Single-session mechanical thrombectomy for iliofemoral deep vein thrombosis using a dual mechanism of action device combining basket and rotational thrombectomy.

OBJECTIVE: Interventional treatments for acute iliofemoral deep vein thrombosis (DVT) remain controversial after publication of the Acute Venous Thrombosis: Thrombus Removal with Adjunctive Catheter-Directed Thrombolysis (ATTRACT) study. Interventions have been shown to reduce post-thrombotic syndrome severity and improve quality of life in DVT patients, but have been accompanied by risk of major bleeding from thrombolytics. We describe thrombus removal using a novel combined basket-rotational thrombectomy device that minimizes the need for thrombolytics or repeat procedures. METHODS: The aim of this prospective, nonrandomized, multicenter, first-in-human study of 19 patients with acute iliofemoral DVT was to evaluate the safety and performance of the Pounce venous thrombectomy system ≤12 months after treatment. The primary performance end point was defined as procedural success through achievement of Society of Interventional Radiology (SIR) grade II lysis in treated vessels with freedom from procedural adverse events. Secondary end points included venous disease severity assessments using the Villalta scale and the Venous Clinical Severity Score, patient quality-of-life measurement using the Venous Insufficiency Epidemiological and Economic Study-Quality of Life questionnaire, and calf circumference measurements taken at baseline, 24 hours, and 1 month. RESULTS: The primary end point of complete or near-complete thrombus removal (Society of Interventional Radiology grade II or III) was achieved in all patients. All study device-related safety end points were met, with no major bleeding or device-related adverse events. Of the 19 patients treated, 16 (84.2%) did not receive thrombolytics during the procedure. Post-thrombotic syndrome (Villalta scale >4) was identified in 17 of 19 patients (89.5%) at baseline, 4 of 13 patients (30.8%) available for follow-up at 6 months, and 2 of 11 patients (18.2%) at 12 months. The median Venous Clinical Severity Score decreased (P < .001) from 8.5 (interquartile range [IQR], 7-10) at baseline to 4 (IQR, 2-4) at 1 month after the procedure and was similar at 6 months (2; IQR, 2-5) and 12 months (2; IQR, 1.5-3) after the procedure. The median Venous Insufficiency Epidemiological and Economic Study-Quality of Life questionnaire score improved (P < .001) by 39 from baseline (57; IQR, 53.5-74) to 1 month (96; IQR, 86-101) after the procedure, and remained high at 6 months (99; IQR, 75-103) and 12 months (98; IQR, 94.5-100). The median calf circumference decreased (P = .089) from 39 cm (IQR, 35-47.8 cm) at baseline to 36 cm (IQR, 32.5-40.5 cm) at 24 hours after the procedure and was 34.5 cm (IQR, 33.2-38.5 cm) at 1 month. CONCLUSIONS: The Pounce device is safe and effective for removal the of thrombus in patients with acute iliofemoral DVT. Initial results demonstrate improvements in venous disease severity and patient quality of life.

Management of iliofemoral deep vein thrombosis with distal involvement.

Endovascular treatment of iliofemoral deep vein thrombosis (IF DVT) can become more complex when thrombus extends below the knee. This article discusses various techniques that can be used to treat IF DVT with distal involvement.

Lessons Learned With Venous Stenting: In-flow, Outflow, and Beyond.

Venous stents are being used with increasing frequency, with a multitude of dedicated venous stents now well established or emerging onto the market. This review explores the multifaceted aspects of venous stenting. We discuss the history of venous stents, indications for their use, the imaging required before, during and after stenting, as well as some technical tips and tricks which we have found to be helpful in our own daily practice with a particular focus on iliofemoral venous stenting. Ultimately, this article seeks to enhance the understanding of venous stenting, offering insights into what we feel are best practices, challenges, and prospects for improved patient outcomes.

Acute and chronic venous occlusion.

This review article provides an overview of acute and chronic venous occlusion, a condition that can cause significant morbidity and mortality if not diagnosed and treated promptly. The article begins with an introduction to the anatomy of the venous system, followed by a discussion of the causes and clinical features of venous occlusion. The diagnostic tools available for the assessment of venous occlusion, including imaging modalities such as ultrasound, CT, and MRI, are then discussed, along with their respective advantages and limitations. The article also covers the treatment options for acute and chronic venous occlusion, including anticoagulant therapy and endovascular interventions. This review aims to provide radiologists with an updated understanding of the pathophysiology, diagnosis, and management of acute and chronic venous occlusion.

Antithrombotic Therapy After Venous Interventions: AJR Expert Panel Narrative Review.

Interventions for thrombotic and nonthrombotic venous disorders have increased with technical advances and more trained venous specialists. Antithrombotic therapy is essential to clinical and procedural success; however, postprocedural therapeutic regimens exhibit significant heterogeneity due to limited prospective randomized data and incomplete mechanistic understanding of the critical factors driving long-term patency. Postinterventional antithrombotic therapy for thrombotic venous disorders should adhere to existing venous thromboembolism management guidelines, which include 3-6 months of therapeutic anticoagulation at minimum and consideration of extended therapy in patients with higher risk of thrombosis because of procedural or patient factors. The added benefit of antiplatelet agents in the acute and intermediate period is unknown, having shown improved long-term stent patency in some retrospective studies. Dual- and/or triple-agent therapy should be limited based on individual risks of thrombosis and bleeding. The treatment of nonthrombotic disorders is more heterogeneous, though patients with limited flow, extensive stent material, or underlying prothrombotic states such as malignancy or chronic inflammation may benefit from single-agent or multiagent antithrombotic therapy. However, the agent, dose, and duration of therapy remain indeterminate. Future prospective studies are warranted to improve patient risk stratification and standardize postprocedural anti-thrombotic therapy in patients receiving venous interventions.

Endovascular Management of Venous Thromboembolic Disease in the Oncologic Patient Population.

PURPOSE OF REVIEW: Venous thromboembolic disease causes significant mortality and morbidity in the oncologic patient population. Recently, minimally invasive endovascular technologies have been developed as an adjunct to antithrombotic therapy for the management of DVT and PE. The current and potential roles for endovascular treatment of cancer-associated venous thromboembolism (VTE) will be reviewed in this article. RECENT FINDINGS: The recent NCCN guidelines recommend endovascular therapy in patients eligible for therapeutic anticoagulation who present with life-, organ-, or limb-threatening thrombosis. However, symptomatic non-life-threatening VTE can negatively affect QOL and physical function, both of which have prognostic implications in the cancer population. Endovascular therapies have been shown to improve physical function and QOL in prospective trials performed in a non-oncologic patient population as well as small retrospective studies in the cancer population. In addition to treating life- and limb-threatening thrombosis, endovascular therapy for VTE can improve QOL and physical function in comparison to anticoagulation alone. Prospective trials are warranted to assess the benefit of endovascular therapy for quality of life-years, performance status, and overall survival in the oncologic patient population.

A review of the incidence, outcome, and management of venous stent migration.

BACKGROUND: Percutaneous endovenous stenting has emerged during the past decade as the primary method of treating symptomatic venous outflow obstruction. A recognized complication of venous stenting is stent migration. The aim of the present systematic review was to identify the number of cases of stent migration in reported studies to recognize the risk factors that might be associated with this complication and the outcomes following migration. METHODS: A review was conducted in accordance with the MOOSE (meta-analyses of observational studies in epidemiology) and PRIMSA (preferred reporting items for systematic review and meta-analysis) guidelines and registered in the PROSPERO. MEDLINE, EMBASE, and PubMed databases. Key references were searched using specified keywords. All relevant data for the primary procedure and subsequent presentation with stent migration were retrieved. The data were assessed as too low in quality to allow for statistical analysis. RESULTS: Between 1994 and 2020, 31 studies were identified, including 29 case reports and 2 case series, providing data for 54 events of venous stent migration with some data provided regarding the stent used for 47 of the events. The mean age of the 52 patients with stent migration was 50 years (range, 19-88 years) and 30 were men (57.6%). The stents for most of the reported cases were ≤60 mm in length (38 of 46; 82.6%). Only three of the reports were of stents >14 mm in diameter (3 of 47; 3.6%). None of the studies had reported migration of stents >100 mm long. In 85% of the migrated stent events, retrieval was attempted, with 65.2% via an endovascular approach. The immediate outcome was satisfactory for 100% of the reported attempts, whether by an endovascular or open surgical approach. CONCLUSIONS: The findings from our literature review suggest that the risk of migration is rare but might be underreported. Most of reported cases had occurred with shorter and smaller diameter stents. The paucity of reported data and the short-term follow-up provided suggest that more formal data collection would provide a truer reflection of the incidence. However, clear strategies to avoid migration should be followed to prevent this complication from occurring.

One Year Outcomes of the VIVO-EU Study of Treatment of Symptomatic Iliofemoral Outflow Obstruction with the Zilver Vena Venous Self-Expanding Stent.

OBJECTIVE: To evaluate the performance of the Zilver® Vena™ Venous Stent in the treatment of patients with symptomatic iliofemoral outflow obstruction. METHODS: Between August 2012 and January 2015, 35 patients (mean age of 45.1 ± 15.5 years; 77.1% female) with symptomatic iliofemoral venous outflow obstruction were treated with the Zilver Vena Venous Stent (Cook Ireland, Ltd.) as part of this prospective, single arm, multicenter study. Study assessments included procedural success, major adverse events (MAEs), freedom from occlusion and qualitative patency at 6 and 12 month post-procedure, clinical symptoms of venous insufficiency, and reintervention with the treated venous segment. RESULTS: The rate of freedom from occlusion at 6 month and 12 month was 88.2%. The rate of qualitative patency was 88.2% at 6 month and 85.2% at 12 month. Three MAEs were reported: one symptomatic pulmonary embolism and two clinically-driven reinterventions. Following stenting, clinical symptoms of venous insufficiency improved significantly from baseline at each follow-up, as measured by VDS (p < 0.0001), CEAP "C" (p ≤ 0.0001), VCSS (p < 0.0001), and CIVIQ (p < 0.0001). CONCLUSION: Clinical results with the Zilver Vena Venous Stent were favorable through 12 month, with high patency rates, reduction of venous insufficiency symptoms, and low morbidity.

DEep VEin Lesion OPtimisation (DEVELOP) trial: protocol for a randomised, assessor-blinded feasibility trial of iliac vein intervention for venous leg ulcers.

BACKGROUND: Venous leg ulceration is a widespread, debilitating pathology with high recurrence rates. Conservative treatment using graduated compression dressings may be associated with unacceptable ulcer recurrence rates. Early superficial venous ablation encourages ulcer healing and reduces recurrence. However, many of this cohort display concomitant ilio-caval stenosis, which further contributes to lower limb venous hypertension and ulceration. An approach that combines early superficial venous ablation with early treatment of ilio-caval stenotic disease may significantly improve ulcer healing and recurrence rates. We question whether early iliac vein interrogation with intravascular ultrasound (IVUS), stenting of significant occlusive disease plus superficial venous ablation, in patients with active venous leg ulceration, will produce superior ulcer healing to standard therapy. METHODS: This is a prospective, multi-centre, randomised controlled, feasibility trial recruiting patients with lower limb venous ulceration and saphenous venous incompetence. Patients will be randomised to undergo either truncal ablation and compression therapy or truncal ablation, simultaneous iliac interrogation with intravascular ultrasound and stenting of significant (> 50%) iliac vein lesions plus compression therapy. The primary feasibility outcome will be the rate of eligible patient participation while the primary clinical outcomes will be ulcer healing and procedural safety. Secondary outcomes include time to healing, quality of life and clinical scores, ulcer recurrence rates and rates of post-thrombotic syndrome. Follow-up will be over a 5-year period. This feasibility trial is designed to include 60 patients. Should it be practicable a total of 594 patients would be required to adequately power the trial to definitively address ulcer-healing rates. DISCUSSION: This trial will be the first randomised trial to examine the role iliac interrogation and intervention in conjunction with standard operative therapy in the management of venous ulceration related to superficial truncal venous incompetence. ETHICAL COMMITTEE REFERENCE: C.A. 2111 Galway Clinical Research Ethics Committee REGISTRATION: Clinical Trials.gov registration NCT03640689 , Registered on 21 August 2018.

Iliocaval Venous Obstruction, Cardiac Preload Reserve and Exercise Limitation.

Cardiac output during exercise increases by as much as fivefold in the untrained man, and by as much as eightfold in the elite athlete. Increasing venous return is a critical but much overlooked component of the physiological response to exercise. Cardiac disorders such as constrictive pericarditis, restrictive cardiomyopathy and pulmonary hypertension are recognised to impair preload and cause exercise limitation; however, the effects of peripheral venous obstruction on cardiac function have not been well described. This manuscript will discuss how obstruction of the iliocaval venous outflow can lead to impairment in exercise tolerance, how such obstructions may be diagnosed, the potential implications of chronic obstructions on sympathetic nervous system activation, and relevance of venous compression syndromes in heart failure with preserved ejection fraction.

Aiming for the Bottom Corner: How to Score a Field Goal When Landing Venous Stents in May-Thurner Syndrome.

PURPOSE: To report an iliac venous stent landing technique using only fluoroscopy in patients with May-Thurner syndrome (MTS). MATERIAL AND METHODS: Sixty-five patients (69% female) who had self-expanding nitinol stents deployed for symptomatic MTS were retrospectively analyzed. Mean age was 50 years (range 18-80). The cephalic stent right lower corner was deployed to the right of the lumbar vertebra spinous process (SP), but not as far to the right as the right pedicle lateral border. Mode stent diameter and length were 14 mm (range 12-18) and 120 cm (range 60-180), determined by venography, respectively. The anatomical positions of the right common iliac artery, inferior vena cava (IVC), and stent were assessed relative to these bony landmarks on computed tomography venography. RESULTS: Position of the proximal right common iliac artery right lateral border lay a mean distance of 12 mm (±8 to the right of the SP and 13 mm (±7) left of the right pedicle lateral border. Mean position of the IVC right lateral wall lay 1 mm (±6) to the right of the right pedicle lateral border. Mean position of the cephalic stent right lower corner was 6 mm (±6) to the left of the right pedicle lateral border and 19 mm (±7) to the right of the SP. The mean space left between the cephalic stent right lower corner and the IVC right lateral wall was 5 mm (±5). Primary patency rate at 1 year was 88%. CONCLUSIONS: Important vascular structures lie in predictable locations relative to bony landmarks, facilitating accurate venous stent placement using fluoroscopy only.

Using microwave thermal ablation to develop a subtotal, cortical-sparing approach to the management of primary aldosteronism.

Objective: To investigate the feasibility and efficacy of localized, subtotal, cortical-sparing microwave thermal ablation (MTA) as a potential curative management for primary aldosteronism. The study investigated with equal importance the selected ablation of small volumes of adrenal cortex while sparing adjacent cortex. Method: An in-vivo study was carried out in swine (n = 8) where MTA was applied under direct visualization, to the adrenal glands at 45 W or 70 W for 60 s, using a lateral, side-firing probe and a non-penetrative approach. Animals were survived for 48 h post-procedurally. Animals were investigated for markers of histological, immunohistochemical and biochemical evidence of adrenal function and adrenal damage by assessing samples drawn intra-operatively and at the time of euthanasia. Results: Selected MTA (70 W for 60 s) successfully ablated small adrenocortical volumes (∼0.8 cm3) characterized by coagulative necrosis and abnormal expression of functional markers (CYP11B1 and CYP17). Non-ablated, adjacent cortex was not affected and preserved normal expression of functional markers, without increased expression of markers of heat damage (HSP-70 and HMGB-1). Limited adrenal medullary damage was demonstrated histologically, clinically and biochemically. Conclusion: MTA offers potential as an efficient methodology for delivering targeted subtotal cortical-sparing adrenal ablation. Image-guided targeted MTA may also represent a safe future modality for curative management of PA, in the setting of both unilateral and bilateral disease.

11 C-Metomidate PET/CT is a useful adjunct for lateralization of primary aldosteronism in routine clinical practice.

OBJECTIVE: To describe clinical practice experience of 11 C-Metomidate PET/CT as an adjunct to adrenal vein sampling (AVS) in the lateralization of aldosterone-producing adenomas (APA) in primary aldosteronism (PA). CONTEXT: Accurate lateralization of APA in the setting of PA offers the potential for surgical cure and improved long-term cardiovascular outcomes. Challenges associated with AVS, the current gold standard lateralization modality, mean that only a small proportion of potentially eligible patients currently make it through to surgery. This has prompted consideration of alternative strategies for lateralization, including the application of novel molecular PET tracers such as 11 C-Metomidate. DESIGN: Clinical Service Evaluation/Retrospective audit. PATIENTS: Fifteen individuals with a confirmed diagnosis of PA, undergoing lateralization with 11 C-Metomidate PET/CT prior to final clinical decision on surgical vs medical management. MEASUREMENTS: All patients underwent screening aldosterone renin ratio (ARR), followed by confirmatory testing with the seated saline infusion test, according to Endocrine Society Clinical Practice Guidelines. Adrenal glands were imaged using dedicated adrenal CT. 11 C-Metomidate PET/CT was undertaken due to equivocal or failed AVS. Management outcomes were assessed by longitudinal measurement of blood pressure, ARR, number of hypertensive medications following adrenalectomy or institution of medical therapy. RESULTS: We describe the individual lateralization and clinical outcomes for 15 patients with PA. CONCLUSION: 11 C-Metomidate PET/CT in conjunction with adrenal CT and AVS provided useful information which aided clinical decision-making for PA within a multidisciplinary hypertension clinic.

Just How Attractive is the ATTRACT Trial?

Venous thromboembolism (VTE) is a major public health issue; deep vein thrombosis (DVT) affects about 1/1000 patients. Each year, VTE kills more patients in Western Europe than breast cancer, prostate cancer, acquired immune deficiency syndrome (AIDS) and road traffic accidents combined and is responsible for the deaths of approximately 370,000 European citizens (Cohen et al. in Thromb Haemost 98:756-764, 2007; Belohlávek et al. in Exp Clin Cardiol 18(2):129-138, 2013). The recently published ATTRACT trial (Acute Venous Thrombosis Thrombus Removal with Adjunctive Catheter-directed Thrombolysis) (Vedantham et al. in N Engl J Med 377:2240-2252, 2017) concluded that the addition of catheter-directed thrombolysis to standard therapy with anticoagulation and compression stockings offers no significant clinical benefit over standard therapy in terms of reduction in the rate of post-thrombotic syndrome (PTS) at 2 years. It is the largest, prospective, multi-centre, randomised controlled trial (RCT) and represents the culmination over a decade of planning, execution and analysis. In this opinion article, we analyse why it was needed, what it demonstrated, some limitations, and the directions in which this important publication will take us.

Addressing Infra-popliteal Thrombus in Iliofemoral DVT: The Criss-Cross Technique.

PURPOSE: The purpose of this work was to describe the results of a technique of simultaneous antegrade and retrograde vascular access ("criss-cross") to the popliteal vein to achieve venous recanalization in patients with acute, extensive, iliofemoral DVT with concomitant popliteal and calf vein thrombosis. MATERIALS AND METHODS: Seven patients were treated using this technique, in three patients as a bailout option after failed posterior tibial vein puncture and in four as a first option. Antegrade popliteal venous access was performed according to the usual technique using duplex ultrasound (DUS) guidance and thrombolysis (CDT), or thrombectomy (PMT) was performed. Following this, the retrograde sheath was placed under DUS guidance, a tibial vein was selectively catheterized and CDT, and/or a PMT was performed. RESULTS: Three patients underwent isolated CDT, another three had associated PMT, and one patient underwent iliofemoral PMT and catheter thromboaspiration of the popliteal and calf veins. Median thrombolysis duration was 72 h (24-72 h). SIR grade III thrombolysis was achieved in six patients and grade II in one patient. All patients underwent subsequent stenting of their iliac vein lesions. Minor complications were observed in two patients (ecchymosis), while one patient developed a hematoma on the popliteal fossa. CONCLUSION: This "criss-cross" technique represents a safe alternative to the distal (anterior or posterior tibial) vein access both as a bailout option after failed distal venous access as well as a primary approach due to its potential advantage of clearing larger thrombus volume. Experience in ultrasound-guided popliteal vein puncture is crucial to avoid complications. LEVEL OF EVIDENCE: Case series, Level IV.

Semaphorin 6A knockout mice display abnormalities across ethologically-based topographies of exploration and in motor learning.

Semaphorins are secreted or membrane-bound proteins implicated in neurodevelopmental processes of axon guidance and cell migration. Exploratory behaviour and motor learning was examined ethologically in Semaphorin 6A (Sema6A) mutant mice. The ethogram of initial exploration in Sema6A knockout mice was characterised by increased rearing to wall with decreased sifting; over subsequent habituation, locomotion, sniffing and rearing to wall were increased, with reduced habituation of rearing seated. Rotarod analysis indicated delayed motor learning in Sema6A heterozygous mutants. Disruption to the axonal guidance and cell migration processes regulated by Sema6A is associated with topographically specific disruption to fundamental aspects of behaviour, namely the ethogram of initial exploration and subsequent habituation to the environment, and motor learning.

What is the definition of successful lysis: reporting standard?

Deep vein thrombosis, and the resultant development of post-thrombotic syndrome, is a significant health issue. Recent evidence demonstrates that the severity of post-thrombotic syndrome symptoms is directly related to the level of venous thrombosis and following treatment these subsequent symptoms are inversely related to the degree of thrombus removal. If we can improve, and preferably standardise the terminology associated with pre-treatment assessment of thrombus load and post-treatment success of thrombus removal techniques, we should then be able to choose more tailor-made techniques to greater benefit our patients. A number of scoring systems have been devised for the assessment of venous thrombus burden, with a majority impractical for everyday usage. In order to provide a more practical solution, the lower extremity thrombosis classification has been developed, using information on anatomical location for venous thrombus combined with a clinical indicator as to the likely sequelae. Anatomical success following venous thrombolysis can be defined by assessing restoration of anterograde flow in the treated vein or the percentage degree of thrombolysis, using venography. The second option is the method most frequently utilised, with the Venous Registry grading system applied. Data from recent trials have given us conflicting and confusing data mainly because we are not using standardised terminology. We urgently need to agree on a standard method of description of thrombus removal before stent placement which also incorporates the likely clinical impact of the area involved in the thrombosis.

Endovascular Repair of Acute and Chronic Aortic Type B Dissections: Main Factors Affecting Aortic Remodeling and Clinical Outcome.

OBJECTIVES: The aim of this study was to assess factors influencing the clinical outcome and morphological changes of acute and chronic type B aortic dissection after thoracic endovascular aortic repair (TEVAR). BACKGROUND: Aortic remodeling after TEVAR may be associated with clinical outcome, complications, and endoleak development. METHODS: Sixty cases of TEVAR for complicated type B acute aortic dissection (AAD) (n = 29) and chronic aortic dissection (CAD) (n = 31) with a minimum follow-up of 3 years were retrospectively reviewed. Using computed tomography images, we assessed true lumen, false lumen, and total aortic short-axis diameters. Six procedural factors were analyzed in relation to aortic remodeling and other outcomes. Analysis of variance was used to compare short-axis, false lumen, and true lumen diameters during the follow-up period. Univariate and multivariate analyses were used to assess the relationship between procedural factors and multiple outcomes. RESULTS: A total of 100 stent grafts were implanted in 60 consecutive patients with acute aortic dissection (AAD) and CAD. Aortic remodeling consisting of false lumen thrombosis and shrinkage was more prominent in AAD than in CAD, especially within the first 18 months. Of note, the entire aortic diameter increased significantly cephalad to the stent graft in AAD. Only in the AAD group there was increased aortic remodeling related to post-dilation of the stent graft. Type I and II endoleaks occurred in 17 patients (28%); in AAD, embolization of the left subclavian artery after stent graft deployment was significantly associated with a lower risk of endoleak development, but this was not evident in CAD. CONCLUSIONS: Aortic remodeling and clinical outcome after TEVAR can be influenced by procedural techniques (post-dilation and embolization of the left subclavian artery in patients with acute but not chronic aortic dissection).