TUESDAY, May 8, 2007 (HealthDay News) -- Angioplasty works better than drug treatment alone in relieving the dangerous "squeeze" on blood flow called silent ischemia for patients who've had a heart attack, a Swiss study finds.
The number of adverse cardiac events was 6.3 percent lower each year during the 10-year study for patients with silent ischemia who got angioplasty, compared to those who got intense drug treatment, according to a report in the Journal of the American Medical Association.
At the end of the study, almost 30 percent of those who had had drug treatment alone still suffered from symptom-free silent ischemia compared to less than 12 percent of those who had angioplasty.
The report was led by Dr. Paul Erne of Kantonsspital Luzern. Its findings echo those of an even larger Danish trial that followed more than 1,000 people who suffered heart attacks.
In that study, reported in the journal Cardiology, the incidence of repeat heart attacks was halved among those who had angioplasty, with a comparable reduction in hospital admissions for cardiac problems.
Ischemia is defined as insufficient blood flow to the heart muscle. In many causes, this potentially dangerous condition produces no symptoms after a heart attack. In such cases, it is called "silent."
"If people don't have a test, you never find it," explained Dr. Jan. K Madsen, head of cardiology at Gentofte University in Hellerup, Denmark, and the lead researcher on the Danish study. "I strongly recommend an exercise test after a myocardial infarction [heart attack]," he said.
Things have changed a bit since the Swiss was started a decade ago, added Dr. A. Michael Lincoff, vice chairman for research in the Cleveland Clinic's department of cardiovascular medicine.
"Many centers now do emergency angioplasty to treat a heart attack, so there may or may not be a reason for doing a subsequent stress test," Lincoff said. "They may already know all they need to know. But for those who do not get angioplasty or have multiple blockages, we know that a stress test is helpful to determine procedures to restore blood flow."
The recently reported COURAGE trial showed that, in general, drug treatment is as effective as angioplasty for people at cardiovascular risk because of artery blockages, Lincoff noted. "But here, we are talking about a high-risk group of patients, who for several reasons would benefit from having a stress test," he said. "In the setting of silent ischemia following a heart attack, the test is done more to detect patients who are at very high risk."
So, the rule should be that "heart attack patients who do not have their coronary anatomy defined should have a stress test," Lincoff said. And if silent ischemia is detected, those patients may well benefit from angioplasty, he said.
Drug treatment has improved in the 10 years since the Swiss study began, Lincoff noted. But the more recently begun Danish study also gives the edge to angioplasty over intensive drug treatment, Madsen said.
"We should look for signs of ischemia in the myocardium of such patients," he said. "We know they are sick already, so it is reasonable to examine them further."
A description of silent ischemia is provided by the American Heart Association.