Prevention and treatment of the post-thrombotic syndrome

Three-Year Outcomes of the Abre Venous Self-Expanding Stent System in Patients with Symptomatic Iliofemoral Venous Outflow Obstruction

PURPOSE

To report 36-month outcomes and subgroup analysis of the ABRE study evaluating the safety and effectiveness of the Abre venous self-expanding stent system for the treatment of symptomatic iliofemoral venous outflow obstruction disease.

METHODS

The ABRE study was a prospective, multicenter, nonrandomized study that enrolled and implanted Abre venous stents in 200 participants (mean age 51.5 years [SD ± 15.9], 66.5% women) with symptomatic iliofemoral venous outflow obstruction at 24 global sites. Outcomes assessed through 36 months included patency, major adverse events, stent migration, stent fracture, and quality-of-life changes. Adverse events and imaging studies were adjudicated by independent clinical events committee and core laboratories, respectively.

RESULTS

Primary, primary-assisted, and secondary patency through 36 months by Kaplan-Meier estimates were 81.6%, 84.8%, and 86.3%, respectively. The cumulative incidence of major adverse events through 36 months was 10.2%, mainly driven by 12 thrombosis events. Subgroup analyses demonstrated a primary patency of 76.5% in the acute deep vein thrombosis group, 70.4% in the postthrombotic syndrome group, and 97.1% in the nonthrombotic iliac vein lesion group through 36 months. The overall mean lesion length was 112.4 mm (SD ± 66.1). There were no stent fractures or migrations in this study. Quality of life and venous functional assessments demonstrated significant improvements from baseline to 36 months across all patient subsets.

CONCLUSIONS

Results from the ABRE study demonstrated sustained patency with a good safety profile after implantation of a dedicated venous stent in patients with symptomatic iliofemoral venous outflow obstruction disease.

Randomized controlled trials of interventions for acute iliofemoral deep venous thrombosis

Venous thromboembolism (VTE), notably deep venous thrombosis (DVT), represents a significant cardiovascular disease with high morbidity from post-thrombotic syndrome (PTS). Recent advancements in early thrombus removal technologies have prompted randomized controlled trials (RCT) to assess their efficacy and safety, particularly for iliofemoral DVT (IF-DVT), which carries the greatest risk of developing PTS. This narrative review summarizes these trials and introduces upcoming innovations to evaluate acute intervention for IF-DVT. Specific technologies discussed include catheter-directed thrombolysis, pharmacomechanical catheter-directed thrombolysis, ultrasound-accelerated catheter-directed thrombolysis, and non-lytic mechanical thrombectomy. This review underscores the importance of patient selection, with those presenting with extensive, symptomatic IF-DVT likely to benefit most.

Exploring phenotypes of deep vein thrombosis in relation to clinical outcomes beyond recurrence

BACKGROUND

Deep vein thrombosis (DVT) is a multifactorial disease with several outcomes, but current classifications solely stratify it based on recurrence risk.

OBJECTIVES

We aimed to identify DVT phenotypes and assess their relation to recurrent venous thromboembolism (VTE), postthrombotic syndrome, arterial events, and cancer.

PATIENTS/METHODS

Hierarchical clustering was performed on a DVT cohort with a follow-up of up to 5 years using 23 baseline characteristics. Phenotypes were summarized by discriminative characteristics. Hazard ratios (HRs) were calculated using Cox regression; the recurrence risk was adjusted for the anticoagulant therapy duration. The study was carried out in accordance with the Declaration of Helsinki and approved by the medical ethics committee.

RESULTS

In total, 825 patients were clustered into 4 phenotypes: 1. women using estrogen therapy (n = 112); 2. patients with a cardiovascular risk profile (n = 268); 3. patients with previous VTE (n = 128); and 4. patients without discriminant characteristics (n = 317). Overall, the risks of recurrence, postthrombotic syndrome, arterial events, and cancer were low in phenotype 1 (reference), intermediate in phenotype 4 (HR: 4.6, 1.2, 2.2, 1.8), and high in phenotypes 2 (HR: 6.1, 1.6, 4.5, 2.9) and 3 (HR: 5.7, 2.5, 2.3, 3.7).

CONCLUSIONS

This study identified 4 distinct phenotypes among patients with DVT that are not only associated with the increasing recurrence risk but also with outcomes beyond recurrence. Our results thereby highlight the limitations of current risk stratifications that stratify based on the predictors of the recurrence risk only. Overall, risks were lowest in women using estrogen therapy and highest in patients with a cardiovascular risk profile. These findings might inform a more personalized approach to clinical management.

Exploring the Villalta scale to capture postthrombotic syndrome using alternative approaches: A subanalysis of the ATTRACT trial

Background

Clinical trials that evaluated interventions to prevent postthrombotic syndrome (PTS) used the Villalta scale (VS) to define PTS, but there is a lack of consistency in its use.

Objectives

This study aimed to improve the ability to identify patients with clinically meaningful PTS after DVT in participants of the ATTRACT trial.

Methods

We conducted a post hoc exploratory analysis of 691 patients from the ATTRACT study, a randomized trial evaluating the effectiveness of pharmacomechanical thrombolysis to prevent PTS in proximal deep vein thrombosis. We compared 8 VS approaches to classify patients with or without PTS in terms of their ability to discriminate between those with poorer vs better venous disease-specific quality of life (Venous Insufficiency Epidemiological and Economic Study Quality of Life [VEINES-QOL]) between 6- and 24-months follow-up. The difference in the average area under the fitted curve of VEINES-QOL scores between PTS and no PTS ( Δ A U C ¯ ) were compared among approaches.

Results

For any PTS (a single VS score ≥5), approaches 1 to 3 had similar Δ A U C ¯ (-21.2, -23.7, -22.0, respectively). Adjusting the VS for contralateral chronic venous insufficiency (CVI) or restricting to patients without baseline CVI (approaches 7 and 8) did not improve Δ A U C ¯ (-13.6, -19.9, respectively; P >.01). For moderate-to-severe PTS (a single VS score ≥10), approaches 5 and 6 requiring 2 positive assessments had greater but not statistically significant Δ A U C ¯ than approach 4, using one single positive assessment (-31.7, -31.0, -25.5, respectively; P >.01).

Conclusion

A single VS score of ≥ 5 reliably distinguishes patients with clinically meaningful PTS as assessed by impact on QOL and is preferred because of greater convenience (only one assessment needed). Alternative methods to define PTS (ie, adjusting for CVI) do not improve the scale's ability to identify clinically meaningful PTS.

Characteristics and Treatment Strategy of Isolated Calf Deep Venous Thrombosis after Fractures: A Review of Recent Literature

Isolated calf deep venous thrombosis (ICDVT) includes thrombosis located at the far end of the popliteal vein, such as the anterior tibial vein, posterior tibial vein, fibular vein, and intramuscular vein of the soleus and gastrocnemius. This type of thrombosis has the highest incidence, accounting for approximately half of all deep vein thrombosis (DVT) cases; however, there is no consistent recommendation for ICDVT treatment across countries, and there is also no optimal management strategy. In recent years, increasing evidence has shown that ICDVT can develop into proximal DVT, even causing pulmonary embolism (PE). Therefore, some experts suggest anticoagulant therapy for this type of DVT, while others hold an opposing attitude. Therefore, the treatment strategy for this type of DVT has become a hot and difficult research topic. The purpose of this review is to summarize the characteristics of ICDVT and the effects of different treatment strategies by analyzing recent and important classical works in the literature in an attempt to provide recommendations for the treatment of this most common type of DVT in orthopaedic clinics.

A systematic review of current trends in pharmacologic management after stent placement in nonthrombotic iliac vein lesions

Objective

Stenting of the iliac vein is increasingly recognized as a treatment for chronic venous insufficiency (CVI). However, the pharmacologic management after stent placement is unclear. This review was conducted to illustrate recent trends in anticoagulation and antiplatelet regimens following stent placement for nonthrombotic iliac vein lesions (NIVL).

Methods

The MEDLINE database was searched using the term “iliac vein stent.” Retrieval of articles was limited to studies conducted on humans and published in English between 2010 and 2020. Studies were included that described iliac vein stent placement. Studies were excluded that contained fewer than 25 patients, performed procedures other than stent placement, did not specify the postoperative anticoagulant used, or treated lesions of thrombotic origin.

Results

12 articles were included in this review, yielding a total of 2782 patients with a male-to-female ratio of 0.77. The predominant CEAP classification encountered was C3. The most common stent used in the included studies was the Wallstent (9/12), and the most common pharmacologic regimen was 3 months of clopidogrel (6/12). Warfarin, aspirin, cilostazol, and rivaroxaban were among other agents used. Primary stent patency ranged from 63.1 to 98.3%. There was no apparent correlation between pharmacologic agent used and stent patency or subjective patient outcomes.

Conclusion

Multiple different approaches are being taken to pharmacologically manage patients following stent placement for NIVL. There is no consensus on which agent is best, nor is there a formal algorithmic approach for making this decision. Additionally, the findings in this study call into question whether anticoagulation following stenting for NIVL is necessary at all, given the similar outcomes among the different agents utilized. This review underscores the potential value of undertaking a multi-institutional prospective study to determine what is the best pharmacologic therapy following venous stent placement for NIVL.

Ultrahigh field MRI determination of water diffusion rates in ex vivo human lenses of different age

BACKGROUND

The development of presbyopia is correlated with increased lens stiffness. To reveal structural changes with age, ultrahigh field magnetic resonance imaging (UHF-MRI) was used to analyze water diffusion in differently aged human lenses ex vivo.

METHODS

After enucleation lens extractions were performed. Lenses were photographed, weighed, and embedded in 0.5% agarose dissolved in culture medium. UHF-MRI was conducted to analyze anatomical characteristics of the lens using T2-weighted Turbo-RARE imaging and to obtain apparent diffusion coefficients (ADC) measurements. A Gaussian fit routine was used to examine the ADC histograms.

RESULTS

An age-dependent increase in lens wet weight, lens thickness, and lens diameter was found (P<0.001). T2-weighted images revealed a hyperintense lens cortex and a gradually negative gradient in signal intensity towards the nucleus. ADC histograms of the lens showed bimodal distributions (lower ADC values mainly located in the nucleus and higher ADC values mainly located in the cortex), which did not change significantly with age [βPeak1=1.96E-7 (-20E-7, 10E-7), P=0.804 or βPeak2=15.4E-7 (-10E-7, 40E-7), P=0.276; respectively].

CONCLUSIONS

Clinically relevant age dependent lens hardening is probably not correlated with ADC changes within the nucleus, which could be confirmed by further measurements.

Clinical guidelines versus current clinical practice for the management of deep vein thrombosis

BACKGROUND

Deep vein thrombosis (DVT) is one of the major health problems worldwide with potentially serious outcomes related to mortality and morbidity. We provide a current view on how patients with DVT are managed in routine practice compared with the recommendations of published clinical guidelines.

METHODS

A literature review was conducted on studies reporting diagnostic and treatment patterns for acute DVT. Four dimensions were evaluated to compare the differences between clinical practice and clinical guidelines recommendations: diagnostic pathway, prescription of pharmacologic treatment and related duration, and prescription of compression therapy. For each aspect, the agreement with the corresponding guideline has been estimated as a percentage ranging from 0% (no agreement) to 100% (full agreement).

RESULTS

Sixteen studies reported clinical practices in 10 countries. Among them, Japan showed the highest agreement with guidelines, followed by the UK and Switzerland. Hong Kong showed the highest agreement with diagnosis guidelines, Spain for drug treatment, UK for treatment duration, and France for compression therapy. Conversely, Germany reported a complete disagreement with guidelines for diagnosis, followed by low agreement level by UK and Italy, and Switzerland reported a lower agreement level with prescription of compression therapy.

CONCLUSIONS

The implementation of clinical guidelines for the management of patients with DVT varies among countries from strict adherence to a complete lack of adherence. In this context, registries may be a useful tool to analyze clinical practice and produce findings that may be generalizable across populations.

Post-thrombotic syndrome

Post-thrombotic syndrome (PTS) is a chronic venous insufficiency manifestation following an episode of deep-vein thrombosis (DVT). It is an important and frequent long-term adverse event of proximal DVT affecting 20-50% of patients. This position paper integrates data guiding clinicians in deciding PTS diagnosis, treatment and follow-up.

Thrombolytic strategies versus standard anticoagulation for acute deep vein thrombosis of the lower limb

BACKGROUND

Standard treatment for deep vein thrombosis (DVT) aims to reduce immediate complications. Use of thrombolytic clot removal strategies (i.e. thrombolysis (clot dissolving drugs), with or without additional endovascular techniques), could reduce the long-term complications of post-thrombotic syndrome (PTS) including pain, swelling, skin discolouration, or venous ulceration in the affected leg. This is the fourth update of a Cochrane Review first published in 2004.

OBJECTIVES

To assess the effects of thrombolytic clot removal strategies and anticoagulation compared to anticoagulation alone for the management of people with acute deep vein thrombosis (DVT) of the lower limb.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL and AMED and the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registries to 21 April 2020. We also checked the references of relevant articles to identify additional studies.

SELECTION CRITERIA

We considered randomised controlled trials (RCTs) examining thrombolysis (with or without adjunctive clot removal strategies) and anticoagulation versus anticoagulation alone for acute DVT.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as recommended by Cochrane. We assessed the risk of bias in included trials with the Cochrane 'Risk of bias' tool. Certainty of the evidence was evaluated using GRADE. For dichotomous outcomes, we calculated the risk ratio (RR) with the corresponding 95% confidence interval (CI). We pooled data using a fixed-effect model, unless we identified heterogeneity, in which case we used a random-effects model. The primary outcomes of interest were clot lysis, bleeding and post thrombotic syndrome.

MAIN RESULTS

Two new studies were added for this update. Therefore, the review now includes a total of 19 RCTs, with 1943 participants. These studies differed with respect to the thrombolytic agent, the doses of the agent and the techniques used to deliver the agent. Systemic, loco-regional and catheter-directed thrombolysis (CDT) strategies were all included. For this update, CDT interventions also included those involving pharmacomechanical thrombolysis. Three of the 19 included studies reported one or more domain at high risk of bias. We combined the results as any (all) thrombolysis interventions compared to standard anticoagulation. Complete clot lysis occurred more frequently in the thrombolysis group at early follow-up (RR 4.75; 95% CI 1.83 to 12.33; 592 participants; eight studies) and at intermediate follow-up (RR 2.42; 95% CI 1.42 to 4.12; 654 participants; seven studies; moderate-certainty evidence). Two studies reported on clot lysis at late follow-up with no clear benefit from thrombolysis seen at this time point (RR 3.25, 95% CI 0.17 to 62.63; two studies). No differences between strategies (e.g. systemic, loco-regional and CDT) were detected by subgroup analysis at any of these time points (tests for subgroup differences: P = 0.41, P = 0.37 and P = 0.06 respectively). Those receiving thrombolysis had increased bleeding complications (6.7% versus 2.2%) (RR 2.45, 95% CI 1.58 to 3.78; 1943 participants, 19 studies; moderate-certainty evidence). No differences between strategies were detected by subgroup analysis (P = 0.25). Up to five years after treatment, slightly fewer cases of PTS occurred in those receiving thrombolysis; 50% compared with 53% in the standard anticoagulation (RR 0.78, 95% CI 0.66 to 0.93; 1393 participants, six studies; moderate-certainty evidence). This was still observed at late follow-up (beyond five years) in two studies (RR 0.56, 95% CI 0.43 to 0.73; 211 participants; moderate-certainty evidence). We used subgroup analysis to investigate if the level of DVT (iliofemoral, femoropopliteal or non-specified) had an effect on the incidence of PTS. No benefit of thrombolysis was seen for either iliofemoral or femoropopliteal DVT (six studies; test for subgroup differences: P = 0.29). Systemic thrombolysis and CDT had similar levels of effectiveness. Studies of CDT included four trials in femoral and iliofemoral DVT, and results from these are consistent with those from trials of systemic thrombolysis in DVT at other levels of occlusion.

AUTHORS' CONCLUSIONS

Complete clot lysis occurred more frequently after thrombolysis (with or without additional clot removal strategies) and PTS incidence was slightly reduced. Bleeding complications also increased with thrombolysis, but this risk has decreased over time with the use of stricter exclusion criteria of studies. Evidence suggests that systemic administration of thrombolytics and CDT have similar effectiveness. Using GRADE, we judged the evidence to be of moderate-certainty, due to many trials having small numbers of participants or events, or both. Future studies are needed to investigate treatment regimes in terms of agent, dose and adjunctive clot removal methods; prioritising patient-important outcomes, including PTS and quality of life, to aid clinical decision making.

Accuracy of contralateral Villalta score to assess for pre-existing chronic venous insufficiency in patients with unilateral deep vein thrombosis

BACKGROUND

International guidelines recommend using the Villalta score (VS) to diagnose the postthrombotic syndrome (PTS). However, a high proportion of PTS detected with VS could just reflect the presence of preexisting primary venous insufficiency (PVI). Furthermore, it is unclear whether the contralateral VS (cl-VS) can be used to assess for preexisting PVI.

OBJECTIVES

To estimate whether cl-VS can be used to assess for preexisting PVI, and to assess the proportion of PTS that could be attributable to preexisting PVI.

METHODS

Subanalysis of the SOX multicenter randomized trial focusing on patients with a first unilateral proximal deep vein thrombosis (DVT) followed for up to 2 years. PVI was defined as a baseline cl-VS > 4, and PTS as VS > 4 in the leg ipsilateral to DVT starting 6 months after DVT.

RESULTS

Among 680 patients, mean cl-VS remained stable over time: 1.23 (standard deviation [SD] ±2.49) at baseline and 1.17 (±2.20), 1.59 (±2.81), 1.54 (±2.50), 1.65 (±2.82), and 1.55 (±2.63) at the 1-, 6-, 12-, 18-, and 24-month visits, respectively. Baseline cl-VS and ipsilateral VS measured during follow-up were mildly correlated (Pearson correlation = 0.13-0.25). This association disappeared after subtracting the cl-VS measured at the same visit from the ipsilateral VS. Overall, 48.8% of patients developed PTS of whom 12.8% had baseline cl-VS > 4.

CONCLUSION

In our study of patients with a first unilateral proximal DVT, the proportion of patients with PTS who had a cl-VS > 4 is modest. However, cl-VS appears to be stable over time. Its assessment could constitute a simple way of documenting preexisting PVI and help to classify patients as having PTS.

Compression stockings to prevent postthrombotic syndrome: Literature overview and presentation of the CELEST trial

Postthrombotic syndrome (PTS) is a burdensome and costly complication of deep vein thrombosis (DVT) that develops in 20%-40% of patients within 2 years after proximal DVT. In the absence of effective curative treatment, management of PTS relies on its prevention after DVT. The effectiveness of elastic compression stockings (ECS) to prevent PTS is uncertain. We present an overview of published studies assessing the efficacy of ECS to prevent PTS and present the protocol for the CELEST clinical trial. While previous open-label randomized trials have reported a 50% risk reduction in PTS in patients treated with >30 mm Hg ankle pressure ECS, a large double-blind trial reported no effect of ECS. We discuss the main potential limitations of these trials, including a placebo effect and suboptimal compliance to ECS. We present the protocol of the CELEST double-blind randomized trial comparing 2 years of high strength (ankle pressure 35 mm Hg) versus lower strength (ankle pressure 25 mm Hg) ECS in the prevention of PTS after a first acute symptomatic, unilateral, proximal DVT. The use of lower-strength ECS than that used in previous studies should favor compliance. CELEST may provide important evidence about the efficacy of ECS in the prevention of PTS after DVT. The results will be interpreted in the light of results from recent clinical trials assessing ECS for PTS prevention that reported that the duration of ECS use should be tailored to the individual, if ECS are efficacious in the prevention of PTS.

Venous Thromboembolism Research Priorities: A Scientific Statement From the American Heart Association and the International Society on Thrombosis and Haemostasis

Venous thromboembolism is a major cause of morbidity and mortality. The impact of the US Surgeon General's The Surgeon General's Call to Action to Prevent Deep Vein Thrombosis and Pulmonary Embolism in 2008 has been lower than expected given the public health impact of this disease. This scientific statement highlights future research priorities in venous thromboembolism, developed by experts and a crowdsourcing survey across 16 scientific organizations. At the fundamental research level (T0), researchers need to identify pathobiological causative mechanisms for the 50% of patients with unprovoked venous thromboembolism and to better understand mechanisms that differentiate hemostasis from thrombosis. At the human level (T1), new methods for diagnosing, treating, and preventing venous thromboembolism will allow tailoring of diagnostic and therapeutic approaches to individuals. At the patient level (T2), research efforts are required to understand how foundational evidence impacts care of patients (eg, biomarkers). New treatments, such as catheter-based therapies, require further testing to identify which patients are most likely to experience benefit. At the practice level (T3), translating evidence into practice remains challenging. Areas of overuse and underuse will require evidence-based tools to improve care delivery. At the community and population level (T4), public awareness campaigns need thorough impact assessment. Large population-based cohort studies can elucidate the biological and environmental underpinnings of venous thromboembolism and its complications. To achieve these goals, funding agencies and training programs must support a new generation of scientists and clinicians who work in multidisciplinary teams to solve the pressing public health problem of venous thromboembolism.

Venous thromboembolism research priorities: A scientific statement from the American Heart Association and the International Society on Thrombosis and Haemostasis

Venous thromboembolism (VTE) is a major cause of morbidity and mortality. The impact of the Surgeon General's Call to Action in 2008 has been lower than expected given the public health impact of this disease. This scientific statement highlights future research priorities in VTE, developed by experts and a crowdsourcing survey across 16 scientific organizations. At the fundamental research level (T0), researchers need to identify pathobiologic causative mechanisms for the 50% of patients with unprovoked VTE and better understand mechanisms that differentiate hemostasis from thrombosis. At the human level (T1), new methods for diagnosing, treating, and preventing VTE will allow tailoring of diagnostic and therapeutic approaches to individuals. At the patient level (T2), research efforts are required to understand how foundational evidence impacts care of patients (eg, biomarkers). New treatments, such as catheter-based therapies, require further testing to identify which patients are most likely to experience benefit. At the practice level (T3), translating evidence into practice remains challenging. Areas of overuse and underuse will require evidence-based tools to improve care delivery. At the community and population level (T4), public awareness campaigns need thorough impact assessment. Large population-based cohort studies can elucidate the biologic and environmental underpinings of VTE and its complications. To achieve these goals, funding agencies and training programs must support a new generation of scientists and clinicians who work in multidisciplinary teams to solve the pressing public health problem of VTE.

Venous stenting for patients with outflow obstruction and leg ulcers: cost–effectiveness and budget impact analyses

Aim: To perform cost–effectiveness analysis (CEA) and budget impact analysis (BIA) comparing stenting to standard medical treatment (SMT) for the management of deep venous outflow obstruction and leg ulcers from the Italian Healthcare Service perspective. Materials & methods: A Markov model was developed to project costs and quality-adjusted life-years (QALYs) over 3 years, based on data from literature combined with real-world data. Moreover, a BIA was performed comparing the current scenario (100% SMT) with increasing utilization rates of stenting over SMT from 0.5 to 5%, in the next 5 years. Results: Stenting is a cost-effective (incremental cost-utility ratio €12,388/QALY) or dominant option versus SMT, according to in-patient or day-hospital settings, respectively. Increasing use of stenting over SMT, in the next 5 years, is expected to yield additional costs of 39.5 million Euros (in-patient) or savings of 5.1 million Euros (day-hospital). Conclusion: Stenting is a cost-effective option compared with SMT for patients with deep vein occlusion and ulceration in Italy.

Fibroid Expulsion after Uterine Artery Embolization

Uterine artery embolization (UAE) is a ubiquitous procedure, and a broadly recognized alternative to surgical interventions for symptomatic leiomyomata when uterine preservation is desired. Aside from postembolization syndrome (typically considered an expected feature of recovery), the most frequently described complications are temporary or permanent amenorrhea and lingering vaginal discharge. Less frequently described complications include fibroid expulsion (FE), protracted or refractory pain, infection, urinary retention, and access-related injuries. Reported rates of transcervical FE vary in the literature from 3 to 50% but are most often quoted to be around 5 to 15%. Certain features predispose a patient to FE, including size and location of the tumor, with pedunculated submucosal, submucosal, and transmural lesions considered to be "high risk." While the optimal management of FE has not been definitively determined, high rates of nonoperative management of FE are noted in the literature. This article describes a case in which a fibroid was expulsed following UAE, as well as the management of the complication. A literature review and recommendations for the management of FE is also given.