COBRA Supports SFA Treatment With Boston Scientific's PolarCath in Diabetic Patients

November 11, 2011—Boston Scientific Corporation (Natick, MA) announced that Principal Investigator Subhash Banerjee, MD, presented data from the COBRA clinical trial during a late-breaking clinical trial session at the annual Transcatheter Cardiovascular Therapeutics scientific symposium in San Francisco. COBRA evaluated postdilation of nitinol stents using cryoplasty therapy with Boston Scientific's PolarCath peripheral dilatation system compared to stenting with conventional balloon angioplasty (CBA) in patients with diabetes who presented with blockages of the superficial femoral artery (SFA).



According to the company, results from the prospective, randomized, multicenter trial demonstrated a significant 47% relative reduction in binary restenosis rates for patients treated with nitinol self-expanding stents using postdilation with the PolarCath system.


The COBRA trial enrolled 76 patients with 90 SFA lesions who were randomized to cryoplasty therapy or CBA for postdilation of nitinol stents used to treat SFA blockages. Inclusion criteria included diabetes, severe claudication, and SFA lesions requiring stents > 5 mm in diameter and > 60 mm in length. The primary endpoint was the rate of binary in-segment restenosis as determined by duplex ultrasonography.




The company stated that follow-up data have been completed on 41 lesions in the cryoplasty group and 43 lesions in the CBA group. Results at 12 months showed that binary restenosis was significantly lower in the cryoplasty group (29.3% vs 55.8%; P = .01). The secondary endpoint of change in ankle-brachial index from baseline to 12 months showed significant improvement in the cryoplasty group (0.59 ± 0.21 to 0.77 ± 0.3; P = .004) compared to the CBA group (0.62 ± 0.19 to 0.65 ± 0.26; P = .66). Procedural success was achieved in 100% of procedures in the cryoplasty group.




"High restenosis rates remain a major limitation for peripheral stenting in treating patients with peripheral artery disease, particularly in patients with diabetes mellitus," commented Dr. Banerjee. "Reducing revascularization rates is critical to improving outcomes, and these trial results show that cryoplasty therapy can significantly reduce binary restenosis at least to 12 months in the studied patient population."

Cryoplasty therapy using the PolarCath peripheral dilatation system is a form of balloon angioplasty that is designed to treat atherosclerotic lesions in the peripheral arteries. This technology uses nitrous oxide in place of standard saline to fill an angioplasty balloon within a blocked artery, cooling the balloon's surface to –10° C. As the balloon is inflated, its surface cools and dilates the vascular lesion, potentially helping to prevent artery reblockage. Boston Scientific's PolarCath peripheral dilatation system is approved in the United States for treating blockages in the peripheral vasculature and for postdilation of self-expanding peripheral vascular stents, advised the company.