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.

Editor's Choice - Management of Lower Extremity Venous Outflow Obstruction: Results of an International Delphi Consensus.

OBJECTIVE: The endovascular treatment of venous obstruction has expanded significantly in recent years. Best practices for optimal patient outcomes are not well established and the evidence base is poor. The purpose of this study was to obtain consensus on management criteria for patients with lower extremity venous outflow obstruction. METHODS: The study was conducted as a two round Delphi consensus. Statements addressed imaging, symptoms and other baseline measures, differential diagnosis, treatment algorithm, indications for stenting, inflow and outflow assessment, successful procedural outcomes, post-procedure therapies and stent surveillance, and clinical success factors. Statements were prepared by six expert physicians (round 1, 40 statements) and an expanded panel of 24 physicians (round 2, 80 statements) and sent to a pre-identified group of venous experts who met qualifying criteria. A 9 point Likert scale was used and consensus was defined as ≥ 70% of respondents rating a statement between 7 and 9 (agreement) or between 1 and 3 (disagreement). Round 1 results were used to guide rewording and splitting compound statements for greater clarity in round 2. RESULTS: In round 1, 75 of 110 (68%) experts responded, and 91 of 121 (75%) experts responded in round 2. Round 1 achieved consensus in 32/40 (80%) statements. Consensus was not reached in the treatment algorithm section. Round 2 achieved consensus in 50/80 (62.5%). Statements reaching consensus were imaging (2/3, 66%), symptoms and other baseline measures (12/24, 50%), differential diagnosis (2/8, 25%), treatment algorithm (10/17, 59%), indications for stenting (10/10, 100%), inflow and outflow assessment (2/2, 100%), procedural outcomes (2/2, 100%), post-procedure therapies and stent surveillance, (5/7, 71%), and clinical success factors (5/7, 71%). CONCLUSION: This study demonstrated that considerable consensus was achieved between venous experts on the optimal management of lower extremity venous outflow obstruction. There were multiple domains where consensus is lacking, highlighting important areas for further investigation and research.

Fatigue Test Method to Evaluate the 50 Year Durability of Venous Stents.

OBJECTIVE: Iliofemoral venous obstructive disease can result in significant, potentially debilitating symptoms that can negatively affect quality of life. Unlike arterial disease, patients with deep venous disease have a significantly lower median age, therefore the need for long term stent patency becomes a matter of decades rather than years. Furthermore, iliofemoral lesions frequently require stent placement across the inguinal ligament. Such stents are subject to dynamic stress from leg movement and associated concerns for device fatigue, resulting in stent fracture. The aim of this study was to describe an in vitro 50 year stent fatigue test method designed to assess durability against dynamic stress induced device fracture. METHODS: Through literature review, cadaver studies, and computer modelling, the most challenging loading was confirmed to be hip flexion across the inguinal ligament. This occurs when the patient adjusts between a seated and standing position. Sit to stand hip flexion at the inguinal ligament was effectively simulated on the bench in this in vitro experimental study. RESULTS: When tested under challenge parameters, hip flexion was reliably found to cause fractures in non-venous nitinol stents. However, a dedicated self expanding nitinol venous stent, engineered for improved durability, underwent up to 50 years of simulated loading on the bench with 15% (3/20) of stents experiencing fractures at 50 years, compared with fractures in 35% (14/40) of non-venous stents tested to 1.4 years; no statistical testing was performed as durations do not match and the objective was to demonstrate the test method. CONCLUSION: The presented fatigue test method is a suitable approach for evaluating the durability of stents intended for venous use. Venous stents demonstrated superior fatigue resistance compared with non-venous stents via in vitro hip flexion testing.

Leg Ulcer Pathway Acceleration (LUPA) study.

BACKGROUND: Leg ulcers are common, costly, and significantly impair quality of life, but their management is variable and associated with considerable delays in healing. The aim of this study was to design an accelerated leg ulcer care pathway in a community and hospital setting to improve patient outcomes. METHODS: A new referral pathway was developed using a series of healthcare professional and patient interviews, focus groups, and stakeholder workshops. The referral pathway, investigation and treatment protocols were further informed by clinical guidelines to develop the Leg Ulcer Pathway Acceleration care pathway. The outcomes of a consecutive series of patients enrolled in the Leg Ulcer Pathway Acceleration care pathway were compared with the outcomes of patients from a historical leg ulcer cohort from the same community and hospital setting. RESULTS: A total of 110 eligible patients were enrolled and followed prospectively through the Leg Ulcer Pathway Acceleration care pathway. Their outcomes were compared with those of 183 patients with venous leg ulcers identified from existing hospital and community ulcer centres, and acting as the historical control group. The 110 patients in the Leg Ulcer Pathway Acceleration group consisted of 73 (66 per cent) men, had a mean(s.d.) age of 55.7(17.2) years, and had a median initial ulcer duration of 14.5 (i.q.r. 6-30) months. The 183 patients in the historical control group consisted of 119 (65 per cent) men, had a mean(s.d.) age of 56.4(17.2) years, and had a median initial ulcer duration of 13.5 (i.q.r. 6-47) months. Venous disease was treated in 67/110 (61 per cent) and deep venous disease was treated in 33/110 (30 per cent) of patients in the Leg Ulcer Pathway Acceleration cohort. In contrast, only 16/183 (8 per cent) of patients in the control group were treated for superficial venous insufficiency and 4/183 (2 per cent) of patients in the control group were treated for deep venous disease. Ulcer healing rates at 12 months were 80 and 20 per cent in the Leg Ulcer Pathway Acceleration group and the control group respectively (P < 0.001). Adjusted for baseline characteristics, the OR for a healed ulcer at 12 months was 21.21 (95 per cent c.i.. 11.32 to 42.46) (P < 0.001). CONCLUSION: The introduction of an accelerated leg ulcer care pathway significantly improves ulcer healing when compared with historical controls.

A Systematic Review of the Safety and Efficacy of Inferior Vena Cava Stenting.

OBJECTIVE: Inferior vena cava (IVC) stenting may provide benefit to patients with symptomatic obstruction; however, there are no devices currently licensed for use in the IVC and systematic reviews on the topic are lacking. The aim of this study was to carry out a systematic review of the literature and meta-analysis to investigate the safety and efficacy of IVC stenting in all adult patient groups. DATA SOURCES: The Medline and Embase databases were searched for studies reporting outcomes for safety and effectiveness of IVC stenting for any indication in series of 10 or more patients. REVIEW METHODS: A systematic review of the literature was carried out according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. RESULTS: Thirty-three studies were included describing 1 575 patients. Indications for stenting were malignant IVC syndrome (229 patients), thrombotic disease (807 patients), Budd-Chiari syndrome (501 patients), and IVC stenosis post liver transplantation (47 patients). The male:female ratio was 2:1 and the median age ranged from 30 to 61 years. The studies included were not suitable for formal meta-analysis as 30/33 were single centre retrospective studies with no control groups and there was considerable inconsistency in outcome reporting. There was significant risk of bias in 94% of studies. Median reported technical success was 100% (range 78 - 100%), primary patency was 75% (38 - 98%), and secondary patency was 91.5% (77 - 100%). Major complications were pulmonary embolism (three cases), stent migration (12 cases), and major bleeding (15 cases), and there were three deaths in the immediate post-operative period. Most studies reported improvement in clinical symptoms but formal reporting tools were not used consistently. CONCLUSION: The evidence base for IVC stenting consists of predominantly single centre, retrospective, observational studies that have a high risk of bias. Nonetheless the procedure appears safe with few major adverse events, and studies that reported clinical outcomes demonstrate improvement in symptoms and quality of life. Randomised controlled trials and prospective registry based studies with larger patient numbers and standardised outcome are required to improve the evidence base for this procedure.

Performance of Open and Closed Cell Laser Cut Nitinol Stents for the Treatment of Chronic Iliofemoral Venous Outflow Obstruction in Patients Treated at a Single Centre.

OBJECTIVE: A number of dedicated self expanding nitinol stents have been developed for use in the venous system, with both open cell (OC) and closed cell (CC) designs available. Data comparing these different designs are lacking. The objective of this study was to evaluate outcomes in patients treated with open and closed cells for unilateral chronic iliac vein obstruction. METHODS: A single centre retrospective cohort study was conducted, including all patients treated with a dedicated nitinol venous stent between 2014 and 2019. Stent patency and details of re-interventions (including lysis, venoplasty, reinforcement, extension, arteriovenous fistula formation) were examined in the first post-operative year. Subgroup analysis described outcomes for patients treated with OC and CC stents ending above the inguinal ligament and those who required extension into the common femoral vein. Cox regression analysis was used to identify factors associated with loss of primary patency. RESULTS: A total of 207 patients were included (OC 100 patients, CC 107 patients). There was no significant difference between the groups for age (OC 42 years, CC 44 years); gender (OC and CC 67% female); presence of post-thrombotic lesions (OC 71%, CC 73%); stenting across the inguinal ligament (OC 58%, CC 56%), or presence of inflow disease (OC 49%, CC 47%). Primary and cumulative patency at 12 months were similar between groups (primary: OC 63%, CC 65%; cumulative: OC 93%, CC 90%). Patients with a CC stent across the inguinal ligament had a greater risk of needing multiple re-interventions at one year compared with those with an OC stent (odds ratio 2.84, 95% confidence interval [CI] 1.16 - 6.9) but overall, the only factor significantly associated with loss of primary patency was inflow vessel disease (hazard ratio 3.39, 95% CI 1.73 - 6.62, p < .001). CONCLUSION: OC and CC dedicated nitinol venous stents were observed to perform similarly in terms of patency and symptom improvement at one year. Disease of the inflow vessels was the most important factor associated with a loss of stent patency irrespective of stent design.

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.

AngioJet Pharmacomechanical Thrombectomy and Catheter Directed Thrombolysis vs. Catheter Directed Thrombolysis Alone for the Treatment of Iliofemoral Deep Vein Thrombosis: A Single Centre Retrospective Cohort Study.

OBJECTIVE: Percutaneous thrombus removal is used for the treatment of iliofemoral deep vein thrombosis (DVT), but the efficacy of different treatment modalities has not yet been determined. The aim of this study was to compare the outcomes of patients treated with additional AngioJet pharmacomechanical thrombectomy (PCDT) vs. catheter directed lysis (CDT) alone. METHODS: A retrospective review of all patients who received thrombolysis for the treatment of symptomatic acute iliofemoral DVT between 2011 and 2017 was carried out. Outcome measures included the incidence of post-thrombotic syndrome (PTS), procedural outcomes (lytic exposure), the incidence of complications, and vessel patency. All patients were followed up for a minimum of one year. RESULTS: A total of 151 limbs were treated, 70 limbs with PCDT and 81 limbs with CDT alone. Demographic data and prevalence of risk factors were comparable. Incidence of PTS (Villalta score at one year) showed no significant difference (22.2% PCDT vs. 24.7% CDT alone, p = .74). Use of PCDT resulted in a non-statistically significant trend for fewer bleeds (n = 4/63 [6.3%] vs. 13/76 [17.1%]; relative risk 0.37, 95% confidence interval [CI] 0.13-1.08; p = .07), a statistically significant reduction in lysis duration (40 h [95% CI 34-46] vs. 53 h [95% CI 49-58]; p < .001) and a reduction in lytic dose (49 mg [95% CI 42-55] vs. 57 mg [95% CI 52-61]; p = .011) compared with CDT. This reduction was accentuated in 24 cases primarily treated with AngioJet PowerPulse mode (27 h, 95% CI 20-34 [p < .001] and 42 mg, 95% CI 34-50 [p = .009]). Incidences of complications were comparable between groups, with one death due to an intracranial haemorrhage following CDT. Although the incidence of haemoglobinuria was increased following PCDT (12/63 [19.0%] vs. 3/76 [3.9%]; p = .006), no significant difference in acute kidney injury was observed (3/63 [4.8%] vs. 1/76 [1.3%]; p = .33). No significant difference in vessel patency over two years was observed (p = .73). CONCLUSION: The use of PCDT for the treatment of iliofemoral DVT was observed to provide comparable patient outcomes, comparable vessel patency, an acceptable safety profile, and reduced overall lytic dose.

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.

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.

Nutcracker Syndrome (a Delphi consensus).

INTRODUCTION: Nutcracker syndrome describes the symptomatic compression of the left renal vein between the aorta and superior mesenteric artery. Whereas asymptomatic compression is a common radiological finding, patients with nutcracker syndrome can report a range of symptoms. There are no specific diagnostic criteria and interventions include a range of open surgical and endovascular procedures. Therefore, we wished to develop an international consensus document covering aspects of diagnosis, management, and follow-up for patients with nutcracker syndrome. METHODS: A three-stage modified Delphi consensus was performed. A steering committee developed 37 statements covering three categories for patients with nutcracker syndrome: diagnosis, management and follow-up. These statements were reported individually by 20 international experts in the management of venous disease, using a five-point Likert scale. Consensus was defined if ≥70% of respondents rated the statement between 1 or 2 (agreement) and between 4 or 5 (disagreement). Those statements without consensus were recirculated in a second round of voting. A third round of the questionnaire was performed with 14 additional statements to clarify diagnostic values of nutcracker syndrome. RESULTS: Responses were achieved by 20 of 20 (100%) experts in round one and 17 of 20 (85%) in round two. Initial consensus was reached in 24 of 37 statements (65%) spread over all categories. Round two achieved a further consensus on five out of ten statements (50%). No categories reported consensus on all statements. In round two consensus was reached in the category of Follow-up (4/5 statements, 80%). The final round reached consensus on 5 out of 14 statements (36%). Experts agreed that imaging is obligated to confirm NCS. Experts did not agree on specific diagnostic cut-off values. There was a consensus that the first choice of operative treatment is left renal vein transposition and that the risk of stent migration outweighs the advantages of a percutaneous procedure. CONCLUSION: Consensus was achieved on most statements concerning the assessment and management of nutcracker syndrome. This Delphi consensus identified those areas in which further research is needed, such as anti-platelet therapy, endovascular treatment and renal autotransplantation. A rare disease registry to improve data and reports of patient outcomes is warranted.

Successful use of talc sclerodesis to control a persistent high-output groin seroma following endovascular abdominal aortic aneurysm repair.

Groin wound lymphatic complications after vascular procedures are accompanied by increased risk of infection, prolonged hospital stay, and greater patient morbidity. High-output groin seromas can be difficult to manage and refractory to established interventions. Although subcutaneous talc has been used to prevent seroma accumulation in other high-risk surgical fields, such as after axillary lymph node dissection, it has not been described in the context of vascular surgery. This article presents the first reported case of a persistent high-output groin seroma after endovascular abdominal aortic aneurysm repair managed successfully with intraoperative application of sterile talc.