Biliary stent undergoes study for PVD applications

Favorable results from trial could raise awareness of option for patients at risk of limb loss

A newly approved clinical trial could raise the profile of the Xpert expandable nitinol stent for treating critical limb ischemia. Currently cleared in the U.S. to treat biliary blockages, the stent will be tested by researchers assessing its viability in patients with peripheral arterial occlusive disease.

The standard of care for patients with advanced peripheral arterial disease is bypass surgery or angioplasty. Many patients are not candidates for these procedures, and angioplasty's long-term efficacy is suboptimal. Stenting is an option, but long-term data are scarce and attempts with earlier generation stents demonstrated mixed results.

"There's a fair amount of skepticism about whether stenting below the knee has benefit. We need data that show this procedure makes a difference so practitioners are willing to look at it more seriously," said Dr. J. Fritz Angle, an interventional radiologist with the University of Virginia Health System and an investigator in the trial, dubbed XCELL.

A few interventionalists around the country have used the self-expanding Xpert biliary stent from Abbott Vascular to treat peripheral occlusive disease, and they have had favorable results. It is the only FDA-approved stent that comes in sizes (from 2 mm to 7 mm in diameter) small enough to fit easily and safely into the tiny arteries below the knee. But reliable long-term data need to be published before a majority of physicians will be swayed to offer this option to patients with critical limb ischemia.

In June, the FDA approved the XCELL trial to test the biliary stent below the knee. It is sponsored by VIVA Physicians (VPI), a multidisciplinary group of 10 physicians specializing in peripheral vascular disease diagnosis and management based in Rosemont, IL. The trial is supported by a restricted educational grant from Abbott Vascular, a division of Abbott Labs, manufacturer of the Xpert stent. VPI set the protocol, applied for the investigational device exemption from the FDA, and will be responsible for data collection, evaluation, and reporting. It is the group's first clinical trial.

VPI will recruit 140 patients from 10 institutions and publish the results by the end of 2007. Trial protocols limit treating blockages up to 15 cm in length. The Xpert stent is currently available in four lengths: 2, 3, 4, and 6 cm.

The study is intended to demonstrate the clinical viability of the device, said Dr. James Joye, an interventional cardiologist and director of the cardiac cath program at El Camino Hospital in Mountain View, CA. Joye is lead investigator of the XCELL trial.

Additional studies will be conducted to further define the product's use in this population if the results of XCELL indicate that use of the stent in patients with severe peripheral arterial disease in small vessels below the knee can delay or even prevent amputation, according to Abbott.

The goal of the study is to avoid amputation after 12 months follow-up through use of the device, Joye said. The trial will also evaluate vessel response to stenting, the degree of in-stent restenosis at six and 12 months, and the effectiveness of the approach for saving limbs.

Joye hopes the study will increase awareness among physicians of this treatment option.