Stents may be harmful in heart attack patients

(CNN) -- Doctors often use stents to keep blood vessels in the heart open after angioplasty. But new research shows when used in the treatment of heart attacks, these devices may increase a person's risk of death.

During angioplasty, doctors inflate a balloon tipped catheter into a blood vessel and dilate it. This is done to improve blood flow. In some cases, a stent is needed to keep a blood vessel open to maintain blood flow.

"Stents decrease the chances of acute complication and also decrease the chance of the blockage to come back by half," said Dr. Samin Sharma of Mt. Sinai Medical Center in New York.

Doctors also use stents is to treat patients in the midst of a heart attack. But a new study, published in this week's New England Journal of Medicine, finds stents placed during heart attacks may increase the risk of death.

"Once the stent was put into the vessel, the blood flow actually diminished a little bit and that is not a good thing in the midst of a heart attack because our entire purpose is to enhance or improve the coronary blood flow," said Dr. Cindy Grines of William Beaumont Hospital in Michigan.

Over time, Grines said there "appeared to be a slightly higher risk of dying from a heart attack after receiving a stent compared to people who were treated with balloon angioplasty."

One reason for the reduction in blood flow is that stents actually stimulate platelets, or small particles that help blood to clot, and therefore reduce the blood flow even though the vessel is open.

"It's possible that by placement of this bulky stent and expanding that metal, that there's some blood clot that can break off and go downstream and that risk might be slightly higher with stenting when compared with balloon angioplasty," Grines said.

According to Sharma, many doctors are already aware of the problem and use powerful anti-clotting drugs to deactivate the platelets.

"They (patients) are started on antiplatelet agent, and arteries are opened with the balloon followed by a stent insertion in more than 90 percent of cases all across the United States at present -- Because we know the stent alone is not the answer," Sharma said.

Researchers say more studies on a larger scale are needed to determine if stenting should be done routinely in heart attack patients. For now, doctors have to carefully chose which patients would benefit most from stents without increasing their risk of death.