Wednesday, January 25, 2006

Drug-coated balloons with 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.

Restenosis (re-narrowing) 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. Our early results suggest the effects of drug-coated balloons are by far superior to uncoated balloons. Careful analysis of data and more research are required to confirm the findings and explore additional applications."

Coating the balloon with the drug allows more of the drug to come in contact with the plaque than is the case with stents. The drug covers the balloon and is then transferred to the entire artery surface that comes in contact with it. Because stents are mesh, not solid, drug concentration is highest on their struts. Tissue that comes in contact with the struts receives much more of the drug than the tissue that doesn't.

Drug-coated stents are also called drug-eluting stents, because the stent continues to release the drug for about 30 days after placement. In the case of drug-coated balloons, the drug is delivered to the vessel wall immediately, in one dose. Early research on animals suggests that the effect persists in spite of rapidly decreasing drug concentration.

Spraying the balloon with a drug is a new and exciting way to treat stenosis. We know that the rate of retenosis in a treated artery without a stent or with an uncoated stent is unacceptably high. Researchers have also found some long-term problems with coated stents. I'm looking forward to upcoming research on this new strategy to attack those nasty blockages.

Here is a short interview with the researcher who performed the first study of drug-coated balloons.

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