WEDNESDAY, March 10, 2004 (HealthDayNews) -- Many heart attack patients admitted to the emergency room are going without drugs or surgical procedures that could extend their lives, despite blood test results indicating a need for more aggressive therapy, researchers report.
A new study finds too many cardiologists downplaying the results of blood tests that measure levels of troponin, a chemical leaked from heart muscle into the bloodstream after a heart attack. Experts now consider troponin levels key in classifying patients at either "high" or "low" risk for a second heart attack.
"Even though we have these markers of risk available to us early in the patient's hospital course, we don't always apply the therapies that we know are beneficial," says lead researcher Dr. Kristin Newby, a cardiologist at Duke University Medical Center. She presented the findings Wednesday at the annual meeting of the American College of Cardiology in New Orleans.
People experiencing chest pain or other potential signs of a heart attack must get themselves to emergency care as quickly as possible. Once they are under medical care, doctors quickly run a battery of tests -- including a troponin test and an older, less-accurate blood test measuring the compound creatine kinase-MB -- to determine whether a heart attack has occurred and, if so, the extent of heart muscle damage.
The results of these tests help determine a patient's need for aggressive therapies such as powerful anti-clotting drugs or cardiac catheterization -- treatments that could greatly reduce the risk of a second, potentially fatal heart attack in the days and months to come.
The troponin test is now considered the "gold standard" for blood tests measuring heart damage and assessing long-term prognosis. In fact, the American Heart Association now recommends that doctors focus on troponin test results when making treatment decisions, rather than on levels of creatine kinase-MB (CK-MB).
But are doctors getting the message?
In their study, Newby and her team examined the in-hospital medical records of almost 30,000 patients with suspected heart attack, all of whom were tested upon arrival at the ER for both troponin and CK-MB.
They found that patients with dangerously high levels of both troponin and CK-MB did receive aggressive treatments like clot-busting drugs or interventional surgeries.
But about 18 percent of patients admitted had "discordant" blood test results -- testing high for troponin, but low for CK-MB. Patients in this group tended to get less aggressive therapy, with doctors focusing on CK-MB and ignoring troponin.
"We tend to bias toward treating them like a lower-risk group, rather than acting on that troponin result," Newby says. "We're not doing a good job at applying what we see."
The result, she says, are under-treated patients at higher risk for a second heart attack.
Dr. Nieca Goldberg, a New York City cardiologist and an American Heart Association spokeswoman, says she's dismayed by the findings.
"What's surprising is the fact that, considering that these AHA guidelines have been out for a couple of years, and the troponin test is so widely and easily available, that it's not being used to its optimal potential. We really have to close this gap," she says.
Goldberg suspects a lack of familiarity with the newer troponin test may be behind the trend. "CK's been around a lot longer and it's clearly gotten into everyone's clinical practice," she says. "But from the study, it appears that we need to increase the utilization and interpretation of the troponin test in order to improve patient care."
Should patients double-check that their therapy matches their test results?
According to Goldberg, that's tough to do in the first hours or days of treatment. But Newby believes patients and their loved ones do have the right to ask questions as treatment continues into the longer term.
"There's a set of medications that virtually all patients who have positive cardiac markers should be on," Newby explains. "If they hear they have a positive troponin, or they are told they have these proteins in their blood, they should ask, 'Am I getting an aspirin? Should I take a statin? Should I be on a beta-blocker?' "
Patients should "be able to talk to their physicians about whether they are getting these drugs, and if they are not getting them, why not?" Newby says.
Still, educating physicians remains key to more effective treatment, Newby says.
"Troponin is both newer and more specific for heart muscle damage than CK-MB," Newby says. "We know it does a better job at predicting who's going to have another heart attack or who's going to die after they have a heart attack. So it's prognostically more helpful."
More information
For more information on heart health and the warning signs of heart attack, visit the American Heart Association and the National Heart, Lung, and Blood Institute.
