Iliac Vein Chronic Total Occlusion Revascularization Using the Vici Venous Stent System

VASCULAR DISEASE MANAGEMENT 2019;16(10):E130-E133

Abstract

Chronic venous insufficiency due to central venous obstruction is an underrecognized and undertreated disease that can be associated with significant morbidity, including non-healing ulcers, venous claudication, and recurrent cellulitis. Iliac vein stenting is the preferred methodology for treating these patients due to the lack of dedicated venous stents in the United States. However, the results of stenting in complex venous disease, such as chronic total occlusions or severe fibrotic lesions, have been suboptimal. Herein, we demonstrate a case of iliac vein chronic total occlusion revascularized with the Vici Venous Stent (Boston Scientific).

Chronic venous insufficiency has a devastating effect on patient quality of life, and also has significant adverse socioeconomic consequences. Chronic venous insufficiency encompasses an entire range of morphologic and functional abnormalities, such as venous claudication, and may result in swelling, dry skin, itching, muscle cramps, lipodermatosclerosis, ulceration, and/or pain and heaviness in the legs.^1,2 Central venous obstruction (CVO) due to post-thrombotic syndrome or due to non-thrombotic disorders such as May-Thurner syndrome often results in chronic venous insufficiency. The exact incidence of CVO is unknown since most patients are asymptomatic, but based on a computed tomography study of 50 individuals, the incidence of hemodynamically significant CVO is about 25%.³ In the last decade, percutaneous endovascular stenting has emerged as the treatment of choice for CVO and has shown great efficacy.^4,5 The overall cumulative primary, primary-assisted, and secondary patency rates up to 72 months have been reported as 67% to 73%, 76% to 88%, and 90% to 93%, respectively.^6,7 However, the primary patency at 60 months is only 50% in chronic total occlusions (CTOs) of the inferior vena cava (IVC) or iliac veins.⁸ Surgical bypass for iliac vein/IVC CTOs also has low patency rates and high morbidity.⁹ Thus, endovascular reconstruction is the preferred revascularization method in CTOs. 

Case Report

A 90-year-old man with a history of left-sided deep vein thrombosis (DVT) after receiving an IVC filter 8 years ago presented with Clinical-Etiology-Anatomy-Pathophysiology (CEAP) 4 symptoms of venous insufficiency in his right leg. Additionally, he had CEAP 6 symptoms of venous insufficiency and a 3 cm non-healing venous ulcer on his left ankle. There was no evidence of superficial venous reflux. The patient was brought to the cardiac catheterization laboratory to evaluate for CVO. The first venogram was not recorded but showed a bilateral iliac vein CTO through the IVC filter. The IVC filter seemed well embedded in the IVC wall and did not appear to be retrievable. 

The CTO could not be crossed with a .035-inch Glidewire (Terumo). A stiff .014-inch guidewire and a 5 French support catheter were required for crossing. The first recorded images were obtained after the CTO had been crossed with the 5 French support catheter (Figure 1).  After crossing, J-tipped .035-inch wires were placed in the IVC from the bilateral groins. We thought there was a post-thrombotic occlusion, so we performed rheolytic thrombectomy with the AngioJet ZelanteDVT thrombectomy catheter (Boston Scientific) in the bilateral iliac veins and into the IVC filter, after which intravascular ultrasound (IVUS) was performed (Figure 2). 

The vessels were diffusely diseased, making it difficult to establish a distal landing zone and reference vessel size. The hard, fibrotic plaque needed to yield before stenting, and the reference vessel size could not be adequately determined, so we decided to perform initial balloon angioplasty with undersized balloons at high pressure. Kissing balloon inflation through the IVC filter struts was performed with two 8 × 100 mm balloons at 20 atmospheres. These balloons were used sequentially to dilate the entire iliofemoral system (Figure 3). Following this dilation, we performed angioplasty in the bilateral iliac veins with 14 × 40 mm Atlas balloons (BD) with high pressure inflations. Based on IVUS measurements, two 16 × 90 mm Vici Venous Stents (Boston Scientific) were placed in a kissing manner starting just below the level of the IVC filter in the IVC and extended into the iliac veins. There was no foreshortening with these stents, which allowed for precise stent delivery. On the left side, there was an additional lesion below the stent that extended into the common femoral vein, which was treated with another 14 × 60 mm Protégé stent (Medtronic). This stent was selected instead of a conventional Wallstent (Boston Scientific) since the distal edge of the lesion was very close to the sheath insertion site, and we wanted a precise stent landing without any foreshortening or lengthening. Final venogram and IVUS demonstrated brisk flow bilaterally and a good, final luminal area of 136 mm²(Figures 4-5). 

Discussion

We suspect that the patient had underlying May-Thurner syndrome on the left side, which probably resulted in the original DVT. Over the years, he likely developed a CTO due to the post-thrombotic process, with additional thrombosis in the IVC and right iliac veins under the IVC filter.  

In large arteries, the phenomenon of auto-regulation results in peripheral vasodilation, which offsets the effect of stenosis. Perfusion is not hampered until there is 60% to 70% stenosis, but this phenomenon is lacking in the venous system. Thus, as little as  a 13% caliber reduction can result in hemodynamic alteration.¹⁰ The minimally invasive nature of iliac vein stenting, and its excellent safety profile, has made iliac vein stenting an attractive option in patients who fail conservative therapies.^1,5 

There are some important technical features to highlight in this case. In cases of post-thrombotic occlusions, dense fibrotic tissue requires adequate pre-dilation with large, high-pressure, non-compliant balloons. Prior experience has shown that use of 18 to 20 mm balloons up to 16 to 18 atmospheres is well tolerated in the iliofemoral system.⁸ In our case, we performed high-pressure balloon inflations with Atlas balloons for adequate luminal gain and disruption of the thick, fibrous tissue. IVUS imaging is mandatory for identifying adequate landing zones, as poor inflow and outflow created by underestimating the length can result in stent malfunction.^11,12 

The development of new, dedicated venous stents deserves a special mention. Originally, arterial stents were adapted for use in veins, with a reasonable outcome expected. However, as compared to the arterial system, venous vessel stenting requires stents with a larger diameter and higher radial force in order to serve anatomical needs and to overcome underlying external compression.^13,14 Although there are 8 different dedicated venous stents available in the European market, there were no dedicated venous stents available in the United States until the recent FDA approval of the Vici Venous Stent System. The VIRTUS clinical trial demonstrated 84% primary patency rates of the Vici stents in clinically significant iliofemoral venous lesions.¹⁵ These stents have a high radial strength and, unlike the previously used Wallstents, they do not foreshorten, allowing for more accurate placement. Accurate placement was very important in this case because the stents had to abut the IVC filter with precise placement. These dedicated venous stents may help to improve the patency rates of venous CTOs in the future.

In most reported series, venous stenting carried no risk of death, pulmonary embolism, or major bleeding, and the procedural success rate has been exceptional.^8,16,17 Symptom relief is profound, with 91% of patients reporting improvement in pain and 83% reporting improvement in swelling.⁸

Conclusion 

Endovascular management of CVO has a high technical success rate and a low complication rate that can significantly help  to improve patient morbidity and symptoms. With the advent of new, dedicated venous stents, there is great potential for incremental benefits in endovascular revascularization of complex venous obstructive lesions.  

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest and report no conflicts of interest regarding the content herein.

Manuscript submitted on June 2, 2019; accepted on June 27, 2019.

Address for correspondence: Craig M. Walker, MD, Cardiovascular Institute of the South, 225 Dunn Street, Houma, Louisiana, 70360. Email: craig.walker@cardio.com

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