Opening Blocked Arteries with Drug Coating but No Stent

In a new twist on combining drugs and minimally invasive therapy, early research suggests drug-coated angioplasty balloons keeps narrowed leg arteries open, avoiding the use of a stent altogether. Early multi-center data on the use of angioplasty balloons sprayed with a chemotherapeutic agent are being presented for the first time in the United States at the 18th Annual International Symposium on Endovascular Therapy (ISET).

The use of drug-coated stents to open narrowed and blocked heart arteries has skyrocketed and the devices are now used in the majority of such minimally invasive procedures. The drug coating is intended to reduce the incidence of restenosis, or renarrowing of the artery. Restenosis is common after conventional balloon angioplasty or placement of bare metal (non-drug-coated) stents, tiny mesh tubes that are left behind in the artery as scaffolding to prop it open. The drug-coated balloon concept has proven effective in opening previously stented coronary arteries.

The balloon is coated with paclitaxel, which is used in the treatment of breast and other cancers and also one of the drugs used to coat stents.

"The drug prevents the growth of scar tissue that can cause the vessels to renarrow," said Gunnar Tepe, M.D., an assistant professor of radiology at the University of Tuebingen, Germany, who is presenting the data at ISET. "We're employing the same drug concept used in drug-coated stents, except the drug is delivered in a much shorter period of time and we don't leave behind a foreign object, a coated stent, which itself can cause problems down the road. Also, the drug is embedded in a coating material on the stent, which remains after the drug has been completely delivered to the vessel wall. This coating material may cause undesired effects later, as well."

Narrowed and blocked leg arteries are a common symptom of peripheral arterial disease (PAD). Like heart arteries, leg arteries can become clogged by plaque (fatty deposits) that slows or stops the flow of blood. From 8 to 12 million people in the United States have PAD, according to the American Heart Association. PAD can cause pain while walking and, in extreme cases, lead to gangrene, amputation of the toes, feet or legs or even death.

In conventional balloon angioplasty, a small cut is made in the groin and a thin tube, called a catheter, is advanced through the arteries to the site of the blockage, whether in the neck, heart, abdomen or legs. A tiny balloon is advanced to the blockage through the catheter and then inflated, compressing the plaque against the artery wall and opening it to allow better blood flow.

In the new procedure, the drug is sprayed onto a conventional angioplasty balloon. When the balloon is inflated, the drug is transferred from the balloon to the plaque.

Studies have shown that, within a year, about 4 in 10 conventional angioplasty procedures in the legs need to be repeated because the blood vessels have renarrowed, in part due to a bodily reaction to the trauma of the procedure. To improve results, physicians in recent years have tested other minimally invasive methods, including balloon angioplasty followed by placement of a stent, and more recently, coating those stents with drugs to prevent renarrowing.