Lessons & Perspectives: What is the role of Cryoplasty in SFA Intervention?

Transcription

1 Lessons & Perspectives: What is the role of Cryoplasty in SFA Intervention? Michael Wholey, MD, MBA San Antonio, TX USA 19/06/2009 at 09:35 during 4mn as a Speaker Session: Improving Femoral Artery Recanalization & Popliteal Artery Angioplasty Main auditorium

2 The SFA Problem Despite a variety of modifications and adjuncts to angioplasty such as bare metal stents, covered stents, and drug eluting stents as well as a number of new technologies like laser angioplasty and cutting balloon angioplasty, restenosis rates have not been significantly affected and remain inferior to those for surgery for long lesions in the femoropopliteal segment

3 SFA Dilemma 77 yr old female with non-healing ulcer with occluded SFA/Pop with two self-expandable stents, Healed, then cramping pain 3 mos later Able to re-open but had to place two additional stents within the stents. Patency? Coumadin?

4 Severe restenosis at 8 months myointimal hyperplasia

5 PolarCath Cyroplasty Balloon Coaxial, dual balloon design. Gas is contained in the inner balloon enhancing procedural safety Multiple InflationsThe thermocouple and pressure transducer are located inside the inner balloon to monitor balloon pressure and temperature during the procedure. May be used up to 12 inflations.

6 Cyroplasty Balloon Balloon Diameters: 0.035" 4 thru 8mm 0.014" 2.0mm, 2.5mm, 3mm, 3.5mm, 4mm, 5 mm, 6 mm Balloon Lengths: 0.035" 20, 40, 60, 80 & 100mm 0.014" 20, 40, 60 & 100mm The inflation unit contains a microprocessor to automatically control & monitor the procedure Sheath Compatibility 0.035" -- 4mm and 5mm - 6F 6mm and 7mm - 7F 8mm - 8F 0.014" -- 2mm thru 4mm - 5F 5mm & 6mm - 6F

7 Cryoplasty Cryoplasty combines angioplasty and cold therapy using liquid nitrous oxide as the balloon inflation media. During cryoplasty, the liquid nitrous oxide expands into gas and the PolarCath balloon inflates in stepped 2 atm increments to 8 atm. The phase shift from liquid to gas draws energy, driving the balloon surface temperature down to the desired temperature of 10 C. The treatment cycle lasts 20 seconds, the gas is expelled, and the balloon warms and is deflated. The potential advantages of cryoplasty include : Altered plaque response with more uniform vessel dilation and less medial injury Reduced elastic recoil Positive vessel remodeling Smooth muscle cell apoptosis

8 Freezing Philospsophy Interstitial saline freezes when plaque is exposed to temperatures below 1 C. As ice forms, it expands, generating forces that weaken the plaque. In the unfrozen state, plaque distensibility is significantly less than that of the arterial wall. Freezing reduces vessel elasticity and should result in more homogenous circumferential distensibility and uniform response to dilation pressure. Uniform dilation minimizes medial injury and flow limiting dissections.

9 Cyroplasty Compliments of Scott M Surowiec MD

10 IDE Study Treatment Outcomes: 94% acute angiographic success 7% flow limiting dissection rate 9% concomitant stent rate Patency Outcomes: 17.8% target lesion revascularization rate 70% primary patency 82% clinical patency 80% of treated patients experienced ABI improvement 89% of treated patients experienced claudication improvement Extended Follow up Up to 3.4 years, 75% freedom from TLR Laird et al J Vasc Interv Radiol. 2005;16:

11 Below The Knee Chill 180 Day Outcomes: 97% Acute technical success (N = 111) 2% >50% residual stenosis 1% Clinically significant dissections (due to guide wire Investigator Report) 6% Non clinically significant dissections (Type A or B) 93% 180 day freedom from major amputation (N = 91)* 85% 365 day freedom from major amputation (N = 78)* *N = total limbs reported. Presented by McNamara, Das, Gray at 2007 ISET

12 Cryoplasty Dilemna Trials: not comparative or controlled studies and have not been performed, analyzed or reported in accordance with recognized reporting standards for peripheral vascular intervention. The studies on SFA disease have selected favorable patients. Of greatest concern is the use of surrogate endpoints in lieu of objective demonstration of vessel patency. Kessel et al. J Cardiovasc Surg (Torino) Apr;49(2):

13 Is Cryoplasty Really Different Than Routine PTA? In Vitro: application of cryothermal energy to the endothelium during angioplasty leads to apoptosis induction and reduced proliferation rates In Vivo: The present results show that the release of adhesion molecules, growth factors and cytokines is similar between balloon angioplasty and cryoplasty. Wildgrubber et al. Br J Radiol Jun;80(954):430-6.

14 In Vivo Study Adhesion molecules after PTA and Cryoplasty: Intercellular adhesion molecule (ICAM) Vascular cell adhesion molecule (VCAM), e selectin, p selectin and monocyte chemoatlractant protein 1 (MCP 1)) Growth factors (transforming growth factor beta (TGFbeta) Basic fibroblast growth factor (bfgf)) Cytokine tumour necrosis factor alpha (TNFalpha) Femoropopliteal artery in the early course of 4 weeks in 29 patients with peripheral arterial occlusive Wildgrubber et al. Br J Radiol Jun;80(954):430-6.

15 In Vivo Study Adhesion molecules after PTA and Cryoplasty: Intercellular adhesion molecule (ICAM) Vascular cell adhesion molecule (VCAM), RESULTS: e selectin, p selectin and monocyte chemoatlractant protein 1 (MCP The 1)) present results show that the release of adhesion Growth factors molecules, (transforming growth growth factors beta and (TGFbeta) cytokines is similar between balloon angioplasty and cryoplasty. Basic fibroblast growth factor (bfgf)) Cytokine tumour necrosis factor alpha (TNFalpha) Femoropopliteal artery in the early course of 4 weeks in 29 patients with peripheral arterial occlusive Wildgrubber et al. Br J Radiol Jun;80(954):430-6.

16 Cyroplasty Conclusion The benefit of cryoplasty over conventional angioplasty has not been established as no randomised controlled trials exist to properly evaluate this method. Technical success and primary patency rates seen in the prospective series are encouraging and may suggest a future role for cryoplasty in the treatment of PAD, but cannot be reliably interpreted due to the nature of the studies McCaslin et al Cochrane Database Syst Rev Oct 17;(4)

17

18 Conclusion Cryoplasty for SFA disease may hold promise to prevent restenosis, but it would be good to have a trial to compare against other devices (i.e., PTA)

19 Cyroplasty: Better than PTA? The results of the clinical studies suggest that cryoplasty is a feasible and safe technique in the treatment of femoropopliteal disease, however, they have failed to prove any superiority of cryoplasty over conventional angioplasty.

20 Stent Fractures Scheinert et al (Journal American College of Cardiology, 18 January 2005) that reported the results X ray screening at 10.7 months follow up. The study found fractures in 45 of 121 treated legs (37.2%) and in 64 of 261 implanted stents (24.5%).

21 Cyroplasty Dilemna Review discusses the basic principles of cryoplasty, summarizes the current data on restenosis rates after cryoplasty treatment, and evaluates cryoplasty as a new treatment method to solve the problems associated with restenosis development. The results of the clinical studies suggest that cryoplasty is a feasible and safe technique in the treatment of femoropopliteal disease, however, they have failed to prove any superiority of cryoplasty over conventional angioplasty.

22 Cyroplasty Dilemna Review discusses the basic principles of cryoplasty, summarizes the current data on restenosis rates after cryoplasty treatment, and evaluates cryoplasty as a new treatment method to solve the problems associated with restenosis development. The results of the clinical studies suggest that cryoplasty is a feasible and safe technique in the treatment of femoropopliteal disease, however, they have failed to prove any superiority of cryoplasty over conventional angioplasty. Wildgruber et atl/cardiovasc Intervent Radiol Nov-Dec;31(6):

23 Cryoplasty Cyroplasty for SFA Disease Cryoplasty is a technique for treating vascular stenosis which combines balloon angioplasty with cold injury. The combination is proposed to reduce the incidence of restenosis by inhibition of neointimal hyperplasia

24 In Vivo Study In the present study we assessed the distribution pattern of the soluble forms of e selectin, p selectin, ICAM, VCAM, MCP 1, TGFbeta, bfgf and TNFalpha after angiography, angioplasty and cryoplasty of the femoropopliteal artery in the early course of 4 weeks in 29 patients with peripheral arterial occlusive

25 Cochrane Review Trials in which patients with peripheral arterial disease (PAD) of the iliac or infrainguinal arteries were randomised to cryoplasty with or without another procedure versus a procedure without cryoplasty. This includes trials where all patients receive angioplasty and the randomisation is for cryoplasty versus none. No randomised controlled trials of cryoplasty were identified

26 IDE Study Extended clinical follow up was obtained for 70 patients (45 men; mean age 70.5 yr) who originally received cryoplasty therapy to treat symptoms of intermittent claudication as part of a multicenter investigational device exemption (IDE) study. For all subjects, cryoplasty was used to treat stenoses or occlusions 10 cm in the femoropopliteal arteries. The original IDE study protocol enrolled 102 patients with a primary endpoint of target lesion patency at 9 months post treatment. This collection of additional longer term follow up data was initiated 2.5 years after the onset of study enrollment. Results: Extended clinical follow up ranged from 11 to 41 months (mean 31). The clinical patency rate (freedom from target lesion revascularization) calculated by the Kaplan Meier method was 83.2% after the original follow up period of 300 days. After 3 years, the clinical patency rate was well maintained at 75.0%. Laird et al J ENDOVASC THER 2006;13(Suppl II):II-52 II-59

27

28