For many years, the standard treatment for infrarenal abdominal aortic aneurisms (AAA) has been open surgery. An investigational stent system from Vascutek (Glasgow, Scotland) will enable a minimally invasive treatment.
A surgeon from Arizona Heart Institute (Phoenix) earlier this month performed the first procedure in the U.S. Anaconda Phase II Study using the Vascutek Anaconda Stent Graft System.
AAAs are a ballooning of the body's main artery and can cause sudden death. Even with open surgery, there's a 25% to 50% risk of death. The minimally invasive approach uses stent grafts and has been associated with a decreased risk of death, faster recovery, minimal blood loss and shorter hospital stays.
"The advantage of this graft is that even after you deploy it, you can relocate and reposition it," Julio Rodriguez, MD, vascular surgeon at the Arizona Heart Institute and Arizona Heart Hospital, and the study's principal investigator, told Medical Device Daily. "The danger is that if you deploy too low or too high, you compromise flow to the kidney. So, technically speaking that's [Vascutek's Anaconda Stent Graft System] a real advantage. It's also very flexible and allows you to use them in a very tough anatomy."
Although the stent system is being tested in the U.S. for FDA approval, plenty of data already are available, with nearly 4,000 patients having been treated in Europe.
"Experience with the device has been very positive," said Donald Reid, MD, chairman of vascular surgery at Wishaw General Hospital and University of Glasgow (both Glasgow), who attended the procedure at Arizona Heart Hospital.
The Vascutek Anaconda Stent Graft System has magnetic wire technology to ease the deployment of the contralateral leg. A dual proximal ring stent design with four pairs of nitinol hooks provides a seal with positive fixation as security against stent graft migration. Radiopaque markers aid with the device placement. The graft system is constructed from woven polyester fabric.
Rodriguez said the first procedure was performed on June 8 on a relatively healthy man in his late 50s who required only a single night's stay in the hospital.
"The patient did fine and there were no complications," he said.
The Phase II study, which is being sponsored by Vascutek parent company Terumo Cardiovascular Systems (Ann Arbor, Michigan), intends to enroll 180 patients at 20 centers.
"The primary endpoint is feasibility and safety of the device," Rodriguez said. "We're looking into complication rates and following up with the patients and any technical issues that compare to other devices and techniques."
The control group will be AAA patients who undergo open surgery. Investigators will also use historical data to compare complication and success rates as well as mortality.
The typical mortality rate for open surgery within 30 days after procedure is in a range of 4% and 10%. The goal of this study is to stay at 4% or lower.
Rodriguez said the new stent system would require no particular training for surgeons familiar with endovascular techniques.
"Of course, there is a learning curve in first five to 10 cases, but it's not difficult," he added.
The study is expected to end within 1-1/2 years and patients will be followed for up to five years.
Published: June 29, 2009