Researchers estimate by 2004, more than 78 percent of stents used in coronary angioplasty were the drug-eluting kind. However, even these stents have been found to cause some problems. Some patients with drug-eluting stents develop blood clots six months to a year or more later. One study comparing bare metal with drug-eluting stents found a 30 percent increased risk of death after six months among those receiving the drug-eluting stents.
At Thomas Jefferson University Hospital, researchers studied stent use in heart patients who require surgery for a non-cardiac related problem, such as hip replacement. Cardiologist Michael Savage, M.D., says, for these patients, the stress of surgery and the anesthesia can precipitate a heart attack.
The study involved 60 patients with an average age of 68 who were found to have significant coronary artery disease during preoperative evaluation for other problems. These patients required angioplasty before surgeons could address the other medical issues. During angioplasty, doctors used bare-metal stents instead of the drug-eluting stents. The second, non-cardiac surgery was delayed for at least five weeks. In addition, anti-clotting medication was discontinued at least five days before the second surgery (discontinuation of this treatment is needed to reduce the risk of serious blood loss during surgery). With this treatment protocol, doctors found the second surgery could be safely performed with minimal risk of clotting or stent-related complications.
According to Savage, drug-eluting stents may delay healing of the target area of an artery and increase the risk of clot formation and restenosis during a second surgery. By using bare-metal stents and waiting several weeks to perform the second surgery, the body has time to heal and cover the stent with the protective endothelial cells. With the natural layer of protection, anti-clotting medications can be safely stopped before surgery.
Savage says there is still a place for drug-eluting stents. The type of stent chosen for a patient should be made on a case-by-case basis. Those who receive the drug-eluting stents need to be able to take anti-clotting medications for at least a year. Those who may require other surgery in the near future or who may be at risk of developing problems with anti-clotting medication may be better off with the bare-metal stents.