Characteristics and outcomes of stent occlusion after iliocaval stenting

RevCore thrombectomy system for treatment of chronic left external and common iliac vein stent occlusion

In recent years, deep venous stenting has increasingly become a treatment strategy for post-thrombotic syndrome. Stent thrombosis can occur, resulting in symptom recurrence despite medical therapy, and there are few options available for durable stent patency restoration. We present a case of a 50-year-old male with prior iliocaval reconstruction that experienced recurrent left lower extremity swelling secondary to occlusion of left external iliac and common iliac vein stents during follow-up. Mechanical thrombectomy with the RevCore System and angioplasty was performed. One month later, the patient demonstrated widely patent bilateral iliac vein stents and complete symptomatic resolution. The RevCore System is a feasible alternative for treatment of chronic in-stent thrombosis.

Indications, technical aspects, and outcomes of stent placement in chronic iliofemoral venous obstruction

BACKGROUND

Iliofemoral Venous Stent Placement (IVS) has evolved to a well-established endovascular treatment modality for chronic iliofemoral venous obstruction (CIVO). Dedicated venous stents gained FDA approval in 2019 and solidified IVS as a defined intervention with clear indications, contraindications, risks, benefits, and procedural management principles. This review focuses on the indications, technical aspects and outcomes of stenting for CIVO. Other aspects pertaining to IVS are covered in manuscripts that are part of this series.

METHODS

This study conducted a literature search limited to English articles. Three search strategies were employed, and references were managed in Covidence software. Four investigators independently screened and evaluated articles, excluding meta-analyses, clinical trial protocols, and non-relevant studies. Eligible studies, focused on clinical outcomes and stent patencies, underwent thorough review.

RESULTS

The literature search yielded 1,704 studies, with 147 meeting eligibility criteria after screening and evaluation. Exclusions were based on duplicates, irrelevant content, and non-iliac vein stent placement.

CONCLUSION

Successful IVS for CIVO relies on meticulous patient selection, consistent use of IVUS during procedures, and attention to the technical details of IVS.

Treating Chronic Iliac Vein Stent Occlusion in an Office-Based Lab Setting

Iliac vein stenting is performed when sufficient venous patency is not achieved via angioplasty or lysis. Iliac vein stenting is known to be effective; however, occlusion of the stent occurs occasionally. There is a lack of effective treatment options for those with failed prior venous stents, and traditional methods may involve the removal of the stent and surgical reconstruction. We present a patient with a right leg post-thrombotic syndrome and narcotic abuse after occlusion of a previously placed right common iliac/external iliac vein stent 25 years prior. After transfer to an office-based lab (OBL), femoral vein access was achieved. Then, a second stent was deployed adjacent to the previously chronically thrombosed stent. Imaging confirmed adequate deployment of the new stent and venous flow. Treatment resulted in a significant decrease in patient pain and cessation of narcotics. We demonstrate successful recanalization of a right iliac vein thrombosis via parallel deployment of a stent adjacent to a chronically thrombosed stent.

Impact of native iliac vein aspect ratio on initial clinical presentation and outcomes following stenting for symptomatic chronic iliofemoral venous obstruction

OBJECTIVE

Venous stenting has become the first line of treatment for patients with symptomatic chronic iliofemoral venous obstruction (CIVO) in whom conservative therapy has failed. Intravascular ultrasound (IVUS) interrogation with the use of normal minimal luminal diameters or areas has become the standard to confirm the diagnosis and determine the adequacy of stenting. However, the aspect ratio (ratio between the maximal and minimal luminal diameters) has also been put forth as a possible metric for determining stent adequacy. This study explores the utility of the native iliac vein and stent aspect ratios in determining the initial presentation and outcomes after stenting.

METHODS

A retrospective analysis of contemporaneously entered data from patients who underwent stenting for quality of life (QoL)-impairing clinical manifestations of CIVO for whom conservative therapy had failed formed the study cohort. The limbs were grouped into three at the time of intervention using the IVUS-determined native vein aspect ratio: group I, those with a ratio of ≤1.4; group II, those with a ratio of 1.41 to 1.99; and group III, those with a ratio of ≥2. The characteristics appraised initially and after stenting included the venous clinical severity score, grade of swelling (GOS), visual analog scale (VAS) for pain score, and the CIVIQ-20 QoL score. Analysis of variance and paired and unpaired t tests were used for comparison of clinical and QoL variables, and Kaplan-Meier analysis was used to evaluate stent patency, with the log-rank test used to discriminate between different curves.

RESULTS

There were a total of 236 limbs (236 patients). The median age for the entire cohort was 62 years (range, 16-92 years). There were 161 women in the study, and left laterality was more common (137 limbs). Post-thrombotic obstruction was noted in 201 limbs (86%). The median body mass index was 36 kg/m2. There were 54 (23%), 64 (27%), and 118 (50%) limbs in groups I, II, and III, respectively. The median follow-up was 65 months. For the entire cohort, after stenting, the venous clinical severity score improved from 6 to 4 (P < .0001) at 3 months and remained at 4 at 6 months (P < .0001), 12 months (P < .0001), and 24 months (P < .0001). The GOS for the entire cohort improved from 3 to 1 (P < .0001) at 3 months and remained at 1 at 6 months (P < .0001), 12 months (P < .0001), and 24 months (P < .0001). The VAS for pain score for the entire cohort improved from 7 to 0 (P < .0001) at 3 months, increased to 2 (P < .0001) at 6 months, and remained at 2 (P < .0001) at 12 months. At 24 months, the VAS for pain score worsened to 3 (P < .0001). For the entire cohort, the CIVIQ-20 score improved from 62 to 40 (P < .0001). There was no difference in the GOS, VAS for pain score, or CIVIQ-20 score between the groups at baseline or at 6, 12, and 24 months after intervention. At 60 months, the primary stent patency was 89% for group I, 80% for group II, and 75% for group III (P = .85). The primary assisted stent patency was 100% for group I, 98% for group II, and 98% for group III (P = .5). Secondary patency was 100% for groups II and III (P > .5). Reintervention was pursued for QoL-impairing clinical manifestations in 53 limbs (22%) without a significant difference between the three groups (P = .13).

CONCLUSIONS

The native vein aspect ratio does not appear to determine the initial clinical presentation or QoL or impact the clinical or QoL outcomes after stenting for CIVO. Following stenting, no patient had an aspect ratio >2, with 97% of patients having an aspect ratio ≤1.4 and the remaining 3% having an aspect ratio of 1.41 to 1.99. IVUS-determined minimal cross-sectional luminal area and not the aspect ratios should be used for confirmation of the diagnosis of CIVO and to assess the adequacy of stenting.

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.

The beneficial role of complex decongestive therapy in patients with symptomatic chronic iliofemoral venous obstruction with phlebolymphedema

OBJECTIVE

Phlebolymphedema has been noted to be one of the most common causes of lymphedema in the lower extremity in western societies. Although complex decongestive therapy (CDT) represents the mainstay of lymphedema treatment, its role for phlebolymphedema arising from chronic iliofemoral venous obstruction (CIVO) merits further exploration. We evaluated this through the use of a protocol of CDT first for limbs with CEAP (clinical, etiologic, anatomic, pathophysiologic) clinical C3 disease and stent correction of obstruction before CDT for those with more advanced disease (CEAP C4-C6). In the present study, we analyzed the outcomes after the use of such a protocol.

METHODS

We analyzed prospectively collected data for 192 limbs (166 patients) that underwent treatment of quality-of-life (QoL) impairing symptoms from CIVO due to lymphoscintigraphically determined phlebolymphedema between 2017 and 2022. The characteristics evaluated included CEAP clinical class, venous clinical severity score (VCSS), grade of swelling (GOS), visual analog scale (VAS) pain score, QoL (CIVIQ-20 [20-item chronic venous disease quality of life questionnaire]), stenting for CIVO, and outcomes related to CDT and stenting. For the limbs undergoing CDT or stenting followed by CDT, the outcomes were evaluated at 6 weeks and 3, 6, and 12 months after completion of CDT. Paired and unpaired t tests, χ2 tests, and analysis of variance were used for comparisons of clinical variables. Kaplan-Meier analysis was used to evaluate stent patency, with the log-rank test used to discriminate between different curves.

RESULTS

Of the 192 limbs (166 patients) in the entire cohort, 74 were in the C3 group and 118 were in the C4-C6 group. The median patient age was 63 years; 57 were men and 109 were women. In the C3 group, after CDT, improvement had occurred in the VCSS and VAS pain score at 6 weeks (P < .0001) and at 3 (P < .0001), 6 (P < .0001), and 12 (P < .0001) months. Improvement in the GOS was noted at 6 (P < .0001) and 12 (P = .0005) months. The CIVIQ-20 score improved from 63 to 38 (P = .009). Nine limbs (12%) in the C3 group required stenting after CDT. In the C4-C6 group, of the 118 limbs, 75 (64%) underwent stenting only and 43 (36%) underwent stenting followed by CDT for persistent QoL impairing symptoms. For this latter group, after CDT, improvement occurred in the VCSS, GOS, and VAS pain score at 6 weeks (P < .0001) and 3 (P < .0001), 6 (P < .0001), and 12 (P < .0001) months. The CIVIQ-20 score improved from 61 to 34 (P < .0001). The primary, primary assisted, and secondary patency in the C4-C6 group at 36 months was 92%, 100%, and 100%, respectively.

CONCLUSIONS

For CEAP C3 patients with phlebolymphedema due to CIVO, CDT should be a part of the first line of treatment. Stenting should be reserved for those with QoL impairing symptoms despite the use of CDT. Additionally, CDT helps provide symptom relief for patients with more advanced CEAP C4-C6 disease with persistent or residual edema after stenting. Further study is warranted.

Ultrasound-guided stenting in the common femoral vein for accurate stent distal landing

Objective/Background

Venous stenting has been reported with excellent clinical results; however, inadequate inflow can increase the risk of stent occlusion. When extending the stent into the common femoral vein (CFV), it is essential to ensure adequate inflow from the femoral vein, deep femoral vein (DFV), and great saphenous vein. Accurate identification of the distal landing zone (DLZ) of the stent is crucial to ensure adequate inflow. The DLZ is usually determined by venography or intravascular ultrasound (IVUS) with reference to bony landmarks. However, the uncertainty can lead to misidentification of the DLZ and inadequate stent placement, resulting in stent occlusion.

Methods

From December 2016 to December 2022, 42 venous stent placements were performed in 40 patients with post-thrombotic iliofemoral vein obstruction and/or stenosis. Three patients had developed early stent occlusion owing to a misidentified DLZ. To improve accuracy in identifying the DLZ during venous stenting, ultrasound-guided placement was performed in the CFV of five patients (four on the left and one on the right) with post-thrombotic changes in the CFV and occlusion of the common iliac vein and external iliac vein. The distal end of the stent was adjusted just above the saphenofemoral junction in two cases and just proximal to the DFV confluence in three cases. Stent placement was verified using both long-axis ultrasound and fluoroscopy.

Results

Ultrasound images of the CFV region provided clear visualization of the stent deployment site and accurate landmark locations, such as the saphenofemoral junction and DFV confluence, allowing for precise adjustments during stent deployment. This technique enabled easier and more definitive identification of other branches of the CFV than previously provided by IVUS and venography. No complications were observed in any of the 42 cases, and long-term patency was achieved at the final follow-up after stenting (average, 10 months; range, 3-14 months).

Conclusions

Ultrasound-guided stenting in the CFV allows for real-time and accurate stent deployment with precise adjustment to the optimal DLZ. Using this technique, combined with venography and IVUS, missed distal lesions and subsequent stent occlusion can be prevented, potentially contributing to better treatment outcomes.

Evaluation of safety and performance of a new prototype self-expandable nitinol venous stent in an ovine model

Objective

Our study was a prospective in vivo study performed on an animal model to evaluate the safety and performance of a novel venous stent designed specifically for venous applications.

Methods

The novel stents were implanted in the inferior vena cava of nine sheep. The stents were deployed with different distances between the closed cell rings to test for if the segments might migrate after being deployed at maximal distance. Three different total lengths were 9, 11, and 13 cm. After 1, 3, and 6 months, vascular injury, thrombus, neointima coverage, and stent migration were evaluated through computed tomography venography and histopathology. Imaging, histology, and integration data were analyzed for each group.

Results

All stents were deployed successfully, and all sheep survived until the time of harvesting. In all cases, the native blood vessel sections were intact. The segmented stent parts showed a differently pronounced tissue coverage, depending on the duration of the implantation.

Conclusions

The new nitinol stent is safe and feasible to implant in the venous system with a rapid surface coverage. Alteration of stent length did not affect the development of neointimal formation and did not cause migration.

Stenting across inferior vena cava filters can be a safe and effective alternative to complex retrieval

OBJECTIVE

Venous stenting for acute and chronic venous disease has been increasingly used as more evidence has accumulated on the efficacy and durability of these interventions for symptomatic patients. Inferior vena cava (IVC) filters that could have been present for years will often be implicated in the obstructive pathology and removal can be challenging. The purpose of the present study was to evaluate whether stenting across an indwelling IVC filter is a safe and effective alternative to removal.

METHODS

Consecutive patients who had undergone iliocaval stenting at our institution from 2007 to 2020 were identified and divided into groups stratified by the presence of an IVC filter. The operative notes, venography findings, and the electronic health records were queried to obtain the operative details, patient characteristics, postoperative outcomes, stent patency, and survival outcomes. The primary end point was iliocaval stent patency. The patients were divided into two groups according to the presence of an IVC filter with or without overstenting. We used the χ2 test and survival analysis as appropriate.

RESULTS

A total of 224 consecutive patients were identified, of whom 71 were found to have undergone iliocaval stenting (age, 48 ± 18 years; 47.9% male; body mass index, 31 ± 9 kg/m2). Of the 71 patients, 15 had had stents placed across an indwelling IVC filter (overstented group) and 56 had not had an IVC filter present (non-overstented group). No differences were found in presentation between the overstented group (acute occlusion, 4 of 15 [26.7%]; chronic occlusion, 8 of 15 [53.3%]; and nonocclusive lesions, 3 of 15 [20%]) and the non-overstented group (acute occlusion, 29 of 56 [52%]; chronic occlusion, 18 of 56 [32%]; nonocclusive lesions, 9 of 56 [16%]; P = .2). Comparisons between the two groups revealed no differences in the baseline characteristics except for age (overstented, 57 ± 15 years; non-overstented, 46 ± 18 years; P = 0.03), preoperative anticoagulation therapy (overstented, 66.6%; non-overstented, 26.9%; P = .01), and bilateral leg symptoms (overstented, 86.7%; non-overstented, 23.2%; P < .001). Primary patency at 30 months was 85.6% in the overstented group and 86.1% in the non-overstented group (P = .78). At follow-up, no adverse events related to filter crushing were reported, and no differences were found in 30-month survival.

CONCLUSIONS

In our single-center, retrospective study of iliocaval stenting, patients who had undergone overstenting across an indwelling IVC filter had had patency rates similar to those whose stents had been placed with no IVC filter in place. Thus, complex IVC filter removal, when not possible or when the risk of operative complications is too high, can be forgone in favor of stenting across the IVC filter, with no implications on midterm patency or adverse events.

Technique of stent sizing in patients with symptomatic chronic iliofemoral venous obstruction-the case for intravascular ultrasound-determined inflow channel luminal area-based stenting and associated long-term outcomes

OBJECTIVE

Femoroiliocaval stenting has become the standard of care for patients with quality-of-life impairing chronic iliofemoral venous obstruction not responding to conservative measures. Although improvement after stenting has been noted in multiple large studies, sizing of stents has been subjective in nature with a general tendency to use smaller stents that would be required to relieve venous hypertension. This study evaluates the authors' technique of using the intravascular ultrasound (IVUS) inflow channel luminal area to guide stent sizing.

METHODS

Patients who underwent femoroiliocaval stenting for quality-of-life impairing chronic iliofemoral venous obstruction and had failed conservative therapy from 2015 to 2021 were included in the study. Clinical outcomes including venous clinical severity score (VCSS), visual analog scale (VAS) pain score, and grade of swelling (GOS) were appraised before and after stenting. Also evaluated were quality of life (Chronic Venous Insufficiency Questionnaire-20 [CIVIQ-20] instrument) and stent outcomes including patencies and reinterventions. Comparisons were made between limbs that underwent placement of larger caliber stents (largest stent diameter >20 mm: >20 mm stent group) vs smaller caliber stents (largest stent diameter ≤20 mm: ≤20 mm stent group). t tests and analysis of variance were used to compare outcomes, whereas the Kaplan-Meier analysis was used to evaluate patencies with log rank used to compare the curves.

RESULTS

A total of 300 patients (300 limbs) underwent stenting with a median age of 58 years. There was a preponderance of men (159 of 300), left laterality (176 of 300), and post-thrombotic syndrome (176 of 300). The median body mass index was 41. There were 120 limbs in the >20 mm stent group and 180 limbs in the ≤20 mm stent group. The median follow-up was 23 months. There was no significant difference in baseline VCSS, VAS pain score, or GOS between the two groups. However, there was a significant difference in IVUS-determined inflow channel luminal area between the two groups (228 mm² >20 mm stent group vs 176 mm² for ≤20 mm stent group [P < .0001]). After stenting there was a significant improvement in the VCSS, VAS pain score, and GOS at 6 weeks, 3, 6, 12, and 24 months (P < .0001) without any difference between the groups (P > .05). The CIVIQ-20 score also improved from 58 to 38 (P < .0001) for the entire cohort and for the two groups (P < .0001). Overall primary, primary-assisted, and secondary patencies at 60 months were 84%, 100%, and 100%, respectively. Reintervention rate was 10% without any difference between the groups.

CONCLUSIONS

Stent sizing using IVUS-determined inflow channel luminal area in patients undergoing stenting for quality-of-life impairing chronic iliofemoral venous obstruction resulted in a significant improvement in the VCSS, VAS pain score, GOS, and quality of life (CIVIQ-20) after stenting. Excellent stent patencies and low reintervention rates were also noted. IVUS-determined inflow channel luminal area represents an objective technique of stent sizing in comparison to the subjective techniques that currently exist.

Gender Differences in Iliofemoral Vein Stenting for Chronic Venous Insufficiency

INTRODUCTION

Little is known about gender's role in chronic venous insufficiency (CVI). The aim of this study was to evaluate the impact of gender on outcomes of iliac vein stenting(IVS) for CVI.

METHODS

866 patients who underwent vein stenting for CVI at one institution from August 2011 to June 2021 were analyzed via retrospective review. Patients were followed up to 5 years after initial stent placement. Presenting symptoms were quantified using Venous Clinical Severity Score(VCSS), Clinical Assessment Score(CAS), and Clinical, Etiology, Anatomy, and Pathophysiology (CEAP) class. Reoperations after initial IVS were recorded. Major reoperations were defined as iliac interventions using venography. Minor reoperations were defined as thermal ablation. Multivariate logistic regression models were used determine odds of any and major reintervention.

RESULTS

Compared to females, males pre-operatively presented with a higher mean CEAP class (3.6 vs .3.3; P < .001), VCSS composite (11.3 vs .9.9; P < .001), and smoking history (134 vs .49; P < .001). The 2 groups were similar in age (P = .125), BMI(P = .898), previous DVT (P = .085), diabetes (P = .386), hypertension (P = 1.0), and CAD (P = .499). Multivariate analyses revealed no association between gender and any reintervention (OR, 1.02; 95%CI, .71-1.46; P = .935) or gender and major reintervention (OR, 1.39; 95% CI, .86-2.23 P = .177). There were no differences in number of stents placed (P = .736) or symptomatic improvement at 1 month (P = .951), 3 months (P = .233), 6 months(P = .068), and greater than 1 year (P = .287). At the 1 year follow-up, the male cohort had higher CAS values than females P = .034). Males had larger reduction in composite VCSS than women at 1 year (5.1 vs. 3.8; P = .003) and 3 years (5.3 vs .3.7; P = .031) of follow-up and similar levels of improvement in post-op (4.0 vs .3.5; P = .059), 2 years (4.3 vs .3.8; P = .295), 4-years (5.1 vs .4.6; P = .529), 5 years (5.6 vs .4.2; P = .174), and 6 years (5.93vs.3.3 P = .089).

CONCLUSIONS

In a single site study of IVS in patients with CVI, males tended to present worse symptoms than females. After surgery, however, both cohorts showed improvement, and both seemed to improve to the same degree of residual symptoms.

Iliac vein stent failure in community practice and results of corrective reinterventions

OBJECTIVE

The goal of endovenous stenting is to relieve venous obstruction and reduce peripheral venous hypertension by using large caliber venous stents in the presence of adequate venous inflow and outflow for the stented conduit. The aim of this report is to describe the technical reasons and outcomes for reinterventions in a subset of patients who had a history of iliac vein stenting and were now referred to us at a specialty venous clinic for further care.

METHODS

From January 2016 to December 2021, records of all patients who were referred to us with a history of iliac vein stenting performed at an outside facility and who had a reoperation performed at our center were retrospectively analyzed.

RESULTS

A total of 149 limbs underwent a deep venous reintervention after a failure of a trial of conservative therapy. The mean age of the sample was 57 ± 16 years. The ratio of non-thrombotic iliac vein lesions to post-thrombotic lesions was 1:2.5. The majority of the patients (84%) were CEAP class C4 or higher. The most common reason for reintervention was stent occlusion (74%), followed by iatrogenic stenosis (53%) and in-stent restenosis/shelving (38%). There was a trend for improvement in all clinical parameters (venous clinical severity score, visual analog scale for pain, and edema grade) after the reintervention. Poor inflow was present in 70% of limbs with stent occlusion. The median diameters of stented common femoral vein, external iliac vein, and common iliac vein prior to reintervention were 12, 12, and 13 mm, respectively. The median diameters of stented common femoral vein, external iliac vein, and common iliac vein after reintervention were 14, 15, and 16 mm, respectively. Eighty-eight percent of limbs required at least one further reintervention after initial reoperation.

CONCLUSIONS

Venous reoperations are generally infrequent and required in a small number of patients. Poor inflow appeared to be a common cause of stent occlusion. Iatrogenic stenosis is another common reason for venous reoperation and is difficult to fully rectify through current endovascular techniques and tools. Use of intravascular ultrasound planimetry routinely in every deep venous intervention and thorough knowledge of the principles of venous stenting outlined in this report may help forestall the need for reoperative deep venous surgery in some cases.

Angioscopic evaluation after venous stents

BACKGROUND

Venous stenting is increasingly used to manage femoro-ilio-caval venous outflow obstruction/stenosis due to post-thrombotic syndrome. Although the safety, efficacy, and long-term patency of venous stents have been reported, re-interventions due to stent occlusion and in-stent restenosis (ISR) have also been reported. The mechanism of ISR and the in-stent neointimal growth after venous stenting remains unclear. We performed angioscopy to evaluate intraluminal details after venous stenting, allowing real-time direct visualization of the vessel lumen.

METHODS

Ten angioscopic procedures in four patients with post-thrombotic syndrome were performed. All evaluated vessels were stented iliac veins, and their native pathology was chronic post-thrombotic occlusion. Nine procedures in three patients underwent serial evaluation of the neointimal changes after stent implantation to study the natural time course of neointimal proliferation/coverage over the stent. The serial follow-up angioscopic evaluations were performed at the end of the venous stent deployment procedure, and at 6 months, 12 months, and 24 months. One procedure was performed 1 month after the stent implantation to evaluate ISR, which was observed at the first month of routine stent surveillance. A 5.7F angioscope was used to visualize the target veins. Continuous irrigation was used to displace blood and clear the visual field.

RESULTS

At 6 months after stent implantation, stent struts were covered by a thin neointima in two of the three patients. The struts were partially covered in one patient, but there was little neointimal growth overall. Neointimal coverage increased over time, and at 12 months stent struts in 2 patients were almost completely covered. There was no significant change between the 12 and 24 months after stent implantation. In the ISR case, angioscopy demonstrated an overgrown thickened neointima, and the stent struts were fully embedded and invisible in the entire stented area. No thrombus and no webs or trabeculae were found in the area evaluated as an ISR lesion.

CONCLUSIONS

At 6 months after stent placement, the stent struts were almost covered by a neointima. The stent struts were completely covered 1 year after stent implantation. Neointimal coverage was unchanged from the 1-year follow-up to the 2-year follow-up, suggesting that neointimal proliferation proceeded gradually with subsequent neointimal remodeling up to 1 year. The cause of ISR might be the overgrown thickened neointima rather than the formation of thrombosis.

Improvement following restoration of inline flow argues against comprehensive thrombus removal strategies and for selective stenting in acute symptomatic iliofemoral venous thrombosis

OBJECTIVE

Randomized trials have demonstrated the benefit of thrombus removal strategies in iliofemoral deep venous thrombosis (IFDVT) in providing early symptom relief and decreasing the incidence of post-thrombotic syndrome (PTS), especially severe PTS. However, the impact of quantum of residual thrombus burden (RTB) on PTS as determined by intravascular ultrasound examination and the role of venous stenting in the acute setting have not been evaluated and represent the focus of this study.

METHODS

Sixty-nine limbs (65 patients) undergoing thrombus removal for acute symptomatic IFDVT between 2015 and 2021 formed the study cohort. The Venous Clinical Severity Score (VCSS) (range, 0-27) grade of swelling (GOS) (range, 0-4), and visual analog scale (VAS) pain scores (range, 0-10) were evaluated initially and at 6, 12, and 24 months after thrombus removal. Quality of life was appraised using the CIVIQ-20 instrument. The extent of initial and RTB after the intervention was estimated using intravascular ultrasound examination. Grading was done as less than 50% (1), 50% to 99% (2), or 100% (3) of luminal thrombus fill within each segment (common femoral vein, external iliac vein, and common iliac vein) by a blinded rater and then combined to generate a total score. The use of stenting, both concurrent (severe residual stenosis/persistent occlusion) and delayed (quality of life impairing residual or recurrent symptoms), was evaluated.

RESULTS

Of the 69 limbs, 53 underwent pharmacomechanical/mechanical thrombectomy (PMT), whereas 16 patients underwent PMT and catheter-directed thrombolysis with restoration of inline flow in all limbs. Post-intervention VCSS improved from 6 to 2 at 24 months (P < .0001). GOS improved from 4 to 0 at 24 months (P < .0001). The VAS pain score went from 5 to 0 at 6 months (P < .0001) and remained at 0 at 12 months (P < .0001), but increased to 3 at 24 months (P = .02). The CIVIQ-20 score improved from 38 to 22 (P = .001) over a median follow-up of 19 months. The median RTB total score improved from 9 to 4 (P < .0001). There was no impact of RTB total score (<3 vs >3) on VCSS (P = NS), GOS (P = NS), VAS pain score (P = NS) or CIVIQ-20 score (P = NS) at the various time points. Concurrent stenting was used in 23 limbs (33%) and delayed stenting was carried out in 10 limbs (14%). The median time to delayed stenting was 4 months after the initial thrombus removal intervention.

CONCLUSIONS

In patients undergoing PMT or PMT with catheter-directed thrombolysis for acute symptomatic IFDVT, the restoration of inline flow seems to be adequate to provide symptom relief and decrease the incidence of PTS. The extent of RTB does not seem to impact the VCSS, GOS, VAS pain score, or quality of life after such restoration. Stenting can be pursued selectively in the acute setting to help restore inline flow.

Comparison between a dedicated venous stent and standard composite Wallstent-Z stent approach to iliofemoral venous stenting: Intermediate-term outcomes

OBJECTIVE

Dedicated venous stents have not been used in the management of symptomatic chronic iliofemoral venous obstruction (CIVO) until recently. The Bard Venovo stent (Becton, Dickinson, and Co, Franklin Lakes, NJ) is one such stent noted to have an increased chronic outward force and radial resistive force compared with the Wallstent (Boston Scientific, Marlborough, MA). In the present study, we evaluated the outcomes following the use of the Bard Venovo stent vs a matched cohort of limbs that had undergone stenting with the Wallstent-Zenith (Z) stent (Cook Medical Inc, Bloomington, IN) composite configuration.

METHODS

A review of contemporaneously entered electronic medical record data for 167 patients (167 limbs) with initial iliofemoral stents placed from 2019 to 2020 for quality of life (QOL)-impairing CIVO that had failed conservative therapy was performed. The visual analog scale for pain score (score, 0-10), grade of swelling (score, 0-4), venous clinical severity score (score, 0-27), and the 20-item chronic venous insufficiency quality of life questionnaire instrument for QOL were evaluated before and after intervention to assess the effects of stenting. A Kaplan-Meier analysis was used to examine primary, primary-assisted and secondary stent patency, and analysis of variance with repeated measures was used to compare clinical outcomes.

RESULTS

A total of 167 limbs had undergone Bard Venovo stenting (56 men and 111 women). Their median age was 61 years. The laterality was right and left in 70 and 97 limbs, respectively. Post-thrombotic syndrome was seen in 84 limbs and nonthrombotic iliac vein lesions/May-Thurner syndrome in 83 limbs. At 6 months, the venous clinical severity score had improved from 7 to 4 in the limbs with a unilateral Venovo (UV) stent and from 5 to 4 in the composite Wallstent-Z stent group (P = .9). The grade of swelling had improved from 3 to 1 in the UV group and from 3 to 1 in the composite group (P = .6), and the visual analog scale for pain score had improved from 7 to 2 in the UV group and from 5 to 0 in the composite group (P = .007). At 12 months, ulcers had healed in 53% (8 of 15) of the UV group and 56% (5 of 9) of the composite group (P = .7). The global 20-item chronic venous insufficiency quality of life questionnaire scores had improved from 58 to 28 in the UV group and from 59 to 40 in the composite group (P = .6). The cumulative primary, primary-assisted, and secondary patency at 18 months was 81%, 97%, and 98% in the UV group and 87%, 98%, and 100% in the composite group, respectively (P > .4). No difference in the reintervention rates was noted between the two groups (P = .5).

CONCLUSIONS

For patients who had undergone stenting for QOL-impairing CIVO, the results with the Bard Venovo venous stent were comparable to those with the composite Wallstent-Z stent configuration for clinical outcomes, QOL improvement, and stent patency. Further study is, however, required to confirm this improvement in the long term.

Iliofemoral venous configurations from three-dimensional computed tomography venogram and their relevance to stent design

OBJECTIVE

Iliofemoral venous stenting has become the standard of care for patients presenting with quality-of-life impairing symptoms of chronic iliofemoral venous obstruction not responding to conservative measures. This has led to an increased use of venous stenting over the last several years. However, iliofemoral venous anatomy in patients requiring such intervention remains poorly elucidated. This study attempts to fill that gap.

METHODS

Twenty-two consecutive patients with intravascular ultrasound examination-confirmed chronic iliofemoral venous obstruction underwent three-dimensional reconstruction of their computed tomography venogram images. Relevant angles, tortuosity (tort index-ratio between centerline length, and straight line length), lengths, and diameters were computed and analyzed. We used t tests for comparisons between the right and left sides. A P value of .05 or less was considered significant.

RESULTS

Of the angles calculated, the median of the angles between the horizontal and common iliac vein (CIV) was 66° on the right and 60° on the left (P < .01). The median inferior vena cava-CIV angle was 172° on the right and 165° on the left (P < .0001). The CIV-EIV angle was 159° on the right and 151° on the L (P = .01). Overall, the median tortuosity was 1.07 on the right and 1.12 on the left (P = .007). The median centerline length of the CIV was 42mm on the right and 60mm on the left (P < .0001). The median external iliac vein length was 73 mm on the right and 88 mm on the left (P < .0001). The overall median iliac vein length was 220 mm on the right and 237 mm on the left (P < .01). The median diameters of the inferior vena cava at the iliocaval confluence, 20, 40, and 60 mm cranial to the confluence, were 23, 20, 22, and 23 mm, respectively.

CONCLUSIONS

Overall, the left side has steeper angles, greater tortuosity, and longer lengths than the right side. These disparities should be considered during femoroiliocaval stent construction.

Percutaneous laser recanalization in chronically occluded iliofemoral venous stents

Occlusion is a challenging complication of endovenous stenting. The treatment of chronic iliofemoral stent occlusion involves wire recanalization followed by balloon angioplasty. However, this approach will not always be successful. To treat such cases, we have successfully used a laser recanalization technique in 34 limbs (31 patients). This technique involved the use of a laser to first create a channel through the chronically occluded stent, followed by balloon angioplasty to improve the caliber of this recanalized tract. The mean age of the patients was 52 ± 13.6 years (range, 24-73 years). No adverse events related to the use of the laser occurred. Following laser recanalization, the venous clinical severity score had improved from 8.2 ± 4 to 5.1 ± 3.3 (P < .0001). The visual analog scale score for pain had improved from 7.8 ± 2.5 to 4.9 ± 3 (P = .0009). The grade of swelling had improved from 2.7 ± 1.3 to 1.6 ± 1.4 (P = .0001). At 12 months after intervention, the primary stent patency was 60% (standard error of the mean, 9.3%), and the secondary stent patency was 80%. Excimer laser recanalization of chronically occluded venous stents appears to be a rarely required but useful modality with reasonable clinical outcomes. Further reinterventions might be required to maintain long-term stent patency.

Endovenous Iliocaval Revascularization for Transplant Kidney Salvage

PURPOSE

We report the case of a venous iliocaval recanalization to preserve a transplant kidney.

CASE REPORT

A young patient with a nephrotic syndrome caused by focal segmental glomerulosclerosis (FSGS) underwent a robot-assisted living-donor kidney transplant. The postoperative course was uneventful; serum creatinine at discharge was 1.51 mg/dL (normal range = 0.72-1.17 mg/dL). In the course of the following months, the patient was readmitted repeatedly due to acute kidney failure not related to rejection, recurrent FSGS, or anastomotic stenosis. All episodes started after prolonged standing and renal function improved after bed rest. Several hospital admissions and investigations later, phlebography revealed an occlusion of the inferior vena cava (IVC) and both common iliac veins with large collateral vessels through the azygos system. An endovenous recanalization of the iliocaval tract was performed, with subsequent normalization of transplant kidney function.

CONCLUSION

Vascular complications after renal transplantation are an important cause of graft loss. We present an endovenous treatment option for a chronic occlusion of the IVC and common iliac vein with intermittent venous congestion as a cause of transplant failure.

An overview of in-stent restenosis in iliofemoral venous stents

BACKGROUND

Although endovenous stents have been associated with overall low morbidity, they can require reinterventions to correct stent malfunction due to in-stent restenosis (ISR). ISR has often occurred iliofemoral venous stents but has not been well described. It has been reported to develop in >70% of patients who have undergone iliofemoral venous stenting. We sought to provide an overview of ISR in iliofemoral venous stents, including the pathologic, diagnostic, and management considerations and the identification of several areas of potential research in the future.

METHODS

A search of reported English-language studies was performed in PubMed and the Cochrane Library. "In-stent restenosis," "vein," "venous," "iliac," and "iliofemoral" were used as keywords. The pertinent reports included in the present review had addressed the pathology, diagnosis, and current management options for ISR.

RESULTS

ISR refers to the narrowing of the luminal caliber of the stent owing to the development of stenosis inside the stent itself. ISR should be differentiated from stent compression. Two main types of ISR have been described: soft and hard lesions. These lesions respond differently to angioplasty. Stent inflow and shear stress are important factors in the development of ISR. The treatment options available at present include balloon angioplasty (hyperdilation or isodilation), laser ablation, atherectomy, and Z-stent placement.

CONCLUSIONS

Reintervention for ISR should be determined by the presence of residual or recurrent symptoms and not simply by a numeric value obtained from an imaging study. Overall stent occlusion due to ISR is rare, and no role exists for prophylactic angioplasty to treat asymptomatic ISR. The current treatment options for ISR are mostly durable and effective. However, more research is needed on methods to prevent the development of ISR. The role of antiplatelet and anticoagulant agents in the prevention of ISR requires further investigation, with particular attention to unique subset of patients (after thrombosis vs nonthrombotic iliac vein lesions). For high-risk, post-thrombotic patients, anticoagulation can be considered to prevent ISR. The role of triple therapy (anticoagulation and dual antiplatelet therapy) in the prevention of ISR remains unclear.

Iliofemoral venous stenting in patients with central neuromuscular disorders

BACKGROUND

Leg swelling in patients with various central neuromuscular disorders is a common clinical scenario and can lead to significant morbidity. The aim of the present study was to evaluate a subset of patients with central neuromuscular disorders who had undergone iliofemoral venous stenting at a specialty venous clinic at a tertiary care hospital.

METHODS

From January 2000 to December 2020, the medical records of all patients with a known central neuromuscular disorder who had undergone iliofemoral venous stenting for chronic iliofemoral venous obstruction were retrospectively analyzed.

RESULTS

A total of 42 patients (45 limbs) with central neuromuscular disorders had undergone iliofemoral stenting after failure of a trial of conservative therapy. The central neuromuscular disorders included Parkinson disease (n = 20 limbs), multiple sclerosis (n = 15 limbs), and other neuromuscular conditions (n = 10 limbs). The mean age of the sample was 59 ± 14 years. The ratio of post-thrombotic to nonthrombotic iliac vein lesions was 3:1. Most of the patients had had CEAP (clinical, etiologic, anatomic, pathophysiologic) class ≥C4 (64.4%); 25 limbs had a history of venous thromboembolism (56%). A trend was seen toward improvement in all clinical parameters measured (venous clinical severity score, visual analog scale for pain score, and edema grade) after stenting. An ulcer healing rate of ≤90% was noted after stenting. Of the 45 limbs, 24 had required some form of reintervention (53%) after initial stent placement.

CONCLUSIONS

Venous intervention in the form of endovenous stenting was associated with improvement in the clinical parameters for patients with central neuromuscular disorders. However, these patients should be counseled regarding the relatively higher rate of reinterventions that might be required to correct residual or recurrent symptoms.

Female Gender is a Predictor of Lower Iliac Vein Stenting Patency Rates

BACKGROUND

Iliac venous stenting (IVS) for thrombotic and nonthrombotic venous disease is increasingly used as evidence of the safety, efficacy and durability of these interventions increases. Female gender has been implicated as a predictor of failure in arterial endovascular interventions. We hypothesize that female gender could be predictive of patency rates of iliac vein stenting.

METHODS

Consecutive patients who underwent IVS for thrombotic or nonthrombotic venous disease at our institution from 2007 until 2019 were identified and divided into groups based on gender. Operative notes, venograms, and the electronic health record were then queried to obtain operative details, co-morbid conditions, postoperative outcomes and stent patency. Study outcome was long term patency rate. The data was analyzed using chi-square, logistic regression, and Kaplan-Meier analysis as appropriate.

RESULTS

A total of 200 consecutive patients (231 limbs) were identified in our retrospective analysis, with a mean age of 48.8 ± 17.3, and BMI of 31.6 ± 8.6. Of those, 119 (59.5%) patients, (131 [56.8%] limbs) were female. Comparisons between the gender groups revealed no difference in age, BMI, or preoperative comorbidities. There was no difference in type of venous disease between male (85% thrombotic, 15% nonthrombotic) and female (84% thrombotic, 16% nonthrombotic), P= 0.830. The male cohort was more likely to present with leg ulceration (17% vs. 4.6%, P = 0.002), and the female cohort was more likely to present with leg edema (98.5% vs. 93.0%, P= 0.03). The male cohort had a higher rate of caval (48% vs. 33.6%, P= 0.027) and infrainguinal stent extension. (11% vs. 6.9%, P= 0.02). Females had a higher rate of left sided stenting (80.9% vs. 66/0%, P= 0.010). There was no difference in the median stent diameter used between the cohorts. Primary patency at 5 years was significantly higher for the male cohort (94.1% vs. 74.4%, P= 0.01) On adjusted multivariable cox regression female gender was a predictor of loss of primary patency within 5 years (HR, 4.04; P= 0.007).

CONCLUSIONS

In this single center retrospective analysis of IVS, male patients were found to have better primary stent patency compared to female.

Deep venous stenting improves healing of lower extremity venous ulcers

BACKGROUND

Long standing, recalcitrant venous ulcers fail to heal despite standard compression therapy and wound care. Stenting of central veins has been reported to assist in venous ulcer healing. This study reports outcomes of deep venous stenting for central venous obstruction in patients with recalcitrant venous ulcers at a single comprehensive wound care center.

METHODS

A single center retrospective analysis was conducted of patients with CEAP (Clinical, Etiology, Anatomy, and Pathophysiology) 6 disease that had undergone deep venous stenting in addition to wound care and compression therapy. Intra-operative details, wound healing, and stent patency rates were recorded. Stent patency and intra-operative details were compared between the healed and unhealed groups.

RESULTS

Between 2010 and 2019, 15 patients met inclusion criteria (mean age: 63 years old, 12 males). Pre-operative mean wound area was 14.1 cm2 with mean wound duration of 30 months. 93% of patients healed the ulcers at mean healing time of 10.6 months. Wound recurrence rate was 57% with mean recurrence time of 14.8 months. Ten patients presented with an inferior vena cava (IVC) filter, 4 in the healed group and 6 in the unhealed group. The common iliac vein was stented in all patients. Extension into the IVC was required in 4, the common femoral vein in 11, and femoral vein in 2 patients. The average stent length was 190cm. During the follow-up period, primary patency rates in healed patients (mean follow-up time: 19.2 months) was 83% and 59% in the unhealed group (mean follow-up time: 36.6 months); secondary patency rates were 83% and 89%, respectively.

CONCLUSIONS

In patients with recalcitrant venous ulcers with central venous obstruction, deep venous stenting resulted in a high rate of healing. However, a prolonged 10 month healing time was observed and despite high stent patency, wound recurrence rate was high.

Effect of body mass index on initial presentation and outcomes after stenting for quality of life-impairing chronic iliofemoral venous obstruction

OBJECTIVE

The incidence of obesity has been increasing, with recent data indicating that the age-adjusted mean body mass index (BMI) is close to 30 kg/m² in the United States. Prior studies have raised concerns for an increased incidence of chronic venous insufficiency in the obese population. We aimed to build on current knowledge by assessing the effects of BMI on the initial presentation and outcomes after intravascular ultrasound (IVUS) luminal area-guided stenting in patients presenting with quality of life (QOL)-impairing chronic iliofemoral venous obstruction (CIVO).

METHODS

A retrospective analysis of contemporaneously entered electronic medical record data on 464 continuous patients (464 limbs) with initial iliofemoral stents (2014-2017) for QOL-impairing CIVO was performed. The characteristics evaluated and compared included the degree of iliofemoral compression, CEAP (clinical, etiologic, anatomic, pathophysiologic) clinical class, venous clinical severity score (VCSS), grade of swelling (GOS), visual analog scale (VAS) for pain score, ulcer healing, reflux (venous segmental disease score; venous filling index-90), calf pump function (ejection fraction; residual volume fraction), and quality of life (CIVIQ-20 [chronic lower limb venous insufficiency 20-item questionnaire]) for those with a BMI <30 kg/m² (group I) and a BMI ≥30 kg/m² (group II). Paired and unpaired t tests were used for comparisons of the clinical variables and a Kaplan-Meier analysis was used to evaluate stent patency.

RESULTS

Of the 464 limbs in the study cohort, 122 were in group I and 342 in group II. The median BMI was 26.3 kg/m² (interquartile range, 19.6-29.9 kg/m²) in group I and 38.9 kg/m² (interquartile range, 30.0-66.9 kg/m²) in group II. The IVUS luminal area-determined degree of compression was higher in group I than in group II across the common iliac, external iliac, and common femoral segments (P < .01). The supine foot venous and femoral venous pressures were higher in group II than in group I (P < .001). The ejection fraction was higher (57.4% vs 45.6%; P = .0008) and residual volume fraction was lower (27.5% vs 40.5%; P = .0008) in group II than in group I. Although the baseline VCSS and GOS were lower in group I than in group II (P < .05), no differences were found in the VAS for pain scores or ulcer prevalence. The median follow-up was 22 months. At 24 months after stenting, improvement was found in the VCSS, GOS, and VAS for pain score in both groups. The CIVIQ-20 QOL score had improved from 58.1 to 18.8 in group I (P = .0002) and from 60 to 37.5 in group II (P < .0001). At 5 years, primary patency was 70% in group I and 73% in group II (P = .6) and primary assisted patency was 100% in both groups (P = .99) without a significant difference in the reintervention rate (P = .5).

CONCLUSIONS

Obese patients with CIVO-impairing QOL have a lesser degree of iliofemoral venous stenosis, more severe venous hypertension, and better calf pump function than their nonobese counterparts. After stenting, no differences were found in the clinical, stent patency, or QOL-related outcomes between the two groups.

In-stent restenosis and stent compression following stenting for chronic iliofemoral venous obstruction

OBJECTIVE

In-stent restenosis (ISR) and stent compression (SC) are problems encountered after stenting for chronic iliofemoral venous obstruction that are responsible for a majority of reinterventions. However, characteristics of ISR and SC, in addition to outcomes after reintervention, have not been explored in detail and represent the focus of this study.

METHODS

A retrospective analysis of contemporaneously entered electronic medical record data on 578 limbs/patients with initial unilateral iliofemoral venous stents placed from 2014 to 2018 was performed. ISR was estimated from stent and flow channel diameters measured using duplex ultrasound. SC was estimated from rated stent diameter and actual stent diameter on duplex ultrasound. Characteristics evaluated included onset of ISR/SC after stent placement and progression over time. Analysis was performed to evaluate risk factors for the development of ISR and SC. Outcomes after reintervention for ISR/SC were also appraised.

RESULTS

A total of 578 limbs underwent stenting for stenotic lesions (nonthrombotic iliac vein lesion/post-thrombotic syndrome). ISR was noted in 27% of limbs on post-intervention day 1. The prevalence of ISR increased to 74% by 3 months and stabilized thereafter. SC was noted in 80% of limbs on day 1 and plateaued. Of the variables evaluated as potential risk factors for ISR, intravascular ultrasound determined that stent inflow luminal area and shear rate were found to be significant. For SC, asymmetric stent sizing was a significant risk factor. Over a median follow-up of 24 months, 95 of 578 (16.4%) limbs underwent reintervention for ISR, SC, or a combination. The median time to reintervention was 11 months. There was no statistically significant difference in the degree of ISR/SC among patients who underwent reintervention vs those who did not (P > .05). However, there was a statistically significant difference in the grade of swelling (P = .006) and visual analog scale pain scores (P < .0001) between those who underwent reintervention and those who did not. Primary, primary assisted, and secondary patencies at 60 months were 70%, 98%, and 84% after reintervention for ISR and 70%, 99%, and 84% for SC, respectively.

CONCLUSIONS

Although ISR and SC are both common after stenting for chronic iliofemoral venous obstruction, neither are relentlessly progressive. Indication for reintervention must be a recurrence of symptoms with impairment of quality of life and not the percentage of ISR or degree of SC. After reintervention good outcomes can be expected both in terms of clinical improvement and stent patency. Further study of the impact of shear rate on stent flow is required to help reduce the incidence of ISR.

What are the ideal characteristics of a venous stent?

Historically, the stents used in the venous system were not dedicated scaffolds. They were largely adapted arterial stents. An essential feature of a venous stent is compliance, in order to adapt its crosssectional area to the vein. It should also be crush resistant, corrosion resistant and fatigue resistant. The material should be radiopaque, for follow-up. Another characteristic of the ideal venous stent is flexibility, to adapt its shape to the vein, not vice versa. The scaffold should be uncovered too, in order to avoid the occlusion of collaterals. The ideal venous stent should not migrate, so it is necessary a large diameter and a long length. The radial force is important to prevent migration. However, current stents derived from arterial use display high radial force, which could affect the patency of the thin venous wall. Alternatively, if the stent has an anchor point, that permits a passive anchoring, the radial force required to avoid migration will be lower. Dedicated venous stents were not available until very recently. Furthermore, there is a preclinical study about a new compliant nitinol stent, denominated Petalo CVS. Out of the commonest causes of large veins obstruction, dedicated venous stent could also treat other diseases described more recently, such as the jugular variant of the Eagle syndrome, JEDI syndrome and jugular lesions of the chronic cerebrospinal venous insufficiency that result unfavorable for angioplasty according to Giaquinta classification.

Utility of the 50% stenosis criterion for patients undergoing stenting for chronic iliofemoral venous obstruction

OBJECTIVE

The criterion for venous stenting in symptomatic chronic iliofemoral venous obstruction has been the arbitrary use of stenosis of ≥50%. In the present study, we evaluated the intravascular ultrasound (IVUS)-determined degree of stenosis in patients who had undergone stenting for quality of life (QOL)-impairing symptoms and assessed the utility of the 50% stenosis cutoff.

METHODS

A retrospective review of contemporaneously entered electronic medical record data from 480 continuous patients (480 limbs) with initial iliofemoral stents placed (2014 to 2017) for symptomatic chronic iliofemoral venous obstruction impairing their QOL was performed. The IVUS-determined normal minimal luminal areas for the common femoral vein (125 mm), external iliac vein (150 mm), and common iliac vein (200 mm) were used to group limbs as having <50% (low-grade stenosis [LGS]) or ≥50% (high-grade stenosis [HGS]) stenosis. The variables compared included the visual analog scale (VAS) for pain score, venous clinical severity score (VCSS; range, 0-27), ulcer healing, supine foot venous pressures, QOL (20-item chronic venous disease QOL questionnaire), and stent patency. A composite chronic venous insufficiency score (CCVIS) incorporating the VAS score, VCSS, and CIVIQ-20 score for predicting improvement after stenting was evaluated.

RESULTS

Of the 480 limbs, 283 and 197 were in the LGS and HGS groups, respectively. A preponderance of women, left laterality, and post-thrombotic syndrome were noted in both groups. At baseline, although no difference was found in the VAS for pain score between groups, the LGS group had a higher VCSS than did the HGS group (P = .05). The baseline median supine foot venous pressure was 15 and 14 mm Hg in the LGS and HGS groups, respectively (P = .17). At 24 months after stenting, the mean VCSS had improved from 6.3 to 4.4 (P < .0001) and from 5.7 to 3.7 (P < .0001) in the LGS and HGS groups, respectively, without significant differences between the two groups (P = .07). A greater prevalence of ulcers was found in the LGS group (18% vs 11%; P = .04), with no differences in healing (P = .41) or recurrence rates (P = .36). The QOL scores had improved in both groups (LGS, from 58 to 37 [P < .0001]; HGS, from 61 to 35 [P < .0001]), without differences between the two groups (P > .3). No significant differences in stent patency or reinterventions rates were found. A baseline CCVIS of ≥84.5, ≥86.9, or ≥105.3 was needed for a 30-, 40-, and 50-point improvement in most limbs after stenting.

CONCLUSIONS

The degree of IVUS-determined iliofemoral venous stenosis did not appear to affect the initial clinical presentation, CEAP (clinical, etiologic, anatomic, pathophysiologic) clinical class, supine foot venous pressure, clinical improvement, QOL improvement, stent patency, or reintervention rates after stenting. Patients presenting with QOL-impairing symptoms in whom conservative treatment has failed merit consideration of correction of their obstruction even if the degree of stenosis is <50%. The use of a CCVIS might be helpful but requires further study.

The effect of stent compression on in-stent restenosis and clinical outcomes in iliac vein compression syndrome

Background

To evaluate the effect of stent compression on in-stent restenosis (ISR) and clinical outcomes in patients with iliac vein compression syndrome (IVCS) after iliac vein stenting.

Methods

Fifty patients with IVCS treated with iliac vein stenting (Smart Control, Cordis, USA) between March 2017 and October 2018 were consecutively enrolled in this study. Computed tomography venography (CTV) was performed to assess stent compression and ISR. Based on the degree of stent compression, patients were allocated to a significant stent compression (SSC) group and an insignificant stent compression (ISC) group. The incidence of ISR was analyzed between the SSC and ISC groups. Patients' venous clinical severity scores (VCSSs) and responses to the chronic venous insufficiency questionnaire (CIVIQ) one year after stenting were compared between the two groups to evaluate the clinical improvement of venous insufficiency.

Results

In total, 34% of patients had SSC. There were significant differences in the incidence of ISR (52.9% vs. 21.2%, P=0.023), and in each group, there was one case of stent occlusion (5.88% vs. 3.03%, P=0.999). Patients in the SSC group had a higher VCSS score (8.41±5.92 vs. 3.15±2.87, P=0.04) and a lower CIVIQ score (83.35±8.86 vs. 92.21±4.32, P=0.001).

Conclusions

SSC has a significant effect on the incidence of ISR and the clinical outcomes of venous insufficiency. Thus, a dedicated iliac venous stent with sufficient radial resistive force, crush resistance, and outward radial force is needed to prevent the occurrence of stent compression.

Transabdominal duplex ultrasound and intravascular ultrasound planimetry measures of common iliac vein stenosis are significantly correlated in a symptomatic population

OBJECTIVE

The objectives of the present study were to determine the validity of transabdominal duplex ultrasound (TAUS) against the reference standard of intravascular ultrasound (IVUS) examinations for the detection of iliac vein obstruction (IVO).

METHODS

We analyzed the data from patients at a private vascular laboratory who had undergone IVUS investigation with an intention to treat because of symptoms of chronic venous insufficiency and a high suspicion of IVO. These patients had also previously undergone a TAUS examination at the same location. The TAUS and IVUS planimetry measures of the left common iliac vein (CIV) were correlated. These included the TAUS-measured minimum and maximum diameter and the percentage of stenosis with the IVUS-measured minimum and maximum diameter and area and the percentage of stenosis.

RESULTS

The TAUS and IVUS data from 47 patients (83% female; age, 49.3 ± 17.3 years; 64% obese) were included in the analyses. We found 89% agreement between the TAUS and IVUS findings regarding the identification of left CIV stenosis of ≥50%. The TAUS data had a positive predictive value of 95.5%. The TAUS measures of the minimum diameter and percentage of stenosis correlated significantly with the IVUS measures of the minimum diameter, minimum area, and cross-sectional area of the percentage of stenosis. The strongest correlations were between the TAUS-measured minimum diameter and IVUS-measured minimum area and percentage of the area of stenosis according to the literature-derived value. The TAUS-measured vein diameter of 8 mm equated to an IVUS cross-sectional area of 94.2 mm² (53% stenosis), and an IVUS cross-sectional area of 50% of stenosis equated to a TAUS diameter of 8.56 mm.

CONCLUSIONS

The findings from the present study support the validity of TAUS evaluation as a workup diagnostic tool for the detection of IVO. Our findings also support the use of TAUS planimetry-in particular, the CIV diameter of ≤8 mm as a threshold value-to indicate clinically relevant stenosis and trigger an IVUS investigation with an intention to treat, because this correlated with a cross-sectional area stenosis of ≥50%, as determined by IVUS examination.

Doppler ultrasound and contrast-enhanced ultrasound in detection of stent stenosis after iliac vein stenting

Background

To compare the diagnostic accuracy of Doppler ultrasound (DUS) with contrast-enhanced ultrasound (CEUS) for detection of iliac vein stent stenosis using multidetector computed tomography venography (MDCTV) as the reference method.

Methods

Patients with iliac vein obstructive disease treated with nitinol stents (Smart Control, Cordis, USA) between January 2016 and December 2017 were consecutively included in this study. DUS, CEUS, and MDCTV were carried out in all patients within one week of each other at 1 year post stenting to investigate the presence of stent compression and in-stent restenosis (ISR).

Results

The study included 139 patients (87 females; mean age 58 ± 15 years). For detecting stent compression, the kappa coefficient between the ultrasound modality of gray-scale imaging and MDCTV was 0.901, indicating very good agreement between these two modalities. ISR was detected in 50, 61, and 65 patients by DUS, CEUS, and MDCTV, respectively. DUS and CEUS (kappa = 0.449) and DUS and MDCTV (kappa = 0.516) had moderate agreement for ISR diagnosis, while for which CEUS and MDCTV (kappa 0.884) had very good agreement. The sensitivity and specificity of DUS and CEUS for diagnosing ISR were 63.1% and 90.8%, 87.8% and 97.3%, respectively.

Conclusions

CEUS is probably superior to DUS in terms of diagnostic accuracy for the follow-up of patients with iliac vein stent stenosis.

Stent characteristics of 32 patients with early (<14 days) iliofemoral stent occlusion

OBJECTIVE

Endovascular treatment with percutaneous transluminal angioplasty and stenting has quickly gained popularity for treatment of deep venous obstructive disease. Early thrombosis after stenting in iliofemoral veins is uncommon. The treatment and analysis of the underlying factors leading to the rethrombosis of stents placed in the previous 14 days are reported in this study.

METHODS

Patients diagnosed with early in-stent thrombosis after iliofemoral stenting were reviewed in this retrospective analysis. Patients with acute occlusion were routinely treated by catheter-directed thrombolysis (CDT), and the underlying causes of early occlusion were identified during the procedure. After successful CDT procedures, patients received additional interventions (percutaneous transluminal angioplasty with or without stenting) if indicated.

RESULTS

A total of 527 patients underwent stenting in the iliofemoral veins, and 32 patients (20 men [63%]) with acute thrombosis in iliofemoral venous stents placed in the previous 14 days were treated in our center from January 2015 to December 2018. The mean time from the onset of symptoms to the intervention was 6 days. Successful thrombolysis was achieved in 31 of the 32 patients, and additional stents were implanted in 16 patients. Patency was achieved in all cases. The underlying factors of early stent thrombosis were technical failure of the initial procedure, such as suboptimal positioning, failure owing to stent characteristics (stent kinking, compression, and angulation), in-stent residual thrombus, and inadequate anticoagulation. In all cases, recanalization was achieved through successful thrombolysis with or without restenting.

CONCLUSIONS

Treatment with CDT and stenting of early in-stent thrombosis is effective and feasible. Recanalization of stented segment(s) can be achieved in most cases of recent thrombosis (<14 days). Early stent-related occlusion is mainly caused by stent-related problems and technical inadequacies.

Long-term outcomes following use of a composite Wallstent-Z stent approach to iliofemoral venous stenting

OBJECTIVE

An endovascular approach has essentially replaced open surgery in the management of symptomatic chronic obstructive iliofemoral venous disease. In the last several years, such a minimally invasive approach has shifted from use of Wallstents alone to a combination of Wallstent-Z stent (composite stenting) to better deal with the iliocaval confluence. This study evaluates the clinical and stent related outcomes following use of composite stenting.

METHODS

A retrospective review of contemporaneously entered EMR data on 535 patients (545 limbs) with initial iliofemoral stents placed over a 4-year period from 2014 to 2017 for symptomatic chronic iliofemoral venous obstruction was performed. Patients who underwent stenting after intervention for acute deep venous thrombosis were excluded. The impact of stenting on clinical outcomes before and after the intervention were evaluated through use of the visual analog scale pain score (0-10), grade of swelling (0-4), and Venous Clinical Severity Score (0-27). Quality of life was appraised using the Chronic Venous Disease quality of life Questionnaire 20 instrument. Kaplan-Meier analysis was used to assess primary, primary assisted and secondary stent patencies, and paired and unpaired t-tests were used to examine clinical outcomes.

RESULTS

Of the 545 limbs that underwent stenting, 183 were in men and 362 were in women. The median age was 60 years. Laterality was right in 205 limbs and left in 340 limbs. Post-thrombotic syndrome was seen in 441 limbs and nonthrombotic iliac vein lesions/May-Thurner syndrome in 104 limbs. At 24 months, visual analog scale pain score went from 5 to 2 (P < .0001), grade of swelling went from 3 to 1 (P < .0001), and Venous Clinical Severity Score went from 6 to 4 (P < .0001). Ulcers were present in 67 limbs and had healed in 49 limbs (73%) over a median follow-up of 26 months. Global Chronic Venous Disease quality of life Questionnaire scores improved from 60 to 36 (P < .0001) after stenting. Cumulative primary, primary-assisted, and secondary patencies at 60 months were 70%, 99% and 91%, respectively. Thirty limbs (5.5%) required contralateral stenting. There was only one instance (0.2%) of contralateral iliofemoral deep venous thrombosis. One hundred eleven limbs (20%) underwent reintervention, including for in-stent restenosis in 44 limbs, stent compression in 2 limbs, in-stent restenosis and stent compression in 48 limbs, and stent occlusion in 17 limbs.

CONCLUSIONS

In patients undergoing iliofemoral venous stenting for obstructive disease, clinical improvement, quality of life improvement, and stent patencies after use of a composite stent configuration are comparable with those seen after exclusive use of Wallstents. However, the use of a composite stent configuration not only decreases the need for contralateral stenting to relieve chronic obstruction, but also decreases the incidence of contralateral iliofemoral deep venous thrombosis.

Impact of Presence of Inferior Vena Cava Filter on Iliocaval Stent Outcomes

BACKGROUND

The impact of presence of an IVC filter in patients undergoing stenting for symptomatic femoroiliocaval obstruction has not been explored in detail. This study attempts to fill this gap by evaluating clinical and stent-related outcomes in such patients. The incidence of deep vein thrombosis (DVT) in this setting is also analyzed.

METHODS

A retrospective review of contemporaneously entered EMR data on initial iliocaval stents placed in patients with an indwelling IVC filter (or placed after stenting) over a 15-year period from 2000 to 2015 was performed. A separate matched cohort that underwent initial stenting during the time frame, but which did not have an IVC filter, was utilized as the control group. Clinical outcomes were evaluated through use of the venous clinical severity score (VCSS) and visual analog scale (VAS) pain scores. Incidence of deep venous thrombosis after stenting was also reviewed in both groups. The Kaplan-Meier analysis was used to assess stent patency after intervention while t-tests were used to examine preintervention and postintervention outcomes within and in-between groups.

RESULTS

A total of 50 limbs (40 patients) underwent placement of a femoroiliocaval stent in the setting of a preexisting (49) or post-stent (1) IVC filter [filter group]. The control group had 156 limbs (155 patients). There was no difference in VCSS, VAS pain score, or grade of swelling at baseline between the 2 groups. Over the median follow-up duration (43 months-filter group; 40 months-control group), VCSS went from 6 to 4 at 12 months (P = 0.0001) in the filter group and from 6 to 4 in the control group (P < 0.0001). VAS pain scores went from 7 to 0 at 12 months (P < 0.0001) in the filter group and from 5 to 0 in the control group (P < 0.0001). There was no significant difference in the VCSS scores or VAS pain score between the 2 groups at 12 months (P > 0.05). Overall, there was a statistically significant increase in the incidence of DVT in the filter group (10%) compared to the control group (3%) [P = 0.03%]. Primary, primary assisted, and secondary patencies in the filter/control groups at 48 months were 64%/65% (P = 0.6), 100%/97% (P = 0.5), and 100%/75% (P = 0.4), respectively. Reintervention from in-stent restenosis was noted in 16% of patients in the filter group compared to 4% in the control group (P = 0.006).

CONCLUSIONS

Patients with an IVC filter in the setting of a femoroiliocaval stent tend to have an increased rate of deep venous thrombosis on the stented side. In addition, an increased rate of reintervention secondary to in-stent restenosis was also noted. In light of this, every attempt should be made to remove the IVC filter as soon as the need for the filter no longer exists.