But author of one of studies in the review challenges the finding
MONDAY, Feb. 25 (HealthDay News) -- The artery-opening procedure called angioplasty does provide a benefit over drug therapy even if it's done long after a heart attack happens, a new analysis of studies claims.
However, that finding was immediately challenged by the leader of one of the studies that was analyzed.
"What we found is that putting all these studies together, altogether there is a marked survival benefit in favor of revascularization [angioplasty]," said Dr. Antonio Abbate, an assistant professor of medicine at Virginia Commonwealth University and lead author of the meta-analysis in the March 4 issue of the Journal of the American College of Cardiology.
"They're mixing apples and oranges," said Dr. Judith Hochman, the Harold Snyder Family professor of cardiology at New York University School of Medicine and leader of a widely publicized study reported in 2006 that found no such benefit. "The major principle of meta-analysis is that you include all studies that meet your criteria in an unbiased way. Their meta-analysis shows highly significant heterogeneity."
Specifically, the new analysis included six studies -- among them the one headed by Hochman -- of heart attack survivors who had completely blocked coronary arteries, and four studies of survivors with partially blocked arteries, she said.
That mixture produced "substantial flaws in terms of the violation of the principles of meta-analysis," Hochman said.
One of the studies included in the Abbate meta-analysis was a Swiss trial that he praised for having a much longer follow-up period than the Hochman study. The Swiss study followed participants for 10 years, while the follow-up in the Hochman trial was about three years. "In general, those studies that had a longer follow-up tended to show more benefit," Abbate said.
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The new meta-analysis is imperfect, Abbate acknowledged. "I'm not saying that it is the last word, but it helps us put things in perspective," he said. The study indicates that "if you take the entire group of patients after myocardial infarction [heart attack] who do not get revascularization within 12 hours, some groups will have a greater benefit from later revascularization," Abbate said.
The report does not invalidate the current guidelines of the American Heart Association and the American College of Cardiology, which recommend angioplasty within 12 hours of a heart attack and limit later use of the procedure to specific indications, Hochman said. The guidelines for a later angioplasty include cases where there is severe blockage of arteries, with severe symptoms, and where the left main coronary artery is affected, she said.
"The list of those who want mechanical intervention is not changed by this study," Hochman said.
What angioplasty is and why it is done is explained by the U.S. National Heart, Lung, and Blood Institute.
SOURCES: Antonio Abbate, M.D., assistant professor, medicine, Virginia Commonwealth University, Richmond; Judith Hochman, Harold Snyder Family professor of cardiology, New York University, New York City; March 4, 2008, Journal of the American College of Cardiology
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