Drug-Eluting Stents not so Safe

A new study, published in the January issue of the Journal of the American College of Cardiology, shows that drug-eluting stents may actually hamper the body's ability to reroute blood past arteries that are blocked, in some cases leading to heart attacks.

Scientists studying patients with both drug-eluting stents (DES) and bare-metal stents (BMS) found that six months after implantation, patients with the drug-eluting stents had 30 to 40 percent less coronary collateral function than the patients with bare-metal stents.

Under normal conditions, the body can naturally reroute blood (a process called coronary collateral function) so that it bypasses blocked arteries. This rerouting can prevent heart attacks. However, researchers found that when drug-eluting stents were used to keep blocked arteries open, more blockages were caused.

These blockages occur because the body is unable to form corollary blood vessels which increases the strain on the heart muscles. This strain then renders the heart less able to handle sudden blood clots.

According to the researchers, "The combination of sudden arterial blockages due to a rare condition called stent thrombosis, and the absence or impairment of the self-healing mechanism of coronary collateral function, potentially leads to a larger and deadlier heart attack in patients with drug-eluting stents."

Drug-eluting stents are coated with medication in order to reduce the risk of restenosis (reblocking of the arteries) by preventing the formation of scar tissue. The stents were first approved for use by the US Food and Drug Administration on April 24, 2003 and were intended to replace bare-metal stents.

On October 29, 2003 the FDA issued a warning about drug-eluting stents. By that time the FDA received almost 300 reports of negative reactions to the stents. Of those 300 reactions, 60 patients died. Additionally, there were reports of allergic reactions including pain, rash, breathing problems, blood pressure changes, and fever.

Recently, some medical professionals have argued that drug-eluting stents have a higher risk of blood clots that can potentially lead to heart attacks and strokes. The FDA held a public advisory panel in December, 2006 to discuss concerns about drug-eluting stents. The outcome of the panel was that drug-eluting stents were safe for certain patients but were associated with a higher risk of blood clots, heart attacks, and death in most patients. The panel recommended the FDA issue warnings about the risks associated with drug-eluting stents and recommended that "off-label" use of the stents should be discouraged.

Drug-eluting stents were developed under the name Cypher (coated with sirolimus) by Cordis Corporation, a division of Johnson & Johnson. In March, 2004 Boston Scientific released its own drug-eluting stent, known as the Taxus which was coated with paclitaxel.

If you have had a drug-eluting stent implanted and are suffering adverse reactions to the stent, speak to your doctor immediately about your concerns.