By: Diana Barnes-Brown for Veins1A new type of stent has come through its first clinical trial with favorable results, causing a great deal of excitement in the medical community.
A stent is a small tube made out of metal mesh, used to keep arteries open and allow blood to continue circulating to tissue that needs it. The stents currently in general use are permanent medical apparatuses, surgically placed in clogged or collapsed arteries, where they stay unless removed by a second surgery. The new stent is unique because it is made out of “bioabsorbable” material, that is, the body can absorb it completely, preventing complications associated with leaving a foreign object in the body for a long period of time.
The new stent, invented by Belgian doctors and scientists at A.Z. Sint-Blasius Hospital in Dendermonde “is 90 percent magnesium, which you find in normal blood and normal tissue,” noted the hospital’s head of vascular surgery, Dr. Marc Boisiers.
After eight years of testing in animals and an initial human trial of 20 patients, the inventors have shown that the magnesium-based stents begin being absorbed after about 10 days, and are completely absorbed after no more than 60.
The stents appear to be more effective, as well, with arteries staying open for roughly six months longer in patients who received the new type of stent than in those who received older, permanent types.
This is because permanent stents can cause irritation and inflammation in the long term, which in turn leads to new tissue growth that can block the artery all over again. The absorbable stent is advantageous because it does not stay in the body for long enough to cause chronic inflammation, and are only needed for 10 to 14 days to prevent arteries from closing.
Some critics of the new technology voiced concerns that the stents’ dissolution would lead to toxicity within the body, but Boisiers noted that after extensive testing for blood toxins, nothing abnormal showed up.
The stents are currently undergoing further testing in Belgium, and will soon be tested in two large clinical trails, one testing efficacy and safety in blocked arteries below the knee, and the other testing the same for blocked coronary (heart) arteries.
If this testing goes well, the field experts hope that the next step will be to introduce a drug-treated bioabsorbable stent. Current non-absorbable stents are treated with anti-clotting medication to reduce the chance that arteries will re-clog after treatment.
Boisiers noted in interviews with multiple health news sources that an ideal scenario would have the research team making the stents available for commercial marketing in Europe by the beginning of next year, and that United States-based studies are expected to start towards the end of 2005, with hopes of going commercial in the States in 2007.
