Venous angioplasty (with or without stent placement) has been used in the treatment of obstructed hemodialysis access grafts, superior vena cava syndrome, Budd-Chiari syndrome and congenital cardiac defects. Venous angioplasty, also known as venoplasty, has been investigated as a method to improve venous flow in a relatively new condition known as chronic cerebrospinal venous insufficiency (CCSVI). CCSVI has been reported in some individuals with multiple sclerosis (MS). Venous angioplasty has also been investigated in the treatment of lower extremity venous congestion. This document addresses the use of venous angioplasty as a treatment modality.

Medically Necessary:

Venous angioplasty (with or without stent placement) is considered medically necessary for treatment of the following conditions:

• Arterio-venous dialysis access grafts which are stenotic or thrombosed; or
• Thrombotic obstruction of major hepatic veins (Budd-Chiari syndrome); or
• Superior vena cava syndrome; or
• Congenital heart disease including, but not limited to:
  • Stenosis or hypoplasia of a pulmonary artery in a child; or
  • Symptomatic stenosis/occlusion of superior or inferior vena cava; or
  • Venous narrowing due to repair of sinus venosus atrial septal defect (ASD); or
  • Venous obstruction of an atrial baffle following Mustard or Senning repair of transposition of the great arteries.

Investigational and Not Medically Necessary:

Venous angioplasty (with or without stent placement) is considered investigational and not medically necessary for the treatment of multiple sclerosis, chronically occluded iliac veins, iliac vein compression syndrome (also known as May-Thurner syndrome), ilio-femoral venous thrombosis, and any other conditions not listed above as medically necessary.

Stenotic or Thrombosed Arterio-venous Dialysis Access Grafts

The maintenance of thrombosed dialysis access grafts has been a challenging undertaking for many years. Once a dialysis access graft is thrombosed or stenosed, balloon angioplasty has been shown to effectively restore graft function (Beathard, 1992; Beathard 2003; Kanterman, 1995; Pappas 2002). Van Ha (2004) reported that there has been an evolution in the percutaneous treatment of thrombosed dialysis access grafts during the last 20 years allowing for safe and efficacious restoration of flow in thrombosed grafts.

The National Kidney Foundation (NKF) (2006) guideline update for the treatment of arteriovenous graft complications states in regards to stenosis without thrombosis:

Stenoses that are associated with AVGs should be treated with angioplasty or surgical revision if the lesion causes a greater than 50% decrease in the luminal diameter and is associated with the following clinical/physiological abnormalities:

• Abnormal physical findings.
• Decreasing intragraft blood flow (<600 mL/min).
• Elevated static pressure within the graft.

For treatment of thrombosis or associated thrombosis the NKF states:

Each institution should determine which procedure, percutaneous thrombectomy with angioplasty or surgical thrombectomy with AVG revision, is preferable based upon expediency and physician expertise at that center.

• Treatment of AVG thrombosis should be performed urgently to minimize the need for a temporary HD catheter.
• Treatment of AVG thrombosis can be performed by using either percutaneous or surgical techniques. Local or regional anesthesia should be used for the majority of patients.
• The thrombectomy procedure can be performed in either an outpatient or inpatient environment.
• Ideally, the AVG and native veins should be evaluated by using intraprocedural imaging.
•  Stenoses should be corrected by using angioplasty or surgical revision.
• Methods for monitoring or surveillance of AVG abnormalities that are used to screen for venous stenosis should return to normal after intervention.

Thrombotic Obstruction of Major Hepatic Veins (Budd-Chiari Syndrome)

Data to support angioplasty with or without stent placement for the treatment of Budd-Chiari syndrome consists of multiple retrospective studies or case series of varying size (Fisher, 1999; Han, 2013; Meng, 2011; Pelage, 2003; Qiao, 2005; Zhang, 2003).

In the largest case series, Meng and colleagues (2011) evaluated endovascular treatment of Budd-Chiari syndrome (BCS) in 903 cases at a single Chinese center. The obstruction in the inferior vena cava (IVC) was carried out first, then obliteration or stenosis in the IVC was opened or dilated and a stent was placed. The procedure was reported to be successful in 821 out of 903 cases. Complications included acute renal failure (eight cases), hepatic coma (two cases), and acute heart failure (43 cases). The authors concluded that endovascular treatment has become the treatment of choice for BCS because of its minimal trauma and fast recovery.

More recently, Han and colleagues (2013) evaluated the long-term outcomes of percutaneous recanalization and predictors of patency and survival in a retrospective case series of individuals with BCS at a single Chinese center.  Between July 1999 and August 2010, 177 consecutive cases of primary BCS were treated with percutaneous recanalization and followed up until their last clinical evaluation or death. Percutaneous recanalization was reported as technically successful in 168 of the 177 cases (95%). Fifty-one of the 168 individuals (30%) were treated with percutaneous transluminal angioplasty (PTA) alone and 117 (70%) were treated with a combination of PTA and stent placement. Procedure-related complications occurred in seven of the 168 individuals (4%). The cumulative 1-, 5-, and 10-year primary patency rates were 95%, 77%, and 58%, respectively. Independent predictors of reocclusion included increased white blood cell count and use of PTA alone. The cumulative 1-, 5-, and 10-year secondary patency rates were 97%, 90%, and 86%, respectively. There were 22 deaths during a median follow-up of 30 months (range, 0.25-137 months). The cumulative 1-, 5-, and 10-year survival rates were 96%, 83%, and 73%, respectively. Independent predictors of survival included variceal bleeding, increased alkaline phosphatase and blood urea nitrogen levels, and reocclusion.

Venous Angioplasty for Individuals with Congenital Heart Disease:

Angioplasty has long played a role in the treatment of numerous congenital cardiac defects including stenosis or hypoplasia of a pulmonary artery; coarctation of the aorta, transposition of the great arteries, repair of sinus venosus atrial septal defect (ASD); or venous obstruction following Mustard or Senning repair of transposition of the great arteries (Allen, 1998).

Venous Angioplasty for Stenosis or Occlusion associated with Superior Vena Cava Syndrome

Superior vena cava stenting for the treatment of malignant superior vena cava obstruction is well established (Uberoi, 2006; Schindler, 1999). Venous angioplasty is often necessary prior to stenting to offer safe palliation of potentially fatal complications associated with mediastinal malignant disease and compares very favorably with standard therapies such as chemotherapy and radiotherapy.

Treatment of Multiple Sclerosis

Various reports in the peer reviewed published literature (Zamboni 2009a; Zamboni, 2009b) describe a potential relationship between the abnormal venous circulation termed chronic cerebrospinal venous insufficiency (CCSVI) and MS.

The role of venous angioplasty as a potential treatment option for those with MS and CCSVI has been investigated. Zamboni and colleagues (2009c) evaluated the influence of venous angioplasty on the clinical outcome of CCSVI and MS. The authors characterized CCSVI as multiple stenoses of the principal pathways of extracranial venous drainage, including the internal jugular veins (IJV) and the azygous (AZY) vein with development of insufficient drainage evidenced by cerebral magnetic resonance (MR) perfusion studies. In this study, a total of 65 consecutive participants with CCSVI and MS (35 with relapsing remitting MS [RRMS], 20 with secondary progressive MS [SPMS], and 10 with primary progressive MS [PPMS]), underwent venous angioplasty. Mean follow-up time was 18 months. Reported study results included lower postoperative venous pressure in the IJVs and AZY, a higher risk of restenosis in the IJVs compared with the AZY, improved MS clinical outcomes, and improved mental quality of life outcomes in all types of MS, except SPMS.

Doepp and colleagues (2010) investigated the hypotheses of CCSVI by performing extended extracranial and transcranial color coded sonography studies on 56 participants with MS and 20 controls. Study results demonstrated that blood flow direction in the internal jugular veins (IJVs) and vertebral veins was normal (in all but one person) and IJV stenosis was not present in any participants. The authors concluded that the results of their study did not suggest restricted venous drainage in participants with MS and challenged the hypothesis that CCSVI plays a role in the pathogenesis of MS.

Sundstrom and colleagues (2010) tested the hypothesis of CCSVI on 21 individuals with RRMS and 20 controls. All study participants were examined with magnetic resonance imaging (MRI) and those with RRMS also received contrast enhanced magnetic resonance angiography (MRA). Findings reported to be associated with the MS hypothesis of CCSVI were not able to be reproduced. The authors concluded they found no support for a treatment rationale of endovascular procedures like angioplasty or stenting for the treatment of individuals with CCSVI and MS.

In a larger, more recent controlled and blinded study, Zivadinov and colleagues (2011) performed transcranial and extracranial Doppler imaging on 499 people to determine the prevalence of CCSVI. The participants included 289 people with MS, 163 healthy controls (HC), 26 with other neurological diseases (OND), and 21 with clinically isolated syndrome (CIS) (having a first neurological episode that can often lead to definite MS). Researchers found an increased prevalence of CCSVI in MS, although lower than in earlier reports. In addition, CCSVI was found in non-MS participants. Variable rates were reported depending on whether or not borderline cases were included. When borderline cases were considered not to have CCSVI, the prevalence was 56.1% in MS, 42.3% in OND, 38.1% in CIS and 22.7% in HC. When borderline cases were excluded from calculations, the prevalence of CCSVI was 62.5% in MS, 45.8% in OND, 42.1% in CIS and 25.5% in HC. The researchers reported modest sensitivity and specificity and stated that their findings point against CCSVI as having a primary causative role in MS.

Kostecki and colleagues (2011) prospectively evaluated six month follow-up results of endovascular treatment of CCSVI and MS. Thirty-six participants with confirmed MS and CCSVI underwent endovascular treatment by means of a uni- or bilateral jugular vein angioplasty with optional stent placement. Their MS-related disability status and quality of life were evaluated at one, three and six months postoperatively by the following scales: Expanded Disability Status Scale (EDSS), Multiple Sclerosis Impact Scale (MSIS-29), Epworth Sleepiness Scale (ESS), Heat Intolerance scale (HIS) and Fatigue Severity Scale (FSS). For patency and restenosis rate assessment, the control US duplex Doppler examination was used. Six months after the procedure, restenosis in post-PTA jugular veins was found in 33% of cases. Among 17 individuals who underwent stent implantation into the jugular vein, restenosis or partial in-stent thrombosis was identified in 55% of the cases. At the six month follow-up, there was no significant improvement in the EDSS or the ESS. The endovascular treatment of the CCSVI improved the quality of life according to the MSIS-29 scale but only up to three months after the procedure (with no differences in the six month follow-up assessment). Six months after the jugular vein angioplasty (with or without stent placement), a statistically significant improvement was observed only in the FSS and the HIS. Based on their findings, the researchers concluded that "endovascular treatment in individuals with MS and concomitant CCSVI did not have an influence on the patient's neurological condition; however, in the mid-term follow-up, an improvement concerning some parameters influencing the patient's quality-of-life parameters was observed." They also emphasized that there is an urgent need for a well-designed randomized controlled trial.

Zamboni and colleagues (2012) reported on a small series of eight individuals with ultrasound criteria for CCSVI undergoing immediate venoplasty compared to seven individuals undergoing delayed venoplasty. There were improvements on the EDSS (expanded disability status scale) for both groups following treatment, but no difference between groups in the first six months comparing immediate versus delayed treatment subjects. The relapse rate during the initial six months was 0.12% in the treatment group versus 0.66% in the control group; however this difference did not meet statistical significance. There were also trends toward improvement for the immediate treatment group on magnetic resonance imaging (MRI) scans, such as the number of T2 lesions, but these differences also did not reach statistical significance. No short-term adverse events were reported following the procedure, but the rate of restenosis at one year was 27% in treated individuals.

Van Zuuren and colleagues (2012), in a Cochrane Review, concluded there was no high level evidence to either support or refute the efficacy and safety of angioplasty for CCSVI in people with MS. The authors further noted that additional robust and well designed studies are needed.

There have been various reports of serious adverse and potentially fatal events occurring as a result of venous angioplasty for the treatment of MS (Doepp, 2010; Kahn, 2010; Qui 2010). Khan (2010) states: "Any invasive endovascular procedures including angioplasty and venous stent placement should be discouraged until there is conclusive evidence to justify their indication in MS."

More recently, Mandato and colleagues (2012) evaluated the safety of outpatient endovascular treatment in those with MS and CCSVI. A retrospective analysis was performed to assess complications occurring within 30 days of endovascular treatment of CCSVI. The study was comprised of 240 individuals and 257 procedures performed over eight months. The indication for treatment was symptomatic MS. Primary procedures accounted for 93.0% (239 of 257) of procedures, and repeat interventions accounted for 7% (18 of 257). For individuals treated primarily, 87% (208 of 239) had angioplasty and 11% (26 of 239) had stent placement. Five individuals were not treated. Of those with restenosis, 50% (9 of 18) had angioplasty and 50% (9 of 18) had stent placement. Complications reported in the participants after the procedures included headache in 8.2% (21 of 257) and neck pain in 15.6% (40 of 57); 52.5% (21 of 40) of these individuals underwent stent placement. Three individuals experienced venous thrombosis requiring retreatment within 30 days. Sustained intra-procedural cardiac arrhythmias were observed in three individuals with two requiring hospitalization. The authors reported that the correlation between MS and CCSVI is a new theory and future research is needed in this area to show the effectiveness of endovascular treatment.  This particular study demonstrated the risks of angioplasty and did not assess clinical outcomes after endovascular treatment of CCSVI.

The United States Food and Drug Administration (FDA) (2012) issued an alert  concerning the potential for adverse events following endovascular interventions for MS. Reports of adverse events obtained by the FDA included death, stroke, detachment and/or migration of stents, vein damage, thrombosis, cranial nerve damage, and abdominal bleeding. This alert cautioned that clinical trials of this procedure require FDA approval and an investigational device exemption due to potential for harms.

The American Academy of Neurology does not currently address venous angioplasty for the treatment of MS or CCSVI in any of their current MS guidelines. The Cardiovascular and Interventional Radiological Society of Europe (CIRSE) (2010) in a commentary on the treatment of CCSVI indicates there is a lack of evidence for the treatment of CCSVI, stresses the need for randomized trials and advises that this treatment should not be offered to those with MS outside of a well-designed clinical trial.

The U.K. National Center for Clinical Excellence (NICE) (2012) issued guidance on the use of percutaneous venoplasty to treat CCSVI in those with MS. The following statements on the diagnosis and treatment of CCSVI were included in this document:

• Current evidence on the efficacy of percutaneous venoplasty for chronic cerebrospinal venous insufficiency (CCSVI) for multiple sclerosis (MS) is inadequate in quality and quantity. Therefore, this procedure should only be used in the context of research.
• NICE encourages further research on percutaneous venoplasty for CCSVI for MS, in the form of robust controlled clinical trials. Studies should clearly define selection criteria and patient characteristics. They should also clearly define technical success which may include measurement of pressure gradients across treated vein segments before and after venoplasty. Outcomes should include clinical and quality of life measures.

At this time there is insufficient evidence available in the peer-reviewed published literature to support the use of venous angioplasty (with or without stent placement) for the treatment MS. The relationship between CCSVI and MS is not certain, the impact of treating CCSVI on outcomes of MS is not known and the safety and efficacy of this treatment have not been proven. Limitations of recent published studies include small sample size and lack of randomization. Current findings are preliminary and there are studies which demonstrate conflicting results. Results from large randomized controlled clinical trials are needed to further assess this proposed treatment modality.

Venous Angioplasty for Stenotic or Thrombosed Lower Extremities

Chronically Occluded Iliac Veins

Treatment of chronically occluded iliac veins has typically consisted of endovenous bypass. Raju and colleagues (2009) reported on 167 post-thrombotic total iliac occlusions which had been treated with percutaneous recanalization. The procedure was reportedly successful in 129 of 167 limbs (83%). During a 48-month follow-up period, 39 out of 139 stented limbs (28%) occluded. Seventeen of these individuals had patency restored but seven later re-occluded. The four-year secondary stent patency was 66%. While the majority of chronic total occlusions were successfully recanalized with very little morbidity, minimal downtime, sustained long-term stent patency, and substantial clinical improvement, one third of the study subjects failed to maintain patency.

Iliac Vein Compression Syndrome (also known as May-Thurner Syndrome)

Endovascular therapy, specifically catheter-directed thrombolysis followed by stent placement, is the current primary intervention for May-Thurner syndrome (Moudgill, 2009). Review of the current literature, primarily case studies and case series, indicates that angioplasty has also been used with mixed results. Peters and colleagues (2012) reports three cases and Zander (2008) reports one case of successful intervention in May-Thurner compression with angioplasty. However, Patel (2000) reports that 10 women with symptomatic May-Thurner syndrome failed an initial course of angioplasty and subsequently progressed to urokinase and stenting. One retrospective case review from a surgical registry included 15 May-Thurner cases in which venous angioplasty with stenting restored and maintained venous flow through the compressed area. Titus and colleagues (2011) described a series of iliofemoral venous angioplasty and stenting occurring over a four-year period. Charts were retrospectively reviewed for individual demographics, the extent of venous system involvement, the time course of the venous pathology, and any underlying cause. The 15 (42%) individuals with a recognized underlying etiology had been diagnosed with May-Thurner syndrome. An etiology was not recognized in nine cases. A total of 36 subjects (40 limbs) were stented from January 2005 through December 2008. Both lower extremities were involved in four subjects. Thrombolysis was performed in 19 cases (52.8%). The mean follow-up time period in the study population was 10.5 months. One stent in the study occluded acutely and required restenting. Primary patency rates at 6, 12, and 24 months were 88%, 78.3%, and 78.3%, respectively. Secondary patency rates for the same time frames were 100%, 95%, and 95%. Better outcomes were seen in stenting for May-Thurner syndrome and idiopathic causes, whereas external compression and thrombophilia seemed to portend less favorable outcomes (P < .001). Symptomatic improvement was reported in 24 of 29 individuals (83%) contacted by telephone follow-up. The authors concluded that iliofemoral venous stenting is a safe and effective method for the treatment of iliac venous occlusive disease. Acceptable patency rates can be expected through short-term follow-up, especially in the case of May-Thurner syndrome and idiopathic occlusion. The published evidence in support of venous angioplasty for May-Thurner syndrome is limited and further study is needed.

Ilio-femoral Venous Thrombosis

Kurklinsky and colleagues (2012) retrospectively analyzed 30-day, 1-year, and 3-year patency of chronically occluded ilio-femoral venous thrombosis treated with stent placement in a case series from a single institution. Records of 189 consecutive individuals treated by interventional radiology for ilio-femoral venous occlusions between March 1, 2003, and December 1, 2008, were reviewed. A total of 89 cases of chronic iliac or ilio-femoral deep vein thrombosis without involvement of the inferior vena cava met criteria for analysis. All individuals (91 limbs) successfully underwent angioplasty with placement of venous self-expanding stents. Patency rate at discharge was 100%. Following the index procedure, mean pressure gradient across the lesion decreased from 5.63 mm Hg to 0.71 mm. Median follow-up was 11.3 months (range, 0.8-72.4 mo). Follow-up at 30 days demonstrated 90 of 91 limbs to be patent. Primary patency rates of treated limbs at 1 and 3 years were 81% and 71%, respectively. Primary patency was lost in 17 cases (19.1%); interventions to maintain or restore stent patency were performed in 13 cases (14.6%). Primary assisted limb patency rates at 1 and 3 years were 94% and 90%, respectively; secondary patency rate was 95%. The authors concluded that angioplasty with stent placement for treatment of chronically thrombosed ilio-femoral veins is a low-risk procedure with acceptable patency rates for as long as three years. Although the authors concluded that angioplasty with stent placement for the treatment of chronically thrombosed ilio-femoral veins is a low-risk procedure with acceptable patency rates, the available peer reviewed literature is limited and additional study is needed.

Venous angioplasty is a procedure which can be performed during a venogram to open or bypass veins. It also can be used for placement of a stent, which keeps the vessel in an open position to allow for improved blood flow.

There are numerous conditions which have been successfully treated with venous angioplasty, including stenotic or thrombosed arterio-venous-dialysis access grafts; Budd-Chiari syndrome, superior vena cava syndrome and congenital heart disease. Venous angioplasty has not been proven to be efficacious in a variety of other conditions, including but not limited to the treatment of MS or CCSVI, chronically occluded iliac veins, iliac vein compression syndrome (May-Thurner syndrome), and ileo-femoral venous thrombosis.

Budd-Chiari syndrome: A rare disease characterized by obstruction of outflow from the small hepatic veins to the level of termination of the inferior vena cava.

May-Thurner syndrome: A rarely diagnosed condition caused by compression of the left iliac vein by the right iliac artery, which increases the risk of deep vein thrombosis in the left extremity.

Superior vena cava syndrome: A group of symptoms that occur (most often as a result of cancer) when the superior vena cava is partially blocked. The most common symptoms are coughing, trouble breathing, and swelling in the face, neck, upper body or arms.

Venogram: An X-ray test that takes pictures of blood flow through the veins in a certain area of the body.

The following codes for treatments and procedures applicable to this document are included below for informational purposes.  A draft of future ICD-10 Coding (effective 10/01/2014) related to this document, as it might look today, is included below for your reference.  Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy.  Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

When services are Medically Necessary:

When services are Investigational and Not Medically Necessary:
For the procedure codes listed above for all other diagnoses, or when the code describes a procedure indicated in the Position Statement section as investigational and not medically necessary.

Peer Reviewed Publications:

1. Beathard GA. Management of complications of endovascular dialysis access procedures. Semin Dial. 2003; 16(4):309.
2. Beathard GA. Percutaneous transvenous angioplasty in the treatment of vascular access stenosis. Kidney Int. 1992; 42(6):1390.
3. Doepp F, Paul F, Valdueza JM, et al. No cerebrocervical venous congestion in patients with multiple sclerosis. Ann Neurol. 2010; 68(2):173-183.
4. Fisher NC, McCafferty I, Dolapci M, Wali M, Buckels JA, Olliff SP, Elias E. Managing Budd-Chiari syndrome: a retrospective review of percutaneous hepatic vein angioplasty and surgical shunting. Gut. 1999; 44(4):568.
5. Han G, Qi X, Zhang W, et al. Percutaneous recanalization for Budd-Chiari syndrome: an 11-year retrospective study on patency and survival in 177 Chinese patients from a single center. Radiology. 2013; 266(2):657-667.
6. Kanterman RY, Vesely TM, Pilgram TK, et al. Dialysis access grafts: anatomic location of venous stenosis and results of angioplasty. Radiology. 1995; 195(1):135.
7. Khan O, Filippi M, Freedman MS, et al. Chronic cerebrospinal venous insufficiency and multiple sclerosis. Ann Neurol. 2010; 67(3):286-290.
8. Kostecki J, Zaniewski M, Ziaja K, et al. An endovascular treatment of Chronic Cerebro-Spinal Venous Insufficiency in multiple sclerosis patients - 6 month follow-up results. Neuro Endocrinol Lett. 2011; 32(4):557-562.
9. Kurklinsky AK, Bjarnason H, Friese JL, et al. Outcomes of venoplasty with stent placement for chronic thrombosis of the iliac and femoral veins: single-center experience. J VascInterv Radiol. 2012; 23(8):1009-1015.
10. Mandato KD, Hegener PF, Siskin GP, et al. Safety of endovascular treatment of chronic cerebrospinalvenous insufficiency: a report of 240 patients with multiple sclerosis. J Vasc Interv Radiol. 2012; 23(1):55-59.
11. Meng QY, Sun NF, Wang JX, Wang RH, Liu ZX. Endovascular treatment of Budd-Chiari syndrome. Chin Med J (Engl). 2011; 124(20):3289-3292.
12. Moudgill N, Hager E, Gonsalves C, et al. May-Thurner syndrome: case report and review of the literature involving modern endovascular therapy. Vascular. 2009; 17(6):330-335.
13. Pappas JN, Vesely TM. Vascular rupture during angioplasty of hemodialysis raft-related stenoses. J Vasc Access. 2002; 3(3):120.
14. Patel NH, Stookey KR, Ketcham DB, Cragg AH. Endovascular management of acute extensive iliofemoral deep venous thrombosis caused by May-Thurner syndrome. J Vasc Interv Radiol. 2000; 11(10):1297-1302.
15. Pelage JP, Denys A, Valla D, et al. Budd-Chiari syndrome due to prothrombotic disorder: mid-term patency and efficacy of endovascular stents. Eur Radiol. 2003; 13(2):286-293.
16. Peters M, Syed RK, Katz M, et al. May-Thurner syndrome: a not so uncommon cause of a common condition. Proc (Bayl Univ Med Cent). 2012; 25(3):231-233.
17. Qiao T, Liu CJ, Liu C, et al. Interventional endovascular treatment for Budd-Chiari syndrome with long-term follow-up. Swiss Med Wkly. 2005; 135(21-22):318-326.
18. Qiu J. Venous abnormalities and multiple sclerosis: another breakthrough claim? Lancet Neurol. 2010; 9(5):464-465.
19. Raju S, Neglén P. Percutaneous recanalization of total occlusions of the iliac vein. J Vasc Surg. 2009; 50(2):360-368.
20. Schindler N, Vogelzang RL. Superior vena cava syndrome. Experience with endovascular stents and surgical therapy. Surg Clin North Am. 1999; 79(3):683.
21. Sundström P, Wåhlin A, Ambarki K, et al. Venous and cerebrospinal fluid flow in multiple sclerosis: a case-control study. Ann Neurol. 2010; 68(2):255-259.
22. Titus JM, Moise MA, Bena J, et al. Iliofemoral stenting for venous occlusive disease. J Vasc Surg. 2011; 53(3):706-712.
23. Uberoi R. Quality assurance guidelines for superior vena cava stenting in malignant disease. Cardiovasc Intervent Radiol. 2006; 29(3):319.
24. Van Ha T. Percutaneous management of thrombosed dialysis access grafts. Semin Intervent Radiol. 2004; 21(2):77-81.
25. Zamboni P, Galeotti R, Menegatti E, et al. A prospective open-label study of endovascular treatment of chronic cerebrospinal venous insufficiency. J Vasc Surg. 2009c; 50(6):1348-1358.e1-3. Erratum in: J Vasc Surg. 2010; 51(4):1079.
26. Zamboni P, Galeotti R, Menegatti E, et al. Chronic cerebrospinal venous insufficiency in patients with multiple sclerosis. J Neurol Neurosurg Psychiatry. 2009a; 80(4):392-399.
27. Zamboni P, Galeotti R, Weinstock-Guttman B, et al. Venous angioplasty in patients with multiple sclerosis: results of a pilot study. Eur J Vasc Endovasc Surg. 2012; 43(1):116-122.
28. Zamboni P, Menegatti E, Galeotti R, et al. The value of cerebral Doppler venous haemodynamics in the assessment of multiple sclerosis. J Neurol Sci. 2009b; 282(1-2):21-27.
29. Zander KD, Staat B, Galan H. May-Thurner Syndrome resulting in acute iliofemoral deep vein thrombosis in the postpartum period. Obstet Gynecol. 2008; 111(2 Pt 2):565-569.
30. Zhang CQ, Fu LN, Xu L, et al. Long-term effect of stent placement in 115 patients with Budd-Chiari syndrome. World J Gastroenterol. 2003; 9(11):2587-2591.
31. Zivadinov R, Marr K, Cutter G, et al. Prevalence, sensitivity, and specificity of chronic cerebrospinal venous insufficiency in MS. Neurology. 2011; 77(2):138-144.

Government Agency, Medical Society, and Other Authoritative Publications:

1. Allen HD, Beekman RH 3rd, Garson A Jr, et al. Pediatric therapeutic cardiac catheterization: a statement for healthcare professionals from the Council on Cardiovascular Disease in the Young, American Heart Association. Circulation. 1998; 97(6):609-625.
2. American Academy of Neurology. Practice Guidelines. Available at: http://www.aan.com/go/practice/guidelines. Accessed on April 10, 2013.
3. FDA News Release: FDA issues alert on potential dangers of unproven treatment for multiple sclerosis. Available at: http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm303538.htm?source=govdelivery. Accessed on April 10, 2013.
4. National Kidney Foundation Clinical Practice Guidelines and Clinical Practice Recommendations. 2006 updates. Guideline 6. Treatment of Arteriovenous graft complications. Available at: http://www.kidney.org/professionals/KDOQI/guideline_upHD_PD_VA/va_guide6.htm. Accessed on April 10, 2013.
5. NICE. Percutaneous venoplasty for chronic cerebrospinal venous insufficiency for multiple sclerosis. March 2012. Available at:  http://www.nice.org.uk/nicemedia/live/13064/58610/58610.pdf. Assessed on April 10, 2013.
6. Reekers JA, Lee MJ, Belli AM, Barkhof F. Cardiovascular and Interventional Radiological Society of Europe Commentary on the Treatment of Chronic Cerebrospinal Venous Insufficiency. Cardiovasc Intervent Radiol. 2011; 34(1):1-2.
7. van Zuuren EJ, Fedorowicz Z, Pucci E, et al. Percutaneous transluminal angioplasty for treatment of chronic cerebrospinal venous insufficiency (CCSVI) in multiple sclerosis patients. Cochrane Database Syst Rev. 2012; 12:CD009903. doi: 10.1002/14651858.CD009903.pub2.

1. American Academy of Neurology. This Way In: CCSVI and Multiple Sclerosis. Neurology Now. 2010. Available at: http://www.aan.com/elibrary/neurologynow/?event=home.showArticle&id=ovid.com:/bib/ovftdb/01222928-201006040-00007. Accessed on April 10, 2013.
2. National Multiple Sclerosis Society. Chronic Cerebrospinal Venous Insufficiency (CCSVI). Available at: http://www.nationalmssociety.org/research/intriguing-leads-on-the-horizon/ccsvi/index.aspx. Accessed on April 10, 2013.

Endovascular Treatment
Liberation Procedure
Percutaneous Transluminal Angioplasty (PTA)
Percutaneous Venoplasty
Venous Angioplasty

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