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.

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.

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.

A systematic review of reported outcomes in people with lower limb chronic venous insufficiency of the deep veins.

OBJECTIVE: The prevalence of lower limb chronic venous insufficiency (CVI) of the deep veins is increasing and presents a significant burden to patients and health care services. To improve the evaluation of interventions it is necessary to standardise their reporting. The aim of this study was to perform a systematic review of the outcomes of interventions delivered to people with CVI of the deep veins as part of the development of a novel core outcome set (COS). METHODS: Following the Core Outcome Measures in Effectiveness Trials (COMET) framework for COS development, a systematic review was conducted to PRISMA guidance. The protocol was preregistered on PROSPERO (CRD42021236795). MEDLINE, Embase, Emcare, CINAHL, and the Cochrane Central Register of Controlled Trials (CENTRAL), Cochrane Database of Systematic Reviews and Clinicaltrials.gov were searched from January 2018 to January 2021. Clinical trials and observational studies involving more than 20 participants, reporting outcomes for patients with CVI of the deep veins were eligible. Outcomes were extracted verbatim, condensed into agreed outcome terms and coded into domains using standard COMET taxonomy. Outcome reporting consistency, where outcomes were fully reported throughout the methods and results of their respective articles was also assessed. RESULTS: Some 103 studies were eligible. There were 1183 verbatim outcomes extracted, spanning 22 domains. No outcome was reported unanimously, with the most widely reported outcome of primary patency featuring in 51 articles (<50%). There was a predominant focus on reporting clinical outcomes (n = 963 [81%]), with treatment durability (n = 278 [23%]) and clinical severity (n = 108 [9%]) reported frequently. Life impact outcomes were relatively under-reported (n = 60 [5%]). Outcome reporting consistency was poor, with just 50% of outcomes reported fully. CONCLUSIONS: Outcome reporting in studies of people with CVI of the deep veins is currently heterogeneous. Life impact outcomes, which likely reflect patients' priorities are under-reported. This study provides the first step in the development of a COS for people with lower limb CVI of the deep veins.

Use of patient-reported outcome measures in patients with venous thromboembolism: communication from the ISTH SSC Subcommittee on Predictive and Diagnostic Variables in Thrombotic Disease.

Patient-reported outcome measures (PROMs) are patient-completed instruments that capture patient-perceived health status and well-being. PROMs measure disease impact and outcomes of care as reported by those who experience the disease. After pulmonary embolism or deep vein thrombosis, patients may face a broad spectrum of complications and long-term sequelae beyond the usual quality-of-care indicators of recurrent venous thromboembolism (VTE), bleeding complications, and survival. The full impact of VTE on individual patients can only be captured by assessing all relevant health outcomes from the patient's perspective in addition to the traditionally recognized complications. Defining and measuring all important outcomes will help facilitate treatment tailored to the needs and preferences of patients and may improve health outcomes. The International Society on Thrombosis and Haemostasis Scientific and Standardization Committee Subcommittee on Predictive and Diagnostic Variables in Thrombotic Disease endorsed the International Consortium for Health Outcomes Measurement (ICHOM) VTE project on development of a standardized set of patient-centered outcome measures for patients with VTE. In this communication, the course and result of the project are summarized, and based on these findings, we propose recommendations for the use of PROMs during clinical follow-up of patients with VTE. We describe challenges to implementation of PROMs and explore barriers and enablers.

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.

Development of an international standard set of outcome measures for patients with venous thromboembolism: an International Consortium for Health Outcomes Measurement consensus recommendation.

The International Consortium for Health Outcomes Measurement assembled an international working group of venous thromboembolism experts and patient representatives to develop a standardised minimum set of outcomes and outcome measurements for integration into clinical practice and potentially research to support clinical decision making and benchmarking of quality of care. 15 core outcomes important to patients and health-care professionals were selected and categorised into four domains: patient-reported outcomes, long term consequences of the disease, disease-specific complications, and treatment-related complications. The outcomes and outcome measures were designed to apply to all patients with venous thromboembolism aged 16 years or older. A measurement tool package was selected for inclusion in the core standard set, with a minimum number of items to be measured at predefined timepoints, which capture all core outcomes. Additional measures can be introduced to the user by a cascade opt-in system that allows for further assessment if required. This set of outcomes and measurement tools will facilitate the implementation of the use of patient-centred outcomes in daily practice.

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.

Risk factors and classification of reintervention following deep venous stenting for acute iliofemoral deep vein thrombosis.

BACKGROUND: Acute iliofemoral deep vein thrombosis (DVT) is associated with the development of post-thrombotic syndrome (PTS). Thrombolysis and deep venous stenting can restore vessel outflow and can reduce the incidence of PTS. However, for a proportion of patients, subsequent stenosis or reocclusion will necessitate further intervention. In the present study, we aimed to identify the risk factors, examine the outcomes (reintervention success and PTS), and develop a classification system for reintervention. METHODS: A retrospective single-center cohort study of patients who had undergone successful lysis for iliofemoral DVT from 2013 to 2017. The patients' records and imaging studies were examined for demographics, risk factors, extent of thrombus and vessel clearance, stenting, flow, reintervention, anticoagulation compliance, Villalta score, and secondary patency. From our findings, a system of classification for patients for whom procedures have failed was developed, constituting technical, hematologic, flow related, or multiple factors. RESULTS: Of 143 limbs (133 patients), 48 (33.6%) had required reintervention, of which 25 had presented with reocclusion (17.4%). The median time to reintervention was 45 days. The need for reintervention was associated with inferior vena cava thrombus (risk ratio [RR], 2.16; P < .01), stenting across the inguinal ligament (RR, 2.08; P < .01), and anticoagulation noncompliance (RR, 7.09; P < .01). Successful reintervention was achieved in 31 limbs (64.6%): 23 of 23 (100%) treated before occlusion vs 8 of 25 (36.4%) treated after occlusion (RR, 32.31; P < .01). A greater incidence of any PTS was observed for patients requiring reintervention (median Villalta score, 3 [interquartile range, 1-5]; vs 1 [interquartile range, 1-4]; RR, 2.28; P = .029). Cases without complete vessel occlusion (reintervention and control) had a lower rate of any PTS (14.0% vs 42.9%; RR, 3.06; P < .01) and moderate to severe PTS (3.0% vs 14.3%; RR, 4.76; P = .046) Technical issues were observed in 54.2% of reintervention cases and 6.3% of cases not requiring reintervention (P < .01). Hematologic issues were identified in 33.3% of reintervention cases and 1.1% of cases not requiring reintervention (P < .01). Flow-related issues were observed in 43.8% of the reintervention cases and no cases not requiring reintervention (P < .01). Of the reintervention cases, 27.1% were multifactorial and were associated with a lower rate of vessel salvage; however, this did not translate into a significant difference in secondary patency on survival analysis (RR, 1.70; P = .429). CONCLUSIONS: A large proportion of patients required reintervention because of potentially preventable factors. Anticoagulation compliance, thrombus burden, and poor flow are important risk factors to consider in patient selection. Reintervention increased the risk of PTS and was more often successful when achieved before vessel occlusion.

Mechanical characteristics of venous stents to overcome challenges of venous outflow obstruction.

INTRODUCTION: Many challenges posed by the venous outflow obstruction (VOO) are unique to the venous system which require specific mechanical characteristics of stents to overcome them. Therefore, this article aims to review and discuss these challenges and the stent mechanical characteristics required to overcome them. EVIDENCE ACQUISITION: A literature search was performed with Pubmed with the terms "mechanical characteristics of venous stents" and "mechanical properties of venous stents". EVIDENCE SYNTHESIS: The venous system poses unique anatomical, physiological and pathological challenges when compared to the arterial counterpart. Several mechanical characteristics specific to venous stents which include the size, inherent forces, and flexibility are important to overcome these unique challenges when treating VOO. The most important stent inherent forces for venous stents include the chronic outward force, radial resistive force, and crush resistance. Various stent materials and designs, particularly laser-cut versus braided-structure stents, and open-cell versus closed-cell stents, determine the mechanical characteristics including the inherent forces of the venous stents. The desired mechanical characteristics of stents needed to overcome the venous system challenges often in conflict or with opposing effects. Therefore, it is important to fine adjust and optimize these characteristics. CONCLUSIONS: There are many anatomical, physiological, and pathological challenges unique to the venous system which need to be overcome by the stent system mechanically when treating VOO. Therefore, dedicated venous stents with optimal mechanical characteristics are being developed with different designs and properties to treat VOO. Further research and innovations are needed to improve the stent technology that targets the venous system specifically.

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.

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.