guidelines are the result of a close collaboration between interventional radiologists and vascular surgeons. The goals of these guidelines are to improve treatment, to serve as a guide to the clinician, and consequently to contribute to public health care.

Incidence and Outcomes of Inferior Vena Cava Filter Thrombus during Catheter-directed Thrombolysis for Proximal Deep Venous Thrombosis

BACKGROUND

The aim of the study was to retrospectively evaluate the incidence and outcomes of inferior vena cava (IVC) filter thrombus during catheter-directed thrombolysis (CDT) for acute proximal deep venous thrombosis (DVT).

METHODS

From October 2006 to June 2015, patients diagnosed with acute proximal DVT and received CDT after a retrievable IVC filter was placed were included. The incidence, treatment, and outcomes of IVC filter thrombus during CDT were recorded and analyzed.

RESULTS

A total of 189 patients (91 women, 98 men; mean age, 57.6 ± 9.8 years; range, 24-85 years) were included in this study. Among the 189 cases, the DVTs involved popliteal iliofemoral veins in 54 patients, iliofemoral veins in 113 patients, and iliac veins in 22 patients, of which 18 patients had thrombus extended into the IVC. Of the 189 patients, a total of 8 (4.2%, 8 of 189) patients were identified with IVC filter thrombus during CDT. The IVC filter thrombus was detected on a median of 2 days (range, 2-4 days) of CDT therapy, including small-size (n = 6) and large-size (n = 2) filter thrombus. Of the 8 patients, CDTs were performed with a mean 7.6 ± 1.1 days (range, 6-11 days) after the presence of symptoms for the treatment of proximal DVT, and all the IVC filter thrombi were lysed during CDT for the proximal DVT. All the IVC filters were removed successfully with a mean of 12.8 ± 0.93 days from placement. There were no procedure- or thrombolysis-related major complications, and no symptomatic pulmonary embolism breakthrough was seen in any of the patients after the filter placement.

CONCLUSIONS

IVC filter thrombus during CDT for the acute proximal DVT is uncommon, and all of them did not need any additional treatment.

Safety and Effectiveness of Stent Placement for Iliofemoral Venous Outflow Obstruction: Systematic Review and Meta-Analysis

BACKGROUND

Endovenous recanalization of iliofemoral stenosis or occlusion with angioplasty and stent placement has been increasingly used to maintain long-term venous patency in patients with iliofemoral venous outflow obstruction. The purpose of this systematic review and meta-analysis was to determine safety and effectiveness of venous stent placement in patients with iliofemoral venous outflow obstruction.

METHODS AND RESULTS

We searched MEDLINE and EMBASE for studies evaluating safety or effectiveness of stent placement in patients with iliofemoral venous outflow obstruction. Data were extracted by disease pathogenesis: nonthrombotic, acute thrombotic, or chronic post-thrombotic. Main outcomes included technical success, periprocedural complications, symptom relief at final follow-up, and primary/secondary patency through 5 years. A total of 37 studies reporting 45 treatment effects (nonthrombotic, 8; acute thrombotic, 19; and chronic post-thrombotic, 18) from 2869 patients (nonthrombotic, 1122; acute thrombotic, 629; and chronic post-thrombotic, 1118) were included. Technical success rates were comparable among groups, ranging from 94% to 96%. Complication rates ranged from 0.3% to 1.1% among groups for major bleeding, from 0.2% to 0.9% for pulmonary embolism, from 0.1% to 0.7% for periprocedural mortality, and from 1.0% to 6.8% for early thrombosis. Patient symptom relief data were reported inconsistently. At 1 year, primary and secondary patency were 96% and 99% for nonthrombotic, 87% and 89% for acute thrombotic, and 79% and 94% for chronic post-thrombotic.

CONCLUSIONS

Stent placement for iliofemoral venous outflow obstruction results in high technical success and acceptable complication rates regardless of cause of obstruction.