New research has overturned one of the most fundamental beliefs among doctors treating heart attacks: that opening a blocked artery is always a good idea, even days or weeks later.
Instead, the study revealed that doing this too late may not help, and there were disturbing hints that it might even be harmful.
This contradicts two decades of the so-called "open artery theory" — that angioplasty performed days or even weeks after a heart attack would also help prevent future cardiac events, reports CBS News correspondent Dr. Jon LaPook.
"If you open an artery, it makes sense that you would do better than if you had a closed artery. It just biologically makes sense," said Dr. Judith Hochman, cardiovascular research chief at New York University School of Medicine.
People who had balloon angioplasty to open an artery three to 28 days after their heart attacks fared no better than those given standard medicines to prevent a second attack.
The results don't apply to most Americans suffering a heart attack, but suggest that 100,000 of them a year might be able to skip the expense and risk of angioplasty and take medications instead, doctors said.
"These findings were really a surprise," said Dr. Elizabeth Nabel, director of the National Heart, Lung and Blood Institute, which funded the large international study. "For a long time we thought that opening up the artery any time after a heart attack was better than leaving it closed. My guess is you may see some guideline recommendations" on what to do in such situations, she said.
Opening arteries quickly is crucial to surviving heart attacks, and the study's findings do not change the need for urgent action or the evidence that angioplasty saves lives when done soon after an attack.
Nearly 1 million heart attacks occur in the United States each year, typically when a vessel squeezes shut, preventing enough blood and oxygen from reaching the heart.
The usual treatment is angioplasty, in which doctors snake a tube through a blood vessel in the groin to the blockage. A tiny balloon is inflated and a mesh stent is put in place to prop the artery open.
But one-third of heart attack victims do not seek care within 12 hours, when angioplasty has the best chance of helping. Clot-dissolving drugs don't always work. No guidelines say what to do in such situations, but most doctors have assumed that an angioplasty, even if done late, still would help prevent further damage to the heart muscle and future attacks.
This bias was so strong that the study took more than five years to recruit enough patients because doctors were unwilling to risk randomly assigning some of them to drug treatment alone, said Hochman.
Some studies suggested "that if you left the hospital with an open artery, you did better over the long term," but this had never been firmly tested, said Hochman, who led the new study and gave results Tuesday at an American Heart Association conference. They also were published online by the New England Journal of Medicine and will appear in its Dec. 7 issue.
Researchers enrolled 2,166 people in 27 countries to get either angioplasty three to 28 days after their heart attack and standard drug treatment — medicines to lower blood pressure and cholesterol, and aspirin and other anti-clotting drugs — or medicines alone.
These were patients who had survived their original heart attack but had a single vessel completely blocked, yet were stable because the heart was still receiving sufficient blood and oxygen from other vessels.
Four years later, 17 percent of those given angioplasty and drugs and nearly 16 percent of those given drugs alone had either died, suffered another heart attack or developed heart failure — results considered to be statistically the same.
There was a worrisome trend toward more heart attacks in the angioplasty group — 7 percent vs. 5 percent of the others — as time went on, though this could have been a statistical fluke, Hochman said.
The lack of benefit from angioplasty was not because the procedure didn't work — it successfully reopened arteries more than 90 percent of the time, Hochman said.
Instead, the findings suggest that once a blocked vessel had caused a heart attack, opening it was no better than taking standard medications for preventing future problems.
"There is a reason to rethink angioplasty" in such situations, said Dr. Timothy Gardner, a cardiologist at Christiana Care Health Services in Wilmington, Del., and chairman of the Heart Association program committee that reviewed the research.
Angioplasty did seem to help prevent chest pain years after the procedure, Hochman said.
"People need to be clear about why they're having the angioplasty" and discuss with their doctor whether it is being done to try to improve symptoms or to try to prevent heart attacks and death, she said.
The study also underscores the importance of fast medical help for heart attacks.
"It is critical to seek medical care quickly. Don't deny that something is happening. Don't sit at home and take antacids," Hochman said.
A dozen or so companies donated drugs and devices for the study and many of the researchers have consulted for them. The federal government paid 94 percent of the study's cost.