An Update on Three Venous Stent Trials


The VIRTUS Trial for the VENITI™ VICI™ Venous Stent System

Percutaneous stenting of the iliofemoral venous outflow system has evolved in to the preferred approach for management of chronic venous obstruction. The procedure can be performed with low morbidity, low mortality, long-term high patency rate, and low rate of in-stent restenosis. It has replaced bypass surgery as the primary treatment. In 2007, the American Venous Forum stated that, “iliocaval venoplasty and stenting has emerged as the ‘method of choice’ in relieving proximal iliofemoral obstruction.” Although the data available indicate that stenting for chronic obstructive iliofemoral lesions comes with a very low risk, there are still no randomized or multicenter trials on venous stenting. The literature to date consists mainly of retrospective single center trials. 

The Veniti VIRTUS study is a randomized multicenter trial designed to assess the safety and efficacy of the VENITI™ VICI™ Venous Stent System (VENITI, Inc.) when used to treat clinically significant chronic non-malignant obstruction of the Iliofemoral venous segment. This study is unique in that it is prospective, has three core labs, and will have the safety data adjudicated by a DSMB and CEC. The study will recruit up to 200 patients at up to 30 global centers. Primary patency at the 12-month follow-up is the efficacy endpoint. The primary safety endpoint for this study will be a composite endpoint of any major adverse event within 30 days. The trial will look at several QoL scales such as CIVQ2 and VCSS as secondary endpoints and will include a specific algorithm for antiplatelet/anti-coagulation post stenting. Patients will be followed for up to five years.

VENITI is committed to investing in this clinical research to demonstrate the clinical value of its industry-leading venous stenting technology to ensure the treatment becomes available to those who may benefit. The Venous Stent System is CE marked under the European Medical Devices Directive (93/42/EEC) and commercially available in Europe. CAUTION: Investigational device. Limited by United States law to investigational use. VENITI and VENITI VICI are trademarks of VENITI, Inc. ©2014 VENITI, Inc. All Rights Reserved. Produced in the U.S. For more information, call +1 (314) 282-3753 or visit www.veniti.com. For more information on the VIRTUS Trial please refer to www.clincal trials.gov  NCT NCT02112877


Cook Medical – Zilver Vena VIVO Study Summary

Cook Incorporated (Bloomington, Indiana) is sponsor of the VIVO clinical study to evaluate the safety and effectiveness of the Zilver Vena Venous Stent in the treatment of symptomatic iliofemoral venous outflow obstruction.  The Zilver Vena Venous Stent is a self-expanding nitinol stent, available in 14 and 16 mm diameters and 60, 100, and 140 mm lengths, designed specifically for use in the iliofemoral veins.  The Zilver Vena stent has increased radial force compared to arterial stents, with similar flexibility, both of which are important in the dynamic iliofemoral vein environment.  The Zilver Vena Venous Stent has been commercially-available in Europe since October 2010, and remains an investigational device in the United States.

The VIVO study is led by co-Global Principal Investigators Dr. Anthony J. Comerota (Jobst Vascular Institute, OH) and Dr. Lawrence “Rusty” Hofmann (Stanford University, CA).  The VIVO study will enroll a total of 243 patients at up to 30 institutions in the United States and Taiwan.  Enrollment in the study began in December 2013; 21 sites are currently eligible to enroll patients, and a total of 78 patients have been enrolled in the study to date.  Adults with an age 18 years and older who have symptomatic venous outflow obstruction (i.e., CEAP “C” ≥ 3 or VCSS pain score ≥ 2) in one iliofemoral venous segment (i.e., one limb) are being screened at eligible sites; other eligibility criteria apply.  The primary study outcomes are freedom from major adverse events at 30 days and primary patency at 1 year, and the secondary outcome measure is the change in the Venous Clinical Severity Score (VCSS) at 1 and 12 months.   

For additional study information, please refer to ClinicalTrials.gov (NCT01970007).


The Use of GORE VIABAHN Endoprosthesis with Heparin Bioactive Surface to treat venous occlusions

This is a Physician-Sponsored IDE study held by Dr. Hofmann.
PI : Lawrence “Rusty” Hofmann, MD

Background:

Patients with venous occlusions experience significant pain and swelling of the effected extremity due to venous hypertension. The majority of these occlusions are the result of chronic deep venous thrombosis and the current treatment is compression stockings.  Recent publication have focused on stenting the iliac veins and inferior vena cava, and have demonstrated impressive results.  These studies use large diameter bare metal stents.  To date, there has only been a limited report of stenting the femoralpopliteal veins.  In the Deep Venous Registry, the authors reported that 5 patients had a bare metal stent placed in the femoral-popliteal segment. Four of these 5 stents thrombosed within a mean of 42 days (range 17-70 days).  The thrombosis rate would likely decrease significantly with the use of a stent with an anticoagulant bioactive surface.

The focus of this proposal is to determine the safety and feasibility of using the GORE VIABAHN endoprosthesis with heparin bioactive surface to treat venous occlusions and stenosis in locations that have demonstrated poor patency rates with bare metal stents. These locations include the popliteal vein, femoral vein, brachial vein, axillary vein, subclavian vein, and jugular vein.

Primary Endpoint: Decrease in pain (visual analog scale) and swelling of effected extremity (grade 0, absent; grade 1, pitting, not obvious; grade 2, visible ankle edema; and grade 3, massive, encompassing the entire leg; circumference)

Secondary Endpoints:

  1. Primary patency
  2. Assisted-primary patency
  3. Secondary patency
  4. Adverse events
  5. Venous Symptom Severity Scale and VEINS-QOL questionnaire

  *Patency rates determined by either venography, computed tomographic venography, magnetic resonance venography or ultrasound.

Sample Size = 15 patients
Length of Study = 2 years 

Inclusion Criteria:

a.     Patient is at least 18 years old.
b.     Patient has clinical manifestations (i.e. symptoms and/or signs) of chroic DVT of an extremity
c.     Patient is at least 18 years old.
d.     Imaging confirmation of venous stenosis or occlusion involving the brachial, axillary, subclavian, femoral, and/or politeal veins.
e.     Obstructed vessel caliber can accommodate a 8FR System, from insertion site to target segment
f.      Patient is able to read and answer a questionnaire in English.

Exclusion Criteria:

a.     History of life-threatening reaction to contrast material
b.     Unwilling or unable to provide informed consent, or return for required follow-up evaluations.
c.     Participating in another investigational study that has not completed follow-up testing.
d.     Cannot receive LMWH and vitamin K antagonists (VKA) due to: contraindications to anticoagulation or patient will receive LMWH alone.
e.     Documented intracranial or intraspinal tumor .
f.      Intracranial or intraspinal surgery within the past 3 months, or other major surgery within the past 10 days prior to planned index procedure.
g.     Acute or chronic symptomatic musculoskeletal condition in target limb (e.g. trauma, fracture, moderate/severe arthritis).
h.     Documented patent foramen ovale or other right-to-left cardiac shunt.
i.      Absolute contraindication to contrast media or renal insufficiency (baseline creatinine >2.0 mg/dL).
j.      Unwilling or unable to provide informed consent, or return for required follow-up evaluations.
k.     Participating in another investigational study that has not completed follow-up testing.
l.      Pregnancy or nursing.

The study has been closed due to limited enrollment. There were a few factors that contributed to limited enrollment. The first is that many patients presents also with iliofemoral disease. Once this was treated, the patients were relatively asymptomatic and thus ethically, I did not enroll them to treat the fem-pop disease.  Secondly, there were some patients that would have required stenting over either the deep femoral vein orifice and thus did not feel it was appropriate to jail off that vessel.  It was these patients that I treated with venoplasty alone of the femoral vein and got encouraging results. So now, our default protocol is to do venoplasty, and not stent, even with a bare stent in the femoral vein due to the good results from venoplasty alone.

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