Mini heart attack best treated like the big one

NEW ORLEANS — People who show up at a hospital with mild heart attack symptoms, but only ambiguous scores on medical tests, might still warrant emergency treatment, according to research presented at a meeting of the American Heart Association.

The new study, reported November 10 at the AHA’s annual Scientific Sessions meeting, suggests that getting some of these marginal patients into a heart catheterization lab within 24 hours causes no harm and sharply lessens their risk of having the problem recur over the following six months.

People with chest pains arriving in an emergency room get attention right away — for good reason. After ruling out those who are having acid reflux pain or an anxiety attack, doctors use an electrocardiogram (EKG) to assess the person’s heart function and a blood analysis to reveal any damage to the heart muscle.

These simple tests, coupled with obvious signs of distress, are often enough to diagnose a person suffering from a heart attack. Those patients are wheeled into a catheterization lab, where doctors thread a line from a leg artery up to the patient’s heart to open the coronary artery blockage that is causing the heart attack.

But only about one-third of people who show up with some measure of heart distress have such clear warning signs of a heart attack, says Deepak Bhatt, chief of cardiology at the Veterans Affairs Boston Healthcare System and an interventional cardiologist at Brigham and Women’s Hospital in Boston. The other two-thirds have EKG scores that are not clearly in the heart attack range, and/or have blood tests that may or may not reveal warning signs.

Physicians have struggled with the best emergency plan for these in-between patients, Bhatt says, particularly since many hospitals in smaller communities don’t have a catheterization team — which includes an interventional cardiologist, specialized nurse and technician — onsite around the clock.

To delineate clearly who among these heart patients in the gray zone between a real heart attack and a potential one might benefit from immediate catheterization, Shamir Mehta, a cardiologist at McMaster University in Hamilton, Ontario, and his colleagues randomly assigned 1,593 such patients to get drugs plus catheterization as soon as possible, but within 24 hours. Another 1,438 received only drugs at first, then catheterization at some point more than 36 hours later.

During the six months that followed, patients who had gotten early catheterization were 70 percent less likely to have repeat coronary blockage as were those who received late catheterization, Mehta reported.

When the researchers analyzed these patients’ risk of death, heart attack or stroke within the six months of follow-up, they found that delaying catheterization didn’t significantly affect these risks, Mehta says.

But the researchers found a different story when they analyzed only patients who had two of three common risk factors for a heart attack — being over age 60, having some evidence of a blockage on their EKG or having one telltale blood reading that hinted at heart attack. These people still fell into the gray zone somewhere short of a heart attack. But those who received prompt catheterization were somewhat less likely to die, have a heart attack or have a stroke within six months as were similar patients who got delayed catheterization.

“Timing matters in unstable angina or small heart attacks,” Mehta concludes. The study showed no detrimental effects from early catheterization.

There are medical guidelines for physicians trying to determine which of such patients should be moved quickly to a catheterization lab.

“Frequently, all the messages in the guidelines are not widely appreciated,” says Sidney Smith, a cardiologist at the University of North Carolina in Chapel Hill. “This is a very important trial,” he says, and it will likely bolster adherence to the guidelines.

The issue often arises in hospitals on weekends, when there isn’t a catheterization team on hand, Bhatt says. If a patient comes in on a Saturday night, he says, the question becomes whether to bring in a catheterization team that’s on call, “or wait until Monday morning.” It’s more than a matter of inconvenience, he says. “There are financial costs to the health care system.”

As they did in this study, heart patients routinely receive aspirin and an anticoagulant upon arrival at a hospital, says Gordon Tomaselli, chief of cardiology at Johns Hopkins Medicine in Baltimore. But these drugs don’t necessarily ease the problem, even in people in the gray zone, he says. The new study is likely to result in more of such patients getting into the catheterization lab early, particularly during working hours when there is a full lab staff on hand to handle the load, he says.

“This study clearly says there’s no harm in a patient going in early” to undergo catheterization, Bhatt says. “I honestly don’t see the downside from the patient’s perspective.”