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NCT Number: NCT00827853

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

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.

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Key information

Conditions

Peripheral Vascular Disease Cardiovascular Diseases Diabetes Mellitus Endocrine System Diseases Glucose Metabolism Disorders Metabolic Diseases Nutritional and Metabolic Diseases Peripheral Vascular Diseases Vascular Diseases

Age range

21 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Midwest Cardiovascular Research Foundation, Davenport, Iowa, United States

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About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Conventional angioplasty balloon

Procedure

Post-dilation of clinically indicated nitinol self-expanding stents in the SFA using conventional angioplasty balloon

cryoplasty balloon

Procedure

Post-dilation of clinically indicated nitinol self-expanding stents in the SFA using cryoplasty balloon

Primary outcomes

  1. Rate of binary restenosis as determined by duplex ultrasound.

    Time frame: 1 year

Secondary outcomes

  1. Resting ankle-brachial index

    Time frame: 6 months and 1 year

Sponsors and collaborators

Lead sponsor

North Texas Veterans Healthcare System

Fed

Collaborators

  • Boston Scientific Corporation

Registry information

Official study title

PolarCath® Cryoplasty Versus Conventional Balloon Post-dilation of Nitinol Stents for Peripheral Vascular Interventions (COBRA)

Acronym: COBRA

Important dates

Study start
2008
Primary completion
2011
Study completion
2012
First posted
Jan 23, 2009
Registry last updated
Nov 4, 2013

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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