Nov. 14, 2006 — -- The way in which doctors treat heart-attack patients may soon change because of the results of a new study.
The findings of the study, released today at the American Heart Association meeting in Chicago, show that percutaneous coronary intervention (PCI), a practice in which doctors mechanically open a clogged artery, does not reduce the chances of death or a second heart attack over the next four years if performed three days to 28 days after a heart attack.
The randomized study involved 2,166 heart patients, and is published in this week's issue of the New England Journal of Medicine.
A heart attack occurs when there is a blockage of one or more of the coronary arteries -- the smaller vessels that wrap around the heart and supply the heart muscle with blood. This blockage often comes in the form of plaque buildup on the artery walls or a clot that has become lodged in the vessel.
A blockage means no blood, and no blood means that the part of the heart muscle that is supplied by the vessel will die. Traditionally, doctors believed that re-opening the blocked vessel with an angioplasty and propping it open with a tiny wire tube called a stent, even days after an attack, increased the patient's chances of ending up with a healthier heart.
The findings of the study, however, suggest otherwise -- and they could bring about a major change in protocol for doctors who treat heart-attack patients.
Experts say the change could affect tens of thousands of patients, although firm numbers are difficult to nail down.
"We had expected that angioplasty to open arteries would reduce the risk of subsequent clinical events, specifically heart failure and death in this population that was stable after the initial heart attack but at increased risk of events in the future," said Judith Hochman, the study's lead author and the director of cardiovascular clinical research at the New York University School of Medicine. "We thought it was possible that the risk of a recurrent heart attack would also be reduced. … The results were surprising and do warrant a major change in practice."
The change suggested by the findings involves reserving an angioplasty for patients who are still in the acute phase of their heart attacks, within hours of onset.
Patients who had experienced a heart attack after more than 12 hours would not be given the treatment; doctors instead would rely on medication.
"Some ardent advocates of the 'open-artery hypothesis' have proposed that it is always better to open any closed vessel after a heart attack," said Dr. Steven Nissen, chairman of the department of cardiovascular medicine at the Cleveland Clinic Foundation in Cleveland. "Although virtually every study shows that opening the closed artery within 12 hours is beneficial, we have never examined the value of later intervention."
"Dr. Hochman's study fairly convincingly shows that late reopening doesn't help and may actually harm," Nissen said.
Some say the study's findings will change the way doctors treat heart-attack victims.
"This is an important study and will change practice," said Dr. Christopher Cannon, associate professor of medicine at Harvard Medical School and an investigator in the Thrombolysis in Myocardial Infarction (TIMI) Study Group, in Boston. "The use of procedures had been a topic of long debate, and the accusations have been that we use too many in the U.S."
Still, Cannon says, the benefits of angioplasty in patients who are still in the acute phase of their cardiac episodes are still clear.
For patients who are already stable, however, he says there is no advantage to performing the treatment.
The lack of clear benefit becomes even less warranted when the usual risks of angioplasty are considered. Experts say the procedure opens up the possibility of an artery reclosing, bringing on another heart attack. The procedures also carry a risk of heart damage.
"[The study] thus highlights the fact that 'if it ain't broke, don't fix it,'" Cannon said.
Some experts say, however, that the changes that will be brought about by this study will not be as drastic as others suggest.
"I'm not sure that this study will 'warrant a major change in practice,'" said Dr. Cindy Grines of the division of cardiology in William Beaumont Hospital, in Royal Oak, Mich. "This was a low-risk population of patients who were asymptomatic. … They enrolled only two-thirds of the necessary sample size, plus the events were lower than anticipated, so it would have required a larger, higher risk population to show any benefit. Therefore, I'm not sure if this will have an impact on current practice."
As far as patients themselves are concerned, however, the study underscores the need for those experiencing the heart-attack symptoms to seek medical attention immediately to get the most out of treatment.
"It is critical that patients [are] present immediately after the onset of symptoms of a heart attack," Hochman said. "If they miss the reperfusion treatment window, they should receive optimal medication therapy."