ShareThisBy LEE BOWMAN
Tuesday, November 14, 2006
In a finding that challenges the way American cardiologists treat tens of thousands for heart attacks each year, a new study concludes patients who undergo a balloon angioplasty to open a blocked artery days after a heart attack gain no advantage over drug treatment.
Opening arteries that are 100 percent blocked within the first 12 hours after a heart attack through angioplasty to quickly restore blood flow to the heart is considered the gold standard for cardiac care.
But many doctors believe that eliminating the blockage, even well beyond the initial treatment window, is still a good strategy to prevent another heart attack, heart failure or death.
Each year, about 1 million people in the United States have a heart attack, and about half of them die. About half of those who die succumb within an hour of the first symptoms and before reaching a hospital.
About 1 million angioplasty procedures are performed in the United States each year, and researchers estimate that at least 100,000 are done on heart-attack patients beyond the 12-hour window.
The new study, carried out at more than 200 sites on five continents, analyzed the outcome of 2,166 heart attack patients diagnosed with a completely blocked artery three to 28 days after the heart attack. Each was randomly assigned by a computer to either undergo angioplasty and stenting (a wire patch inserted in the blocked section of artery to keep it from closing) or medical therapy with drugs alone.
There was no statistically significant difference between the two groups in terms of death, heart attack or heart failure during up to five years of follow-up. And the researchers noted what they call a "worrisome" trend toward excessive rates of heart attack among those patients who got the angioplasty procedure, although the numbers were not considered statistically significant.
"Our findings indicate that routine late opening of the heart attack related coronary artery is not appropriate and should be reserved only for certain patients, such as those who are unstable or continue to have chest pain following a heart attack'' said the study's lead author, Dr. Judith Hochman, clinical chief of cardiology and director of the Cardiovascular Clinical Research Center at New York University School of Medicine in New York City.
The study, sponsored by the National Heart, Lung and Blood Institute, was presented Tuesday before a scientific meeting of the American Heart Association in Chicago, and was published online by The New England Journal of Medicine.
"These results challenge the long-standing belief that opening a blocked artery is always good,'' said Dr. Elizabeth Nabel, director of the heart institute. "Instead, the study suggests that late angioplasty is unnecessary in this circumstance. The good news is there have been tremendous advances in drug therapy for heart attack patients, and this is an important treatment option."
Hochman noted that angioplasty has been proven to improve symptoms in patients with angina and prolong life in patients if done quickly. "It's critical that patients get to treatment quickly immediately after the onset of symptoms,'' Hochman said.
The researchers say further monitoring of the surviving patients may help determine if angioplasty really has an effect on repeat heart-attack risk.
Hochman said there might be several reasons that the balloon procedure increases risk. She explained that when someone has a 100 percent blocked artery, the heart muscle may still be somewhat protected by small vessels that supply blood from the other coronary arteries.
"These vessels are so small that if an easier blood flow path is reestablished through angioplasty, they close down, either temporarily or permanently. If the artery that had the angioplasty recloses, these small vessels would not be able to supply blood to your heart muscle at the time of your next heart attack,'' Hochman said.
She also said it's possible that some heart muscle damage occurs due to the dislodging of clots and plaques during the mechanical procedure that may not happen so readily when a clot is dissolved with drugs.
