Absorbable Stent for Blocked Leg Arteries

After initial use to prop open a leg artery, a new metal stent is absorbed when it is no longer needed.

This is the first bioabsorbable metal stent tested in humans. It is made of an alloy of 90% magnesium and 10% rare earth elements. An absorbable polymer stent has been tested but does not appear to be as effective as the metal stent in propping open the artery.

Stents are a minimally invasive alternative to surgery to open up arteries in the heart and legs that have become blocked with plaque. However, depending on the implant locations, up to 40% of the time, arteries reclog, a process called restenosis. One cause of restenosis is recurrent inflammation prompted by the stent itself. Once absorbed, the resorbable metal stent no longer inflames the blood vessel, theoretically reducing restenosis.

The new absorbable metal stent is completely absorbed into the vessel wall without freeing particles into the blood stream. As soon as it is in place, the body begins to cover it with a layer of cells and then the vessel wall begins absorbing the stent. This process begins within a week to 10 days and the stent is fully absorbed within 60 days. In a study of 20 patients who received absorbable metal stents to treat blocked arteries below the knee, 15 of 19 (79%) remained open. Usually, only about 60% of narrowed below-the-knee arteries treated with standard stents remain open after six months. The study results were presented at the International Symposium on Endovascular Therapy in January 2005 in Miami Beach (FL, USA).

"A stent is really only needed for a couple of weeks, to allow the blood vessel to reshape and get strong, and after time it is useless,” pointed out Marc Bosiers, M.D., lead author of the study and head of the department of vascular surgery at A.Z. Sint-Blasius Hospital (Dendermonde, Belgium). "We believe the absorbable metal stent
could be a major breakthrough, because it provides a temporary solution to a temporary problem.”




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A.Z. Sint-Blasius Hospital