ADA 2008: Endovascular interventions for PAD proliferate

The range of endothelial interventions for peripheral artery disease (PAD) is proliferating. Today's choices includetraditional balloon angioplasty, stents, drug eluting stents and fabric-covered stents. Newer technologies allow cliniciansto cut out occlusions, freeze them, scrape them, laser them and kill them.

"Below-the-knee technology is very much in a state of flux," said Timothy Murphy, MD, Brown Medical School,Providence, RI. "When we have this many competing technologies, it usually means we don't know what we're doing."

In the case of endovascular interventions, the conventional wisdom is only half wrong, Dr. Murphy said. More familiarprocedures such as angioplasty and stenting, are well studied and well supported with randomized, controlled trials. Newerprocedures that employ cryoplasty, laser removal, radiofrequency ablation, aspiration and other evolving technologies havesuccessful case reports and FDA approval but, little or no comparative data.

"Some of these new technologies are justified and some of them are still works in progress," Dr. Murphy cautioned."All we have at this point are case reports. We have very little scientific evidence. But we do have plenty of marketingsupport from the technology companies that sell these devices."

Evidence to date indicates that familiar balloon angioplasty remains a safe and highly effective treatment for short,uncomplicated lesions. That generally includes lesions that are less then 3 to 5 centimeters and have not calcified.Angioplasty and stent placement produces similar results for these small lesions.

For longer lesions, up to about 12 to 15 cm, randomized controlled trials suggest that metal stents are the preferredtreatment for occlusions below the knee. More recent trials have indicated little, if any advantage for bare metal stints orfor drug-eluting stents in the treatment of PAD, Dr. Murphy said.

The most recent development in stenting is the stent graft, a stent covered with fabric to form a hollow tube. Stentgrafts have been very successful in clinical trials clearing occlusions longer than 20 cm.

"You're pushing the envelope using angioplasty and stents on these long lesions," Dr. Murphy said. "Stent grafts havebecome the most popular and the most successful treatment.