The incidence of contralateral iliac venous thrombosis after stenting across the iliocaval confluence in patients with acute or chronic venous outflow obstruction

In vivo evaluation of safety and performance of a tapered nitinol venous stent with inclined proximal end in an ovine iliac venous model

A tapered stent with inclined proximal end is designed for fitting the iliac anatomically. The aim of the present study was to evaluate the safety and performance of the new stent in ovine left iliac veins. The experiment was performed in 30 adult sheep, and one nitinol-based VENA-BT® iliac venous stent (KYD stent) was implanted into each animal's left common iliac vein. Follow-up in all sheep consisted of angiographic, macroscopic, and microscopic examinations at Day 0 (< 24 h), Day 30, Day 90, Day 180 and Day 360 post-stenting (six animals per each time-point). 30 healthy ~ 50 kg sheep were included in this study and randomly divided into five groups according to the follow-up timepoint. All stents were implanted successfully into the left ovine common iliac vein. No significant migration occurred at follow-up. There is no statistically significant difference between the groups (p > 0.05), indicating no serious lumen loss occurred during the follow-up period. Common iliac venous pressure was further measured and the results further indicated the lumen patency at follow-up. Histological examinations indicated that no vessel injury and wall rupture, stent damage, and luminal thrombus occurred. There was moderate inflammatory cell infiltration around the stent in Day-0 and Day-30 groups with the average inflammation score of 2.278 and 2.167, respectively. The inflammatory reaction was significantly reduced in Day-90, Day-180 and Day-360 groups and the average inflammation scores were 0.9444 (p < 0.001, Day-90 vs Day-0), 1.167 (p < 0.001, Day-180 vs Day-0) and 0.667 (p < 0.001, Day-90 vs Day-0), respectively. The microscopic examinations found that the stents were well covered by endothelial cells in all follow-up time points. The results suggested that the KYD stent is feasible and safe in animal model. Future clinical studies may be required to further evaluate its safety and efficacy.

Deep venous thrombosis of the contralateral iliac vein after stenting of the iliocaval confluence: a therapeutic challenge

The treatment of choice for patients with symptomatic venous compression syndrome is venous stenting. However, this treatment has well-documented complications and, although rare, contralateral deep venous thrombosis is one of these complications. Our objective is to present a case of deep venous thrombosis of the contralateral iliac vein resulting from placement of the stent beyond the recommended position and the therapeutic challenge is to recanalize the vein with reconstruction of the iliocaval confluence.

The incidence, risk factors, characteristics, and prognosis of recurrent deep venous thrombosis in the contralateral lower extremity

BACKGROUND

Recurrent events after a first symptomatic deep venous thrombosis (DVT) are relatively frequent, but little is known about contralateral recurrent DVT (RDVT).

METHODS

We retrospectively reviewed the medical records of patients with a first symptomatic lower extremity DVT between January 2017 and April 2021. The incidence, demographics, risk factors, and prognosis of RDVT were analyzed, with differences compared between patients with contralateral RDVT and those with ipsilateral RDVT.

RESULTS

In 570 consecutive patients with DVT, 28 patients (4.91%) developed contralateral RDVT, and 49 patients (8.60%) developed ipsilateral RDVT during a mean follow-up of 27.62 ± 14.84 months. Contralateral RDVT was more frequently found in the right lower extremity, whereas ipsilateral RDVT had more left lower extremity involvement. The median follow-up was 12 months until ipsilateral RDVT and 26.5 months until contralateral RDVT. In multivariate Cox analysis, inherited thrombophilia, stent extension with 50% to 100% coverage, autoimmune disease and anticoagulation noncompliance were identified as risk factors for contralateral RDVT. During follow-up, 5 patients (17.86%) with contralateral RDVT and 10 patients (20.41%) with ipsilateral RDVT died (P > .05), with 12 of 15 dying of an underlying malignancy.

CONCLUSIONS

The incidence of contralateral RDVT after a first symptomatic DVT is relatively low, and contralateral DVT is strongly associated with stent extension with 50% to 100% coverage, autoimmune disease, anticoagulation noncompliance, and inherited thrombophilia. Compared with ipsilateral RDVT, contralateral RDVT occurs later and is more often in the right lower extremity. Survival following contralateral RDVT is similar to survival following ipsilateral RDVT, with underlying malignancy being the leading cause of death.

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.

Endovascular Treatment for Lower Extremity Deep Vein Thrombosis: An Overview

Lower extremity deep vein thrombosis (DVT) is a serious medical condition that can result in local pain and gait disturbance. DVT progression can also lead to death or major disability as a result of pulmonary embolism, postthrombotic syndrome, or limb amputation. However, early thrombus removal can rapidly relieve symptoms and prevent disease progression. Various endovascular procedures have been developed in the recent years to treat DVT, and endovascular treatment has been established as one of the major therapeutic methods to treat lower extremity DVT. However, the treatment of lower extremity DVT varies according to the disease duration, location of affected vessels, and the presence of symptoms. This article reviews and discusses effective endovascular treatment methods for lower extremity DVT.

PERFORMANCE TEST AND EXPERIMENTAL STUDY OF SPECIAL STENT FOR TREATMENT OF ILIAC VEIN STENOSIS

Objective: Animal experiments and clinical trials were carried out to evaluate the efficiency of a new stent for the treatment of iliac vein stenosis. Methods: The new iliac vein stent and the control stent were implanted, respectively, into the 12 experimental pigs. Digital Subtraction Angiography was done separately at the same day, 14th, 30th, 60th and 90th day after stent implantation to observe the stent deployment. One patient was implanted with a new iliac vein stent. Digital subtraction angiography (DSA) was done after the operation to calculate the lumen loss value and lumen loss rate of the stent and evaluate the performance of the new iliac vein stent at 12 months of follow-up. Results: The mechanical experiment and finite element analysis of the stent proved that the radial support force of the new stent is significantly better than that of the control stent. In animal experimental verification, both groups of stent were released satisfactorily during implantation. No obvious stent displacement was found at each time point. The patency rate of stents was 100%. Except for a small amount of old thrombosis in the stent in the control group, no other stents were found in that condition. The diameter of the stent lumen was retracted in different degrees in both groups after the operation, but no significant statistical difference was found in the comparison of the stent lumen loss rate at each relative inspection day. Conclusion: The new nickel-titanium alloy iliac vein stent has excellent radial support performance, which may be an ideal iliac vein stent.

Best practices in diagnosis and treatment of chronic iliac vein obstruction

Iliac vein obstruction occurs in 20-30% of the general population. In patients with severe chronic venous insufficiency, this prevalence can be even higher, reaching 50-90% when the obstruction is investigated using intravascular ultrasound. Less invasive methods, such as venous Duplex Scanning, and even invasive ones such as venography may fail to diagnose the condition. Endovascular treatment of these obstructions is effective, safe, and associated with excellent clinical outcomes and stent patency rates, provided that fundamental anatomical and technical principles are considered and applied.

Contralateral deep vein thrombosis after stenting across the iliocaval confluence in chronic venous disease – A systematic review

Objective

Stenting of the iliac veins is increasingly considered in the presence of symptomatic obstructive chronic lesions in the iliac vein segment. However, it is often necessary to extend the stented zone into the inferior vena cava, increasing the risk of contralateral iliac vein thrombosis. This study aims to review the current literature concerning the incidence of contralateral deep vein thrombosis after stenting across the iliocaval confluence.

Methods

A systematic review from potentially relevant published articles reporting contralateral deep vein thrombosis after iliac venous stenting between January 2007 and February 2019 was performed.

Results

A total of 764 references were retrieved initially. Twelve studies reporting events of contralateral deep vein thrombosis were selected for review, with a total of 1864 patients. Contralateral deep vein thrombosis incidence varied between 0% and 15.6%. The post-interventional and follow-up anticoagulation regimens were heterogeneous between studies. The decision to maintain patients on anticoagulation and the duration of treatment was based on the presence of comorbidities, hypercoagulable states, post-thrombotic syndrome and history of recurrent deep vein thrombosis. Patients with non-thrombotic iliac vein lesions were either anticoagulated for three or six months after stenting or received no anticoagulation. Patients with post-thrombotic syndrome were anticoagulated for longer periods. Most studies (eight studies) used an oral vitamin K antagonist agent. The data on compliance with anticoagulation treatment is scarce and few references present data on whether contralateral deep vein thrombosis occurred during anticoagulation treatment. The use of antiplatelet agents in addition to the anticoagulant treatment in the follow-up period was also variable.

Conclusion

The incidence of contralateral deep vein thrombosis due to iliac vein jailing is not negligible and reported being as high as 15.6%. Large-scale studies on the ideal antithrombotic treatment and its impact are necessary. It is possible that patients with stent crossing the iliocaval confluence might benefit from long-term antithrombotic treatment.

Aiming for the Bottom Corner: How to Score a Field Goal When Landing Venous Stents in May-Thurner Syndrome

PURPOSE

To report an iliac venous stent landing technique using only fluoroscopy in patients with May-Thurner syndrome (MTS).

MATERIAL AND METHODS

Sixty-five patients (69% female) who had self-expanding nitinol stents deployed for symptomatic MTS were retrospectively analyzed. Mean age was 50 years (range 18-80). The cephalic stent right lower corner was deployed to the right of the lumbar vertebra spinous process (SP), but not as far to the right as the right pedicle lateral border. Mode stent diameter and length were 14 mm (range 12-18) and 120 cm (range 60-180), determined by venography, respectively. The anatomical positions of the right common iliac artery, inferior vena cava (IVC), and stent were assessed relative to these bony landmarks on computed tomography venography.

RESULTS

Position of the proximal right common iliac artery right lateral border lay a mean distance of 12 mm (±8 to the right of the SP and 13 mm (±7) left of the right pedicle lateral border. Mean position of the IVC right lateral wall lay 1 mm (±6) to the right of the right pedicle lateral border. Mean position of the cephalic stent right lower corner was 6 mm (±6) to the left of the right pedicle lateral border and 19 mm (±7) to the right of the SP. The mean space left between the cephalic stent right lower corner and the IVC right lateral wall was 5 mm (±5). Primary patency rate at 1 year was 88%.

CONCLUSIONS

Important vascular structures lie in predictable locations relative to bony landmarks, facilitating accurate venous stent placement using fluoroscopy only.

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.

Endovascular Treatment for Iliofemoral Vein Thrombosis with Composite Stents

BACKGROUND

To evaluate the applicability of endovascular treatment for iliofemoral vein thrombosis with composite stents.

METHODS

Between September 2013 and August 2016, 29 consecutive patients underwent endovascular therapy with composite stents for iliofemoral vein thrombosis and were followed up at our institution. All the patients with acute or chronic iliofemoral vein thrombosis enrolled in this study were evaluated by color Doppler ultrasonography and diagnosed by venography. Treatment measures and related complications were recorded, and cumulative stent patency was assessed with Kaplan-Meier curves.

RESULTS

Patients with acute iliofemoral vein thrombosis (n = 7) were successfully treated with catheter-directed thrombolysis treatment, balloon angioplasty, and stents, whereas patients (n =  = 22) with chronic deep vein thrombosis were treated successfully by balloon angioplasty and stent only. Among all patients, 2 stents were inserted in 25 patients, whereas 3 stents were deployed in 4 patients. Endovascular treatment for iliofemoral vein thrombosis with laser-cut stents combined with Wallstents showed primary patency of treated limbs at 6, 12, and 24 months was 96.6%, 93.1% and 93.1%, respectively. Mean duration of follow-up was 23 months, and there was no occurrence of contralateral vein thrombosis during follow-up by ultrasound.

CONCLUSIONS

Iliofemoral vein thrombosis was successfully recanalized by endovascular therapy with composite stents, and there was no occurrence of contralateral vein thrombosis by ultrasound during follow-up.

Novel Compliant Scaffold with Specific Design for Venous System: Results of a Porcine Model Study

Background

Stenting has become the first-line treatment of obstructive venous disease because of poor results of balloon angioplasty. This preclinical study aimed to investigate the safety and efficacy profile of a novel compliant venous scaffold (CVS) denominated Petalo CVS, specifically designed for venous diseases.

Materials and Methods

Twelve healthy pigs weighing 90 kg were used to test Petalo CVS. The devices were implanted into the internal jugular veins (IJVs) using a femoral vein percutaneous approach. The safety profile including the success rate of device releasing, anchoring, and positioning was evaluated immediately. Fracture, migration, primary patency, and endothelial response were assessed at 1, 2, 3, and 6 months after the study procedure.

Results

A total of 32 devices were successfully released in both IJVs. No procedure- or device-related complications were reported, and all pigs successfully completed the different scheduled follow-up periods. The primary patency rate was 100%, and no fracture or migration of the device into the brachiocephalic trunk was reported. Histological examination revealed only minimal lesions with minimal or absent inflammatory reaction surrounding the incorporated metallic rods.

Conclusions

This porcine model study showed a promising safety and efficacy profile of Petalo CVS, a novel endovenous device based on specific concepts.

Patency rates and clinical outcomes in a cohort of 200 patients treated with a dedicated venous stent

OBJECTIVE

Minimally invasive interventions by recanalization, percutaneous transluminal angioplasty, and stenting in post-thrombotic syndrome (PTS) obstructions and iliac vein compression syndrome (IVCS) have shown good results. Until recently, no dedicated venous stents were available, and stent-related issues accounted for a decrease in patency scores. The introduction of dedicated stents with more flexibility and higher radial forces could result in higher patency scores. This study focused on the outcomes of patients treated by a dedicated sinus-Venous stent (OptiMed GmbH, Ettlingen, Germany). Patency rates and clinical evaluation are described for both PTS and IVCS patients.

METHODS

A total of 200 patients treated at a tertiary university referral center were analyzed. A percutaneous procedure was performed in 103 (51%) PTS patients and 48 (24%) IVCS patients. In 49 (25%) patients, a hybrid procedure was executed. Patency rates and complications were analyzed by duplex ultrasound. Clinical improvement was scored by Venous Clinical Severity Score, Villalta scale, and venous claudication rates.

RESULTS

The mean age was 43.2 ± 14.5 (17-81) years, and 66% were female. Mean Villalta score decreased from 10.5 ± 4.2 (3-24) to 5.3 ± 3.8 (0-14) at the latest follow-up (P < .001). Venous Clinical Severity Score decreased by a total of 3 points (P < .001). At baseline, venous claudication was present in 132 patients, which subsided in 115 (87%). Overall patency scores revealed a primary patency of 68%, assisted primary patency of 83%, and secondary patency of 90% with a median follow-up of 12 (11-12) months. Of all included patients, 122 (61%) did not have a complication during follow-up; the most frequent complications were in-stent restenosis (n = 23) and occlusion (n = 25) of the stented tract.

CONCLUSIONS

Short-term clinical results using the sinus-Venous stent are comparable to previous research. Loss of stent patency due to stent-related issues like kinking or tapering is hardly ever seen in this short-term follow-up.

Factors Associated with Contralateral Deep Venous Thrombosis after Iliocaval Venous Stenting

BACKGROUND

The majority of iliac venous obstructions occur on the left side, and endovascular therapy has become the first line treatment for this condition. A left common iliac venous stent will protrude into the inferior vena cava (IVC) to some extent, thereby covering the contralateral common iliac vein (CIV) outflow. This may increase the risk of thrombosis of the contralateral iliac vein. The aim of this paper was to determine the rate of, and factors associated with, contralateral lower limb venous thrombosis after stenting, and to evaluate the results of salvage revascularisation.

METHODS

A total of 376 patients (102 from UCH, Galway, Ireland, 2008-16, and 274 from, CHU Nord, Marseille, France, 2000-15) with symptomatic acute or chronic left iliocaval venous obstruction were retrospectively evaluated. Either duplex ultrasound scanning (DUS) or computed tomographic venography (CTV) was used for pre- and post-operative imaging. Data were collected from the PACS system (IMPAX, Agfa, BE) of the Radiology Department, UCH, Galway, and from the electronic medical records of Vascular Surgery department, CHU Nord, Marseille.

RESULTS

The median age of stented patients was 46 (range 15-86 years), 80% were female (301/376). Following left CIV stent placement, 10 patients later presented with a right (contralateral) iliac deep venous thrombosis (DVT) resulting in a cumulative incidence of contralateral DVT of 4% according to Kaplan-Meier analysis. Acute DVT (p=.001), non-compliance with the prescribed 6 months anticoagulation (p = 0.05), pre-operative contralateral internal iliac vein (IIV) thrombosis (p = 0.001), and pre-existing IVC filter placement (p = 0.003) were all statistically significantly associated with contralateral DVT. All patients with symptomatic contralateral iliac DVT underwent clot removal in the acute phase. The primary patency of these limbs was 100% at 3 years.

CONCLUSION

Stent placement across the iliocaval confluence from the left CIV is associated with a low but definite rate of contralateral iliac vein thrombosis. Acute DVT, pre-operative contralateral IIV thrombosis, pre-existing IVC filters, and anticoagulation non-compliance are significant risk factors.