According to preliminary data on 22 patients being presented at the 17th Annual International Symposium on Endovascular Therapy (ISET), all patients who were facing almost-certain amputation were successfully treated with a new non-surgical therapy that gently cools and opens leg arteries clogged with plaque. CryoPlasty therapy treats patients with arteries that are blocked below the knee as a result of peripheral arterial disease (PAD).
CryoPlasty therapy fits into the treatment spectrum before the use of angioplasty and appears to lessen some of the complications seen in that procedure. It also can be used to treat other vessels affected by PAD, including arteries in the thighs and abdomen.
"Previously, amputation was the only option for some people with such advanced disease in arteries below the knee, many of whom are diabetic," said Dr James D Joye, director of the Cardiac Catheterization Lab at El Camino Hospital, Mountain View, Calif., and co-inventor of the CryoPlasty technique. "CryoPlasty is a 'no-harm' treatment that offers early, conservative management and can be used repeatedly - not only avoiding or delaying amputation, but postponing the use of more invasive procedures."
The data on 22 patients presented at ISET by Joye are the first results from 'Below the Knee Chill', an ongoing multi-center study at 30 hospitals across the US, which will enroll 100 patients who are likely facing amputation of a foot or leg within six months. All of the patients in the study have critical limb ischemia, meaning they have severely clogged leg arteries, causing extremely poor blood flow. Treatment in all 22 patients resulted in procedural success, meaning artery blockages (stenoses) were 50% or less after CryoPlasty therapy. After treatment, the average blockage was 19%, compared to 87% before treatment. Immediately after the procedure, ankle or toe pulses improved in 17 of 20 patients (85%), meaning blood flow increased. Pulses were not measured in two patients. There were no procedural complications or adverse events. Follow-up is ongoing.
Other data, on 102 patients who received CryoPlasty therapy to treat blocked upper leg or knee arteries, have shown that 83% of the arteries remained opened after nine months. An estimated 60% of blocked blood vessels treated with traditional angioplasty and/or stenting remain open after one year, with 89% of people reported an improvement in leg pain while walking.
In a separate single-center study, 51 people received CryoPlasty therapy for 64 blockages, the majority in the thighs, abdomen or lower legs and follow up ranged from three months to one year. After CryoPlasty therapy, only two of the blockages (3%) required placement of a stent. Placement of a stent after traditional angioplasty has been reported as high as 80% and a majority of the time multiple stents are required. A total of 53% of the patients had critical limb ischemia (CLI), meaning their lower leg arteries were so severely blocked, that they suffered pain in their legs and were at risk of amputation of a foot or leg. To date none of the patients have required amputation. Thirteen (48%) of the CLI patients have been followed for six months, and 11 (86%) say their leg pain has improved dramatically.
After CryoPlasty therapy, the overall rate of dissection was 8%, which compares favourably to the dissection rate for angioplasty which ranges from 40% to 70%. CryoPlasty therapy involves the use of nitrous oxide, rather than saline, to inflate the balloon and cool it to
-10°C. This in turn prompts several physical responses that open the artery and cause less scarring than occurs with traditional angioplasty. Repeat procedures for patients treated with standard balloon angioplasty and stent technology of the arteries below the knee are reported to be as high as 85%. The below-the-knee CryoPlasty procedure is performed using one of several new smaller sized catheters, which received clearance from the FDA.
The PolarCath System is a proprietary technology for delivering the CryoPlasty therapy developed by CryoVascular Systems, who has a strategic partnership with Boston Scientific Corporation.