Review of the literature supporting international clinical practice guidelines on iliac venous stenting and their applicability to Australia and New Zealand practice

BACKGROUND

The overall goal of this report is to provide a high-level, practical approach to managing venous outflow obstruction (VOO).

METHODS

A group of vascular surgeons from Australia and New Zealand with specific interest, training, and experience in the management of VOO were surveyed to assess current local practices. The results were analyzed and areas of disagreement identified. After this, the group performed a literature review of consensus guidelines published by leading international organizations focused on the management of chronic venous disease, namely, the Society for Vascular Surgery, American Venous Forum, European Society for Vascular Surgery, American Vein and Lymphatic Society, Cardiovascular and Interventional Radiology Society of Europe, and American Heart Association. These guidelines were compared against the consensus statements obtained through the surveys to determine how they relate to Australian and New Zealand practice. In addition, selected key studies, reviews, and meta-analyses on venous stenting were discussed and added to the document. A selection of statements with >75% agreement was voted on, and barriers to the guideline's applicability were identified. The final recommendations were further reviewed and endorsed by another group of venous experts.

RESULTS

The document addresses two key areas: patient selection and technical aspects of venous stenting. Regarding patient selection, patients with clinically relevant VOO, a Clinical-Etiologic-Anatomic-Physiologic score of ≥3 or a Venous Clinical Severity Score for pain of ≥2, or both, including venous claudication, with evidence of >50% stenosis should be considered for venous stenting (Level of Recommendation Ib). Patients with chronic pelvic pain, deep dyspareunia, postcoital pain affecting their quality of life, when other causes have been ruled out, should also be considered for venous stenting (Level of Recommendation Ic). Asymptomatic patients should not be offered venous stenting (Level of Recommendation IIIc). Patients undergoing thrombus removal for acute iliofemoral deep vein thrombosis, in whom a culprit stenotic lesion of >50% has been uncovered, should be considered for venous stenting (Level of Recommendation Ib).

CONCLUSIONS

Patients with VOO have been underdiagnosed and undertreated for decades; however, in recent years, interest from physicians and industry has grown substantially. International guidelines aimed at developing standards of care to avoid undertreating and overtreating patients are applicable to Australia and New Zealand practice and will serve as an educational platform for future developments.

Optimizing Venous Stenting: Consensus Recommendations for Enhanced Management of Lower Extremity Deep Vein Thrombosis

INTRODUCTION

 Deep vein thrombosis (DVT) poses a complex challenge and often leads to postthrombotic syndrome (PTS), a debilitating complication. The emergence of venous stents offers a potential preventive avenue against this complication. This study aimed to provide consensus recommendations on the use of venous stent for DVT.

MATERIALS AND METHODS

 From June to July 2023, 20 internal medicine, angiology and vascular surgery, and vascular and interventional radiology experts were involved in the Delphi process. Thirty-one recommendations, categorized into three thematic areas, were rigorously evaluated: indications for stent use, stent selection and placement, and monitoring and prevention of complications. Agreement was evaluated using a Likert scale, with consensus defined as agreement by two-thirds of the participants.

RESULTS

 Consensus was reached for 23 (74.2%) of 31 recommendations. The agreement was centered on considerations, such as stent placement in specific acute DVT scenarios, emphasizing pivotal stent characteristics. However, there were divergences in the recommended stent length to prevent migration and stent characteristics based on iliocaval bifurcation morphology. Notably, there was no consensus on whether patients with DVT caused by a major transient risk factor need more than 3 months of anticoagulation therapy or whether aspirin should be added to anticoagulant treatment after venous stenting.

CONCLUSIONS

 These consensus recommendations offer practical insights into optimizing venous stent use to prevent PTS in DVT patients. Addressing the critical aspects of stent selection, placement, and postprocedural care, these recommendations contribute to clinical decision-making. The identified divergences underscore the importance of consensus and thus indicate the need for further investigation.

Endovascular treatment of chronic ilio-femoral vein obstruction with extension below the inguinal ligament in patients with post-thrombotic syndrome

OBJECTIVE

This study aimed to evaluate postoperative outcomes of patients with chronic iliofemoral venous outflow obstruction and post-thrombotic syndrome (PTS) who underwent endovascular recanalization and stenting across the inguinal ligament.

METHODS

All consecutive patients with chronic iliofemoral venous outflow obstruction and PTS were included in the analysis, from January 2018 and February 2022. Preoperative, intraoperative, and postoperative outcomes were assessed. Primary endpoints analyzed were major adverse events (MAEs) at 30 days and primary patency rate at 2 years of follow-up. Secondary endpoints assessed were secondary patency rate, target vessel revascularization, and clinical improvement evaluated with the Venous Clinical Severity Score (VCSS) classification, Villalta scale, and visual analog scale (VAS), respectively.

RESULTS

A total of 63 patients (mean age, 48.1 ± 15.5 years; female, 61.9%) were evaluated. No intraoperative and 30-day postoperative complications were documented. The technical success rate was achieved at 100%. Overall, one in-stent occlusion and five in-stent restenosis were detected during follow-up. The primary patency rate was 93.7% (95% confidence interval [CI], 87.8%-99.9%) and 92.1% (95% CI, 85.6%-99%), at 1- and 2-year follow-up, respectively (Kaplan-Meier analysis). Target vessel revascularization was conducted in two cases, resulting in a secondary patency of 98.4% (95% CI, 95.4%-100%) at 2 years of follow-up. Stent fracture and/or migration were not observed during follow-up. A significant clinical improvement in the patient's quality of life was documented. The median improvement of VCSS and Villalta scores were 4 (interquartile range, 2-7; P = .001), and 3 (interquartile range, 1.5-5; P = .001) vs baseline at the last follow-up. Overall, pain reduction of 17 mm on the VAS scale was documented at 2 years of follow-up. At multivariate analysis, presence of trabeculation into the femoral vein and deep femoral vein (odds ratio, 1.89; 95% CI, 0.15-6.11; P = .043), and Villalta scale >15 points at admission (odds ratio, 1.89; 95% CI, 0.15-6.11; P = .043) were predictive for in-stent occlusion during the follow-up.

CONCLUSIONS

The use of a dedicated venous stent across the inguinal ligament was safe and effective for the treatment of symptomatic iliofemoral venous disease with acceptable primary and secondary patency rates at 2 years of follow-up.

The background and role of catheter-directed thrombolysis evolving procedures for acute iliofemoral deep venous thrombosis

Minimal invasive treatment such as early endovenous thrombus removal for iliofemoral deep venous thrombosis (DVT) emerged in the end of last century. The principle is catheter-directed thrombolysis (CDT) using either plasminogen activating agents alone, as ultrasound-assisted CDT, or in combination with mechanical devices as pharmaco-mechanical CDT. The interest for this treatment modality is the high rate of post-thrombotic syndrome (PTS) with anticoagulation (AC) alone, especially after iliofemoral DVT. Recently published randomized controlled trials (RCTs) comparing early thrombus removal with AC alone, as well as non-randomized studies, have demonstrated favorable rates, or at least a decrease of moderate and severe PTS, in favor of these procedures. This article will summarize the background and evolution of the procedures in the last three decades and discuss fundamental criteria for inclusion and exclusion, focusing on the procedures regarding thrombus age and location, technical issues, complications and results including different outcome measures for PTS, for which iliac DVT involvement is a massive risk factor to be prevented.

Iliac vein stenting and pregnancy

Venous stenting is the mainstay treatment of symptomatic iliofemoral venous outflow obstruction. However, because pregnancy and the postpartum period are hypercoagulable, concerns exist regarding stent placement in women of childbearing age. We performed a systematic review up to April 2023 of studies reporting on the performance of venous stents in women who subsequently became pregnant. The data collected included demographics, indication for stenting, stent characteristics, stent-related complications, incidence of venous thromboembolism, medical management during pregnancy, and follow-up. The indications for stenting included acute iliofemoral deep vein thrombosis in 39 patients (51%), nonthrombotic iliac vein lesions in 35 (46%), and post-thrombotic lesions in 2 patients. A total of 76 women with 87 subsequent pregnancies after stenting were included. Of the 76 women, 1 (1.14%) experienced stent occlusion, 2 (2.29%) developed asymptomatic nonocclusive in-stent thrombus, and 2 (2.29%) experienced permanent stent compression. The only patency loss occurred because of inadequate anticoagulation therapy in a patient with antiphospholipid antibodies. The two cases of permanent compression occurred in an arterial stent and a balloon-fenestrated Vici stent (Boston Scientific). Venous stents performed well through pregnancy and can be safely used in women of childbearing age. Given the increased risk of venous thromboembolism and the low bleeding risk, it is prudent to recommend anticoagulation therapy for all stented patients until more data are available.

Readability of patient educational materials in venous thrombosis. Analysis of the 2021 ESVS guidelines and comparison with other medical societies information

BACKGROUND

In order for patients to comprehend health related information, it must be written at a level that can be readily understood by the intended population. During 2021 the European Society for Vascular Surgery (ESVS) published a sub-section about information for patients into its Guidelines on the Management of Venous Thrombosis.

METHODS

Nine readability measures were used to evaluate the patient educational material regarding venous thrombosis published by seven medical societies: ESVS, Society for Vascular Medicine (SVM), Society for Vascular Surgery (SVS), Vascular Society for Great Britain and Ireland (VS), Australia and New Zealand Society for Vascular Surgery (ANZSVS), Canadian Society for Vascular Surgery (CSVS) and American Heart Association (AHA).

RESULTS

The mean reading grade level (RGL) for all the 58 recommendations was 10.61 (range 6.4-14.5) and the mean Flesch Reading Ease (FRE) was 56.10 (51.3-62.9), corresponding to a "fairly difficult" reading level. The mean RGL of the ESVS recommendations (11.45, 95% CI, 9.90-13.00) was significantly higher than the others. Post-hoc analysis determined a significant difference between the ESVS and the SVS (10.86, 95% CI, 9.84-11.91) recommendations (p=0.005). All the patient's education information published by the medical societies presented a RGL higher than recommended. The fifteen sub-sections of the information for patients included into the ESVS clinical guidelines presented a mean RGL above 9.5 points, revealing that no one (0%) was written at or below the recommended GRL. The mean FRE was 47.63 (28.2-61.6), corresponding to a "difficult" reading level.

CONCLUSIONS

Venous thrombosis patient educational materials produced by leading medical societies have readability scores that are above the recommended levels. The innovative patient's information included into the ESVS venous thrombosis guidelines represents an important advance in the amelioration of the medical information for patients but their readability should be improved to adapt the understanding to the general-population.

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

BACKGROUND

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.

METHODS

A literature search was performed with Pubmed with the terms "mechanical characteristics of venous stents" and "mechanical properties of venous stents".

RESULTS

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 optimise 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.

The impact of venous stenting across the inguinal ligament on primary patency: a systematic review

INTRODUCTION

Iliac venous stenting is an established treatment option for both post-thrombotic and non-thrombotic iliac venous obstructions. Nonetheless, there is still no consensus on the best medical practice regarding some of these interventions. One area of debate is the safety of extending venous stents across the inguinal ligament (IL), with contradictory results from various authors and overall poor-quality research. This review aims to summarise current knowledge on the effect of venous stent placement across the IL on primary patency.

EVIDENCE ACQUISITION

A literature search was performed on the MEDLINE, Scopus and Web of Science databases, which returned 531 studies. Eleven studies were included. Data were extracted using piloted forms, and, if necessary, authors were contacted to obtain further information.

EVIDENCE SYNTHESIS

Two studies were prospective cohorts, whereas the remaining 9 were retrospective cohorts. Overall study quality was weak. Four studies showed a statistically significant association between stent placement across the IL and decreased primary patency. A multivariate analysis was performed in two of those studies, yet only one maintained statistical significance after multivariate analysis. Two studies reported 4 cases of stent fracture in total, and one study reported 5 cases of stent compression. All cases of stent fracture or compression occurred at the inguinal ligament.

CONCLUSIONS

Although current expert opinion favours stent placement across the IL, there is still insufficient evidence to recommend for or against venous stenting across the IL. Further research is required on comparing alternatives for the treatment of iliac venous lesions that extend into the common femoral vein.

WHAT THIS PAPER ADDS

Despite the establishment of venous stenting as a viable treatment option for both post-thrombotic and non-thrombotic iliac venous obstructions, there is an ongoing debate on the safety of extending such stents across the inguinal ligament. There are several publications on this subject, with conflicting results and overall poor-quality research. This is the first systematic review of published clinical evidence on the impact of venous stent placement across the IL on primary patency.

Mid-term patency of iliac venous stenting for post-thrombotic syndrome

INTRODUCTION

Post-thrombotic syndrome (PTS) is the most common chronic complication of deep vein thrombosis. Recent studies suggested that iliac stenting in chronic obstructive venous disease is safe and effective. However, systematic reviews focusing on mid-term efficacy of iliac stenting in post-thrombotic syndrome are lacking. This systematic review aimed to analyze mid-term stent patency rates and clinical outcomes of iliac stenting in post-thrombotic syndrome.

EVIDENCE ACQUISITION

Two databases were searched: Pubmed/Medline and Scopus. Articles published between January 2000 and July 2020 were selected and titles and abstracts were independently reviewed. Eighteen articles were included for the qualitative analysis. From this initial set of articles, fourteen articles were included for the quantitative analysis.

EVIDENCE SYNTHESIS

Overall, 1008 patients were included in this study. The pooled technical success rate was 96%. The pooled primary and secondary patency rates were 98.2% and 100% at 30 days, 78.1% and 94.5% at 12 months and 66.3% and 89.4% at 36 months, respectively. The rates of ulcer healing, pain and edema relief were 78.1%, 53.4% and 48.8%, respectively. The pooled rate of complications including intraoperative venous injury, back pain and stent fracture were 28%, 57.1%, and 5.9%, respectively.

CONCLUSIONS

Iliac venous stenting in PTS presents durable mid-term patency rates, as well as significant symptomatic improvement. Therefore, endovascular treatment should be considered in symptomatic patients with PTS.

Endovascular treatment of iliofemoral vein obstruction below the inguinal ligament using a new-dedicated stent: early experience from a single center

BACKGROUND

The aim of this study was to assess our experience with a new commercially available venous stent as an extension below the inguinal ligament in patients with iliofemoral venous outflow obstruction involving the common femoral vein.

METHODS

We treated 16 patients with iliofemoral venous outflow occlusion and post-thrombotic syndrome (PTS) (mean age: 52.5±20.2; female: 87.5%) with the Blueflow Venous Stent (plusmedica GmbH & Co. KG, Düsseldorf, Germany) between 2019 and 2020. All patients had unilateral venous disease with >50% stenosis in the iliofemoral veins. The primary endpoints assessed were technical success, primary and secondary patency rate at 1 year of follow-up, respectively. Clinical improvement was assessed with the Villalta Scale, revised venous clinical severity score (rVCSS) classification and visual analog-scale (VAS) respectively.

RESULTS

The technical success rate was 100%. No intraoperative and 30-days postoperative complications were documented. The primary and secondary patency rates were 80.2% and 100% respectively, at 1 year of follow-up. One in-stent occlusion and two in-stent restenosis were detected during follow-up. Stent fracture and/or migration were not observed during follow-up. A significant improvement in the Villalta Scale and rVCSS score was documented with a median score of 3 (IQR: 2-6) and 2.5 (IQR: 1-5) versus baseline at the last follow-up. A pain reduction of 18 mm on the VAS scale was documented at 1-year follow-up.

CONCLUSIONS

In this cohort of patients, the Blueflow Venous Stent across the inguinal ligament was safe and effective for the treatment of symptomatic iliofemoral venous disease, with a high primary patency rate at 1-year of follow-up. However, longer follow-up and larger cohorts are still needed.

Role of venous stenting for venous thromboembolism

Endovenous stenting has emerged as the method of choice to treat iliofemoral venous outflow obstruction. It is used in patients with established postthrombotic syndrome (PTS) after previous deep vein thrombosis (DVT) to reduce symptoms of chronic pain and swelling and to aid ulcer healing in severe cases. Venous stenting is used to alleviate symptoms of obstruction in patients presenting with acute DVT, with the aim of preventing development of PTS. There is a low risk of morbidity and mortality associated with the use of endovenous stenting, and although significant advances have been made, particularly improvements in stent design for use in the venous circulation, data are lacking on beneficial long-term outcomes. Unmet research needs include optimal patient selection, anticoagulant choice and duration, best practice for postoperative surveillance, and use of validated assessment tools to measure outcomes. In this article, I address the potential benefits, as well as the challenges, of endovenous stenting.

Iliac vein pathology and short-term stenting outcomes in a South-East Asian population: A single-centre experience

OBJECTIVE

Current literature regarding iliofemoral intervention and stenting is mostly based on Western populations. We present our experience of iliofemoral stenting for chronic venous disease within a South-East Asian population.

METHODS

This is a single-centre retrospective review of a prospectively collected registry. Seventy-one patients with 105 limbs underwent iliac vein IVUS and stenting between 2016 and 2019. All patients underwent pre-procedure ultrasound venous scan and MRI venogram. Pre- and post-operative CEAP classification, Villalta score and Venous Clinical Severity Score (VCSS), technical results, stent patency rates and complication rates are documented.

RESULTS

Seventy-six per cent of the cases are non-thrombotic iliac vein lesion, and 68% of patients have C4 to C6 disease. Ten percentage of patients had acute thrombosis on presentation. There was 100% technical success. A 6- and 7-point reduction in the mean VCSS and Villalta score, respectively, were noted post-stenting (baseline of 10 points and P < 0.001 in both categories). Post-stenting ulcer healing rate was 91% at 6 and 12 months. One-year ulcer recurrence and cellulites recurrence were at 8% and 7%, respectively. One unplanned 30-day readmission (not related to procedure) and no 30-day mortality were noted. Bleeding complication from anticoagulation was 3%. There was 10% in-stent non-flow limiting stenosis on surveillance. One-year primary patency was 91%, and secondary patency was 100%.

CONCLUSION

Within our series, iliofemoral stenting has 100% technical success, with statistically significant reduction in VCSS and Villalta score, good wound healing rates, low ulcer and cellulites recurrence and good primary and secondary patency rates at 1 year.