Iliac vein stenting and contralateral deep vein thrombosis

Embolization of a duplicated femoral vein for treatment of lower extremity deep venous insufficiency: A case report

BACKGROUND

Lower extremity deep venous insufficiency (DVI) occurs secondary to structural or functional abnormalities of deep venous valves in the affected extremities. The effectiveness of surgical treatment for improvement of the hemodynamic status in these patients remains controversial in clinical practice.

METHOD

In this case report, we describe a patient who presented with severe right lower extremity edema and liposclerosis and underwent venography, which suggested a variation in the number of femoral veins. The valve within the duplicated femoral vein was significantly incompetent; however, the valve of the main trunk of the femoral vein showed normal function. We performed embolization of the duplicated femoral vein.

RESULTS

The patient tolerated the procedure well without recurrent symptoms.

CONCLUSIONS

Individualized assessment based on venography findings is useful to establish the therapeutic approach in patients with DVI.

Treatment of Non-thrombotic Iliac Vein Stenosis: Where is the Evidence?

Non-thrombotic iliac vein lesions (NIVLs) refer to iliac vein lumen stenosis, usually secondary to extrinsic compression, without associated thrombosis. Clinical presentation varies; patients may be asymptomatic, have symptoms of lower extremity venous hypertension, or in women, may be associated with chronic pelvic pain. Given the significant variability in symptomatology, thorough history and physical examination are mandatory in excluding other causes of symptoms. Non-invasive imaging, such as venous duplex/insufficiency ultrasound examinations, and axial imaging aid in the diagnosis of a NIVL in the appropriate clinical context. Catheter venography and intravascular ultrasound remain the primary modalities for definitive diagnosis, treatment planning, and ultimately placement of self-expanding venous stents to resolve the causative iliofemoral venous obstruction. In appropriately selected patients, stent placement can lead to marked improvements in symptoms, heal stasis ulceration when present, and improve disease-specific and overall quality of life. Stents placed in patients with NIVL demonstrate high long-term primary patency. In this article, the authors discuss clinical presentation, diagnostic workup, endovascular interventions and outcomes of NIVL treatment.

May Thurner syndrome: Sixty years later

May-Thurner syndrome (MTS) was described sixty years ago. Once ignored for several years, it is currently a recognized pathology in the vascular surgery community; but not long ago due to several factors, it was underdiagnosed and sub-optimally treated. In the last 20 years, with renewed interest in venous pathology, technical imaging advances and the recent interventional procedures, it has become a better known disease. On the other hand, nowadays the easiness in diagnosis and treatment of the syndrome has lead to overtreatment of such patients. In this article, we do a historical review and describe the significant advances and current management of May-Thurner syndrome.

Nightmare after iliac vein stenting: Spinal epidural hematoma

Spinal epidural hematoma is a rare but devastating complication of iliac vein stenting. Radicular back pain during and after procedure is an alarming sign for this complication.

Treatment of Nonthrombotic Iliac Vein Lesions

Nonthrombotic iliac vein lesions (NIVLs) most frequently result from extrinsic compression of various segments of the common or external iliac vein. Patients develop symptoms associated with chronic venous insufficiency (CVI); female patients may develop symptoms of pelvic venous disease. Given that iliac vein compression can be clinically silent, a thorough history and physical examination is mandatory to exclude other causes of a patient's symptoms. Venous duplex ultrasound, insufficiency examinations, and axial imaging are most commonly used to assess for the presence of a NIVL. Catheter venography and intravascular ultrasound (IVUS) are the mainstay for invasive assessment of NIVLs and planning prior to stent placement. IVUS in particular has become the primary modality by which NIVLs are evaluated; recent evidence has clarified the lesion threshold for stent placement, which is indicated in patients with moderate to severe symptoms. In appropriately selected patients, stent placement results in improved pain, swelling, quality of life, and, when present, healing of venous stasis ulcers. Stent patency is well preserved in the majority of cases, with a low incidence of clinically driven need for reintervention. In this article, we will discuss the clinical features, workup, endovascular management, and treatment outcomes of NIVL.

Effect of Pre-Procedure Clopidogrel With Iliac Vein Stenting in Non-Thrombotic Vein Lesions

OBJECTIVES

Iliac vein stenting is a relatively new procedure in the treatment of chronic venous insufficiency. Research has shown that it is a safe and effective form of treatment, however, one of the well-known risks is in-stent thrombosis. We hypothesize that a single 75 mg dose of Clopidogrel the night prior to the procedures along with a 3-month regimen post-op would decrease the 30-day thrombosis rate.

METHODS

A retrospective study was performed on 3,518 patients from September 2012 to August 2018 who received an iliofemoral stent. Patients were broken down into 2 main groups: those given Clopidogrel post-stent and those given Clopidogrel both pre- and post-stent. In our practice, we prescribe a 3-month course of Clopidogrel after iliac vein stenting. Patients were also checked for any anticoagulant medications pre- and/or post-stent. The 30-day thrombosis rates were recorded for each patient.

RESULTS

1,205 patients received Clopidogrel pre-procedurally and post-procedurally, 1,941 patients received Clopidogrel only post-procedurally. 372 patients were excluded from the study because they were on other anti-coagulant medications. Mean follow-up for this cohort was 17 months. 112 total patients developed some degree of 30 day in-stent thrombosis (3.6%). 74 patients developed a complete thrombosis of the stent and 38 developed a partial (≤60% occlusion) thrombosis. Of the 1,205 patients who were on clopidogrel pre-stenting, 28 had a complete thrombosis and 10 had a partial in-stent thrombosis. Of the 1,941 patients on Clopidogrel only post-stenting, 46 had a complete thrombosis and 28 had a partial in-stent thrombosis. Using the Chi-squared test, there were no statistically significant differences between the group of patients receiving Clopidogrel pre- and post-stent vs. just post-stent with respect to 30-day any degree of thrombosis rates (complete and partial thrombosis) (p = .33). Using the Chi-squared test, there were no statistically significant differences between the group of patients receiving Clopidogrel pre- and post-stent vs. just post-stent with respect to 30-day complete thrombosis rates (p = .93).

CONCLUSIONS

There appears to be no statistical difference in 30-day thrombosis rates between those receiving Clopidogrel the night prior vs. those who do not receive Clopidogrel the night prior. Therefore, we conclude that it is not necessary to give this single dose the night prior to iliac vein stenting procedures.

A unique complication of double barrel Wallstent technique in iliac-caval stenting

The “double barrel” technique has been a popular option in reconstituting the iliac-caval confluence in bilateral stenting. It has been mostly used with the Wallstent (Boston Scientific, Marlborough, Mass). The technique, although generally trouble-free, has a unique long-term complication. One stent barrel was found to compress the other from a late developing compliance mismatch. The complication is easily missed unless an intravascular ultrasound examination is performed. A cross-fenestration between the two barrels supported by a Z stent might provide clinical relief if the double barrel extension into the vena cava is relatively short in length.

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.

Caliber-targeted reinterventional overdilation of iliac vein Wallstents

BACKGROUND

Wallstents (Boston Scientific, Marlborough, Mass) are most commonly used in iliac-caval stenting. Approximately 20% of stented limbs require reintervention to correct in-stent restenosis (ISR) or stent compression (SC). Corrective balloon dilation to rated stent caliber (isodilation) is not always successful. We investigated whether modest overdilation of the Wallstent by 2 to 4 mm (10%-20%) beyond the rated diameter would yield better mechanical clearance of ISR/SC, leading to a larger flow channel, improved conductance, reduction of peripheral venous pressure, and better clinical outcome. Outflow lumen caliber exponentially influences peripheral venous pressure, a key mechanism in chronic venous disease. Beyond the mechanical effects, the rationale for overdilation rests on the theory that an improvement in flow channel at the margins may yield an outsized pressure reduction and clinical improvement.

METHODS

There were 274 previously stented limbs that underwent reinterventional balloon dilation for clearance of ISR/SC during a recent 3-year period. Isodilation to rated diameter of the stent was judged effective in 71 limbs (isodilated subset); 203 limbs (overdilated subset) for which initial isodilation was ineffective underwent overdilation of the resident Wallstent by 2 to 4 mm (10%-20%) beyond the original rated diameter. IVUS planimetry was used intraoperatively to calculate SC and ISR and their subsequent clearance in the two subsets. The dilated segments were observed by clinical and duplex ultrasound examination afterward. The two subsets were compared in the following outcome measures: intraprocedural efficacy in clearing ISR/SC and achieving target lumen caliber, subsequent clinical outcomes, duplex ultrasound caliber durability, and improvement in supine foot venous pressures. This is a single-center retrospective analysis of data contemporaneously entered into a time stamped electronic medical record system.

RESULTS

The median follow-up was 18 months (range, 1-35 months). Overdilation of the stent resulted in significantly better intraoperative flow channel area improvement per intravascular ultrasound. This was reflected in significantly better clinical outcome and improvement in peripheral venous pressure in the overdilated subset. Overdilation appeared to be durable up to 20 months after intervention by duplex ultrasound monitoring.

CONCLUSIONS

Overdilation appears to be a useful technique to correct ISR/SC and to restore target lumen caliber during reinterventional correction of a resident iliac vein Wallstent. More durable caliber improvement, superior clinical outcome, and reduction in peripheral venous hypertension were noticed in overdilated stents compared with isodilation.

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.

Study on the Patency of the Contralateral Iliac Vein After Stenting Across the Iliocaval Confluence With an Experimental In Vivo Model

OBJECTIVE

Stenting is the preferred treatment for iliac vein lesions. For the treatment of occlusions in the junction of the iliac vein and the inferior vena cava (IVC), the stent needs to be positioned in the IVC to cover the lesion. However, the pathological changes in the contralateral iliac vein due to stent coverage on its ostium remain unclear. We observed the patency of the contralateral iliac vein via animal experiments.

METHODS

The stents were placed in the left iliac vein and extended into the IVC in 8 beagle dogs. Doppler ultrasonography, angiography, and histopathological examination were used to assess the patency and histopathological changes in the contralateral iliac vein.

RESULTS

Angiography showed patency of the contralateral iliac vein and no sign of thrombosis or stenosis. Twelve months after stenting, Doppler ultrasonography showed a stenotic change in the ostium of the contralateral iliac vein. The histopathological examination showed that the stent strut at the ostium of the contralateral iliac vein was mostly covered by the intima, and the cross-sectional stenosis rate was greater than 60%.

CONCLUSIONS

The coverage of the iliac vein stent on the ostium of the contralateral iliac vein does not cause complete occlusion of the contralateral vein but can cause significant stenosis at the ostium of the contralateral iliac vein, which is considered to be a potential risk factor for thrombosis.

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 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.

Simulation, Fabrication and Analysis of Silver Based Ascending Sinusoidal Microchannel (ASMC) for Implant of Varicose Veins

Bioengineered veins can benefit humans needing bypass surgery, dialysis, and now, in the treatment of varicose veins. The implant of this vein in varicose veins has significant advantages over the conventional treatment methods. Deep vein thrombosis (DVT), vein patch repair, pulmonary embolus, and tissue-damaging problems can be solved with this implant. Here, the authors have proposed biomedical microdevices as an alternative for varicose veins. MATLAB and ANSYS Fluent have been used for simulations of blood flow for bioengineered veins. The silver based microchannel has been fabricated by using a micromachining process. The dimensions of the silver substrates are 51 mm, 25 mm, and 1.1 mm, in length, width, and depth respectively. The dimensions of microchannels grooved in the substrates are 0.9 mm in width and depth. The boundary conditions for pressure and velocity were considered, from 1.0 kPa to 1.50 kPa, and 0.02 m/s to 0.07 m/s, respectively. These are the actual values of pressure and velocity in varicose veins. The flow rate of 5.843 (0.1 nL/s) and velocity of 5.843 cm/s were determined at Reynolds number 164.88 in experimental testing. The graphs and results from simulations and experiments are in close agreement. These microchannels can be inserted into varicose veins as a replacement to maintain the excellent blood flow in human legs.

Large vein reconstructions in the endovascular era

Max Ratschow was a remarkable physician and an international authority in the field of angiology and the Ratschow lectureship helps to fulfill this pioneer’s life purpose: to advance evaluation and treatment of vascular diseases. The 2017 Max Ratschow lecture covers some recent advances and controversies in venous diseases. Phlebology, once a neglected field of angiology, is a discipline that has been in constant progress during the past decades. Endovascular techniques revolutionized treatment of patients with large vein obstruction and provided safe, minimally invasive procedures with excellent long term results. Attention now need to focus on comparative studies to provide scientific evidence of efficacy of venous angioplasty and stenting with properly organized randomized controlled trials. Further attempts are needed to develop special venous stents and to decrease thrombotic complications and formation of pseudointima that cause in-stent restenosis. Open and hybrid reconstructions are safe and durable, but the number of procedures in general is small and special training and expertise for reconstructive venous surgery is recommended. Autologous vein should be used for infrainguinal reconstructions and for treatment of unilateral iliac vein obstruction with a femoro-femoral cross-over bypass (Palma procedure). IVC and iliac vein reconstructions with ePTFE grafts provide superb result in patients who need excision of malignant tumors invading large veins. Open and hybrid reconstructions are here to stay and they remain excellent options for those patients who are unsuitable for or fail endovascular repair.