Agency for Healthcare Research and Quality (AHRQ) Jones, et al.7 in conjunction with CMS proposed a technology assessment (TA) on treatment strategies for lower extremity chronic venous disease (LECVD). This systematic review includes a narrative review of diagnostic testing modalities and assesses the comparative effectiveness of exercise training, medical therapy, weight reduction, mechanical compression therapy, and invasive procedures (i.e., surgical and endovascular procedures) in patients with LECVD. Eight studies were included for treatment of adult patients with lower extremity chronic venous thrombosis/obstruction. In seven of the studies, all patients were symptomatic at baseline; in one study only a small minority had unclear symptom severity. Three studies were randomized controlled trials representing a total of 109 patients. The sample size of the five observational studies ranged from 20 to 216 patients. All studies assessed the comparative effectiveness of exercise training, medical therapy, weight reduction, compression therapy, skin/wound care, endovenous intervention and/or surgical intervention on functional outcomes, quality of life, and safety events in patients with lower extremity chronic venous obstruction/thrombosis. Studies that assessed individual treatment modalities or combinations of treatment modalities were analyzed; however differences in the treatment comparisons, outcome measures, and follow-up time points eliminated the possibility that study results could be pooled for analysis of direct comparisons. There were no studies reporting results by the following subgroups: age, race/ethnicity, sex, body weight, CEAP classification, VCSS classification, severity of disease, anatomic segment affected, presence of ulcer, and known malignancy. Unfortunately given the small number of studies, heterogeneity in outcomes and interventions assessed, diverse populations evaluated, and inconsistency in findings, the evidence was insufficient to support any findings.
Evidence-Based / Professional Society Guidelines
The American College of Phlebology, in their practice guidelines on chronic deep venous obstruction of the femoroiliocaval venous system8 recommend venous balloon angioplasty and stenting as an adjunct to catheter-directed thrombolysis for acute femoroiliocaval deep vein thrombosis in order to maintain vein patency and flow when a residual stenosis is found on post thrombolysis imaging. The guidelines state there is robust clinical evidence in the peer-reviewed medical literature that alleviating venous obstruction utilizing balloon angioplasty and stenting is feasible in the vast majority of patients with good to excellent results in terms of stent patency, relief of symptoms, and recurrent stenosis. The evolution of balloon angioplasty and stenting of the femoroiliocaval vein obstructions over the past 20 years has established it as the technique of choice for most severely symptomatic patients.
The American College of Radiology (ACR) Committee represented by Hohenwalter, et al.9 developed criteria for radiologic management of iliofemoral venous thrombosis. The ACR criteria include conventional anticoagulation alone does not prevent post-thrombotic syndrome and catheter-directed thrombolysis and pharmacomechanical thrombolysis may decrease the incidence of PTS in patients with acute iliofemoral DVT with proper patient selection. Patients with iliofemoral DVT are the subset of patients with the largest thrombus burden and the highest risk for postthrombotic morbidity; up to 75% have chronic painful edema, and 40% have venous claudication when treated with anticoagulant therapy alone. The evidence available favors use of catheter-directed thrombolysis (CDT) and pharmacomechanical thrombolysis in DVT patients with clinically severe manifestations of DVT. These severe manifestations include Phlegmasia Cerulea Dolens (PCD), acute IVC thrombosis, and rapid thrombus extension despite anticoagulation as well as anatomically extensive DVT that includes the common femoral and/or iliac vein since this degree of thrombus carries a higher risk of recurrent DVT and PTS.
The ACR Committee and the Society of Interventional Radiology (SIR) collaboratively revised the practice parameter for endovascular management of the thrombosed or dysfunctional dialysis access.10 Endovascular management of hemodialysis access prosthetic grafts and autogenous fistulae is an alternative treatment to surgical thrombectomy and revision. It applies to accesses that have never matured, or accesses that have thrombosed, accesses that have blood flow insufficient to allow hemodialysis, accesses with clinical symptoms or noninvasive assessments that indicate the access is at increased risk of thrombosis, and access complications such as pseudoaneurysm or steal. Endovascular management results in reduced morbidity compared to standard surgical therapy, with less post procedure pain and decreased wound edema. Endovascular management of the thrombosed or dysfunctional hemodialysis access is usually performed on an outpatient basis, with the patient returning home or to the dialysis unit for treatment.
The ACR Committee, the Society of Interventional Radiology (SIR), the Society of Neurointerventional Surgery (SNIS) and the Society for Pediatric Radiology (SPR) collaboratively revised the practice parameter for interventional clinical practice and management.11 The practice parameter states interventional radiology and interventional neuroradiology are clinical subspecialties of radiology focused on minimally invasive, image-guided therapy for numerous diseases. An interventional radiologist or interventional neuroradiologist interacts directly with patients and counsels them regarding their diseases and therapeutic options.
In 2014, the ACR Committee, the Society of Interventional Radiology (SIR), the Society for Pediatric Radiology (SPR) collaboratively revised the practice parameter for reporting and archiving of interventional radiology procedures.12 This practice parameter is intended to improve patient care by improving the consistency of medical record content, the written or dictated reports, and image archiving for vascular/interventional radiology procedures (exclusive of breast interventional procedures). For endovascular interventions, the ACR-SIR-SPR recommend predeployment and postdeployment intervention images should be obtained and archived. Intermediate stages that are pertinent to the performance of the endovascular procedure may also be documented with archived images. Images should detail the position of the device and, when appropriate, the effect of the device on target or nontarget vessels.
The American Heart Association (AHA) represented by Jaff, et al.13 released a scientific statement following review of literature for the management of massive and submassive acute pulmonary embolism (PE), iliofemoral deep vein thrombosis (IFDVT), and chronic thromboembolic pulmonary hypertension (CTEPH). The AHA mentions percutaneous transluminal venous angioplasty and stent placement have been used routinely concomitant with endovascular or surgical thrombus removal to treat obstructive lesions and prevent rethrombosis in patients with acute iliofemoral deep vein thrombosis (IFDVT). The AHA states typically with left common iliac vein stenosis in association with left-sided IFDVT (i.e., May-Thurner syndrome, Cockett syndrome) the treatment is stent placement in catheter-directed thrombolysis (CDT) studies. The authors conclude the body of evidence to guide management for these forms of venous thromboembolism (VTE) is incomplete, and therefore, some recommendations must rely on lower levels of evidence or expert opinion. Further clinical trials of advanced therapies for VTE are strongly advised.
The American Heart Association Scientific Council leadership invited multidisciplinary experts in Post Thrombotic Syndrome (PTS), represented by Kahn, et al.4 to form a writing panel for the construction of a scientific statement. After systematic review of relevant literature on the pathophysiology, epidemiology, prevention, diagnosis, and treatment of PTS, the writing panel developed the peer-reviewed evidence-based recommendations. The authors noted experience with endovascular, surgical, and hybrid approaches to the treatment of PTS is limited and only the most severely affected patients are considered for treatment. The panel acknowledged the body of evidence to guide management of PTS is incomplete and consequently, many recommendations rely on lower levels of evidence.
The Cardiovascular and Interventional Radiological Society of Europe (CIRSE) standards of practice guidelines on iliocaval stenting, represented by Mahnken, et al.14 review the current evidence on iliocaval vein recanalization and provide standards of practice for iliocaval stenting in primary and secondary causes of chronic venous disease. Chronic venous disease (CVD) covers a wide range of symptoms from cosmetic problems to more severe symptoms, such as ulceration. The role of venous obstruction is increasingly recognized as a major cause of CVD, with obstructive lesions in the iliocaval segment being markedly more relevant than lesions at the levels of the crural and femoral veins. Iliac vein obstruction is most commonly due to insufficient recanalization following an episode of acute deep venous thrombosis (DVT), with approximately 70-80% of veins developing a variable degree of obstruction. Non-thrombotic iliac vein obstruction occurs where it is crossed by the iliac or hypogastric artery, a condition known as May-Thurner or Cockett’s syndrome. Patients with CEAP clinical class 3-6 and chronic venous outflow obstructions should be considered for interventional therapy. Stenting of the iliac veins also should be considered in the presence of nonthrombotic obstructive venous lesions in the iliocaval segment with a degree of stenosis of more than 30% and the presence of venous collaterals. Iliocaval stenting should always be considered as an adjunct to interventional or surgical management of iliocaval thrombosis. Clinical improvement appears to be long lasting, although long-term results after treating acute DVT seem to be better than stenting in chronic venous obstruction. The CIRSE guidelines conclude stenting in chronic iliocaval obstruction is safe and effective. It provides excellent long-term results with respect to target vessel revascularization as well as symptom relief, therefore improving the quality of life. In selected patients, it appears to even reverse established PTS. During the past decade, venous outflow obstruction has become recognized as more relevant in CVD than previously anticipated and endovascular correction of outflow obstructions should be liberally indicated.
The European Society of Vascular Surgery (ESVS) represented by Wittens, et al.15 provides Clinical Practice Guidelines for the care of patients with CVD in the lower extremities. Sixteen articles related to percutaneous transluminal angioplasty and stenting were reviewed. Consensus recommendation is that after percutaneous transluminal angioplasty, stent placement should be considered for patients with chronic deep venous obstruction. The stent should ideally have a sufficient high radial force and flexibility to preclude recoil and collapse. It has been shown that in two thirds of patients with post-thrombotic disease it is necessary to implant stents down to the groin below the inguinal ligament to improve inflow into the reconstructed iliac veins. Interventions distal to the groin, including endophlebectomy or stenting further down into the femoral vein or profunda femoral vein are not yet validated. There are several forms of congenital deep venous anomalies causing obstruction of the outflow tract. One severe anomaly is atresia (congenital absence) of the inferior vena cava (IVC) in which the sub-hepatic segment of the IVC has not developed. This may cause CVD because of outflow obstruction, often complicated by recurrent ilio-femoral DVT and subsequent post-thrombotic problems. Clinical results using dedicated venous stents and comparison between different types of stent are lacking. The optimal design and material of a venous stent is presently not known.
The KDOQI 2006 guidelines16 state endovascular stents would seem to be an ideal method to treat angioplasty failures. Stents can oppose elastic recoil and optimize endoluminal dimensions, thereby improving intragraft blood flow and prolonging graft patency. However, the majority of clinical studies showed that the routine use of stents does not provide an additional benefit compared with angioplasty alone. The neointimal hyperplastic tissue continues to grow unabated through the meshwork of the metallic stent. For these reasons, use of endovascular stents to treat HD-related stenoses continues to be a controversial subject. A recent study reported that use of nitinol stents provided superior results compared with stainless steel stents. Continued improvements in stent design, the use of stent grafts, or the use of drug-eluting stents may provide better long-term results. Covered stents have been used to salvage arteriovenous grafts, but efficacy has not been compared with other strategies.
The Society of Interventional Radiology position statement on the treatment of acute iliofemoral deep vein thrombosis with use of adjunctive catheter-directed intrathrombus thrombolysis, represented by Vedantham, et al.17 considers the use of catheter-directed intrathrombus thrombolysis (CDT) as an adjunct to anticoagulant therapy to represent an acceptable initial treatment strategy for carefully selected patients with acute iliofemoral deep vein thrombosis (DVT). Patients with iliofemoral DVT are at particularly high risk for PTS and late disability. The enhanced effectiveness of CDT compared with systemic thrombolysis in reestablishing iliofemoral venous patency is thought to be a result of two main factors: (a) catheter-directed delivery enables a higher intrathrombus drug concentration to be achieved, enhancing thrombus removal and reducing the needed dose; and (b) catheter access into the venous system enables the use of balloon angioplasty and stents to treat underlying venous obstruction that might otherwise predispose to recurrent DVT.
The Society of Interventional Radiology Position Statement, by Baerlocher, et al.18 provides reference guidelines for the requirements for safe operation of interventional radiology (IR) suites. Although the primary focus of the guidelines is to address staffing issues for IR practice, certain clinical aspects merit specific mention. IR is a clinical specialty composed of physicians with extensive knowledge of a broad spectrum of disease that they treat. In 2012, the American Board of Medical Specialties officially recognized IR as the 37th medical specialty. In 2014, the Accreditation Council on Graduate Medical Education approved the new IR residency pathway. One aspect of this expertise requires admitting privileges. It is the unequivocal position of the SIR that IR be provided with admitting privileges and have parity with other admitting physicians. Equally, longitudinal IR care requires dedicated clinic space, typically separate from the inpatient area, and resources for outpatient evaluation, examination, consultation, and charting.
The Society of Interventional Radiology represented by Dolmatch et al.19 identifies four anatomic patterns of obstruction and defines five key reporting dimensions that allow clinicians to describe thoracic central vein obstruction (TCVO) in a straightforward and reproducible manner. TCVO often interferes with vascular access and may cause disability of varying degree and, on occasion, death. Although thoracic aneurysms rarely cause TCVO today, there are a multitude of other conditions that do. Thoracic malignancy, particularly lung cancer and lymphoma, and other neoplastic, infectious, and inflammatory mediastinal processes may obstruct the thoracic central veins. Paget-Schroetter syndrome and subclavian venous thrombosis may cause TCVO. TCVO is frequently associated with the use of indwelling venous devices such as infusion ports, peripherally inserted central catheters, and transvenous cardiac rhythm device leads. Chronic central venous catheters in children and adults have been associated with TCVO. Patients receiving hemodialysis who have had previous venous catheter access or cardiac rhythm device leads are known to have a high prevalence of symptomatic TCVO. Some cases of TCVO cannot be attributed to any particular cause. The type of obstruction should be reported. Additionally, flow leading up to the obstruction is systemic venous return or return from an arteriovenous (AV) circuit (in patients with a working upper-extremity hemodialysis fistula or graft). The type of flow should be noted. If flow is AV, the side of the AV circuit should be reported. Whenever possible, stenosis should be quantified as a percentage diameter narrowing compared with an adjacent nonstenosed venous segment. The guidelines suggest clinical reporting requirements of TCVO pattern of obstruction, type of flow, and degree of obstruction. The authors hope this work will guide the way toward best-practice recommendations, algorithms to track central vein use, strategies that can reduce the incidence of TCVO, and broader adoption of common data elements and standardized reporting structures.
The Society for Vascular Surgery® (SVS) clinical practice guidelines, for the surgical placement and maintenance of arteriovenous hemodialysis access, were developed by Sidawy, et al.20 The SVS involved The Knowledge and Encounter Research Unit (KER) of the Mayo Clinic College of Medicine, Rochester, Minnesota. For the management of nonfunctional or failed arteriovenous (AV) access, the recommendation is open surgery, endovascular means, or a combination of both to maintain or restore patency in AV access. The systematic literature reviews reveal a scarcity of high-quality evidence and many of the recommendations are based on observational studies and consensus of the committee. Despite the lack of high-quality evidence, some of the recommendations were graded as strong because of the values and preferences brought to light by the multidisciplinary committee.
The Society for Vascular Surgery® and the American Venous Forum, represented by Meissner, et al.21 provide clinical practice guidelines for early thrombus removal strategies for acute deep venous thrombosis. The committee of experts in venous disease performed a systematic review and meta-analysis of relevant literature supplemented by less rigorous data as necessary. Regarding adjunctive use of venous stents, the recommendations are to use self-expanding metallic stents for treatment of chronic iliocaval compressive or obstructive lesions that are uncovered by any of the thrombus removal strategies [in the guidelines] and that stents not be used in the femoral and popliteal veins. The committee concluded that most data regarding early thrombus removal strategies are of low quality but do suggest patient-important benefits with respect to reducing postthrombotic morbidity.
The Society for Vascular Surgery® and the American Venous Forum, referenced by O’Donnell, et al.22 provide clinical practice guidelines including recommendations for operative and endovenous management of venous disease. In general, quality of evidence available to support recommendations for operative and endovascular management is mostly limited to observational studies or case series. For all patients with venous leg ulcers who require venous endovascular or operative intervention, outcome assessment should be performed to determine success of the procedure over time. In a patient with inferior vena cava or iliac vein chronic total occlusion or severe stenosis, with or without lower extremity deep venous reflux disease, that is associated with skin changes at risk for venous leg ulcer (C4b), healed venous leg ulcer (C5), or active venous leg ulcer (C6) the recommendation is for venous angioplasty and stent recanalization in addition to standard compression therapy to aid in venous ulcer healing and to prevent recurrence.
Summary of Evidence: Endovenous Stenting Articles
Abou Ali, et al.23 reviews the role of venous stenting for iliofemoral and vena cava obstruction in patients with acute or chronic venous outflow obstruction. The authors describe endovenous balloon angioplasty as a suboptimal intervention with high level of lesion recurrence. Large-caliber stents are required in most cases. Although venography is used to confirm deep venous occlusion, intravascular ultrasound (IVUS) is frequently implemented to determine the extent of the lesion and the proximal and distal stent landing zones. IVUS is recommended for adequate placement of the stent and for stent sizing and determining the extent of disease. Stent sizing is different in venous practice compared with arterial stents. Although it is agreed that stent sizing with arterial lesions is in accordance with normal adjacent vessels, the same approach would lead to significant undersizing with venous lesions. Undersizing venous stents can lead to iatrogenic stenosis, which becomes more pronounced when in-stent restenosis (ISR) develops and possible migration. This finding is particularly important, as 61% of stents in the iliocaval outflow tract experienced ISR between 20% and 50% at 5-year follow-up. Until recently, there have been no venous dedicated stents, but two stent designs have completed clinical trial enrollment in the United States and are awaiting data analysis and subsequent FDA approval. A prospective multicenter nonrandomized study (VIRTUS) has completed enrollment and aims to evaluate the safety and efficacy of venous stents in patients with chronic nonmalignant iliofemoral venous outflow obstruction.
Attaran24 in Latest Innovations in the Treatment of Venous Disease describes current modalities of treatment of venous disease and specifically elaborates on the use of stents in various thrombotic syndromes. The current standard treatment for May–Thurner Syndrome and/or iliac vein stenosis is angioplasty and stenting and has achieved favorable patency rates. Stents must be appropriately selected to avoid undersizing and subsequent stent migration. The use of iliac intervention for the treatment of symptomatic iliac vein stenosis has shown favorable long-term patency, as well as improvement in symptoms including pain, edema, and ulcer healing. The author notes no conflict of interest.
Aydinli and Bayraktar25 discuss the etiology, pathogenesis and diagnosis of Budd-Chiari syndrome (BCS). Throughout the world occurrence of BCS is noted to be rare and a disorder characterized by obstruction of hepatic venous outflow. Patients present with acute signs and symptoms of abdominal pain, ascites and hepatomegaly or more chronic symptoms related to long-standing portal hypertension. The authors review etiology, pathogenesis and diagnosis of BCS stating most patients with BCS have an underlying condition that predisposes the patient to blood clotting with obstruction mainly caused by primary intravascular thrombosis.
Bachleda, et al.26 conducted a study outside of the United States designed to evaluate the results of hybrid treatment of arteriovenous graft thrombosis associated with venous anastomotic stenosis. Sixteen patients with arteriovenous graft (AVG) occlusions were treated. Immediately after the diagnosis of occlusion was made, the patients underwent thrombectomy. After thrombectomy, a diagnostic fistulogram was performed and if stenosis was confirmed at the venous anastomosis of the graft (VAG), it was treated with balloon angioplasty and stent graft introduction. Lesions were dilated to reduce the stenosis in the treated area to less than 25%. Primary patency after 12 months was 32.8%. Primary assisted patency was 44.7%, secondary patency was 47.6%. Restenosis of the stent graft was seen in two patients. Recurring AVG occlusion was observed in four patients. The average number of interventions to maintain AVG patency was 1.18 per patient/1 year of dialysis. Treatment of AVG thrombosis due to VAG stenosis by hybrid procedure proved to be effective and improved secondary patency. Although the sample size is small, it demonstrates that venous anastomosis of the graft (VAG stenosis) leading to arteriovenous grafts (AVG) thrombosis can be managed by angioplasty with stent graft introduction.
Bozkaya, et al.27 in Endovascular Treatment of Iliac Vein Compression (May-Thurner) Syndrome: Angioplasty and Stenting with or without Manual Aspiration Thrombectomy and Catheter-Directed Thrombolysis, describes treatment modalities for May–Thurner syndrome (MTS). May–Thurner syndrome, a rare clinical entity featuring venous obstruction of the left lower extremity is characterized by chronic pulsatile compression of the left iliac vein in the region between the right common iliac artery and the lumbar vertebral body. The study is a retrospective analysis of 23 patients with MTS and to evaluate the utility of treatment using endovascular techniques. Complete left common iliac vein patency was achieved in 21 of the 23 patients (technical success rate: 91.3%). Complete thrombolysis was attained by 14 of the 18 DVT patients (77.7%). The mean clinical and radiological follow-up time was 15.2 ± 16.1 months. Upon follow-up, complete symptomatic regression was observed in 19 of the 23 patients (82.6%). Stent patency was complete in 19 of the 21 patients (90.4%) who received stents. Restenosis occurred in two patients and no treatment-related mortality or morbidity was observed. The study concludes that endovascular treatment of MTS is safe and effective and reduces symptoms in most patients, associated with high medium-term patency rates. The limitations of the present study were the retrospective nature of the work, the limited number of MTS patients evaluated, and the loss of some patients to follow-up (limiting the long-term data). Follow-up periods and control numbers were not standardized, and follow-up periods were relatively short. Another potential limitation is the variability in stent type and size. The authors declare no conflicts of interest.
Brinegar, et al.28 addresses iliac vein compression syndrome and focused on May-Thurner syndrome (MTS), in which the pathologic compression of the left common iliac vein by the right common iliac artery, results in left lower extremity pain, swelling, and deep venous thrombosis. This article is a summary of the historical aspects of the clinical features of this syndrome as well as a comprehensive assessment of the literature on the efficacy of imaging tools available to diagnose MTS. It also provides recommendations to aid physicians in diagnosing the syndrome through the use of provocative measures and provides treatment options.
de Graaf, et al.29 conducted an observational study of forty patients treated for chronic bi-iliocaval obstructions. The study reports on two confluence stenting techniques, one with self-expandable stents and the other with balloon-expandable stents (BECS) bridging the common iliac vein confluence. The total number of legs evaluated was 80 legs with 50 of those for the endovascular only group. The mean age of participants was 41 (+/- 14.9) years (range 16-62 years). Each group performed bilateral iliac extensions using nitinol stents; beginning in 2013 dedicated venous stents were used. Patency was described as patency of more than 50% of the venous lumen on DUS. The primary, assisted-primary, and secondary patency rates of treated lower extremities were 79, 82, and 90% at 12 months and 70, 73, and 78% at three years respectively. The study mentions although dedicated venous stents are purported to perform better in venous vasculature, no proof that dedicated venous stents improve outcome was available at the time of the study. The authors anticipate the evolution of “confluence-stent” devices as the use is already recognized in bifurcated aorta repair and may also be shown to support venous reconstructions in the future.
Dinkin and Patsalides30 presents prospective data after venous sinus stenting for medically-refractory, medication-intolerant, or fulminant Idiopathic Intracranial Hypertension (IIH), and suggests that while this may be considered as an alternative to conventional therapy, concludes that there remains insufficient evidence to support any surgical procedure for IIH over another, and a large, multicenter, randomized, physician-blinded, head-to-head trial comparing venous stenting to shunting is needed to determine the relative safety and efficacy of these options.
Kurklinsky, et al.31 conducted a single-center, retrospective 30-day, 1-year and 3-year review on patency of chronically occluded iliofemoral venous thrombotic lesions treated with stent placement in a case series. Records of 189 consecutive patients treated by interventional radiology for iliofemoral venous occlusions between March 01, 2003, and December 01, 2008, were retrospectively reviewed. Eighty-nine patients (27 males, median age 46.2 years) with chronic iliac or iliofemoral deep vein thrombosis without involvement of the inferior vena cava met criteria for analysis. Eighty-nine patients (91 limbs) successfully underwent placement of venous self-expanding stents. Discharge patency was 100%. Following the index procedure, the mean pressure gradient across the lesion decreased from 5.63 mmHg (95% CI: 3.51 – 7.75) to 0.71 mmHg (95% CI: 0.08 – 1.34) mmHg (p less than 0.0001). There were no bleeding complications. Median follow-up was 11.3 months (range 0.8 – 72.4). Follow-up at 30 days demonstrated 90 of 91 limbs patent. Primary patency of treated limbs at 1 and 3 years was 81 and 71% respectively. Primary patency was lost in 17 (19.1%) cases; interventions to maintain or restore stent patency were performed in 13 (14.6%) cases. Primary assisted limb patency at 1 and 3 years was 94% and 90% respectively; secondary patency was 95%.
Neglen, et al.32 reports a study on stenting of the venous outflow in chronic venous disease. This study reviewed timestamped electronic medical records for patients with venous disease specifically constructed to prospectively collect comprehensive standardized information on symptoms and physical findings in patients with venous disease. This study of 982 (in 870 patients) chronic nonmalignant obstructive lesions of the femoroiliocaval vein were stented under intravascular ultrasound guidance. One hundred and twelve patients (13%) had bilateral treatment with stents for obstruction of the femoroiliocaval vein. Median age was 54. Clinical score of CEAP (classification of varicose veins severity) was 2 in 7%, 3 in 47%, 4 in 24%, 5 in 5%, and 6 in 17%; primary/secondary etiology was 518 limbs/464 limbs, respectively. Stent-related outcome (morbidity, thrombotic events, patency, in-stent recurrent stenosis), clinical outcome, quality of life (QOL) as assessed by the Chronic Venous Insufficiency Quality of Life Questionnaire (ClVlQ), and hemodynamics were evaluated before and after intervention. Monitoring for 94% of patients lasted a mean 22 months (range, 1 to 107 months). Stenting was performed with no mortality (less than 30 days) and low morbidity. Thrombotic events were rare (1.5%) during the postoperative period (less than 30 days) and during later follow-up (3%). At 72 months, primary, assisted-primary, and secondary cumulative patency rates were 79%, 100%, and 100% in nonthrombotic disease and 57%, 80%, and 86% in thrombotic disease, respectively. Cumulative rate of severe in-stent restenosis (greater than 50%) occurred in 5% of limbs at 72 months (10% in thrombotic limbs, 1 % in nonthrombotic limbs). The main risk factors associated with stent occlusion were the presence and severity of thrombotic disease; thrombophilia by itself was not a risk factor. The median pain score and degree of swelling decreased significantly poststent. The mean ClVlQ scores improved significantly in all categories. Mean hand-foot pressure differential decreased and mean ambulatory venous pressure improved in stented limbs with no concomitant reflux. The hemodynamic response was modified, depending on the presence of deep and superficial reflux in subsets of patients with adjunct saphenous procedures. No increase in venous reflux was observed.
Raju, et al.33 assessed stent-related and clinical outcomes following treatment by iliac venous stenting alone in symptomatic limbs with a combination of iliac vein obstruction and deep venous reflux. Over a period of 11 years, a total of 528 limbs in 504 patients, ranging in age from 15 to 87 years (median 55 years) of age, had intravascular ultrasound (IVUS)-guided vein stent placement to correct obstruction. The etiology of obstruction was nonthrombotic in 196 (37%) limbs, post-thrombotic in 285 (54%) limbs, and combined in 47 (9%) limbs. Venography and other functional tests had poor diagnostic sensitivity to detect obstruction, which was ultimately diagnosed by IVUS. The IVUS-guided iliac vein stenting was the only procedure performed and the associated reflux was left uncorrected in this study. The authors stated use of large-caliber (14-18mm) stents, stent coverage of all lesions without skip areas, three to five centimeter (cm) extension of braded iliac stents into inferior vena cava, and extension below the inguinal ligament, as necessary, are essential technical elements for a successful outcome. There was no mortality; morbidity was minor. Wallstents (Boston Scientific, Nantucket, Mass.) were used exclusively in this study. Cumulative secondary stent patency reported was 88% at five years; no stent occlusions occurred in nonthrombotic limbs. Cumulative rates of limbs with healed active ulcers, freedom of ulcer recurrence in legs with healed ulcers and freedom from leg dermatitis at five years was 54%, 88%, and 81% respectively. Cumulative rate of substantial improvement of pain and swelling at five years was 78% and 55% respectively. The study reports quality of life improved significantly and reflux parameters did not deteriorate after stenting was performed. Iliac venous stenting alone sufficiently controlled symptoms in the majority of patients with combined outflow obstruction and deep reflux. The study concludes partial correction of the pathophysiology in limbs with multisystem or multilevel disease can provide substantial symptom relief. The authors state open correction of obstruction or reflux is only required as a “last resort” due to percutaneous stent technology in concert with other minimally invasive techniques to address superficial and/or perforator reflux for patients with advanced CVI and complex venous pathology.
Raju34 retrospectively reviewed a single-arm case series encompassing about 1,500 patients treated for iliac vein stenosis and occlusion. Evidence quality was judged moderate, with a grade 1B recommendation (benefits outweigh risks) for patients with disabling symptoms in whom conservative therapy had failed. A grade 2B recommendation was assigned for patients with less severe symptoms. The author states iliac vein stenting is safe, with negligible morbidity (less than1%). Patency was 90% to 100% for nonthrombotic disease and 74% to 89% for post-thrombotic disease at 3 to 5 years. Clinical relief of pain was 86% to 94%, and relief from swelling was 66% to 89%. From 58% to 89% of venous ulcers healed. Procedural success in recanalization of chronic total occlusions was 83% to 95%. Approximately 25% of stents occlude in thrombotic cases during a 3- to 5-year period. Secondary patency ranged from 90% to 100% in limbs with nonthrombotic iliac vein lesions and from 74% to 89% in post-thrombotic limbs during 4 to 7 years. Patency is somewhat lower, at 66% to 89% at 4 to 7 years, and stent occlusions higher in the group among chronic total occlusion recanalizations. Many areas related to iliac vein stenting require further study and clarification, including the role of IVUS imaging (used in only two studies), the degree of correctible stenosis, the relationship between silent and symptomatic obstructions, inter-relationship of obstruction and reflux, and finally, a hemodynamic metric for obstruction. The author concludes stent placement to correct iliac-caval-femoral obstructions is emerging as a safe, effective, and minimally invasive alternative to traditional open procedures for iliac vein stenting.
Raju and Ward35 reported on clinical research with iliac vein stenting, some with concurrent saphenous ablation, in patients aged 80 years and older in whom the dominant issue was deep venous obstruction. During a 13-year period, iliac vein stenting was performed for 107 limbs in 95 patients who were at least 80 years old. Three procedures were for recanalizations of chronic total occlusion; the remainder of the stenting procedures was for correction of stenosis. Stented patients were seen for follow-up at six weeks, three months, and at six month intervals by the physician or nurse practitioner; mean follow-up was 17 months. No post procedure mortality was noted within 30 days. Among the 95 patients, 45 (47%) were alive at the time the report was written. Regarding the remaining 50 patients, no information was available for 41 and nine other patients were deceased. The authors state lack of mobility due to swelling or orthostatic pain compromises independent living with venous ulcers and cellulitis also impacting factors. The report lists relief of pain and suffering to the extent possible in the last stages of life as central to geriatric care. The authors submit that stenting expertise is widely available and has the potential to benefit the geriatric population reporting advanced manifestations of chronic venous disease since the procedure is minimally invasive with low mortality and morbidity, high patency rate and satisfactory symptom relief.
Raju,36 in Ten Lessons Learned in Iliac Venous Stenting, discusses iliac vein stenting as an extension of arterial stent technology. The two share some technical similarities and much of the hardware; however, the indications for and purpose of iliac vein stenting are fundamentally different from arterial practice. Pathophysiologic differences require specific modifications of techniques as well. Undersizing stents in iliac veins results in residual symptoms, even though the stent may remain patent. For example, placement of a 14-millimeter (mm) stent in the common iliac vein, seemingly a minor downsizing, represents an iatrogenic area stenosis of 25% at the outset, disregarding any in-stent restenosis (ISR) that may develop (25% is common). In addition to ISR, iliac vein stents are prone to stent compression from the outside at anatomical choke points or from recurrent post-thrombotic stenosis. Commensurate with the high patency rate with iliac stenting, a significant improvement in pain was reported in 74% of limbs (cumulative), with complete relief in 65% at 5 years. Swelling improved significantly in 62% of limbs, with complete relief in 32% at 5 years, and 58% of ulcers (cumulative) healed at 5 years. The author states the iliac vein stent experience is with off-label use of a Wallstent endoprosthesis, which is designed for extravascular use. The performance was better than anticipated noting certain deficiencies, some specific to the iliocaval anatomy. A 3- to 5-cm stent extension into the IVC is often required to traverse the lesion completely and minimize end effects, such as coning, and distal migration of the stent. This poses a potential risk of partial jailing of contralateral iliac flow. Simultaneous or sequential bilateral stenting with current stent designs are unsatisfactory and may be technically difficult or impossible. The author purports solutions to these problems can be improvised and that a dedicated venous stent with improved performance is clearly desirable. The author discloses multiple conflicts of interest including stockholder of Venti, Inc., as well as United States patents for IVUS (diagnosis) and venous stent.
Razavi, et al.37 examined the safety and effectiveness of venous stent placement in patients with non-thrombotic, acute thrombotic (AT) and chronic post-thrombotic (CPT) disease pathogenesis. The review consisted of 37 studies reporting 45 treatment effects (non-thrombotic, acute thrombotic [AT], and chronic post-thrombotic [CPT]) from 2,869 individual patients (non-thrombotic, 1,122; AT, 629; CPT, 1,118). Main objectives of the review included technical success, peri-procedural complications (i.e., major bleeding, pulmonary embolism, early thrombosis, and death), patient symptom resolution (i.e., pain, edema, ulcer) at final follow-up, and primary and secondary patency through five years. A secondary objective of the review was to develop performance goals to be used as comparators in single-arm clinical trials of iliofemoral venous stents specifically manufactured for placement in the venous system. Most studies included were retrospective and performed at a single institution. Median sample size of each included study ranged between 26 and 38 and the median follow-up timeframe was between 15 and 19 months. Most often, AT was treated with catheter-directed thrombolysis (with or without thrombectomy) followed by percutaneous transluminal angioplasty (PTA) and stent placement. Non-thrombotic and CPT were typically treated with PTA and stent placement although adjunctive therapies were applied in some cases. Wallstents (Boston Scientific, Marlborough, MA) were used in 78% of the studies included. Only one study (3%) used a stent specifically manufactured for venous applications in three (0.1%) limbs. Technical success rates were comparable among groups; ranging from 94% for AT and CPT to 96% for non-thrombotic patients. The authors note at the time of the review no robust clinical studies with long-term outcomes of stent placement for iliofemoral venous obstructions were available. The study authors anticipate an increase in utilization of venous stents in response to emerging evidence in favor of catheter-based therapies for acute and chronic iliofemoral venous thrombosis.
Seager, et al.38 conducted a systematic review of sixteen studies (14 before-and-after studies, 1 controlled before-and-after study, and 1 case series) encompassing successful deep venous stenting in 2,373 and 2,586 post-thrombotic or nonthrombotic limbs and patients respectively. Meta-analysis was not possible as the data lacked control groups and was too heterogeneous. Significant improvements in validated measures of the severity of CVD and venous disease-specific quality of life were noted. Persistent ulcer healing rates ranged from 56% to 100% in limbs that had often already failed conservative management. Primary and secondary stent patency ranged from 32% to 98.7% and 66% to 96% respectively. The major complication rate ranged from 0 to 8.7% per stented limb. The quality of the evidence for five outcomes was “Very Low” and one “Low” (ulcer healing) as demonstrated by a GRADE assessment. The authors concluded the quality of evidence to support the use of deep venous stenting to treat obstructive CVD is currently weak yet consistent effects and marked changes in disease course with potential impact on quality of life. Seager et al. state the treatment does however, appear promising and is safe and therefore, should be considered as a treatment option while the evidence base is improved with perhaps a randomized control trial comparing the practice against conservative measures, with long-term follow-up and outcome measures including chronic venous disease measures and quality of life scores.
van Vuuren, et al.39 conducted a prospectively randomized controlled single-blind, single-center trial in the Netherlands comparing venous stenting with conservative treatment in patients with deep venous obstruction. One hundred and thirty patients with post-thrombotic syndrome (PTS) or MTS, eligible for interventional percutaneous treatment who did not have previous deep venous intervention, were randomized to conservative treatment or venous stenting and stratified for the PTS or MTS subgroup. The primary end point was the change in quality of life (QoL) at 12 months (on the disease-specific Veines QoL/Sym questionnaire) from baseline. Results are pending and should be interesting.
Yevzlin and Asif,40 in Stent Placement in Hemodialysis Access: Historical Lessons, the State of the Art and Future Directions, provide a review of stent placement in hemodialysis access. Recent data have emphasized that endovascular stents could be used in the treatment of central as well as peripheral stenotic lesions. In general, a peripheral or central vein lesion that is elastic or recurs within a three-month period after an initially successful balloon angioplasty or a stenosis where surgical revision is not possible are some indications for intravascular stent placement. Recent reports have expanded the role of stents in the management of pseudoaneurysms associated with dialysis access. Indeed, recent information from United States Renal Data System (USRDS) is reporting a marked increase of stent placement in hemodialysis access. While the total number of access interventions increased from 52,380 to 98,148 (a 1.8 fold increase), the number of stent placements has increased from 3,792 to 8,514, a 2.2 fold increase. Of note, the relative percentage growth of stent placement has outpaced that of angioplasty each year during the same time period. Studies illustrate that a stent (nitinol alloy) is safe and effective for treating dialysis-access venous stenosis that are resistant to standard angioplasty. While the results were encouraging, the study had several limitations. In addition to the lack of randomization, arteriovenous grafts and arteriovenous fistulas were mixed in the analysis, the type of lesion (e.g., inflow, outflow, or central) was not uniform and patient characteristics (e.g., diabetic or not) were not accounted for in the analysis. The presence of these confounding factors does not conclusively establish the superiority of stents over percutaneous balloon angioplasty. The role of stent placement in the management of hemodialysis access dysfunction remains controversial. It will remain so until large, multi-center, prospective, randomized, controlled trials are conducted. The authors disclose no conflict of interests.