"The results of this study should help change the management of patients that have a heart attack towards earlier revascularization [bypass surgery or angioplasty to open arteries]," says Dr. Ulf Stenestrand, a professor of cardiology at the University Hospital of Linkoping who is the lead author of a report in the May 25 issue of The Lancet.
A survey of more than 20,000 people who had heart attacks in Sweden between 1995 and 1998 finds that the one-year death rate for those who had artery-opening procedures in the first two weeks after a heart attack was half that of patients who did not -- 2.5 percent vs. 5.2 percent, the report says.It's "an interesting and compelling study," says Dr. Sidney Smith, chief scientific officer of the American Heart Association. And, he adds, it's one that "adds to a growing body of evidence that early revascularization can improve the outlook, especially for high-risk patients."
But the weakness of the study is that its data come from a registry, Smith says. "Before drawing a conclusion, we need a randomized trial," he says.
A randomized trial, in which patients are assigned at random to different kinds of treatment, is regarded as the gold standard of proof in medicine.
Smith also notes that patients in the study who got conventional treatment "were more frequently older, more frequently women, and more frequently diabetic, all of which increases risk."
Earlier randomized trials have given inconsistent results about the value of revascularization soon after a heart attack, Stenestrand says, and the new study was done to help resolve the issue.
"There are two possible explanations for these new findings," he says. "First, that both bypass surgery and balloon angioplasty have better success rates today than in the past. Second, that this study included patients that were at higher risk than patients in previous studies."
What also seems to have helped was use of heart medications such as cholesterol-lowering statins and beta blockers, Smith says. And, he adds, "it is also important that these revascularization procedures be performed by institutions that are well-equipped and do them frequently."
In fact, the Swedish study finds that the most important factor in use of artery-opening procedures was whether the hospital had access to a catheterization laboratory, which permits careful study of the arteries.
And the Swedish cardiologists agree with Smith on one key point. Even though their analysis made every effort to account for all the factors that might affect survival, a study based on past data such as a registry "cannot replace a randomized controlled trial," they write.