We updated the design of this site on December 18, 2017. Learn more.
ClinicalTrials.gov Menu

Study Comparing Two Methods of Expanding Stents Placed in Legs of Diabetics With Peripheral Vascular Disease (COBRA)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
ClinicalTrials.gov Identifier: NCT00827853
Recruitment Status : Completed
First Posted : January 23, 2009
Last Update Posted : November 4, 2013
Information provided by (Responsible Party):

Study Description
Brief Summary:

Despite recent advances in stent technology and its widespread application in the treatment of peripheral vascular disease (PVD), incidences of partial or complete blockage of stent lumen (in-stent restenosis) due to in growth of cells (neo-intimal proliferation) is unacceptably high.

In diabetics with long superficial femoral artery (SFA) lesions, in-stent restenosis rates are higher than in non-diabetics. Consequently interventional techniques that curtail in-stent restenosis have to be explored. Cryoplasty is a stent expansion method in which a balloon is expanded using pressurized nitrous oxide gas. As the nitrous oxide expands in the balloon it cools the surroundings to about -10 degrees C. This induces programed death (apoptosis) of the smooth muscle cells in arterial wall.

The investigators hypothesize that Cryoplasty, by inducing an apoptotic smooth muscle cell response, when applied to post-dilation of nitinol self-expanding stents in the Superficial Femoral Artery (SFA) of diabetics, would lead to decreased in-stent restenosis due to decreased neointimal proliferation.

Condition or disease Intervention/treatment
PERIPHERAL VASCULAR DISEASE Procedure: Conventional angioplasty balloon Procedure: cryoplasty balloon

Detailed Description:
The pre-recruitment process would identify diabetics who have life-style limiting claudication in their legs. Based on the physicians decision such patients may have to undergo a peripheral vascular intervention of the SFA, with placement of self-expanding nitinol stents. If such a decision is made, the patient will be randomized to either cryoplasty balloon post-dilation of the stent or to conventional angioplasty balloon post-dilation after obtaining informed consent. At one year, in segment (stent + 10 mm beyond its proximal and distal edges) peak systolic velocity by duplex ultrasound will be measured in all subjects to assess the rate of binary restenosis defined as a > or = 2.5 times increase in peak systolic velocity (primary endpoint). A 6 month resting ankle brachial index, and binary restenosis may be assessed as a secondary endpoint of the study.

Study Design

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 90 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single (Participant)
Primary Purpose: Treatment
Official Title: PolarCath® Cryoplasty Versus Conventional Balloon Post-dilation of Nitinol Stents for Peripheral Vascular Interventions (COBRA)
Study Start Date : November 2008
Primary Completion Date : August 2011
Study Completion Date : February 2012

Resource links provided by the National Library of Medicine

U.S. FDA Resources

Arms and Interventions

Arm Intervention/treatment
Experimental: 1
Conventional angioplasty balloon post-dilation of nitinol self expanding stents
Procedure: Conventional angioplasty balloon
Post-dilation of clinically indicated nitinol self-expanding stents in the SFA using conventional angioplasty balloon
Experimental: 2
Cryoplasty balloon post-dilation
Procedure: cryoplasty balloon
Post-dilation of clinically indicated nitinol self-expanding stents in the SFA using cryoplasty balloon

Outcome Measures

Primary Outcome Measures :
  1. Rate of binary restenosis as determined by duplex ultrasound. [ Time Frame: 1 year ]

Secondary Outcome Measures :
  1. Resting ankle-brachial index [ Time Frame: 6 months and 1 year ]

Eligibility Criteria

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

Ages Eligible for Study:   21 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Diabetics, insulin or non-insulin dependent above 21 years of age
  • Able to provide an informed consent
  • Life expectancy > 1 year
  • Presenting with with moderate claudication (Rutherford stage 2), severe intermittent claudication (Rutherford stage 3), chronic critical limb ischemia with pain while the patient was at rest(Rutherford stage 4), or chronic critical limb ischemia with ischemic ulcers/gangrene(Rutherford stage 5/6)
  • Placement of > 5 mm in diameter self-expanding Nitinol stent in the SFA, with at least 1 vessel infra-popliteal runoff
  • Placement of > 60 mm in length self-expanding Nitinol stent in the SFA, with at least 1 vessel infra-popliteal runoff

Exclusion Criteria:

  • Serum creatinine of >= 2.0 mg/dl
  • Presence of iodinated contrast allergy
  • Presence of allergy to Aspirin and Plavix
  • Pregnancy
  • Relative or absolute contraindication for anticoagulation
  • History of allergy to Angiomax and unfractionated heparin or heparin induced thrombocytopenia (HIT)
  • White blood count < 3000; platelet count < 100000, and baseline hemoglobin < 10 g/dl
  • Absence of brisk at least 1 vessel infra-popliteal runoff to the foot
  • Left ventricular ejection fraction < 25%
  • Relative or absolute contraindication for anticoagulation
Contacts and Locations

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00827853

United States, Iowa
Midwest Cardiovascular Research Foundation
Davenport, Iowa, United States, 52803
United States, Oklahoma
VA Medical Center
Oklahoma City, Oklahoma, United States, 73104
United States, Texas
Dallas Veterans Hospital
Dallas, Texas, United States, 75216
Dallas Presbyterian Hospital
Dallas, Texas, United States, 75231
Sponsors and Collaborators
North Texas Veterans Healthcare System
Boston Scientific Corporation
Principal Investigator: Subhash Banerjee, MD VA North Texas Healthcare Systen, Dallas, TX
Study Director: Emmanouil S Brilakis, MD, PhD VA North Texas Healtcare System, Dallas, TX
Study Director: Tony S Das, MD Texas Health Resources
More Information


Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: Subhash Banerjee, Chief of Cardiology, North Texas Veterans Healthcare System
ClinicalTrials.gov Identifier: NCT00827853     History of Changes
Other Study ID Numbers: BOSTON SCI R&E 9-21-07#2
First Posted: January 23, 2009    Key Record Dates
Last Update Posted: November 4, 2013
Last Verified: November 2013

Keywords provided by Subhash Banerjee, North Texas Veterans Healthcare System:
Peripheral Vascular Disease (PVD)
Superficial Femoral Artery (SFA)

Additional relevant MeSH terms:
Vascular Diseases
Peripheral Vascular Diseases
Peripheral Arterial Disease
Cardiovascular Diseases
Arterial Occlusive Diseases