Artery-opening procedure can be done up to 21 hours later with milder heart attacks, study shows
TUESDAY, Sept. 1 (HealthDay News) -- Many people who arrive at hospital emergency rooms with chest pains can wait as long as 21 hours for artery-opening angioplasty, even if an electrocardiogram (EKG) shows evidence of a heart attack, a new French study suggests.
There was no significant difference in key measures of heart damage and one-month death rates in the study of 352 people with the mild form of heart attack called non-ST elevation myocardial infarction between those who had immediate angioplasty and those who waited an average of 21 hours for the procedure, according to a report in the Sept. 2 issue of the Journal of the American Medical Association.
Indeed, the researchers, from the Centre Hospitalier Universitaire Pitie-Sapetriere in Paris, found the incidence of deaths, second heart attacks or need for second procedures was higher in the group that had angioplasty within 70 minutes of diagnosis (13.7 percent) than in the group of patients who waited nearly a full day (10.2 percent).
About a third of people who come to a hospital with chest pain will have a major ST-elevation heart attack, where the pattern seen on the EKG indicates complete blockage of a heart artery. Another third will have a milder non-ST elevation heart attack, and a third will not have a heart attack, explained Dr. Christopher Granger, director of the cardiac care unit at Duke University, who did not take part in the French study but who did participate in a much larger international study whose results were reported earlier this year.
"The results here are consistent with ours and other studies," Granger said. "There is no need to go to the cath lab immediately."
"Cath lab" is medical jargon for the facility where angioplasty is performed. The earlier study in which Granger participated included about 2,500 persons treated in emergency rooms, nearly 10 times the number seen in the French study.
That earlier study compared angioplasty done within 12 hours to angioplasty done as long as 36 hours after diagnosis. People with the more severe ST-elevation heart attacks definitely benefited from earlier angioplasty, but those with milder heart attacks did not, the researchers found.
The French doctors also used a faster measure of heart performance -- blood levels of troponin, a protein produced by damaged heart tissue. "Troponin I release, as reflected by peak values collected during hospitalization, did not differ between the two strategies in the immediate and delayed intervention groups," the researchers wrote.
Some caution is needed in applying the results of the French study because the number of people treated was small, Granger cautioned.
"We have to be careful with small studies like this not to ascribe a substantial amount of clinical relevance to them," he said. "But the results are consistent with the idea that immediate intervention is not necessary in this kind of myocardial infarction."
The warning signs of a heart attack and what to do about them are described by the American Heart Association.
SOURCES: Christopher Granger, M.D., director, cardiac care unit, and professor, medicine, Duke University, Durham, N.C.; Sept. 2, 2009, Journal of the American Medical Association
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