Cryoplasty Or Conventional Balloon Post-dilation of Nitinol Stents For Revascularization of Peripheral Arterial Segments - COBRA


The goal of the trial was to compare post-dilation of a nitinol self-expanding stent with cryoplasty (PolarCath, Boston Scientific) versus conventional balloon angioplasty for revascularization of the superficial femoral artery.


Post-dilation with a cryoplasty balloon will reduce restenosis.

Study Design

  • Randomized
  • Parallel

Patient Populations:

  • Diabetic patients at least 21 years of age with lifestyle-limiting claudication
  • Use of a nitinol self-expanding stent ≥60 mm in a superficial femoral artery ≥5 mm

    Number of screened applicants: 121
    Number of enrollees: 90
    Duration of follow-up: 1 year
    Mean patient age: 63 years
    Percentage female: 18%


  • Serum creatinine ≥2.0 mg/dl
  • Absence of at least one vessel brisk infrapopliteal run-off to the foot
  • Left ventricular ejection fraction ≤25%
  • Allergy to iodinated contrast, aspirin, or clopidogrel
  • Contraindication to anticoagulation
  • Pregnancy
  • Leukopenia (<3000/L), anemia (<10 g/dl), or thrombocytopenia (<100,000/L)

Primary Endpoints:

  • Binary restenosis at 12 months, defined as ≥2.5 times increase in peak systolic velocity by duplex ultrasound

Drug/Procedures Used:

At baseline, the use of aspirin was 69%, clopidogrel 40%, statin 89%, and angiotensin-converting enzyme inhibitor/angiotensin-receptor blocker 80%.

Concomitant Medications:

Diabetic patients with lifestyle-limiting claudication were randomized to post-dilation of a nitinol self-expanding stent with cryoplasty (n = 45) versus conventional balloon angioplasty (n = 45).

Principal Findings:

Overall, 90 patients were randomized. The mean age was 63 years, 18% were women, 67% had coronary artery disease, 16% of the diabetics were insulin requiring, and the mean glycated hemoglobin was 7.4. The mean Rutherford stage was 3.2, mean ankle-brachial index was 0.6, 56% of lesions were chronic total occlusions, mean lesion length was 147 mm, mean total stent length was 184 mm, and mean stent diameter was 6 mm.

The primary endpoint, restenosis at 12 months, occurred in 29.3% of the cryoplasty group versus 55.8% of the conventional balloon angioplasty group (p = 0.01).


Among diabetic patients with lifestyle-limiting claudication, post-dilation of a nitinol self-expanding stent with cryoplasty reduced restenosis compared with conventional balloon angioplasty. Cryoplasty represents a novel treatment approach to improve revascularization of the lower extremities.


Presented by Dr. Subhash Banerjee at the Transcatheter Cardiovascular Therapeutics Meeting (TCT 2011), San Francisco, CA, November 11, 2011.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention, Atherosclerotic Disease (CAD/PAD), Interventions and Coronary Artery Disease

Keywords: Coronary Artery Disease, Insulin, Life Style, Ankle Brachial Index, Femoral Artery, Ticlopidine, Lower Extremity, Angioplasty, Balloon, Coronary, Stents, Hemoglobin A, Glycosylated, Diabetes Mellitus

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