MONDAY, July 22 (HealthScoutNews) -- A look inside the arteries of people who have had heart attacks shows that many of them are highly vulnerable to more of the same kind of trouble.
French researchers report the new finding, which presents both an opportunity and a challenge to cardiologists. American experts explain that the door could be opened to new ways of preventing further trouble, but the technology that would make such treatment possible doesn't exist and it's not clear what treatments would help.
An advanced technique, intravascular ultrasound, was used by physicians at the Hospices Civils de Lyon to get three-dimensional views of the three major coronary arteries of 24 patients in the month after they had heart attacks, says a report in tomorrow's issue of Circulation: Journal of the American Heart Association. They found that 80 percent of them had a number of the same sort of lesions that first caused the heart attacks scattered throughout those arteries.
The lesions are unstable plaques, fatty deposits in artery walls that are likely to rupture. A plaque that is stable might not be a big problem. However, when it ruptures, the body response to that injury is an inflammatory process that includes formation of blood clots that can block an artery, causing the heart attack. Thus, the report adds to a growing body of evidence that inflammation plays an important role in heart disease.
A heart attack is not just a problem in itself, but also a sign of overall coronary instability, which the French call pancoronarteritis and Americans call acute coronary syndrome, says Dr. Gilles Rioufol, an associate professor in the hemodynamics department at the hospital who led the study.
"The fact that we discovered multiple ruptured plaques means that probably the pancoronarteritis process exists, and so to treat only the simple lesion is not enough," he says. "It is an argument to treat and check inflammation in patients."
"The diagnosis of vulnerable lesions before rupture would have tremendous potential for even prevention," says an accompanying editorial by cardiologists at the Cleveland Clinic. However, a more usable test than the intravascular ultrasound used in the French study is needed. The test used in the study was a 10-minute procedure in which a tiny ultrasound probe was threaded into a coronary artery during routine coronary angiography.
"What this paper demonstrates is what we have been thinking for a long time," says Dr. E. Murat Tuzcu, director of intravascular ultrasound at the Cleveland Clinic and co-author of an accompanying editorial. "When a heart attack patient comes to the hospital, generally you find that one site in a blood vessel suffers severe narrowing created by a plaque that has ruptured. For many years we have been convinced that there are a number of similar sites in the arteries. The implication is that acute coronary syndrome is a systemic disease of the arteries."
The immediate application of that belief is that treatment of a heart attack should be "very aggressive," with cholesterol-lowering drugs, clot preventers such as aspirin, and other heart medications, Tuzcu says. Longer-term, he says, the ideal would be to find and treat the other unstable plaques before they rupture.
That would require easy detection of those plaques. "It would be nice if we had a relatively simple tool that we could put into a coronary artery or, better yet, some way to look into the coronary arteries, find the other plaques and treat them accordingly," Tuzcu says. "Unfortunately, what we have not is not ready for prime time. But as different methodologies improve, then maybe we will be able to identify and treat the unstable plaques."
Treatment of unstable plaque "is equally or more challenging," they say. Maybe existing drugs, such as beta blockers, calcium channel blockers or cholesterol-lowering statins might help, Rioufol says.
Drugs designed to stabilize plaque could also be used, the Cleveland cardiologists say, but they can have damaging side effects. Using stents, hollow tubes, to seal off the unstable plaques might be possible, but "there is no clinical experience in favor of such a treatment." At the moment, it's best to stick with the drugs that are known to be effective against heart disease, they say.
There are also difficulties in putting the findings of this small study to use on a large scale.
"There is presently no diagnostic tool that could guide the operator to those lesions that are at high risk to cause acute coronary events," they write. "Even if such a targeted approach would be safe and effective, it would leave many other sites unprotected and the benefit from treating an individual lesion may be small."
The big point, Rioufol says, is that a heart attack now can be seen as just one aspect of a condition that affects the entire arterial system. "It is important to diagnose it, and understanding it helps to treat it," he says.
What To Do
You can learn about the role of inflammation in heart disease from the American Heart Association, which also has a page on heart attacks.
SOURCES: Gilles Rioufol, M.D., Ph.D, associate professor, hemodynamics, Hospices Civils de Lyon, France; E. Murat Tuzcu, M.D., director of intravascular ultrasound, Cleveland Clinic; July 23, 2002, Circulation: Journal of the American Heart Association ~HATT~~HRTS~
