Factors associated with outcome after interventional treatment of symptomatic iliac vein compression syndrome

Initial experience with the ambulatory management of acute iliofemoral deep vein thrombosis with May-Thurner syndrome with percutaneous mechanical thrombectomy, angioplasty and stenting

OBJECTIVE

Patients undergoing intervention for acute iliofemoral deep vein thrombosis (IFDVT) with May-Thurner syndrome (MTS) typically require inpatient (IP) hospitalization for initial treatment with anticoagulation and management with pharmacomechanical thrombectomy. Direct oral anticoagulants and percutaneous mechanical thrombectomy (PMT) devices offer the opportunity for outpatient (OP) management. We describe our approach with these patients.

METHODS

Patients receiving intervention for acute IFDVT from January 2020 through October 2022 were retrospectively reviewed. Patients undergoing unilateral thrombectomy, venous angioplasty, and stenting for IFDVT with MTS comprised the study population and were divided into two groups: (1) patients admitted to the hospital and treated as IPs and (2) patients who underwent therapy as OPs. The two groups were compared regarding demographics, risk factors, procedural success, complications, and follow-up.

RESULTS

A total of 92 patients were treated for IFDVT with thrombectomy, angioplasty, and stenting of whom 58 comprised the IP group and 34 the OP group. All 92 patients underwent PMT using the Inari ClotTriever (Inari Medical), intravascular ultrasound, angioplasty, and stenting with 100% technical success. Three patients in the IP group required adjuvant thrombolysis. There was no difference in primary patency of the treated IFDVT segment at 12 months between the two groups (IP, 73.5%; OP, 86.7%; P = .21, log-rank test).

CONCLUSIONS

Patients with acute IFDVT and MTS deemed appropriate for thrombectomy and iliac revascularization can be managed with initiation of ambulatory direct oral anticoagulant therapy and subsequent return for ambulatory PMT, angioplasty, and stenting. This approach avoids the expense of IP care and allows for effective use of resources at a time when staffing and supply chain shortages have led to inefficiencies in the provision of IP care for nonemergent conditions.

Criteria to predict midterm outcome after stenting of chronic iliac vein obstructions (PROMISE trial)

BACKGROUND

Endovenous stent placement has become a first-line approach to prevent post-thrombotic syndrome in patients with chronic post-thrombotic obstruction (PTO) or nonthrombotic iliac vein lesions if conservative management fails. This study aims to identify factors associated with loss of patency to facilitate patient selection for endovenous stenting.

METHODS

We retrospectively analyzed 108 consecutive patients after successful endovenous stenting for chronic vein obstruction performed at a single institution from January 2008 to July 2020. Using multivariable logistic regression, we explored potential predictive factors for loss of stent patency, including baseline demographics, post-thrombotic changes, and peak flow velocities measured in the common femoral vein (CFV), deep femoral vein, and femoral vein (FV) using duplex ultrasound examination.

RESULTS

The mean follow-up duration was 41 ± 26 months, and participants had a mean age of 47.4 ± 15.4 years with 46.3% women. Ninety (83.3%) patients had PTO and 18 (16.7%) had nonthrombotic iliac vein lesions, predominantly due to May-Thurner syndrome. Loss of patency occurred in 20 (18.5%) patients, all treated for PTO. Comorbidities, side of intervention, and sex did not differ between patients with occluded and patent stents. Stent occlusion was more common with increasing number of stents implanted (P < .001) and with distal stent extension into and beyond the CFV (P < .001). Preinterventional predictive factors for stent occlusion were lower duplex ultrasound peak velocity in the CFV (odds ratio [OR]: 7.52, 95% confidence interval [CI]: 2.54-22.28; P < .001) and FV (OR: 10.75, 95% CI: 2.07-55.82; P < .005), and post-thrombotic changes in the deep femoral vein (OR: 4.51, 95% CI: 1.53-13.25; P = .006) and FV (OR: 3.62: 95% CI: 1.11-11.84; P = .033). Peak velocities of ≤7 cm/s (interquartile range: 0-20 cm/s) in the CVF and ≤8 cm/s (interquartile range: 5-10 cm/s) in the FV were significantly associated with loss of patency.

CONCLUSIONS

Insufficient venous inflow as assessed by low peak velocities in the CFV and FV as well as post-thrombotic findings represent reliable risk predictors for stent occlusions, warranting their inclusion into the decision-making process for invasive treatment of PTO.

Venous Stenting for Postthrombotic Iliocaval Venous Obstructive Disease: Clinical Efficacy and Mid-term Outcomes

Postthrombotic syndrome (PTS) can cause both venous outflow obstruction and deep venous reflux, and results in severe symptoms of chronic venous disease. Venous stenting in the chronic iliocaval venous obstruction has been shown to be a safe and efficacious procedure. The long-term studies have shown the high patency rate, the good symptom relief, and the low recurrence rate of healed venous ulcerations. Although venous stenting has become a widely accepted treatment option in PTS with chronic venous occlusion or severe stenosis, it is not yet covered by insurance in Japan, and is being performed at limited facilities using off-label arterial stents. In this study, we performed venous stenting in 30 patients with the moderate and severe PTS. All patients showed significant improvement in their venous scores postoperatively, the Villalta score changed from a median of 16 before treatment to a median of 7 after treatment. Likewise, the Venous Clinical Severity Score and the Venous Disability Score dropped from a median of 13, 2.4 before treatment to 6, 1.2 after treatment, respectively. The primary patency and the secondary patency at 40 months were 93% and 96%, respectively. We report the excellent results and discuss current issues and future perspective in Japan. (This is secondary publication from J Jpn Coll Angiol 2021; 61: 99-105.).

Current Status and Prospect of Stent Placement for May-Thurner Syndrome

Stent implantation has been proven to be safe and has become the first-line intervention for May-Thurner syndrome (MTS), with satisfactory mid-term patency rates and clinical outcomes. Recent research has demonstrated that catheter-directed thrombolysis is the preferred strategy when MTS is combined with deep vein thrombosis after self-expanding stent placement. However, the stent used for the venous system was developed based on the experience obtained in the treatment of arterial disease. Consequently, relatively common corresponding complications may come along later, which include stent displacement, deformation, and obstruction. Different measures such as adopting a stent with a larger diameter, improving stent flexibility, and increasing stent strength have been employed in order to prevent these complications. The ideal venous stent is presently being evaluated and will be introduced in detail in this review.

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.

Three-Year Results from the Venovo Venous Stent Study for the Treatment of Iliac and Femoral Vein Obstruction

Purpose

To assess safety and patency of the Venovo venous stent for the treatment of iliofemoral vein obstruction.

Materials and Methods

Twenty-two international centers enrolled 170 patients in the VERNACULAR study (93 post-thrombotic syndrome; 77 non-thrombotic iliac vein lesions). Primary outcome measures were major adverse events at 30 days and 12-month primary patency (freedom from target vessel revascularization, thrombotic occlusion, or stenosis > 50%). Secondary outcomes included the Venous Clinical Severity Score Pain Assessment and Chronic Venous Quality-of-Life Questionnaire assessments (hypothesis tested). Secondary observations included primary patency, target vessel and lesion revascularization (TVR/TLR), and assessment of stent integrity through 36 months.

Results

Freedom from major adverse events through 30 days was 93.5%, statistically higher than a pre-specified performance goal of 89% (p = 0.032) while primary patency at 12 months was 88.6%, also statistically higher than a performance goal of 74% (p < 0.0001). Mean quality-of-life measures were statistically improved compared to baseline values at 12 months (p < 0.0001). Primary patency at 36 months was 84% (Kaplan–Meier analysis) while freedom from TVR/TLR was 88.1%. There was no stent embolization/migration, and no core laboratory assessed stent fractures reported through 36 months. Six deaths were reported; none adjudicated as device or procedure related.

Conclusion

The Venovo venous stent was successfully deployed in obstructive iliofemoral vein lesions and met the pre-specified primary outcome measures through 12 months. At 3 years, primary patency was 84%, reintervention rates were low, standardized quality-of-life and pain measures improved from baseline, and there was no stent migration or fractures.

Level of Evidence

Level 2—prospective, multicenter, controlled clinical study without a concurrent control or randomization. Pre-specified endpoints were hypothesis-tested to performance goals derived from peer-reviewed clinical literature.

Registration clinicaltrials.gov

Unique Identifier NCT02655887.

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.

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.

Timing of Endovascular Interventions for Iliac Vein Compression Syndrome With Thrombus

The aim of this study is to explore the timing and method of endovascular intervention for iliac vein compression syndrome (IVCS) with thrombus. Data from 111 patients with IVCS, complicated acute deep vein thrombosis (DVT), or post-thrombotic syndrome (PTS) who underwent endovascular interventions were analyzed retrospectively. Patients were divided into Group A (DVT group), including 56 patients with IVCS and iliofemoral DVT, with or without femoropopliteal DVT, with sudden lower limb swelling, and Group B (PTS group) included 55 patients with IVCS and PTS, including 18 with lower extremity wet ulcers and 32 with lower limb infections. Interventional therapies were used to treat the thrombus and eliminate stenosis and occlusion of the iliac vein. In both groups, clinical symptoms in the lower limbs after surgery were reduced significantly, and PTS incidence was low during long-term follow-up. The cumulative patency rate was 75.2% in the DVT group and 88.6% in the PTS group. Comprehensive interventional therapies are safe and effective in patients with IVCS and thrombi. Long-term efficacy in the PTS group tended to be better than that in the DVT group.

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.

Association between Laterality and Location of Deep Vein Thrombosis of Lower Extremity and Pulmonary Embolism

Purpose

The aim of this study was to investigate the relationship between the anatomical location of thrombi in the lower extremities and the development of pulmonary embolism (PE).

Methods

Materials and We collected and analyzed the data of patients diagnosed with deep vein thrombosis (DVT) of the lower extremities between 2006 and 2015, and included those whose computed tomography (CT) data were available for PE identification. We evaluated the relationship between the laterality and the proximal/distal location of the thrombi in lower extremites and the location of PE.

Results

CT images were available for 388/452 patients with DVT. After excluding 32 cases with bilateral involvement, 356 cases were included for analysis in this study. The ratio of DVT in the left:right leg was 232:124. PEs developed in 121 (52.2%) patients with left-sided DVT and in 78 (62.9%) with right-sided DVT (P=0.052). PEs in the main pulmonary arteries developed in 36 (15.5%) patients with left leg DVT and in 30 (24.2%) with right leg DVT (P=0.045). The most frequent site of thrombosis associated with the development of PE was the left iliac vein (59/199, 29.6%). According to the anatomical segment of the leg affected by DVT, patients with DVT in the right femoral vein (50/71, 70.4%; P=0.016) had the highest rate of occurrence of PE.

Conclusion

PE develops more frequently in patients with right-sided DVT than in those with left-sided DVT. Therefore, careful observation for the possible development of PE is recommended in cases with right-sided DVT of the lower extremity.

Transient arterial insufficiency and neurologic deficit following external iliac vein stent reconstruction for malignant compression

Acute iliofemoral deep vein thrombosis may present with pain and swelling or phlegmasia cerulea dolens. When thrombosis occurs in the setting of an underlying venous obstruction, stent reconstruction should be performed after thrombus clearance to prevent rethrombosis. Stent reconstruction after thrombus clearance is associated with high technical success rates and durable patency. This report describes transient lower extremity arterial insufficiency and neurologic deficit after external iliac vein stent expansion and reconstruction within a confined space resulting from a malignant obstruction. It serves as a cautionary tale that, in rare cases, aggressive venous stenting within a confined space can transfer clinically significant forces to adjacent arteries and nerves.

Contemporary treatment of May-Thurner Syndrome

Compression of the left common iliac vein by the overlying right common iliac artery is a benign anatomic abnormality in most individuals. However, in patients with significant vein compression, outflow obstruction and chronic intraluminal venous damage may lead to May-Thurner Syndrome. This syndrome commonly manifests as unilateral left leg swelling or acute iliofemoral deep venous thrombosis. In addition to clinical findings, diagnosis is made with ultrasound, computed tomography venography, or magnetic resonance venography. The extent of compression of the iliac vein is best determined by venography with intravascular ultrasound. Symptoms and hemodynamic significance of the compression guides the ideal treatment approach. Iliocaval stenting has become the standard treatment for this condition and has promising patency rates and clinical outcomes. This review paper provides an overview of pathophysiology, and utility and limitations of the existing diagnostic modalities and treatment options in the management of May-Thurner Syndrome.

Comparing the efficacy of endovascular treatment for iliac vein compression syndrome with or without acute deep venous thrombosis: A single-center retrospective study

BACKGROUND

To compare the efficacy of endovascular treatment for iliac vein compression syndrome (IVCS) with or without acute deep venous thrombosis of lower extremity.

METHODS

This study retrospectively analyzed the clinical data of 300 IVCS patients, who received endovascular treatment between January 2013 and December 2017. According to whether IVCS was complicated by deep venous thrombosis or not, these patients were divided into non-thrombotic iliac vein lesion group (NIVL group, n = 127) and post-thrombotic iliac vein lesion group (PIVL group, n = 173). After endovascular treatment, all patients were followed up to assess the symptoms improvement and to evaluate the patency of iliac vein.

RESULTS

The technical success rate was 98% (294/300), and percutaneous transluminal angioplasty with stenting was adopted in 294 cases. The incidence of perioperative complications was 36.33% (109/300), but no severe complications occurred. During a mean follow-up of 22.3 months (range 6-30 months), 9(6.82%, 9/132) patients in PIVL group had recurrence of deep venous thrombosis, but nobody had deep venous thrombosis and varicose veins recurrence in NIVL group. The effective rate of endovascular treatment in NIVL group and PIVL group was 96.88% and 90.15% (P = 0.050), while the cumulative primary patency of iliac vein in NIVL group was significantly higher than that in PIVL group (P = 0.008).

CONCLUSIONS

The endovascular treatment is an effective, feasible, safe method for treating IVCS. There is no difference in the efficacy of IVCS patients with or without deep venous thrombosis, but the medium and long-term patency of patients with deep venous thrombosis is lower than that in patients without deep venous thrombosis.

Clinical Outcomes of Stenting Extending Below the Inguinal Ligament for Treatment of Chronic Iliofemoral Venous Obstruction

BACKGROUND

Patients with chronic iliofemoral venous obstructive lesions that often require stenting extending below the inguinal ligament. However, the issue of stents crossing the inguinal ligament is currently controversial. Some guidelines suggest that it should be avoided, and some guidelines suggest that in order to ensure adequate flow, the inguinal ligament can be crossed if necessary. The aim of this study was to evaluate the technical aspects and examine patency rates of stent placement across the inguinal ligament for managing iliofemoral venous obstruction.

METHODS

A retrospective analysis of 127 patients with chronic iliofemoral venous obstruction were treated with interventional surgery in a single institution from January 2012 to January 2018 was conducted. All patients underwent balloon dilatation and placement of at least 2 stents extending below inguinal ligament. Inflow condition, technical success, operation duration, stent patency rates, anticoagulant selection and duration, and complications were recorded after the interventions.

RESULTS

The technical success rate was 100%. No major perioperative complications occurred. The mean number of stents was 2.14 ± 0.37. Follow up periods ranged from 12 to 60 months (28.79 ± 10.90 months). Overall cumulative primary, assisted primary, and secondary stent patency rates were 81.9%, 90.5%, and 92.9% at 12 months and 70.4%, 80.9%, and 86.0% at 24 months, and 64.2%, 72.3%, and 74.3% at 36months, respectively. Cumulative patency rates at 12 months, 24 months and 36 months were significantly greater in the patients with "good" inflow as compared to "fair" inflow. The symptoms of all patients improved. None of the stents were compressed, fractured or migrated.

CONCLUSIONS

Stenting across the inguinal ligament for treatment of the patients with chronic iliofemoral venous obstruction was a feasible and safe treatment with good patency and clinical results in short and midterm follow up, and stents with good inflow have better patency.

Endovascular and medical therapy of May-Thurner syndrome: Case series and scoping literature review

INTRODUCTION

May-Thurner syndrome has been recognized as a cause of chronic venous insufficiency and a trigger for venous thromboembolism. There is no consensus about the definition, diagnosis, and therapeutic approach. We are aiming to describe its characteristics and a scoping literature review.

METHODS

A retrospective review of patients with May-Thurner syndrome from March 2010 to May 2018 and scoping literature review were made.

RESULTS

Seven patients were identified. All patients were female with a median age of 36 (20-60) years. The median time from the first symptom to diagnosis was 3.41 (0.01-9) years. The primary clinical presentation was post-thrombotic syndrome (4 patients). Six patients had at least one risk factor for deep venous thrombosis. All patients underwent angioplasty with stent; patients with acute deep venous thrombosis, furthermore mechanic thrombectomy with or without catheter-directed thrombolysis were done. There were three complications (one patient, lymphedema, and two venous stent thrombosis). Scoping review results were descriptively summarized.

CONCLUSION

May-Thurner syndrome has a varied spectrum of clinical presentation, and clinical awareness is paramount for diagnosis. Its principal complication is the post-thrombotic syndrome, which is associated with high morbidity. There is no consensus on the antithrombotic treatment approach.

Postinterventional antithrombotic management after venous stenting of the iliofemoral tract in acute and chronic thrombosis: A systematic review

Venous stenting has become a common treatment option for central deep venous outflow obstructions and postthrombotic syndrome. Following successful recanalization and stenting, stent patency is endangered by in-stent thrombosis and recurrent venous thromboembolism. Antithrombotic therapy might reduce patency loss. This systematic review summarizes the literature on antithrombotic therapy following (post)thrombotic venous stenting. A systematic PubMed, MEDLINE, EMBASE, and Cochrane search was performed for studies addressing antithrombotic therapy prescribed following venous stenting of the iliofemoral tract indicated by acute or chronic thrombotic pathology. A total of 277 articles was identified of which 64 (56 original studies) were selected. Overall, a mean primary patency rate of 82.3% was seen 1 year after the intervention, which decreased to 73.3% after 2 years. In the majority (43 of 56 studies, 77%), treatment was based on use of vitamin K antagonists, either with (18%) or without (59%) use of antiplatelet drugs. Only two studies (4%) directly assessed the effect of antithrombotic therapy on treatment outcomes. The impact of postinterventional antithrombotic therapy on stent patency remains unknown because of limited and insufficient data available in current literature. Further clinical research should more clearly address the role of antithrombotic therapy for preservation of long-term patency following venous stenting.

Braided or laser-cut self-expanding nitinol stents for the common femoral vein in patients with post-thrombotic syndrome

BACKGROUND

Chronic obstruction of the common femoral vein in patients with post-thrombotic syndrome after iliofemoral or iliocaval deep vein thrombosis has remained a challenge for endovascular treatment. The patency rates and clinical outcomes of laser-cut and braided nitinol stents extending to the common femoral vein have not yet been studied.

METHODS

From the Swiss and Arnsberg Venous Stent Registries, we included 150 patients with post-thrombotic syndrome (mean age, 44 ± 16 years; 48% women) with laser-cut (n = 101) or braided nitinol (n = 49) stents placed into the common femoral vein across the inguinal ligament. Routine follow-up included duplex ultrasound examinations and assessment of clinical scores. The primary study outcomes were the primary and secondary patency rates at 12 months.

RESULTS

Overall, the mean number of implanted stents was 2.6 ± 1.7. The proximal stent landing zone was the inferior vena cava in 32 patients (21%), the iliac vein in 106 patients (76%), and the common femoral vein in 5 patients (3%). The primary patency rate was 67.3% (95% confidence interval [CI], 58.0%-76.6%) in the laser-cut group and 86.7% (95% CI, 75.3%-98.1%) in the braided stent group (log-rank, P = .016). The corresponding secondary patency rates were 93.9% (95% CI, 89.2%-98.6%) and 100% (log-rank, P = .10). The median improvement in the Villalta score from baseline to the latest follow-up was 4 points (interquartile range, 2-6 points), without significant differences between the two groups. Symptomatic common femoral vein stent fractures were observed in four patients (4%) with laser-cut stents but in no patient with braided stents.

CONCLUSIONS

The use of braided nitinol stents for common femoral vein obstruction appeared to be associated with favorable primary patency rates at 12 months compared with laser-cut nitinol stents. Further studies are needed to confirm that braided nitinol stents remain patent and might be less prone to fractures in the long term.

Association between deep vein thrombosis and stent patency in symptomatic iliac vein compression syndrome: Systematic review and meta-analysis

BACKGROUND

The study intended to evaluate stent primary patency rates for patients with iliac vein obstruction related with iliac vein compression syndrome according to clinic presentation.

METHODS

A systematic review and meta-analysis was conducted of studies that compared: unexposed patients with nonthrombotic iliac vein lesion (NIVL, group 1) vs exposed patients with iliac acute deep vein thrombosis (DVT, group 2); and NIVL (group 1) vs exposed patients with iliac vein obstruction and post-thrombotic syndrome (PTS, group 3). The following databases were searched: EMBASE, PubMed, Web of Science, Scopus, SciELO, and LILACS. Two reviewers independently selected the potential studies and extracted data. The pooled odds ratio (OR) and 95% confidence interval (95% CI) are shown for each outcome.

RESULTS

Five studies with a total of 1050 participants and 1169 lower limbs were included. Five hundred eighty-eight lower limbs presented NIVL (50.3%), 91 lower limbs presented acute DVT (7.7%), and 490 lower limbs presented PTS (42%). The endovascular technical success rate of stenting did not differ in any of the groups: 99.6% in NIVL, 94.5% in acute DVT, and 96.5% in PTS (P = .0632). The primary stent patency rates in the 6-month follow-up were 98.3% in NIVL vs 90.9% in PTS, with a statistical difference showing reduced stent patency rates in PTS (OR, 0.17; 95% CI, 0.06-0.48; P = .0008; I² = 0%), and 100% in the NIVL group vs 91.6% in acute DVT, with no statistical difference (OR, 0.30; 95% CI, 0.06-2.32; P = .30; I² = 0%). The primary stent patency rates in the 12-month follow-up were 94.6% in NIVL vs 84.1% in PTS, with a statistical difference showing decreases stent patency rates in the PTS group (OR, 0.29; 95% CI, 0.14-0.63; P = .0008; I² = 0%), and 91.1% in NIVL vs 90.9% in acute DVT, with no statistical difference (OR, 1.03; 95% CI, 0.26-4.07; P = .96; I² = 0%).

CONCLUSIONS

There is no statistical difference for the stent primary patency rates when the treatment is conducted in NIVL as compared with acute DVT lower limbs (at 6 and 12 months); therefore, other criteria must be considered for the indication of this treatment in NIVL patients. However, because there were better results of stent primary patency rates for NIVL vs PTS patients, this finding favors the treatment of acute DVT instead of PTS in lower limbs, once PTS renders smaller stent patency rates at 6 and 12 months.

Evaluation of anticoagulant and antiplatelet therapy after iliocaval stenting: Factors associated with stent occlusion

OBJECTIVE

Iliocaval stenting has gained increased use over recent years for a variety of indications, including May-Thurner syndrome (MTS), post-thrombotic syndrome (PTS), and acute deep vein thrombosis (DVT).

METHODS

A retrospective review of 155 patients undergoing iliocaval venous stenting at a large teaching hospital was performed. Clinical and procedural data, mode and duration of anticoagulation or antiplatelet therapy, and outcomes were recorded.

RESULTS

Forty-five patients were treated for MTS, 49 for PTS. and 61 for acute DVT. The median follow-up was 19 months (interquartile range, 9-30 months). Primary patency rates were 97.8% in the MTS group, 85.7% in PTS, and 85.2% for the acute DVT group. Stent restenosis or occlusion occurred in one patient with MTS (2.2%), seven patients with PTS (14%), and nine patients with acute DVT (15%). An ipsilateral DVT recurred in 7 patients with PTS (14%) and 15 patients with acute DVT (25%). The stents that occluded had a tendency toward longer length (162.2 vs 125.2 mm; P = NS) and extension into the common femoral vein (18.8 vs 5.3%; P = NS). The patent stent group had statistically larger nominal diameter stents (P = .013). The duration of anticoagulation did not seem to be a significant factor in stent patency.

CONCLUSIONS

Stent diameter has a significant influence on iliocaval stent patency rates.

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.

Inferior Vena Cava Reconstruction in Symptomatic Patients Using Palmaz Stents: A Retrospective Single-Center Experience

BACKGROUND

The use of stents for treating central venous occlusion is well described. Limited evidence exists related to Palmaz balloon-expandable stent use in inferior vena cava (IVC) reconstruction. We analyzed patency and complication rates after IVC reconstruction using Palmaz stents.

METHODS

From 2002 to 2019, 37 patients (mean age: 51 year) underwent IVC reconstruction with 68 Palmaz stents. Indications were symptomatic chronic venous obstruction in the infrarenal (n = 25) and intrahepatic (n = 12) IVC. Demographic, operative, and imaging data were evaluated. Clinical data, abdominal CT, and/or duplex ultrasound were used to determine patency at follow-up.

RESULTS

Restoration of caval patency was achieved in all patients, with complications in 2/37 (5.4%) patients (thrombus formation within the stent; stent embolization eight days after placement). Follow-up data were available for 27 patients. Primary patency was maintained through last follow-up in 19/27 (70%) patients (mean: 1.1 year), with successful stent redilation performed in 6 patients. Mean duration of primary-assisted patency (n = 5) was 1.2 year. Late lumen loss was (n = 13) was 40% during a mean time to follow-up of 2.0 years. Primary patency in patients with occlusion secondary to malignancy was 109 day (range: 1 day-1.0 year), whereas primary patency in patients with occlusion from other etiologies was 1.1 year (range: 2 day-5.9 year). The Kaplan-Meier analysis demonstrated primary and primary-assisted patency of 66% and 84%, respectively, at 24 and 48 months.

CONCLUSIONS

Palmaz balloon-expandable stents for IVC reconstruction is feasible and effective for symptomatic IVC occlusion. Risk of stent migration was low.

Endovenous Intervention of May-Thurner Syndrome with Thrombus beyond Iliac Vein Stenosis

Purpose

With the increase in the incidence of venous thrombosis, interest in May-Thurner syndrome (MTS) accompanying iliac vein compression has increased. Some patients with MTS have inferior vena cava thrombosis or thrombosis beyond iliac vein stenosis (TBIVS). This study aimed to identify the characteristics of MTS with TBIVS including pulmonary embolism (PE) and post-thrombotic syndrome (PTS) compared to those of MTS without TBIVS.

Materials and Methods

Thirty-five patients with deep vein thrombosis associated with MTS were treated between March 2012 and February 2016. Demographic data, medical history, computed tomography findings (iliac vein size of stenosis and stenotic ratio compared with the other side), and clinical outcomes (preoperative PE and PTS) were retrospectively collected and reviewed by dividing into groups with or without TBIVS.

Results

Eight of the 35 patients with MTS had TBIVS. The group with TBIVS had a statistically significantly greater iliac vein size (P<0.001) and ratio (P=0.001). PE was more prevalent in the group with TBIVS (63% vs. 15%, P=0.007). However, no statistically significant intergroup difference in PTS prevalence was found.

Conclusion

The presence of mild iliac vein stenosis in MTS can be used to predict TBIVS and the requirement for more attention to PE.

Outcomes and predictors of failure of iliac vein stenting after catheter-directed thrombolysis for acute iliofemoral thrombosis

OBJECTIVE

Iliac vein stenting is recommended to treat venous outflow obstruction after catheter-directed thrombolysis for acute iliofemoral deep venous thrombosis (DVT). Data on the outcome of proximal and distal stent extension are limited. Proximal stent extension to the vena cava may obstruct the contralateral iliac vein, whereas distal extension below the inguinal ligament contradicts common practice for arterial stents. The aim of this retrospective study was to assess outcomes and predictors of failure of iliac vein stents and contralateral iliac vein thrombosis, taking into consideration stent positioning.

METHODS

Consecutive patients who underwent thrombolysis and stenting for DVT between May 2007 and September 2017 were identified from a prospectively maintained database. The intraoperative venograms were reviewed for proximal stent placement (covering >50% contralateral iliac vein orifice) and distal placement across the inguinal ligament. End points were ipsilateral DVT recurrence, post-thrombotic syndrome (PTS; Villalta score ≥5), and contralateral DVT. Patients with chronic contralateral DVT or contralateral iliac vein stenting at baseline were excluded from the contralateral DVT outcome evaluation. Survival analysis and Cox regression models were used to determine outcomes.

RESULTS

Of 142 patients lysed, 73 patients (12 bilateral DVTs; mean age, 45.8 ± 17.2 years; 46 female patients) were treated with various combinations of thrombolytic techniques and at least one self-expanding iliac stent (77 stented limbs). Thirty-day recurrence developed in nine (12.3%) patients. The 3-year primary patency and secondary patency rates were 75.2% and 82.2%, respectively. The single predictor for loss of primary patency was incomplete thrombolysis (≤50%; hazard ratio [HR], 7.41; P = .002). Overall, 3 of 12 (25%) stents extending below the inguinal ligament occluded at 1 month, 2 months, and 9 months, respectively. The overall rate of PTS (Villalta score ≥5) in the stented cohort was 14.4% at 5 years. This was predicted by incomplete lysis (<50%; HR, 7.09; P = .040), stent extension below the inguinal ligament (HR, 6.68; P = .026), and male sex (HR, 6.02; P = .041). Of the 17 stents that extended into the contralateral common iliac vein and 58 stents that did not, there were 1 (5.9%) and 5 (8.6%) contralateral DVTs (P = .588) at an average follow-up of 27.4 ± 33.7 and 22.2 ± 22.3 months (P = .552), respectively.

CONCLUSIONS

Iliac stenting after thrombolysis for acute DVT guarantees high patency and low PTS rates, provided adequate thrombus resolution has been achieved before stent placement. Stent placement below the inguinal ligament does not affect the patency but may be associated with a higher PTS rate. Stenting proximal to the iliocaval confluence, although a precipitating factor, may not independently increase the likelihood of contralateral DVT.

Characteristics and outcomes of stent occlusion after iliocaval stenting

OBJECTIVE

With increasing use of iliocaval stenting, complications have become more noticeable. Stent occlusion is one such outcome that has not been studied in detail. Characteristics of stent occlusion in addition to outcomes after recanalization are presented.

METHODS

An analysis of 3468 initial iliocaval stents placed during an 18-year period from 1997 to 2015 was performed. A total of 102 stent occlusions were identified, amounting to a 3% stent occlusion rate. Characteristics evaluated included onset after stent placement, techniques used for restoring patency, and their outcome. Kaplan-Meier analysis was used to assess stent patency. Regression analysis was used to evaluate risk factors for stent occlusion.

RESULTS

Stent occlusions occurred at a median of 5.8 months after placement. The occluded stent could be reopened after a wide range of intervals, the longest being 14 years. The majority (69%) of occlusions were chronic (>30 days) and the remainder (31%) were acute; 77% of the occlusions occurred in post-thrombotic limbs. The most common technique used to recanalize the acutely occluded stent was pharmacomechanical thrombectomy, whereas wire recanalization with balloon angioplasty was the technique most used for chronic occlusions. Of the 102 occluded stents, patency was achieved in 75 of 88 (84%) attempts. After successful recanalization, the median primary patency was 7 ± 1.9 months, median primary assisted patency was 7.5 ± 3.5 months, and median secondary patency was 25 ± 8.3 months. Clinically, there was improvement in the visual analog scale pain scores from a median of 3.5 to 1 (P < .01), in the median grade of swelling from 2 to 1 (P < .01), and in the mean Venous Clinical Severity Score from 6.4 to 3.8 (P < .01) after recanalization. A 40% ulcer healing rate was noted after recanalization during a median follow-up period of 17 months. There were no significant adverse events or mortality. Regression analysis revealed stent placement for native vein occlusion as the only statistically significant predictor of stent occlusion.

CONCLUSIONS

Stent occlusion after iliocaval stenting is a rare occurrence. Recanalization of occluded stents can be performed with minimal morbidity even months to years after occlusion with good outcomes. Long-term patency of occluded stents that were recanalized is poor compared with patency of the initially placed stent.

Long-term follow-up of the stenting across the iliocaval confluence in patients with iliac venous lesions

Stent implantation is the common treatment method for iliac vein (IV) occlusion. IV stents usually enter into the inferior vena cava (IVC) to partially or completely cover the contralateral IV, but it is still uncertain whether this can increase the risk of thrombosis in the contralateral IV. The purpose of this study was to investigate the effect of the stent position on the bilateral IVs patency. A total of 261 patients with symptomatic IV lesions, including 177 patients with non-thrombotic iliac vein lesions (NIVLs) and 84 patients with thrombotic iliac vein lesions (TIVLs), were implanted with IV stents between July 2007 and June 2017. The data of these patients were retrospectively studied. The follow-up time was 6-114 months, and the median time was 62 months. A total of 183 cases had stenting into the IVC for more than 5 mm. The incidence of thrombosis in the contralateral IV was only 0.55% (1/183). A total of 17 short- and long-term cumulative cases had ipsilateral thrombosis on the stent side. There was no significant difference between the incidence of patients (8.79%, 7/78) with stenting into the IVC for less than 5 mm and those with more than 5 mm (5.46%, 10/183, P = 0.287). However, in the TIVLs group, the incidence of ipsilateral thrombosis between stenting positions less than 5 mm (29.6%, 8/27) and those more than 5 mm (8.77%, 5/57) was significantly different (P = 0.022). Stent implantation for NIVLs had an excellent long-term patency rate; the primary patency rate and the assisted primary patency rate were 97.7% and 100%, respectively. The entry of IV stents into the IVC was safe and had a very low incidence of thrombosis in the contralateral vein. Stenting less into the IVC increased the incidence of thrombosis in the ipsilateral vein, especially among thrombotic cases. Treatment of NIVLs using stent implantation had a better long-term patency rate. This principle plays an important guiding role in the endovascular therapy of IV lesions.

Endovascular iliocaval reconstruction for the treatment of iliocaval thrombosis: From imaging to intervention

Thrombosis of the inferior vena cava and iliac veins, known as iliocaval thrombosis, is a common cause of significant morbidity. Patients with chronic iliocaval obstruction often present with life-limiting occlusive symptoms secondary to recurrent lower extremity deep venous thrombosis, swelling, pain, venous stasis ulcers, or phlegmasia. Endovascular iliocaval reconstruction is a technically successful procedure that results in favorable clinical outcomes and stent patency rates with few complications and is often able to relieve debilitating symptoms in affected patients. This review presents an approach to endovascular iliocaval stent reconstruction in patients suffering from chronic iliocaval thrombosis, including background, patient selection, timing of intervention, procedural steps, technical considerations, patient follow-up, and a brief review of outcomes. Schematic illustrations and clinical cases outlining iliocaval stent reconstruction and crossing chronic venous occlusions have been provided.

The Treatment of Post-Thrombotic Syndrome

BACKGROUND

Post-thrombotic syndrome (PTS) arises in 20-50% of patients who have sustained a deep vein thrombosis and markedly impairs their quality of life.

METHODS

This review is based on pertinent publications retrieved by a selective literature search in PubMed and the Cochrane Library, and on the guidelines of the German Societies of Phlebology and Vascular Surgery (Deutsche Gesellschaft für Phlebologie, Deutsche Gesellschaft für Gefässchirurgie).

RESULTS

The treatment options are conservative treatment with compression and patient exercises, endovascular recanalization with stent angioplasty, and open bypass surgery of the iliac obstructions. The endovascular techniques yield patency rates of 73 to 100%, with thrombotic stent occlusion and hematoma as potential complications. The open operations have only been documented in studies with small case numbers (3 to 85 cases per study, patency rates 58 to 100%). The complications of these invasive procedures can include thrombotic bypass occlusion, hematoma, and wound infection. There have been randomized trials of conservative treatment, but not of surgical treatment. The American Heart Association, in its guidelines, gives the same weak recommendation for all surgical methods (IIb).

CONCLUSION

All conservative options should be exhausted as the first line of treatment. If PTS symptoms persist and markedly impair the patient's quality of life, the possible indication for surgery should be considered. As PTS hardly ever leads to death or limb loss, its treatment should be as uninvasive as possible. Endovascular recanalization is an attractive option in this respect. A conclusive evaluation of the role of endovascular procedures in PTS must await randomized trials of this form of treatment and of the optimal stent configuration.

Investigation of adverse events associated with an off-label use of arterial stents and CE-marked iliac vein stents in the iliac vein: insights into developing a better iliac vein stent

We analyzed the adverse events associated with an off-label use of arterial stents and CE-marked iliac vein stents for the treatment of iliac venous thromboembolism and investigated their relationships with the anatomical features of the iliac vein, to gain insights into the development of a better iliac vein stent. Reports of adverse events following the use of stents in the iliac vein were retrieved from the Manufacturer and User Facility Device Experience (MAUDE) database that contain suspected device-associated complications reported to the Food and Drug Administration. Data from 2006 to 2016 were investigated. The literature analysis was also conducted using PubMed, Cochrane Library, EMBASE, and Web of Science focusing on English articles published up to 4 October 2016. The analysis of 88 adverse events from the MAUDE database and 182 articles from the literature revealed that a higher number of adverse events had been reported following the use of arterial stents in the iliac vein compared to CE-marked iliac vein stents. While stent migration and shortening were reported only for the arterial stents, stent fracture and compression occurred regardless of the stent type, even though a vein does not pulsate. A study of the anatomical features of the iliac vein implies that bending, compression, and kink loads are applied to the iliac vein stents in vivo. For designing, developing, and pre-clinical testing of stents intended for use in the iliac vein, the above mechanical load environments induced by the anatomical features should be considered.

Detecting stent geometry changes after venous recanalization using duplex ultrasound

Background

Patients with post-thrombotic syndrome due to chronic venous obstruction and resistant to conservative management can benefit from endovenous revascularization. The current study investigated the usefulness of duplex ultrasound in monitoring the stent changes over the time.

Method

All duplex ultrasound images of treated patients were reviewed retrospectively. The stent diameter and area during the follow-up visits have been analyzed.

Result

A total of 210 stents were placed in 137 limbs. Duplex ultrasound findings showed a decrease in area of stent in all patients (mean: 0.69 cm2). Reduction of stent area over the time was a predictor of stent patency (odds ratio: 0.910; confidence interval: 0.832–0.997).

Conclusion

Duplex ultrasound has sufficient accuracy in detection of stent changes and its patency. There is a discrepancy between diameter of the stent lumen in vitro and after deployment in all patients. Stent occlusion is related to reduction of stent lumen over the time rather than the percent of the stenosis.

How We Manage Pediatric Deep Venous Thrombosis

Over the past two decades, the incidence and recognition of venous thromboembolism (VTE) in children has significantly increased, likely as a result of improvements in the medical care of critically ill patients and increased awareness of thrombotic complications among medical providers. Current recommendations for the management of VTE in children are largely based on data from pediatric registries and observational studies, or extrapolated from adult data. The scarcity of high-quality evidence-based recommendations has resulted in marked variations in the management of pediatric VTE among providers. The purpose of this article is to summarize our institutional approach for the management of VTE in children based on available evidence, guidelines, and clinical practice considerations. Therapeutic strategies reviewed in this article include the use of conventional anticoagulants, parenteral targeted anticoagulants, new direct oral anticoagulants, thrombolysis, and mechanical approaches for the management of pediatric VTE.

Diagnosis and Treatment of Lower Extremity Deep Vein Thrombosis: Korean Practice Guidelines

Lower extremity deep vein thrombosis is a serious medical condition that can result in death or major disability due to pulmonary embolism or post-thrombotic syndrome. Appropriate diagnosis and treatment are required to improve symptoms and salvage the affected limb. Early thrombus clearance rapidly resolves symptoms related to venous obstruction, restores valve function and reduces the incidence of post-thrombotic syndrome. Recently, endovascular treatment has been established as a standard method for early thrombus removal. However, there are a variety of views regarding the indications and procedures among medical institutions and operators. Therefore, we intend to provide evidence-based guidelines for diagnosis and treatment of lower extremity deep vein thrombosis by multidisciplinary consensus. These guidelines are the result of a close collaboration between interventional radiologists and vascular surgeons. The goals of these guidelines are to improve treatment, to serve as a guide to the clinician, and consequently to contribute to public health care.

Iliac vein compression syndrome: Clinical, imaging and pathologic findings

May-Thurner syndrome (MTS) is the pathologic compression of the left common iliac vein by the right common iliac artery, resulting in left lower extremity pain, swelling, and deep venous thrombosis. Though this syndrome was first described in 1851, there are currently no standardized criteria to establish the diagnosis of MTS. Since MTS is treated by a wide array of specialties, including interventional radiology, vascular surgery, cardiology, and vascular medicine, the need for an established diagnostic criterion is imperative in order to reduce misdiagnosis and inappropriate treatment. Although MTS has historically been diagnosed by the presence of pathologic features, the use of dynamic imaging techniques has led to a more radiologic based diagnosis. Thus, imaging plays an integral part in screening patients for MTS, and the utility of a wide array of imaging modalities has been evaluated. Here, we summarize the historical aspects of the clinical features of this syndrome. We then provide a comprehensive assessment of the literature on the efficacy of imaging tools available to diagnose MTS. Lastly, we provide clinical pearls and recommendations to aid physicians in diagnosing the syndrome through the use of provocative measures.

Thrombolysis and iliofemoral vein stent placement in cancer patients with lower extremity swelling attributed to lymphedema

PURPOSE

To assess the effects of iliofemoral vein stent placement on symptomatic lower extremity swelling (LES), presumed to be lymphedema, in patients with cancer.

MATERIALS AND METHODS

During the period 2005-2013, 62 patients (38 female; age, 60.4 y ± 15.4) with histology-proven metastatic disease and LES resistant to standard therapies were evaluated and found to have venous outflow obstruction. Stents were placed in the iliofemoral veins or inferior vena cava, or both, and evaluated by color Doppler ultrasound or contrast-enhanced computed tomography during the follow-up period. Patient symptoms were assessed using the Venous Disability Score (VDS) and the Galway Limb Swelling score, a patient-directed, 5-question symptom scoring system.

RESULTS

Stents were successfully placed in all patients. During the follow-up period, in-stent thrombosis occurred in 13 patients, and additional stents were placed in 3 patients to treat luminal narrowing. The mean VDS improved significantly (P < .05): from 3.0 ± 0 on the day of the procedure to 2.95 ± 0.22 on day 3, 2.0 ± 0.33 on day 7, and 1.87 ± 0.34 on day 30. The mean Galway Limb Swelling score also improved significantly (P < 0.001): from 3.6 ± 0.74 on the day of the procedure to 1.96 ± 0.91 on day 3, 1.06 ± 0.78 on day 7, and 0.6 ± 0.66 on day 30. During the follow-up period, 60 patients died as a result of their underlying malignancy (mean, 230 d; range, 5-1,080 d).

CONCLUSIONS

Iliofemoral or iliocaval venous stent placement may have a valuable role in patients with metastatic disease and symptomatic LES associated with venous obstruction.

Combination of factor Xa inhibition and antiplatelet therapy after stenting in patients with iliofemoral post-thrombotic venous obstruction

OBJECTIVES

Studies addressing optimal postprocedural pharmacological management after endovascular stenting of iliofemoral post-thrombotic venous obstruction are lacking. We report our early clinical experience with a combination of rivaroxaban and clopidogrel in patients after iliofemoral post-thrombotic venous obstruction stenting.

METHODS

Demographic, procedural, and follow-up data of nine patients (seven women; mean age of 32 ± 11 years) undergoing 10 procedures for iliofemoral post-thrombotic venous obstruction performed between August 2012 and January 2014 were retrospectively reviewed. After endovascular intervention, all patients were administered 20 mg rivaroxaban once daily (s.i.d.) and 75 mg clopidogrel s.i.d. or every second day depending on the individual drug responsiveness for at least six months. The adenosine diphosphate-induced platelet aggregation (platelet aggregation, in aggregation units × min) was assessed on a Multiplate analyzer. Patency was verified venographically at procedure end and was evaluated with duplex ultrasound in regular follow-ups.

RESULTS

Iliofemoral venous flow was successfully re-established by percutaneous endovascular angioplasty and stent implantation in nine left-sided and one bilateral iliofemoral post-thrombotic venous obstruction. Under dual treatment strategy of rivaroxaban and clopidogrel with platelet aggregation control (median (range): 285 aggregation units × min (192; 402)), none of the patients experienced restenosis or stent thrombosis, respectively. After a median follow-up of 14 months (range: 6-26 months), the primary patency rate was 100% and no in-stent restenosis, stent occlusion or relevant minor or major bleeding occurred.

CONCLUSION

Combined factor Xa inhibition and tailored antiplatelet therapy after stenting of iliofemoral post-thrombotic venous obstruction were safe and performed favorably in terms of vessel patency.

Stent Compression in Iliac Vein Compression Syndrome Associated with Acute Ilio-Femoral Deep Vein Thrombosis

OBJECTIVE

This study was conducted to evaluate stent compression in iliac vein compression syndrome (IVCS) and to identify its association with stent patency.

MATERIALS AND METHODS

Between May 2005 and June 2014, after stent placement for the treatment of IVCS with acute ilio-femoral deep vein thrombosis, follow-up CT venography was performed in 48 patients (35 women, 13 men; age range 23-87 years; median age 56 years). Using follow-up CT venography, the degree of the stent compression was calculated and used to divide patients into two groups. Possible factors associated with stent compression and patency were evaluated. The cumulative degree of stent compression and patency rate were analyzed.

RESULTS

All of the stents used were laser-cut nitinol stents. The proportion of limbs showing significant stent compression was 33%. Fifty-six percent of limbs in the significant stent compression group developed stent occlusion. On the other hand, only 9% of limbs in the insignificant stent compression group developed stent occlusion. Significant stent compression was inversely correlated with stent patency (p < 0.001). The median patency period evaluated with Kaplan-Meier analysis was 20.0 months for patients with significant stent compression. Other factors including gender, age, and type of stent were not correlated with stent patency. Significant stent compression occurred most frequently (87.5%) at the upper end of the stent (ilio-caval junction).

CONCLUSION

Significant compression of nitinol stents placed in IVCS highly affects stent patency. Therefore, in order to prevent stent compression in IVCS, nitinol stents with higher radial resistive force may be required.

Iliocaval Confluence Stenting for Chronic Venous Obstructions

PURPOSE

Different techniques have been described for stenting of venous obstructions. We report our experience with two different confluence stenting techniques to treat chronic bi-iliocaval obstructions.

MATERIALS AND METHODS

Between 11/2009 and 08/2014 we treated 40 patients for chronic total bi-iliocaval obstructions. Pre-operative magnetic resonance venography showed bilateral extensive post-thrombotic scarring in common and external iliac veins as well as obstruction of the inferior vena cava (IVC). Stenting of the IVC was performed with large self-expandable stents down to the level of the iliocaval confluence. To bridge the confluence, either self-expandable stents were placed inside the IVC stent (24 patients, SECS group) or high radial force balloon-expandable stents were placed at the same level (16 patients, BECS group). In both cases, bilateral iliac extensions were performed using nitinol stents.

RESULTS

Recanalization was achieved for all patients. In 15 (38 %) patients, a hybrid procedure with endophlebectomy and arteriovenous fistula creation needed to be performed because of significant involvement of inflow vessels below the inguinal ligament. Mean follow-up was 443 ± 438 days (range 7-1683 days). For all patients, primary, assisted-primary, and secondary patency rate at 36 months were 70, 73, and 78 %, respectively. Twelve-month patency rates in the SECS group were 85, 85, and 95 % for primary, assisted-primary, and secondary patency. In the BECS group, primary patency was 100 % during a mean follow-up period of 134 ± 118 (range 29-337) days.

CONCLUSION

Stenting of chronic bi-iliocaval obstruction shows relatively high patency rates at medium follow-up. Short-term patency seems to favor confluence stenting with balloon-expandable stents.