Iliofemoral deep vein thrombosis: conventional therapy versus lysis and percutaneous transluminal angioplasty and stenting

A mapping review of Pacific Vascular Symposium 6 initiatives

OBJECTIVE

The 2010 Pacific Vascular Symposium 6 (PVS6) brought venous disease content experts together with a goal of addressing critical issues collated together in the next decade with concrete plans to achieve these goals. This mapping review aims to provide a broader representation of how progress in critical issues of chronic venous disease has been made by extrapolating scientific publications related to the PVS6 initiatives.

METHODS

We performed a mapping review identifying original or systematic review/meta-analysis articles related to PVS 6 initiatives (aims) that addressed one of the following key objectives: scales to measure chronic venous disease, effectiveness of interventional deep venous thrombus removal, development of a deep venous valve, and biomarkers related to venous disease. Searches were undertaken in PubMed, Ovid Medline, Cochrane Library, Embase (Elsevier), CINAHL (EBSCO), and Scopus. We extracted descriptive information about the studies and predefined variables for each specific aim, showing what and where research exists on the aims included.

RESULTS

A total of 2138 articles were screened from 3379 retrieved articles from six electronic databases. We mapped 186 included articles, finding that the total number of publications significantly increased after the 2010 PVS6 meeting. Aim results were visually summarized. The largest body of data addressed catheter-based thrombus removal strategies for acute iliofemoral deep venous thrombosis. Primary research on artificial venous valves and venous biomarkers remained limited. No new post-thrombotic syndrome (PTS) score has been developed.

CONCLUSIONS

This mapping review identified and characterized the available evidence and gaps in our knowledge of chronic venous disease that exist visually, which may guide where more significant investments for the future should be targeted.

Cost Effectiveness of Early Endovenous Thrombus Removal for Acute Iliofemoral Deep Vein Thrombosis in the United Kingdom

OBJECTIVE

Early clot removal using endovascular intervention aims to reduce post-thrombotic syndrome (PTS) following iliofemoral deep venous thrombosis (DVT). This may reduce long term morbidity but incurs a higher initial cost. This study examined the cost effectiveness of catheter directed thrombolysis (CDT) and pharmacochemical thrombectomy (PMT) compared with oral anticoagulation (OAC) alone for treatment of acute iliofemoral DVT in the United Kingdom.

METHODS

A combined decision tree (acute DVT complications) and Markov model (long term complications [PTS]) was used for decision analytic modelling with five states: no PTS, mild PTS, moderate PTS, severe PTS, and dead. All patients started with acute DVT. Patients who survived acute complications transitioned into the Markov model. Cycle time was six months. A healthcare payer perspective and lifetime horizon was used, adjusting for excess mortality due to history of thrombosis. Data for probabilities, transition probabilities, mortality, and utilities were obtained from the published literature. Cost data were obtained from UK NHS tariffs and published literature. Outcomes were mean lifetime cost, quality adjusted life years (QALYs), and cost effectiveness.

RESULTS

Over a patient's lifetime, OAC was more costly (£37 206) than CDT (£32 043) and PMT (£36 288). Mean lifetime QALYs for OAC (12.9) were lower than CDT (13.5) and PMT (13.3). Therefore, in the incremental cost effectiveness analysis, both CDT and PMT were dominant: CDT was less costly (-£5 163) and more effective (+0.6 QALYs) than OAC, and PMT was also less costly (-£917) and more effective (+0.3 QALYs) than OAC. Results were robust to univariable sensitivity analyses, but probabilistic sensitivity analyses suggested considerable parameter uncertainty.

CONCLUSION

Early interventional treatment of iliofemoral DVT is cost effective in the UK. Future clinical and epidemiological studies are needed to characterise parameter uncertainty. Further analysis of modern practice, alternative treatments, and optimised care models is warranted.

Antithrombotic management of patients with deep vein thrombosis and venous stents: an international registry

BACKGROUND

In patients with acute deep vein thrombosis (DVT) treated with catheter-based thrombolysis and venous stenting, poststenting anticoagulant management is uncertain.

OBJECTIVES

To determine the type and duration of antithrombotic therapy used in patients who have received venous stents for treatment of acute lower extremity DVT.

METHODS

We created an international registry of patients with leg DVT from 2005 to 2019 who received venous stents as part of their acute management. We collected data on baseline clinical characteristics and pre-venous and post-venous stent antithrombotic therapy.

RESULTS

We studied 173 patients with venous stents: 101 (58%) were aged ≤50 years, 105 (61%) were female, and 128 (74%) had risk factors for thrombotic disease. DVT was iliofemoral in 150 (87%) patients, and catheter-based treatment was given within 7 days of diagnosis in 92 (53%) patients. After venous stenting, 109 (63%) patients received anticoagulant-only therapy with a direct oral anticoagulant (29%), warfarin (22%), or low-molecular-weight heparin (10%), and 59 (34%) received anticoagulant-antiplatelet therapy. In patients taking anticoagulant-only therapy, 29% received indefinite treatment; in patients on anticoagulant-antiplatelet therapy, 19% received indefinite treatment. Factors associated with combined anticoagulant-antiplatelet therapy vs anticoagulant-only therapy were use of thrombolytic, thrombectomy, and aspiration interventions (odds ratio [OR], 5.11; 95% CI, 1.45-18.05); use of balloon angioplasty (OR, 2.62; 95% CI, 1.20-5.76); and immediate stent restenosis (OR, 7.2; 95% CI, 1.45-5.89).

CONCLUSION

Anticoagulant therapy without concomitant antiplatelet therapy appears to be the most common antithrombotic strategy in patients with DVT and venous stenting. More research is needed to determine outcomes of venous stenting in relation to antithrombotic therapy.

Endovascular Thrombectomy for Acute Iliofemoral Deep Venous Thrombosis Through a Jugular Approach with a Rotational Device

PURPOSE

To report the effectiveness of pharmacomechanical catheter-directed thrombolysis (PCDT) in the management of acute iliofemoral deep venous thrombosis (DVT) via the jugular vein using a slow rotation and large-tip device (SRD) in a large cohort of patients.

MATERIAL AND METHODS

From 2011 to 2021, 277 patients (mean age 45 years, 59.2% women) were treated in 6 centres with PCDT for ilio-fémoral DVT. PCDT was performed via the jugular vein and consisted of one session of fragmentation-fibrinolysis, aspiration and, if needed, angioplasty with stenting. The aim of PCDT was to achieve complete clearance of the venous thrombosis and to restore iliofemoral patency. Residual thrombotic load was assessed by angiography, venous patency by duplex ultrasound and clinical effectiveness by the rate of post-thrombotic syndrome (Villalta score > 4).

RESULTS

All patients were treated via the jugular vein using an SRD, and all but one were treated with fibrinolysis. Angioplasty with stenting was performed in 84.1% of patients. After the procedure, the residual thrombotic load at the ilio-fémoral region was < 10% in 96.1% of patients. The rate of major complications was 1.8% (n = 5), the rate of minor complications was 4% (n = 11), and one patient died from pulmonary embolism (0.4%) At a median follow-up of 24 months, primary and secondary iliofemoral patency was 89.6% and 95.8%, respectively. The rate of PTS was 13.8% at 12 months.

CONCLUSION

PCDT via the jugular vein using an SRD is an efficient treatment for acute iliofemoral DVT and results in high long-term venous patency and low PTS rates. Level of evidence Level 4, Case series.

Society of Interventional Radiology Position Statement on the Endovascular Management of Acute Iliofemoral Deep Vein Thrombosis

PURPOSE

To establish the updated position of the Society of Interventional Radiology (SIR) on the endovascular management of acute iliofemoral deep vein thrombosis (DVT).

MATERIALS AND METHODS

A multidisciplinary writing group with expertise in treating venous diseases was convened by SIR. A comprehensive literature search was conducted to identify studies on the topic of interest. Recommendations were drafted and graded according to the updated SIR evidence grading system. A modified Delphi technique was used to achieve consensus agreement on the recommendation statements.

RESULTS

A total of 84 studies, including randomized trials, systematic reviews and meta-analyses, prospective single-arm studies, and retrospective studies were identified and included in the review. The expert writing group developed 17 recommendations that pertain to the care of patients with acute iliofemoral DVT with the use of endovascular venous interventions.

CONCLUSIONS

SIR considers endovascular thrombus removal to be an acceptable treatment option in selected patients with acute iliofemoral DVT. Careful individualized risk assessment, high-quality general DVT care, and close monitoring during and after procedures should be provided.

Outcomes from a tertiary care center using a catheter thrombectomy system for managing acute iliofemoral deep vein thrombosis

OBJECTIVE

The aim of the present study was to report a large, single-center experience using the ClotTriever thrombectomy system (Inari Medical, Irvine, CA) for the management of acute iliofemoral (IF) deep vein thrombosis (DVT). One limitation of all endovascular devices for the treatment of acute IF-DVT has been the inability to completely remove all acute thrombus and the need for adjunctive thrombolysis with its attendant risk of bleeding complications.

METHODS

A single-center retrospective review of consecutive patients with acute IF-DVT treated with the ClotTriever thrombectomy system (Inari Medical) is reported. Procedural efficacy was evaluated by an independent core imaging laboratory (Syntactx, New York, NY). Both procedural and in-hospital safety were assessed during the index hospitalization. The treated vein patency was assessed using duplex ultrasound at 30 days after the procedure.

RESULTS

A total of 96 patients were included in the present retrospective review, 40 of whom (40%) had contraindications to thrombolytic therapy. In terms of efficacy, 93 patients (97%) had ≥75% thrombus removal. During the index hospitalization, two patients (2%) had experienced a symptomatic pulmonary embolus. However, no mortality, major bleeding, or device-related complications had occurred in the study population. Of the 96 patients, 64 had undergone duplex ultrasound at 30 days after the procedure. Of the 64 patients, 62 had normal flow (97%), 53 (83%) had normal compressibility, and 11 (17%) had partial compressibility.

CONCLUSIONS

The ClotTriever thrombectomy catheter was both safe and effective in our cohort of patients with acute IF-DVT outside a randomized clinical trial.

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.

Safety and Efficacy of Endovascular Treatment on Pregnancy-Related Iliofemoral Deep Vein Thrombosis

Objective: This study investigates the safety and efficacy of endovascular treatments on pregnancy-related iliofemoral deep vein thrombosis (DVT). Methods: We retrospectively reviewed data of 46 patients who had symptomatic pregnancy-related iliofemoral DVT and underwent endovascular treatment. The patients treated with catheter-directed thrombolysis (CDT) were classified as the CDT group. In contrast, those treated with CDT combined with pharmacomechanical thrombectomy (PMT) or angioplasty/stenting were classified as the pharmacomechanical catheter-directed thrombolysis (PCDT) group. Results: Based on the immediate post-operative clot burden reduction rate analysis of 46 patients: 22 cases were completely dissolved (lysis grades III), 12 were partially dissolved (lysis grades II), and 12 failed (lysis grades I). There was a statistically significant difference in the rate of clot burden reduction between the CDT group (n = 19) and the PCDT group (n = 27) (p = 0.001). There was no statistically significant difference in the number of bleeding events between the two groups (p = 0.989). At 24 months, cumulative venous patency in the CDT group was 50.0%, compared to 78.2% in the PCDT group. Furthermore, there was a statistically significant difference in Villalta score (p = 0.001) and venous severity scoring (VCSS score) (p = 0.005) between the two groups. Conclusions: CDT treatment combined with PMT or angioplasty/stenting is comparatively safe and effective for pregnant-related DVT patients. PCDT outperforms CDT in terms of immediate efficacy and reduces the incidence of post-thrombotic syndrome with better midterm outcomes.

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 Therapy for the Management of Acute Ilio-femoral Deep Vein Thrombosis

Ilio-femoral deep vein thrombosis (DVT) has a high rate of long-term morbidity in the form of the postthrombotic syndrome (PTS). Therefore, management of acute thrombosis should not only focus on the prevention of acute complications such as propagation or embolisation of the initial clot but also on preventing recurrent thrombosis and PTS. Contemporary catheter-based treatments of deep vein thrombosis have proven to be safe and effective in selected patients. Current guidelines recommend medical therapy with anticoagulation alone for all but the most severe, limb-threatening thrombosis. They additionally allow for consideration of endovascular catheter-based treatment in selected patients with acute proximal ilio-femoral DVT and low risk of bleeding complications to prevent PTS. 

Imaging-guided, catheter-based endovascular therapy has been used in selected patients to alleviate these sequelae, but important questions remain about their optimal use. In this article, we review the available evidence and summarize the rationale for use of catheter-based therapy in specific patient groups with acute iliofemoral DVT.

A systematic review on long-term clinical impact in patients with iliofemoral deep vein thrombosis

OBJECTIVE

The aim of this systematic review was to investigate the long-term clinical impact of iliofemoral (IF) deep vein thrombosis (DVT) based on patient reported outcomes, physician administered test measures and compare medical to interventional treatment.

METHODS

This study was conducted according to the Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines. Criteria for inclusion were patients with thrombus involving the common femoral vein or more proximal veins, ≥5-year follow-up and physician assessment. Data quality was assessed using the Robins-I tool and Cochrane tool.

RESULTS

Eight studies that fulfilled our criteria were deemed eligible and provided data for 499 patients. There were 230 patients who received medical treatment and 269 interventional. Two studies were randomized controlled trials and six observational. Venous claudication, where reported, was found in 7.7% (1/13) of interventionally treated patients and 21% (13/62) of medically treated patients. Long term symptom resolution was reported in 58% (18/31) and 24% (12/50) of interventionally and medically treated patients, respectively. Venous ulcers were seen in 5.5% (7/126) of medically treated patients and 5% (5/100)of interventionally treated patients.

CONCLUSION

A wide range of signs and symptoms was reported at long-term. Interventional treatment appeared to be better than medical one but the evidence was weak. Given the significant lack of patient reported outcomes, objective testing and use of validated instruments, the results should be interpreted in context with these limitations. Data on long-term outcomes after IF DVT have been poorly reported and outcome criteria should be better defined in future studies.

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.

Postinterventional antithrombotic management after venous stenting of the iliofemoral tract in acute and chronic thrombosis: A systematic review

Venous stenting has become a common treatment option for central deep venous outflow obstructions and postthrombotic syndrome. Following successful recanalization and stenting, stent patency is endangered by in-stent thrombosis and recurrent venous thromboembolism. Antithrombotic therapy might reduce patency loss. This systematic review summarizes the literature on antithrombotic therapy following (post)thrombotic venous stenting. A systematic PubMed, MEDLINE, EMBASE, and Cochrane search was performed for studies addressing antithrombotic therapy prescribed following venous stenting of the iliofemoral tract indicated by acute or chronic thrombotic pathology. A total of 277 articles was identified of which 64 (56 original studies) were selected. Overall, a mean primary patency rate of 82.3% was seen 1 year after the intervention, which decreased to 73.3% after 2 years. In the majority (43 of 56 studies, 77%), treatment was based on use of vitamin K antagonists, either with (18%) or without (59%) use of antiplatelet drugs. Only two studies (4%) directly assessed the effect of antithrombotic therapy on treatment outcomes. The impact of postinterventional antithrombotic therapy on stent patency remains unknown because of limited and insufficient data available in current literature. Further clinical research should more clearly address the role of antithrombotic therapy for preservation of long-term patency following venous stenting.

Referral patterns for catheter-directed thrombolysis for iliofemoral deep venous thrombosis

OBJECTIVES

Post thrombotic syndrome (PTS) is a serious complication of deep venous thromboses (DVTs). PTS occurs more frequently and severely following iliofemoral DVT compared to distal DVTs. Catheter directed thrombolysis (CDT) of iliofemoral DVTs may reduce PTS incidence and severity.We aimed to determine the rate of iliofemoral DVT within our institution, their subsequent management, and compliance with NICE guidelines.

METHODS

Retrospective review of all DVTs diagnosed over a 3-year period was conducted. Cases of iliofemoral DVT were identified using ICD-10 codes from patient notes, and radiology reports of Duplex scans. Further details were retrieved, such as patient demographics and referrals to vascular services. NICE guidance was applied to determine if patients would have been suitable for CDT. A survey was sent to clinicians within medicine to identify awareness of CDT and local guidelines for iliofemoral DVT management.

RESULTS

225 patients with lower limb DVTs were identified. Of these, 96 were radiographically confirmed as iliofemoral DVTs. The median age was 77. 67.7% of iliofemoral DVTs affected the left leg. Right leg DVTs made up 30.2% and 2.1% were bilateral DVTs. Of the 96 iliofemoral DVTs, 21 were deemed eligible for CDT. Only 3 patients (14.3%) were referred to vascular services, and 3 received thrombolysis.From our survey, 95.5% of respondents suggested anticoagulation alone as management for iliofemoral DVT. Only one respondent recommended referral to vascular services. There was a knowledge deficiency regarding venous anatomy, including superficial versus deep veins.

CONCLUSIONS

CDT and other mechanochemical procedures have been shown to improve outcomes of patients post-iliofemoral DVT, however a lack of awareness regarding CDT as a management option results in under-referral to vascular services. We suggest closer relations between vascular services and their "tributary" DVT clinics, development of guidelines and robust care pathways in the management of iliofemoral DVT.

Endovascular mechanical thrombectomy versus thrombolysis in patients with iliofemoral deep vein thrombosis – a systematic review and meta-analysis

Summary: Background: This study sought to compare effectiveness and safety of percutaneous mechanical thrombectomy (PMT) and thrombolysis alone (THR) in patients with acute or subacute iliofemoral deep vein thrombosis (IfDVT). Patients and methods: Observational and randomized trials, published between January 2001 to February 2019 were identified by searching MEDLINE. Studies on deep venous thrombosis (DVT) treated with either THR or PMT adjunctive to conventional anticoagulation and compressive intervention were included. Meta-analysis of proportions was conducted to assess effectiveness outcomes of successful lysis and primary patency, post-thrombotic syndrome (PTS), valvular reflux, recurrent DVT, as well as safety outcomes of major bleeding, hematuria, and pulmonary embolism. Results: Of 77 identified records, 17 studies including 1417 patients were eligible. Pooled proportion of successful lysis was similar between groups (THR: 95 % [I2 = 68.4 %], PMT 96 %, [I2 = 0 %]; Qbet [Cochran’s Q between groups] 0.3, p = 0.61). However, pooled proportion of 6-month primary patency was lower after THR than after PMT (68 % [I2 = 15.6 %] versus 94 %; Qbet 26.4, p < 0.001). Considerable heterogeneity within groups did not allow for between-group comparison of PTS and recurrent DVT. Major bleeding was more frequent after THR than after PMT (6.0 % [I2 = 0 %] versus 1.0 % [I2 = 0 %]; Qbet 12.3, p < 0.001). Incidence of hematuria was lower after THR as compared to PMT (2 % [I2 = 56 %] versus 91.3 % [I2 = 91.7 %]; Qbet 714, p < 0.001). Incidences of valvular reflux and pulmonary embolism were similar across groups (THR: 61 % versus PMT: 53 %; Qbet 0.7, p = 0.39 and THR: 2 % versus PMT: 1 %; Qbet 1.1, p = 0.30, respectively). Conclusions: In patients with iliofemoral DVT, percutaneous mechanical thrombectomy was associated with a higher cumulative 6-month primary patency and a lower incidence of major bleeding compared to thrombolysis alone. Risk of hemolysis from mechanical thrombectomy needs further consideration.

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.

Prevention and Management of the Post-Thrombotic Syndrome

The post-thrombotic syndrome (PTS) is a form of chronic venous insufficiency secondary to prior deep vein thrombosis (DVT). It affects up to 50% of patients after proximal DVT. There is no effective treatment of established PTS and its management lies in its prevention after DVT. Optimal anticoagulation is key for PTS prevention. Among anticoagulants, low-molecular-weight heparins have anti-inflammatory properties, and have a particularly attractive profile. Elastic compression stockings (ECS) may be helpful for treating acute DVT symptoms but their benefits for PTS prevention are debated. Catheter-directed techniques reduce acute DVT symptoms and might reduce the risk of moderate-severe PTS in the long term in patients with ilio-femoral DVT at low risk of bleeding. Statins may decrease the risk of PTS, but current evidence is lacking. Treatment of PTS is based on the use of ECS and lifestyle measures such as leg elevation, weight loss and exercise. Venoactive medications may be helpful and research is ongoing. Interventional techniques to treat PTS should be reserved for highly selected patients with chronic iliac obstruction or greater saphenous vein reflux, but have not yet been assessed by robust clinical trials.

Less frequent post-thrombotic syndrome after successful catheter-directed thrombolysis for acute iliofemoral deep vein thrombosis

Post-thrombotic syndrome (PTS) occurs in 20-50% of patients with proximal deep vein thrombosis (DVT). In this study, we aimed to identify potential markers of thrombolysis success at the early stage and to clarify the relationship between early thrombolysis success and subsequent PTS development in patients with acute DVT in the iliac vein. Fifty-two consecutive patients with acute iliofemoral DVT who were treated with catheter-directed thrombolysis (CDT) within 21 days of onset were enrolled. An infusion catheter with multiple side holes was placed to cover the thrombosed vessel entirely. Urokinase solution was administered either continuously or with the pulse-spray method at a dose of 480,000-720,000 IU/day over the course of 2-7 days. During CDT, unfractionated heparin (UFH) was infused simultaneously via the access sheath to prevent thrombus formation. Early success was defined as lysis grade ≥ 50% and restoration of forward flow. PTS was diagnosed based on the Villalta scale. Based on the lysis grading method, complete lysis (grade III) was achieved in 8 of 52 (16%) limbs. Lysis grade II (50-99%) was achieved in 35 of 52 (67%) limbs. Lysis grade I (< 50%) was achieved in 9 of 52 (17%) limbs. Therefore, grade II and grade III lytic outcomes (early success) were observed in 43 patients (83%). One-year clinical follow-up was performed for 43 patients (83%). PTS occurred in seven (16%) patients. Early success was more frequently observed in patients without PTS than in those with PTS (92% vs. 43%; P < 0.01). Early success was only significantly associated with PTS in the multivariate analysis. Patients with acute symptomatic iliofemoral DVT who had early success from CDT treatment during the acute phase less frequently progressed to PTS. Patients with early success tended to undergo the pulse-spray method and had a shorter interval from symptom onset to CDT. The use of pulse-spray method and early initiation of CDT since DVT onset were potential markers of thrombolysis success.

Intervention for Iliofemoral Deep Vein Thrombosis and May-Thurner Syndrome

May-Thurner syndrome, also known as iliac vein compression syndrome, may cause symptoms of venous hypertension and is a predisposing factor for the development of iliofemoral deep vein thrombosis (DVT). Iliofemoral DVT is associated with high rates of development of postthrombotic syndrome, a potentially debilitating condition associated with development of symptoms related to venous outflow obstruction and resulting in reduced quality of life. In this Clinics article, we review procedural intervention with catheter-directed thrombolysis and stenting for iliofemoral DVT and iliac vein compression.

Long-term antithrombotic therapy after venous stent placement

OBJECTIVES

To examine the prescribing patterns and outcomes of antithrombotic regimens after venous stent placement.

METHODS

A total of 87 patients who received inferior vena cava or iliofemoral venous stents were included in the study. A retrospective review was performed to determine the antithrombotic regimens and the subsequent rates of in-stent restenosis, stent thrombosis, and bleeding.

RESULTS

The prescribing patterns of specific antithrombotic regimens were highly variable. In-stent restenosis and stent thrombosis events were observed in 13 of 63 patients (21%) with available follow-up imaging, while major bleeding events were noted in 6 of 87 patients (7%). Triple therapy appeared to reduce the odds of in-stent restenosis/ stent thrombosis when compared to dual antiplatelet therapy (OR = 0.07, P = 0.01).

CONCLUSIONS

Substantial variability exists in antithrombotic therapy following venous stenting at our institution. This study demonstrated a reduction of in-stent restenosis/thrombosis events when utilizing triple therapy compared to antiplatelet-only regimens. However, larger prospective trials are needed to more accurately determine the relative risks and benefits of each antithrombotic regimen.

Single- versus multiple-stage catheter-directed thrombolysis for acute iliofemoral deep venous thrombosis does not have an impact on iliac vein stent length or patency rates

BACKGROUND

Incomplete venous thrombolysis and residual nonstented iliac vein disease are known predictors of recurrent deep venous thrombosis (DVT). Controversy exists as to whether the number of thrombolysis sessions affects total stent treatment length or stent patency. The goal of this study was to evaluate the outcomes of patients who underwent single vs multiple catheter-directed lysis sessions with regard to stent extent and patency.

METHODS

Consecutive patients who underwent thrombolysis and stenting for acute iliofemoral DVT between 2007 and 2018 were identified and divided into two groups on the basis of the number of treatments performed (one vs multiple sessions). Operative notes and venograms were reviewed to determine the number of lytic sessions performed and stent information, including size, location, total number, and length treated. End points included total stent length, 30-day and long-term patency, and post-thrombotic syndrome (Villalta score ≥5). The χ2 comparisons, logistic regression, and survival analysis were used to determine outcomes.

RESULTS

There were 79 patients who underwent lysis and stenting (6 bilateral interventions; mean age, 45.9 ± 17 years; 48 female). Ten patients (12 limbs) underwent single-stage treatment with pharmacomechanical thrombolysis, and the remaining 69 (73 limbs) had two to four operating room sessions combining pharmacomechanical and catheter-directed thrombolysis. Patients who underwent a single-stage procedure were older and more likely to have a malignant disease. These patients received less tissue plasminogen activator compared with the multiple-stage group (17.2 ± 2.2 mg vs 27.6 ± 11.6 mg; P = .008). Average stent length was 8.8 ± 5.2 cm for the single-stage group vs 9.2 ± 4.6 cm for the multiple-stage group (P = .764). Patients who underwent a single-stage procedure had no difference in average length of stay from that of patients who underwent multiple sessions (8.5 days vs 5.9 days; P = .269). The overall 30-day rethrombosis rate was 7.3%. Two-year patency was 72.2% and 74.7% for the single and multiple stages, respectively (P = .909). The major predictors for loss of primary patency were previous DVT (hazard ratio [HR], 5.99; P = .020) and incomplete lysis (HR, 5.39; P = .014) but not number of procedures (HR, 0.957; P = .966). The overall post-thrombotic syndrome rate was 28.4% at 5 years and was also not associated with the number of treatment sessions.

CONCLUSIONS

Single- vs multiple-stage thrombolysis for DVT is not associated with a difference in extent of stent coverage. Patency rates remain high for iliac stenting irrespective of the number of lytic sessions, provided lysis is complete and the diseased segments are appropriately stented.

Long-Term Outcome of Catheter-Directed Thrombolysis in Pregnancy-Related Venous Thrombosis

BACKGROUND Venous thromboembolism (VT) is a leading cause of maternal mortality and morbidity worldwide. Catheter-directed thrombolysis (CDT) is an effective and safe treatment modality for VT patients. However, the long-term outcome of CDT in pregnancy-related venous thrombosis are unclear. The aim of this study was to assess long-term results of pregnancy-related VT patients. MATERIAL AND METHODS We reviewed 41 pregnancy-related deep venous thrombosis (DVT) patients who underwent CDT from February 2008 to May 2015. Clinical data, including demographic variables, disease location, vascular risk factors, treatment regimen, interventional procedure and complications, were collected retrospectively. Clinical and color-duplex ultrasonography were performed to monitor venous patency during follow-up. Post-thrombotic syndrome (PTS) was assessed with the Villalta scale and quality of life (QOL) was evaluated by the VEINES-QOL/Sym questionnaire. RESULTS Twenty-three patients underwent spontaneous abortion or induced abortion within 3 months before DVT, and 18 patients had DVT during the first 3 months after delivery. Technical success was achieved in all patients. Grade III (complete) lysis was obtained in 15 patients and grade II (partial) lysis was obtained in 21 patients. The follow-up period was 3 years. Twenty-eight patients had venous patency at 3-year follow-up; 36.6% of patients developed mild or moderate PTS (Villalta score 5-14) and 4.8% with severe PTS (Villalta score ≥15). VEINES-QOL/Sym scores were 55.24±7.35 and 53.25±6.65, respectively. CONCLUSIONS Catheter-directed thrombolysis is a reliable and safe treatment modality for postnatal or abortion patients with DVT. CDT can reduce the incidence rate of PTS and increase the quality of life.

The case for catheter-directed thrombolysis in selected patients with acute proximal deep vein thrombosis

This article has a companion Counterpoint by Poston and Garcia.

Efficacy and Safety of Catheter-directed Thrombolysis in Preventing Post-thrombotic Syndrome: A Meta-analysis

Post-thrombotic syndrome (PTS) is a complication that can develop after deep vein thrombosis (DVT) of lower extremities. In this meta-analysis, we compare the different modalities for treatment of DVT in reducing the risk of PTS. The primary outcome was the risk of PTS, and the secondary outcome included the risk of bleeding events. Review Manager (version 5.3; Cochrane Collaboration software) was used to analyze the data that are represented as a forest plot. Meta-analysis indicated that catheter-directed thrombolysis (CDT) plus anticoagulation (AC) decreases the likelihood of developing PTS compared with the AC-only group with an odds ratio of 0.28 (0.12-0.64). A subgroup analysis of randomized control trial (RCT) studies was conducted, and findings suggest a slight decrease in the likelihood of PTS incidence in the CDT+AC treatment group compared to the AC treatment group (odds ratio, OR = 0.76; CI = 0.58-0.99). For the secondary outcome, a statistically significant increase in bleeding events in the intervention groups was reported with an OR of 3.38 (1.33-8.61), suggesting that the risk of bleeding was high in the CDT plus AC group. CDT in addition to conventional AC for patients with DVT decreases the likelihood of PTS development. The protective effect of CDT comes at the expense of an increase in bleeding risk by three-fold. The decision to utilize CDT to prevent PTS should be individualized according to patient risk factors for developing PTS and their risk of bleeding.

Endovascular Thrombus Removal for Acute Iliofemoral Deep Vein Thrombosis

BACKGROUND

The ATTRACT trial (Acute Venous Thrombosis: Thrombus Removal with Adjunctive Catheter-Directed Thrombolysis) previously reported that pharmacomechanical catheter-directed thrombolysis (PCDT) did not prevent postthrombotic syndrome (PTS) in patients with acute proximal deep vein thrombosis. In the current analysis, we examine the effect of PCDT in ATTRACT patients with iliofemoral deep vein thrombosis.

METHODS

Within a large multicenter randomized trial, 391 patients with acute deep vein thrombosis involving the iliac or common femoral veins were randomized to PCDT with anticoagulation versus anticoagulation alone (No-PCDT) and were followed for 24 months to compare short-term and long-term outcomes.

RESULTS

Between 6 and 24 months, there was no difference in the occurrence of PTS (Villalta scale ≥5 or ulcer: 49% PCDT versus 51% No-PCDT; risk ratio, 0.95; 95% CI, 0.78-1.15; P=0.59). PCDT led to reduced PTS severity as shown by lower mean Villalta and Venous Clinical Severity Scores ( P<0.01 for comparisons at 6, 12, 18, and 24 months), and fewer patients with moderate-or-severe PTS (Villalta scale ≥10 or ulcer: 18% versus 28%; risk ratio, 0.65; 95% CI, 0.45-0.94; P=0.021) or severe PTS (Villalta scale ≥15 or ulcer: 8.7% versus 15%; risk ratio, 0.57; 95% CI, 0.32-1.01; P=0.048; and Venous Clinical Severity Score ≥8: 6.6% versus 14%; risk ratio, 0.46; 95% CI, 0.24-0.87; P=0.013). From baseline, PCDT led to greater reduction in leg pain and swelling ( P<0.01 for comparisons at 10 and 30 days) and greater improvement in venous disease-specific quality of life (Venous Insufficiency Epidemiological and Economic Study Quality of Life unit difference 5.6 through 24 months, P=0.029), but no difference in generic quality of life ( P>0.2 for comparisons of SF-36 mental and physical component summary scores through 24 months). In patients having PCDT versus No-PCDT, major bleeding within 10 days occurred in 1.5% versus 0.5% ( P=0.32), and recurrent venous thromboembolism over 24 months was observed in 13% versus 9.2% ( P=0.21).

CONCLUSIONS

In patients with acute iliofemoral deep vein thrombosis, PCDT did not influence the occurrence of PTS or recurrent venous thromboembolism. However, PCDT significantly reduced early leg symptoms and, over 24 months, reduced PTS severity scores, reduced the proportion of patients who developed moderate-or-severe PTS, and resulted in greater improvement in venous disease-specific quality of life.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov . Unique identifier: NCT00790335.

Endovascular Therapy for Central Venous Thrombosis

Central vein thrombosis is defined as thrombosis of the major vessels draining either the upper or lower extremities. It presents most commonly in the upper limb, where it affects the subclavian veins and the superior vena cava; in the lower limb, it affects the common iliac veins and the inferior vena cava. These different anatomical segments pose unique challenges in both acute and chronic settings, and this article will summarize the current best practice treatment options.

Rivaroxaban or vitamin-K antagonists following early endovascular thrombus removal and stent placement for acute iliofemoral deep vein thrombosis

BACKGROUND

The optimal anticoagulant following catheter-based therapy of acute iliofemoral deep vein thrombosis (IFDVT) is unknown.

METHODS

From the Swiss Venous Stent registry, an ongoing prospective cohort study, we performed a subgroup analysis of patients with acute IFDVT who underwent catheter-based early thrombus removal followed by nitinol stent placement. Duplex ultrasound and Villalta scores were used to determine patency rates and incidence of the post-thrombotic syndrome (PTS) in patients treated with either rivaroxaban (n = 73) or a vitamin K-antagonist (VKA; n = 38) for a minimum duration of 3 months.

RESULTS

Mean follow-up duration was 24 ± 19 months (range 3 to 77 months). Anticoagulation therapy was time-limited (3 to 12 months) in 56% of patients (47% in the rivaroxaban group and 58% in the VKA group, p = 0.26), with shorter mean duration of anticoagulation in the rivaroxaban group (180 ± 98 days versus 284 ± 199 days, p = 0.01). Overall, primary and secondary patency rates at 24 months were 82% (95%CI, 71-89%) and 95% (95%CI, 87-98%), respectively, with no difference between the rivaroxaban (87% [95%CI, 76-94%] and 95% [95%CI, 85-98%]) and the VKA group (72% [95%CI, 52-86%] and 94% [95%CI, 78-99%]; p > 0.10 for both). Overall, 86 (86%) patients were free from PTS at latest follow-up, with no difference between the rivaroxaban and the VKA groups (57 [85%] versus 29 [88%]; p = 0.76). Two major bleeding complications (1 in each group) occurred in the peri-interventional period, without any major bleeding thereafter.

CONCLUSIONS

In patients with acute IFDVT treated with catheter-based early thrombus removal and venous stent placement, the effectiveness and safety of rivaroxaban and VKA appear to be similar.

CLINICAL TRIAL REGISTRATION

The study is registered on the National Institutes of Health website (ClinicalTrials.gov; identifier NCT02433054).

Endovascular and Open Surgery for Deep Vein Thrombosis

The surgical treatment of deep venous thrombosis (DVT) has significantly evolved and is focused on different strategies of early thrombus removal in the acute phase and deep venous recanalization or bypass in the chronic phase. Along with the use of anticoagulation agents, endovascular techniques based on catheter-directed thrombolysis and pharmacomechanical thrombectomy have been increasingly used in patients with acute extensive DVT. Patient selection is crucial to provide optimal outcomes and minimize complications.

DVT Intervention in the Post-ATTRACT Era

PURPOSE OF REVIEW

Patients suffering from acute lower extremity deep vein thrombosis (DVT) are at risk for developing chronic limb pain, heaviness, and fatigue, known as the post-thrombotic syndrome (PTS).

RECENT FINDINGS

Although several studies have shown that catheter-directed therapy reduces clot burden and may improve clinical outcomes, the multicenter randomized controlled ATTRACT trial showed no difference in PTS or quality of life at 2 years between patients treated with pharmacomechanical catheter-directed thrombolysis (PCDT) and those treated with anticoagulation alone, and a higher major bleeding rate in the PCDT group. PCDT is not indicated for most patients diagnosed with lower extremity DVT. Since PCDT may benefit patients with iliofemoral DVT, intervention can be considered in this subset of patients if they are at low risk of bleeding.

Catheter-directed thrombolysis for patients with acute lower extremity deep vein thrombosis: a meta-analysis

Objectives:

To evaluate case series studies that quantitatively assess the effects of catheter-directed thrombolysis (CDT) and compare the efficacy of CDT and anticoagulation in patients with acute lower extremity deep vein thrombosis (DVT).

Methods:

Relevant databases, including PubMed, Embase, Cochrane, Ovid MEDLINE and Scopus, were searched through January 2017. The inclusion criteria were applied to select patients with acute lower extremity DVT treated with CDT or with anticoagulation. In the case series studies, the pooled estimates of efficacy outcomes for patency rate, complete lysis, rethrombosis and post-thrombotic syndrome (PTS) were calculated across the studies. In studies comparing CDT with anticoagulation, summary odds ratios (ORs) were calculated.

Results:

Twenty-five articles (six comparing CDT with anticoagulation and 19 case series) including 2254 patients met the eligibility criteria. In the case series studies, the pooled results were a patency rate of 0.87 (95% CI: 0.85-0.89), complete lysis 0.58 (95% CI: 0.40-0.75), rethrombosis 0.11 (95% CI: 0.06-0.17) and PTS 0.10 (95% CI: 0.08-0.12). Six studies comparing the efficacy outcomes of CDT and anticoagulation showed that CDT was associated with a reduction of PTS (OR 0.38, 95%CI 0.26-0.55, p<0.0001) and a higher patency rate (OR 4.76, 95%CI 2.14-10.56, p<0.0001).

Conclusion:

Acute lower extremity DVT patients receiving CDT were found to have a lower incidence of PTS and a higher incidence of patency rate. In our meta-analysis, CDT is shown to be an effective treatment for acute lower extremity DVT patients.

Is there a role for intervention radiology for the treatment of lower limb deep vein thrombosis in the era of direct oral anticoagulants? A comprehensive review

Despite recent advances in the treatment of Deep Vein Thrombosis (DVT) provided by Direct Oral Anticoagulants (DOAC), a substantial proportion of lower limb DVT patients will develop some degree of post-thrombotic syndrome (PTS) within 2 years. Systemic thrombolysis, although effective in reducing the risk of PTS and leg ulceration, is associated with a high risk of major bleeding, making it unsuitable for the vast majority of patients. A local approach, aimed at delivering the fibrinolytic drug directly into, or near to, the thrombus surface, is attractive because of the possibility of lowering of the administered drug dose, thus reducing the bleeding risks. However, even after the recent publication of the ATTRACT trial, only weak evidence is available about the efficacy and safety of Catheter Directed Thrombolysis (CDT), either alone (pharmacological technique) or in combination with additional endovascular approaches (pharmacomechanical technique, PMT) including percutaneous mechanical thrombectomy, angioplasty with or without stenting and ultrasound-assisted CDT. The present review is aimed at providing the physicians with a comprehensive evaluation of the current evidence about this relevant topic, in order to build a reliable conceptual framework for a more appropriate use of this resource.

A systematic review on the use of deep venous stenting for acute venous thrombosis of the lower limb

OBJECTIVES

The aim is to evaluate venous stent patency, the development of post-thrombotic syndrome, recurrence, quality of life and the optimal post-procedural anticoagulation regimen in the treatment of iliofemoral deep venous thrombosis.

METHOD AND RESULTS

EMBASE and Medline databases were interrogated to identify studies in which acute deep venous thrombosis patients were stented. Twenty-seven studies and 542 patients were identified. Primary, assisted primary and secondary patency rates 12 months after stent placement ranged from 74 to 95, 90 to 95 and 84 to 100%, respectively. The observed post-thrombotic syndrome rate was 14.6%. The incidence of stent re-thrombosis was 8%. In 26% of studies, patients received additional antiplatelet therapy. Quality of life questionnaires employed in 11% of studies, demonstrating an improvement in the chronic venous insufficiency questionnaire (22.67 ± 3.01 versus 39.34 ± 6.66).

CONCLUSION

Venous stenting appears to be an effective adjunct to early thrombus removal; however, further studies are needed to identify optimal anticoagulant regimen and effect on quality of life.

Duplex Ultrasound Imaging of Iliac Venous Stents

Postthrombotic syndrome (PTS) is characterized by persistent leg edema, discoloration, pain, and ulceration in patients with a history of a deep vein thrombosis (DVT). We describe a 60-year-old man who had unilateral PTS develop from an iliofemoral DVT. The patient was treated with thrombolytic therapy using reteplase (Retavase, Centocor, Malvern, PA) followed by mechanical thrombectomy. Percutaneous transluminal angioplasty of the common and external iliac veins was subsequently performed, and a total of six self-expanding nitinol stents were deployed. Stent patency was assessed using an Advanced Technology Laboratories HDI 5000 (Philips Ultrasound, Bothell, WA) ultrasound machine with a curved 5-2 MHz transducer. B-mode images and color duplex ultrasonography with Doppler signals were recorded. Intraluminal echoes and the lack of vein compressibility confirmed the presence of remote thrombus more distally. However, widely patent stents with spontaneous, phasic blood flow were demonstrated in the common and external iliac veins. The patient's edema significantly improved. Deployment of stents to maintain vessel patency of diseased iliac veins is being performed with increasing frequency. Duplex ultrasonography is an inexpensive, noninvasive modality that can be used to follow patients who have had an endovascular venous intervention.

Safety and Efficacy of Catheter Direct Thrombolysis in Management of Acute Iliofemoral Deep Vein Thrombosis: A Systematic Review

Purpose

Catheter direct thrombolysis (CDT) has been shown to be an effective treatment for deep venous thrombosis. The objective of the review is to improve safety and efficacy of the CDT by using ward based protocol, better able to predict complications and treatment outcome through monitoring of haemostatic parameters and clinical observation during thrombolysis procedure.

Materials and Methods

MEDLINE, EMBASE, CENTRAL and Web of Science were searched for all articles on deep venous thrombosis, thrombolysis and correlations of clinical events (bleeding, successful thrombolysis) during thrombolysis with hemostatic parameters to March 2016. The risk of bias in included studies was assessed by Cochrane Collaboration’s tool and Cochrane Risk of Bias Assessment Tool: for Non-Randomized Studies of Interventions.

Results

Twenty-four studies were included in the review and we found that improving safety and efficacy of CDT by using ward based protocol depending on eight factors; strict patient selection criteria, types of fibrinolytic drugs, mode of fibrinolytic drug injection, biochemical markers monitoring (fibrinogen, D-dimer, activated partial thromboplastin time, plasminogen activator inhibitor-1), timing of intervention, usage of intermittent pneumatic calf, ward monitoring and thrombolysis imaging assessment (intravascular ultrasound). These factors may help to improve safety and efficacy by reducing total thrombolytic drug dosage and at the same time ensure successful lysis. There is a marked lack of randomized controlled trials discussing the safety and efficacy of catheter direct thrombolysis.

Conclusion

CDT can be performed safely and efficiently in clinical ward, providing that careful nursing, biochemical monitoring, proper selection and mode of infusion of fibrinolytic drugs, usage of Intermittent pneumatic calf and adequate thrombolysis imaging assessment are ensured.

Thrombectomy and thrombolysis for the prevention and treatment of postthrombotic syndrome

Postthrombotic syndrome (PTS) is a frequent complication of lower-extremity deep vein thrombosis (DVT), occurring in approximately 40% of patients despite the use of anticoagulant therapy. PTS causes significant impairment of patients' health-related quality of life, and no evidence-based therapies have been consistently effective. Catheter-directed thrombolysis and thrombectomy have been shown to remove acute thrombus, and it has been hypothesized they could prevent or reduce PTS. However, because these procedures can be associated with complications, mainly bleeding, randomized trial data are needed to determine when they should be used. In this article, I summarize the current status of thrombus removal procedures for DVT to provide contemporary guidance to clinicians seeking to individualize treatment decisions for their patients.

Pharmacomechanical Catheter-Directed Thrombolysis for Deep-Vein Thrombosis

BACKGROUND

The post-thrombotic syndrome frequently develops in patients with proximal deep-vein thrombosis despite treatment with anticoagulant therapy. Pharmacomechanical catheter-directed thrombolysis (hereafter "pharmacomechanical thrombolysis") rapidly removes thrombus and is hypothesized to reduce the risk of the post-thrombotic syndrome.

METHODS

We randomly assigned 692 patients with acute proximal deep-vein thrombosis to receive either anticoagulation alone (control group) or anticoagulation plus pharmacomechanical thrombolysis (catheter-mediated or device-mediated intrathrombus delivery of recombinant tissue plasminogen activator and thrombus aspiration or maceration, with or without stenting). The primary outcome was development of the post-thrombotic syndrome between 6 and 24 months of follow-up.

RESULTS

Between 6 and 24 months, there was no significant between-group difference in the percentage of patients with the post-thrombotic syndrome (47% in the pharmacomechanical-thrombolysis group and 48% in the control group; risk ratio, 0.96; 95% confidence interval [CI], 0.82 to 1.11; P=0.56). Pharmacomechanical thrombolysis led to more major bleeding events within 10 days (1.7% vs. 0.3% of patients, P=0.049), but no significant difference in recurrent venous thromboembolism was seen over the 24-month follow-up period (12% in the pharmacomechanical-thrombolysis group and 8% in the control group, P=0.09). Moderate-to-severe post-thrombotic syndrome occurred in 18% of patients in the pharmacomechanical-thrombolysis group versus 24% of those in the control group (risk ratio, 0.73; 95% CI, 0.54 to 0.98; P=0.04). Severity scores for the post-thrombotic syndrome were lower in the pharmacomechanical-thrombolysis group than in the control group at 6, 12, 18, and 24 months of follow-up (P<0.01 for the comparison of the Villalta scores at each time point), but the improvement in quality of life from baseline to 24 months did not differ significantly between the treatment groups.

CONCLUSIONS

Among patients with acute proximal deep-vein thrombosis, the addition of pharmacomechanical catheter-directed thrombolysis to anticoagulation did not result in a lower risk of the post-thrombotic syndrome but did result in a higher risk of major bleeding. (Funded by the National Heart, Lung, and Blood Institute and others; ATTRACT ClinicalTrials.gov number, NCT00790335 .).

Catheter-Directed Thrombolysis Versus Standard Anticoagulation for Acute Lower Extremity Deep Vein Thrombosis: A Meta-Analysis of Clinical Trials

Standard anticoagulant treatment alone for acute lower extremity deep vein thrombosis (DVT) is ineffective in eliminating thrombus from the deep venous system, with many patients developing postthrombotic syndrome (PTS). Because catheter-directed thrombolysis (CDT) can dissolve the clot, reducing the development of PTS in iliofemoral or femoropopliteal DVT. This meta-analysis compares CDT plus anticoagulation versus standard anticoagulation for acute iliofemoral or femoropopliteal DVT. Ten trials were included in the meta-analysis. Compared with anticoagulant alone, CDT was shown to significantly increase the percentage patency of the iliofemoral vein (P < .00001; I² = 44%) and reduce the risk of PTS (P = .0002; I² = 79%). In subgroup analysis of randomized controlled trials, CDT was not shown to prevent PTS (P = .2; I² = 59%). A reduced PTS risk was shown, however, in nonrandomized trials (P < .00001; I² = 47%). Meta-analysis showed that CDT can reduce severe PTS risk (P = .002; I² = 0%). However, CDT was not indicated to prevent mild PTS (P = .91; I² = 79%). A significant increase in bleeding events (P < .00001; I² = 33%) and pulmonary embolism (PE) (P < .00001; I² = 14%) were also demonstrated. However, for the CDT group, the duration of stay in the hospital was significantly prolonged compared to the anticoagulant group (P < .00001; I² = 0%). There was no significant difference in death (P = .09; I² = 0%) or recurrent venous thromboembolism events (P = .52; I² = 58%). This meta-analysis showed that CDT may improve patency of the iliofemoral vein or severe PTS compared with anticoagulation therapy alone, but measuring PTS risk remains controversial. However, CDT could increase the risk of bleeding events, PE events, and duration of hospital stay.

Safety of catheter-directed thrombolysis for the treatment of acute lower extremity deep vein thrombosis: A systematic review and meta-analysis

BACKGROUND

Despite established guidelines, catheter-directed thrombolysis (CDT) for the management of acute lower extremity deep vein thrombosis (DVT) should not be overstated because the risks of CDT are uncertain. We performed a meta-analysis to comprehensively and quantitatively evaluate the safety of CDT for patients with acute lower extremity DVT.

METHODS

Relevant databases, including PubMed, Embase, Cochrane, Ovid MEDLINE, and Scopus, were searched up to January 2017. The inclusion criteria were applied to select patients with acute lower extremity DVT treated by CDT or compared CDT with anticoagulation. In case series studies, the pooled estimates of safety outcomes for complications, pulmonary embolism (PE), and mortality were calculated across studies. In studies comparing CDT with anticoagulation, summary odds ratios (ORs) were calculated.

RESULTS

Of the 1696 citations identified, 24 studies (6 comparing CDT with anticoagulation and 18 case series) including 9157 patients met the eligibility criteria. In the case series studies, the pooled risks of major, minor, and total complications were 0.03 (95% confidence interval [CI]: 0.02-0.04), 0.07 (95% CI: 0.05-0.08), and 0.09 (95% CI: 0.08-0.11), respectively; other pooled risk results were 0.00 for PE (95% CI: 0.00-0.01) and 0.07 for mortality (95% CI: 0.03-0.11). Our meta-analysis of 6 studies comparing the risk of complications and PE related to CDT with those related to anticoagulation showed that CDT was associated with an increased risk of complications (OR = 4.36; 95% CI: 2.94-6.47) and PE (OR = 1.57; 95% CI: 1.37-1.79).

CONCLUSION

Acute lower extremity DVT patients receiving CDT are associated with a low risk of complications. However, compared with anticoagulation, CDT is associated with a higher risk of complications and PE. Rare mortality related to thrombolytic therapy was reported. More evidence should be accumulated to prove the safety of CDT.

Catheter-directed thrombolysis to avoid late consequences of acute deep vein thrombosis

The application of catheter-based methods to treat acute deep vein thrombosis (DVT) has increased in recent years. Catheter-directed thrombolysis (CDT), introduced during the early 1990s, has shown the ability to rapidly eliminate thrombus and is used in many centers as a salvage therapy for DVT patients who exhibit a poor initial response to anticoagulant therapy. However, CDT has disadvantages in terms of safety and resource use. Although CDT methods have evolved substantially to try to address these issues, for most of the last 25years there was little high-quality data on CDT outcomes upon which to base patient care decisions. The paucity of evidence was particularly problematic for long-term outcomes such as recurrent venous thromboembolism (VTE) and the post-thrombotic syndrome (PTS). Fortunately, rigorous studies of CDT are now being completed. Accordingly, the purpose of this article is to: 1) state the known and unknown factors influencing risk and benefit with use of CDT and related methods to treat acute DVT; 2) summarize emerging evidence showing the patient outcomes that occur when CDT is used for first-line management of DVT; and 3) suggest clinical parameters for CDT utilization in light of the available evidence.