COBRA Trial COBRA Trial Cryoplasty 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: ClinicalTrial.gov Identifier: NCT

Disclosure Statement of Financial Interest 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) 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 RelationshipCompany

COBRA Trial COBRA Trial Cryoplasty 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

COBRA Trial COBRA Trial Cryoplasty 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 (-10 o C) is achieved by inflating the balloon with nitrous oxide instead of saline and contrast PolarCath is a trademark of Boston Scientific Corporation and its affiliates. Image property of Boston Scientific Corporation 1 Isner et al, Circulation; Virmani et al, CryoLetters; 2005 Mechanisms of Action  Induces smooth muscle cell (SMC) apoptosis 1  Minimizes SMC necrosis (-5 to -15 o C) 2  Reduces in-stent restenosis (ISR) N 2 O Refrigerant Cylinder Microprocessor-Controlled Inflation Unit Balloon Catheter

COBRA Trial COBRA Trial Cryoplasty 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 1 Bakken et al, Journal of Vasc Surgery; 2007

COBRA Trial Design 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) 121 patients with DM consented between August 2008 and December 2010 in 4 clinical sites in U.S. 47 (39%) patients not stented nSES: nitinol self-expanding stents *Excluded from stent based primary analysis ≥2.5 times increase in Doppler peak systolic velocity (PSV) in the stented segment and 10mm beyond its proximal and distal edges 90 SFA nSES implanted (74 patients/16 B/L) Cryoplasty Group (N=45) Conventional Balloon Group or CBA (N=45) nSES Post-dilation Randomization 1:1 DUS and clinical follow-up at 12 months in 91.1% (N=41) DUS and clinical follow-up at 12 months in 95.5% (N=43) 4 (8.9%) Deaths* 2 (4.4%) Deaths*

COBRA Trial Inclusion Criteria 1.Diabetics, insulin or non-insulin dependent above 21 years of age 2.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) 3.SFA nSES length ≥ 60 mm 4.SFA nSES diameter ≥ 5 mm 1 Banerjee et al, Am J of Cardiology; 2009 Exclusion Criteria 1.Serum creatinine ≥ 2.0 mg/dl 2.Absence of at least 1 vessel brisk infra-popliteal run-off to the foot 3.LV ejection fraction ≤ 25% 4.Allergy to iodinated contrast 5.Allergy to aspirin or clopidogrel 6.Relative or absolute contraindication to anticoagulation 7.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 arm 1

COBRA Trial Cryoplasty n = 45 Conventional balloon n = 45 p Value Age (years ± SD)62.93 ± ± Male82%93%0.11 Hypertension98%96%0.16 Hyperlipidemia96%93%0.32 Diabetes mellitus100% 1.00 Tobacco use56%60%0.76 Chronic kidney disease 9%13%0.59 Coronary artery disease 67%64%0.70 Prior MI24%18%0.44 Baseline Characteristics MI: myocardial infarction

COBRA Trial Cryoplasty n = 45 Conventional balloon n = 45 p Value Hemoglobin A1C 7.43 ± ± Insulin requiring DM 16%22%0.39 Serum creatinine 1.14 ± ± Aspirin 69%60%0.38 Clopidogrel 40%53%0.21 Warfarin 13%4%0.14 Statin 89%76%0.10 ACEI/ARB 80%69%0.23 Beta blocker 62%71%0.38 Proton pump inhibitor 24%20%0.66 Baseline Characteristics ACEI: angiotensin converting enzyme inhibitor ARB: angiotensin receptor blocker

COBRA Trial Cryoplasty n = 45 Conventional balloon n = 45 p Value Mean Rutherford stage Baseline ABI0.59 ± ± Lesion length (mm) ± ± No. of run-off vessels2.1 ± ± Chronic total occlusions56%44%0.06 Total stent length (mm) ± ± Stent diameter (mm)6.09 ± ± Debulking36%27%0.45 Post-dilations Balloon length (mm)83.53 ± ± Balloon diameter (mm)5.23 ± ± Number of dilations2.51 ± ± Procedural Characteristics ABI: ankle-brachial index

COBRA Trial PolarCath ® Post-dilation of nSES ACT: activated clotting time UFH: unfractionated heparin Mid SFA CTO 2v run-off CTO crossing Confirmation Polarcath® postdilFinal result Procedural success 100% Mean fluoroscopy time31.82 ± min Mean ACT ± UFH79% Procedural adverse events 8.9% (Cryo.) 6.7% (Conv.)

COBRA Trial Primary endpoint: 12m binary restenosis 55.8% 29.3% Conventional Balloon Post-dilation n=43 Cryoplasty Balloon Post-dilation n=41 20% 60% 40% p=0.01

COBRA Trial ACT: activated clotting time UFH: unfractionated heparin Cumulative hazard of restenosis Cryoplasty Conventional Time (in days) Cumulative hazard of restenosis HR=2.39, 95% CI 1.19 – 4.78 p<0.01 HR=2.39, 95% CI 1.19 – 4.78 p<0.01 Conventional Cryoplasty Conventional Cryoplasty

COBRA Trial Change in ABI from baseline at 12m Conventional Balloon Post-dilation Baseline 12m Cryoplasty Balloon Post-dilation Baseline 12m p=0.66 ABI: ankle-brachial index

COBRA Trial Change in WIQ* from baseline at 12m Conventional Balloon Post-dilation Cryoplasty Balloon Post-dilation Baseline 12m p=0.002 p=0.005 *Walking impairment questionnaire score

COBRA Trial SFA Chronic total occlusion 12m binary restenosis 70.0% 36.0% Conventional Balloon Post-dilation n=20 Cryoplasty Balloon Post-dilation n=25 30% 90% 60% p=0.06

COBRA Trial *Compared to reference group Cumulative hazard of restenosis (Non-CTO vs. CTO) Cumulative hazard of restenosis Time (in days) Conventional CTO Conventional non-CTO Cryoplasty CTO Cryoplasty non-CTO Conventional CTO Conventional non-CTO Cryoplasty CTO Cryoplasty non-CTO Reference Group HR=2.65, 95% CI 0.72 – 9.80; p=0.15* HR=2.69, 95% CI 0.74 – 9.85; p=0.13* HR=3.61, 95% CI 0.99 –13.18; p=0.05*

COBRA Trial Bilateral SFA nSES Implants 12m binary restenosis 66.7% 26.7% Conventional Balloon Post-dilation n=15 Cryoplasty Balloon Post-dilation n=15 30% 90% 60% p=0.03 Analysis excludes 1 patient with same treatment to B/L LE

COBRA Trial COBRA Trial Cryoplasty 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

COBRA Trial COBRA Trial Cryoplasty 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, MHA Lead study coordinator  Daniel Tran, MSc Data manager  Boston Scientific Corporation Research grant support  Dallas VA Research Corp. Research administration