EMBARGOED UNTIL JULY 30, 2001
Contact: Donna Krupa: 703.527.7357Cell: 703.967.2751 or [email protected]
AACC Newsroom: July 30-August 2, 2001Room: S101b McCormick Place, ChicagoTelephone: 312.791.6671
IDENTIFICATION OF HEART-SPECIFIC PROTEIN AIDS DOCTORS IN IDENTIFYING AND TREATING HEART ATTACK PATIENTS
Had the heart attack Vice President Cheney suffered last November occurred just one month earlier,an accurate diagnosis would not have been made.
CHICAGO -- Had the heart attack Vice President Cheney suffered last November occurred just one month earlier, an accurate diagnosis would not have been made. Thanks, however, to new guidelines issued last September by the European Society of Cardiology and the American College of Cardiology, acute myocardial infarctions ("heart attacks"), can now more easily be ruled in--or ruled out.
Fred Apple, Ph.D., medical director of clinical laboratories at the Hennepin County (MN) Medical Center, will discuss these issues at the 53rd Annual Meeting of the American Association for Clinical Chemistry (AACC). His remarks will assist clinicians and laboratorians in determining whether a patient has had a heart attack, triaging patients to the appropriate level of care, and assisting in the appropriate management and therapeutic decisions for these patients. He will be joined by David Sacks, M.D., of Brigham and Women's Hospital in Boston, and Johannes Mair, M.D., of the University of Innsbruck in Innsbruck, Austria at the AACC meeting being held in Chicago July 30-August 2, 2001.
BackgroundIn their joint publication last fall, the European Society of Cardiology and the American College of Cardiology redefined how heart attacks are determined. Whereas traditionally a heart attack would be diagnosed by a combination of ischemic features (such as chest pain, shortness of breath, nausea, etc.), an abnormal EKG, and creatine kinase MB testing, new guidelines for detecting heart attacks are based on a protein--cardiac troponin I or cardiac troponin T--that is found only in the heart. When the heart is injured, this protein leaks into the blood, providing a sensitive and specific marker for heart injury.
According to Dr. Apple, approximately 50 percent of patients who exhibit symptoms of a heart attack have a normal EKG. A normal EKG and normal cardiac troponin levels rule out a heart attack; on the other hand, says Dr. Apple, a normal EKG, but elevated cardiac troponin levels, indicate a heart attack. (Cardiac troponin levels can also be elevated because of other heart injuries, i.e., chest trauma from automobile accidents). It was these new guidelines that enabled physicians to diagnose Vice President Cheney's heart attack, rather than classifying it as unstable angina.
The use of cardiac troponin to assess and diagnose heart attacks is a "very powerful tool," says Dr. Apple. It can also be used to define a patient's prognosis. An individual with an elevated cardiac troponin level has a 2- to 5-fold higher risk of having a poor outcome--including an acute myocardial infarction or cardiac death--in the following 30 days to one year--than someone who has normal cardiac troponin levels.
The level of cardiac troponin can also guide physicians in the choice of therapy given a patient. The medications indicated where there are elevated cardiac troponin levels are low molecular weight heparin, and glycoprotein IIB IIIA inhibitors. Without this therapy, a patient is at much higher risk of a serious, or even fatal, heart attack; with the therapy, the risk is no greater than for someone with a normal cardiac troponin level.
While numerous cardiac troponin tests have been FDA-approved for diagnostic purposes, only a few have been FDA-approved to be used in a risk stratification manner. "One company's test may not necessarily perform the same as another's," Dr. Apple says. All cardiac troponin tests need to be standardized so that the results will yield reliable numbers. "We are striving to make all assays the best they can be," says Dr. Apple.
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Founded in 1948, the American Association for Clinical Chemistry (AACC) is the world's most prestigious professional association for clinical laboratorians, clinical and molecular pathologists, and others in related fields. Clinical laboratorians are specialists trained in all areas of human laboratory testing, including infectious and genetic diseases, DNA and the presence of tumor markers. The primary professional commitment of clinical laboratorians is the effective understanding and use of laboratory tests in order to detect, monitor and treat human diseases.
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Editor's Note: To set up an interview with Dr. Apple, please contact Donna Krupa at 703.527.7357 (direct dial), 703.967.2751 (cell) or [email protected]. Or log on to the AACC website at www.aacc.org.
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