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Press Release
Is it a heart attack? New ER method gives faster answer
Release 4 p.m. (ET) Friday, Sept. 14, 2001
Using a simple, inexpensive blood test, a Veterans Affairs (VA) cardiologist has developed a faster protocol for diagnosing heart attacks in the emergency room that may save millions of dollars in unnecessary critical-care hospital admissions. The new protocol-which can rule out a heart attack in 90 minutes, compared to 6 to 24 hours for existing methods-combines a "point of care" blood test for three cardiac enzymes with an electrocardiogram and patient history.
Reporting his findings in the Sept. 15 American Journal of Cardiology, Alan S. Maisel, M.D., said the method he tested over nine months on nearly 1,285 emergency-room patients with signs of heart attack led to a 40-percent drop in critical-care admissions. Hundreds of patients that would have previously been admitted to the critical care unit were either sent home or to non-critical units. There was about a 20-percent drop in overall hospital admissions.
"We were able to quickly triage patients to appropriate clinical settings or to home, and thus able to avoid excessive and often unnecessary hospital costs," said Dr. Maisel, director of the Coronary Care Unit at the San Diego VA Medical Center, where the study took place, and a professor of medicine at the University of California, San Diego.
Dr. Maisel developed a 90-minute "critical pathway"-a series of quick actions taken by emergency-room staff-that revolves around a new blood test. The test, approved by the U.S. Food and Drug Administration last year and already in use at many hospitals, takes 15 minutes and is repeated three or four times. It simultaneously checks the blood levels of three cardiac enzymes, or "markers," which are released by distressed heart tissue during an actual heart attack. The enzymes are troponin I, creatine kinase-MB, and myoglobin. In the San Diego study, the triple-marker test, commercially known as the Triage Cardiac System, was 100-percent accurate in ruling out heart attack when combined with an electrocardiogram and patient history.
Most emergency rooms do use blood tests, along with electrocardiograms, but the tests can involve more blood-drawings and longer turnaround times than the triple-marker test used at the San Diego VA. And even then, the results may not be as conclusive.
"Many hospitals use only one marker, and they don't get results back for up to two hours," said Dr. Maisel. "We use rapid point-of-care testing of three markers done three to four times over 90 minutes. We think this is the most accurate method to-date for rapidly triaging both high- and low-risk heart patients."
Though all the 1,285 veterans enrolled in the study reported chest pain in the emergency room, 508 patients were sent home within six hours-most of them within 90 minutes-after negative results for their blood test and electrocardiogram. Of these patients, only one returned to the emergency room with an actual heart attack within the next month.
Studies show that only 10 to 15 percent of the more than five million Americans who show up in emergency rooms with chest pain are actually experiencing a heart attack. Other common causes of chest pain are gastrointestinal, rib, kidney or lung problems. But without quick and accurate ways of ruling out heart attack, emergency-room patients often undergo unnecessary testing and hospitalization, with costs nationwide reaching easily into the hundreds of millions of dollars each year.
In related research, Dr. Maisel earlier this year reported on the effectiveness of a blood test that measures B-type natriuretic peptide (BNP), a cardiac marker that can help emergency-room doctors diagnose congestive heart failure, which has symptoms different from those of heart attack. The VA cardiologist said the BNP test may also be useful in some cases of chest pain, and is being studied further alongside the triple-marker test.
Collaborating with Dr. Maisel on the current study were Siu Ming Ng; Padma Krishnaswamy, MD; Robin Morissey, RN; Paul Clopton, MS; and Robert Fitzgerald, PhD, all with the San Diego VA Healthcare System. Funding for the research was provided by VA and Biosite Diagnostics, producer of the cardiac-marker blood test used in the study.
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