Test to Predict Heart-Attack Risk Underused

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A new test that predicts which patients with heart-attack symptoms are at greater risk of dying isn't being used in younger, healthier patients -- the ones who could benefit most from the exam, a new study contends.

Studies have consistently found that elevated levels of brain natriuretic peptide (BNP) are associated with an increased risk of death in heart attack patients.

In most hospitals, the BNP test is typically performed on patients who already have clinical risk factors, such as a history of congestive heart failure, older age and diabetes, that put them at a higher risk of death, the Duke University researchers found.

Yet younger and healthier patients with elevated BNP levels are at a two- to four-times greater risk of dying in a hospital than high-risk patients with elevated BNP levels, the researchers reported.

Dr. Matthew Roe, from the Duke Clinical Research Institute, presented the findings Tuesday at the American College of Cardiology annual meeting, in Atlanta.

"The BNP test has been used primarily in patients with heart failure to assess their risk of death or other complications," Roe said.

In their study, Roe and his colleagues looked at the use of the BNP test in U.S. hospitals that were part of the CRUSADE study, which stands for "Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes with Early Implementation of the ACC/AHA Guidelines."

Over a 20-month period, Roe's group found that 30,324 patients were treated at 312 CRUSADE hospitals, and 19.4 percent of those patients had their BNP levels measured. "About a quarter of the hospitals did not use the test at all," Roe said.

"We found that in younger patients who did not have heart failure or diabetes, the test was a more powerful predictor of death and other complications than it was in older patients with heart failure," Roe said. "The test was more useful in a lower-risk population in whom it was less likely to be used in the first place," he added.

Roe believes that more studies are needed to determine how to use the test most effectively. "We need to understand who this test will benefit most," he said. "If you can identify patients who are at the most risk, you could treat them more aggressively."

One expert agrees that the BNP test is useful.

"This test is coming into more use in different areas than heart failure, the area it was originally designed for," said Dr. David D. Waters, the chief of cardiology at San Francisco General Hospital and a professor of medicine at the University of California, San Francisco.

There are a lot of different tests to assess risk in heart attack patients, Waters said. "The [BNP] test is a useful tool to add to what we do already," he said, adding that he regularly uses the test with his patients.

Another expert concurred with that view.

"BNP will add information that is separate and unique than what you get from other prognostic indicators," said Dr. Alan S. Maisel, a professor of cardiology at the University of California, San Diego.

Maisel believes it's not yet clear how the test should be used in routine clinical practice. However, he thinks it could help in making treatment decisions. "This data suggests that you should get a BNP, because it's going to be higher in people you don't expect," he said.

Maisel believes the exam will eventually become part of standard guidelines for treating heart attack patients.

Elevated BNP would be a reason to have patients receive further examinations, such as an angiogram, Maisel said. "In addition, elevation in BNP would lead me to get some idea of heart function before sending patients home," he said.