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COBRA Trial C ryoplasty o r Conventional B alloon Post-dilation of Nitinol Stents For R evascularization of Peripheral A rterial Segments PowerPoint PPT Presentation


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ClinicalTrial.gov Identifier: NCT00827853. COBRA Trial C ryoplasty o r Conventional B alloon Post-dilation of Nitinol Stents For R evascularization of Peripheral A rterial Segments . Subhash Banerjee, MD Chief, Division of Cardiology, VA North Texas Health Care

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COBRA Trial C ryoplasty o r Conventional B alloon Post-dilation of Nitinol Stents For R evascularization of Peripheral A rterial Segments

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ClinicalTrial.gov Identifier: NCT00827853

COBRA TrialCryoplasty or Conventional Balloon Post-dilation of Nitinol Stents For Revascularization of Peripheral Arterial Segments

Subhash Banerjee, MD

Chief, Division of Cardiology, VA North Texas Health Care

Associate Prof. of Medicine,

UT Southwestern Medical Center

Dallas, TX

On behalf of COBRA investigators:


Disclosure statement of financial interest l.jpg

Grant/Research Support

Consulting Fees/Honoraria

Major Stock Shareholder/Equity

Ownership/Founder

Intellectual Property Rights

Boston Scientific Corporation, Medicines Company, Gilead, Relypsa

Medtronic, Cordis, St Jude, Gilead, Boehinger, Sanofi

Mdcare Global (spouse)

Mdcare Global (spouse)

Mdcare Global (spouse)

Disclosure Statement of Financial Interest

Within the past 12 months, I or my spouse/partner have had a financial interest/arrangement or affiliation with the organization(s) listed below.

Affiliation/Financial Relationship

Company


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COBRA TrialCryoplasty or Conventional Balloon Post-dilation of Nitinol Stents For Revascularization of Peripheral Arterial Segments

Investigators:

Subhash Banerjee, MD VA North Texas HCS/UTSW

Emmanouil S. Brilakis, MD, PhD VA North Texas HCS/UTSW

Tony Das, MD Presbyterian Hospital of Dallas

Kenneth Saland, MD Presbyterian Hospital of Dallas

Mazen Abu-Fadel, MD Oklahoma City VAMC/OU

Faisal Latif, MD Oklahoma City VAMC/OU

Eric Dipple, MD Midwest CV Research Foundation

Nicholas Shammas, MD Midwest CV Research Foundation

*UTSW: University of Texas Southwestern Medical Center

±VAMC: VA Medical Center

¥ OU: Oklahoma University


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COBRA TrialCryoplasty or Conventional Balloon Post-dilation of Nitinol Stents For Revascularization of Peripheral Arterial Segments

Cryoplasty

  • PolarCath® peripheral dilatation system simultaneously dilates & cools the vessel wall

  • Cooling (-10oC) is achieved by inflating the balloon with nitrous oxide instead of saline and contrast

N2O Refrigerant

Cylinder

Balloon

Catheter

  • Mechanisms of Action

  • Induces smooth muscle cell (SMC) apoptosis1

  • Minimizes SMC necrosis (-5 to -15oC)2

  • Reduces in-stent restenosis (ISR)

Microprocessor-Controlled

Inflation Unit

PolarCath is a trademark of Boston Scientific Corporation and its affiliates.

Image property of Boston Scientific Corporation

1Isner et al, Circulation; 1995 2Virmani et al, CryoLetters; 2005


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COBRA TrialCryoplasty or Conventional Balloon Post-dilation of Nitinol Stents For Revascularization of Peripheral Arterial Segments

Background: Diabetes mellitus is associated with increased risk of in-stent restenosis after superficial femoral artery (SFA) stenting with nitinol self-expanding stents (nSES)1

Hypothesis: When compared to conventional balloon angioplasty, cryoplasty post-dilation decreases the risk of SFA nSES in-stent restenosis

1Bakken et al, Journal of Vasc Surgery; 2007


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COBRA Trial

Design

121 patients with DM consented between August 2008 and December 2010 in 4 clinical sites in U.S.

  • DESIGN: Prospective, randomized, multi-center clinical evaluation of the PolarCath® system vs. conventional balloon post-dilation of nSES implanted in the SFA of patients with DM, presenting with life-style limiting claudication

  • OBJECTIVE: To compare the rates of binary restenosis, at 12 months, as determined by duplex ultrasound (DUS)

4 (8.9%) Deaths*

47 (39%) patients not stented

90 SFA nSES implanted

(74 patients/16 B/L)

nSES Post-dilation

Randomization 1:1

Conventional Balloon Group or CBA (N=45)

Cryoplasty Group

(N=45)

2 (4.4%) Deaths*

≥2.5 times increase in Doppler peak

systolic velocity (PSV) in the stented segment and 10mm beyond its

proximal and distal edges

DUS and clinical follow-up at 12 months in 95.5% (N=43)

DUS and clinical follow-up at 12 months in 91.1% (N=41)

nSES: nitinol self-expanding stents *Excluded from stent based primary analysis


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COBRA Trial

Inclusion Criteria

Exclusion Criteria

  • Diabetics, insulin or non-insulin dependent above 21 years of age

  • Severe intermittent claudication (RB stage 3), chronic critical limb ischemia with rest pain (RB stage 4), or chronic critical limb ischemia with ischemic ulcers (RB stage 5)

  • SFA nSES length ≥ 60 mm

  • SFA nSES diameter ≥ 5 mm

  • Serum creatinine ≥ 2.0 mg/dl

  • Absence of at least 1 vessel brisk infra-popliteal run-off to the foot

  • LV ejection fraction ≤ 25%

  • Allergy to iodinated contrast

  • Allergy to aspirin or clopidogrel

  • Relative or absolute contraindication to anticoagulation

  • WBC < 3,000K/UL; platelet count < 100,000K/UL; Hgb < 10 g/dl

Sample size calculation: assuming 65% and 35% restenosis

with conventional balloon and cryoplasty treatments and 10% attrition, for an alpha = 0.05 and power =80%, 43 vascular segments would be needed in each treatment arm1

1Banerjee et al, Am J of Cardiology; 2009


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COBRA Trial

Baseline Characteristics

MI: myocardial infarction


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COBRA Trial

Baseline Characteristics

ACEI: angiotensin converting enzyme inhibitor ARB: angiotensin receptor blocker


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COBRA Trial

Procedural Characteristics

ABI: ankle-brachial index


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COBRA Trial

PolarCath® Post-dilation of nSES

CTO crossing

Mid SFA CTO

Confirmation

2v run-off

Polarcath® postdil

Final result

Procedural success 100%

Mean fluoroscopy time31.82 ± 20.30 min

Mean ACT 238.21 ± 32.31

UFH79%

Procedural adverse events 8.9% (Cryo.) 6.7% (Conv.)

ACT: activated clotting time UFH: unfractionated heparin


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COBRA Trial

Primary endpoint: 12m binary restenosis

60%

p=0.01

55.8%

40%

29.3%

20%

Cryoplasty

Balloon Post-dilation

n=41

Conventional

Balloon Post-dilation

n=43


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COBRA Trial

Cumulative hazard of restenosis

HR=2.39, 95% CI 1.19 – 4.78

p<0.01

Conventional

Cryoplasty

Cumulative hazard of

restenosis

Time (in days)

Cryoplasty 45 45 45 43 39 35 33

Conventional 45 44 42 36 32 29 21

ACT: activated clotting time UFH: unfractionated heparin


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COBRA Trial

Change in ABI from baseline at 12m

p=0.66

Baseline 12m

Baseline 12m

Conventional Balloon

Post-dilation

Cryoplasty Balloon

Post-dilation

ABI: ankle-brachial index


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COBRA Trial

Change in WIQ* from baseline at 12m

p=0.005

p=0.002

Baseline 12m

Baseline 12m

Conventional Balloon

Post-dilation

Cryoplasty Balloon

Post-dilation

*Walking impairment questionnaire score


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COBRA Trial

SFA Chronic total occlusion

12m binary restenosis

90%

p=0.06

60%

70.0%

36.0%

30%

Cryoplasty

Balloon Post-dilation

n=25

Conventional

Balloon Post-dilation

n=20


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COBRA Trial

Cumulative hazard of restenosis (Non-CTO vs. CTO)

HR=3.61, 95% CI 0.99 –13.18; p=0.05*

Conventional CTO

Conventional non-CTO

Cryoplasty CTO

Cryoplasty non-CTO

HR=2.69, 95% CI 0.74 – 9.85; p=0.13*

Cumulative hazard of

restenosis

HR=2.65, 95% CI 0.72 – 9.80; p=0.15*

Reference Group

Time (in days)

*Comparedtoreferencegroup


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COBRA Trial

Bilateral SFA nSES Implants

12m binary restenosis

90%

p=0.03

60%

66.7%

26.7%

30%

Cryoplasty

Balloon Post-dilation

n=15

Conventional

Balloon Post-dilation

n=15

Analysis excludes 1 patient with same treatment to B/L LE


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COBRA TrialCryoplasty or Conventional Balloon Post-dilation of Nitinol Stents For Revascularization of Peripheral Arterial Segments

Conclusions

In patients with diabetes mellitus presenting with life-style limiting claudication, post-dilation of nitinol self-expanding stents in the SFA using PolarCath®cryoplasty significantly reduced 12-month in-stent restenosis compared to conventional balloon post-dilation

These results indicate the potential impact of stent post-dilation strategies on endovascular treatment of symptomatic peripheral arterial disease


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COBRA TrialCryoplasty or Conventional Balloon Post-dilation of Nitinol Stents For Revascularization of Peripheral Arterial Segments

Acknowledgements:

Tayo Addo, MD DSMB chair

Bertis Little, PhD DSMB member

Kevin Kelly, PharmD DSMB member

Rick Weideman, PharmD DSMB member

Ravi Sarode, MD DSMB member

Christopher Lichtenwalter, MD Core laboratory analysis

Lorenza Makke, RVT Core laboratory analysis

Preeti Kamath, BDS, MHALead study coordinator

Daniel Tran, MSc Data manager

Boston Scientific Corporation Research grant support

Dallas VA Research Corp. Research administration


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