text_1: New heart attack test could identify two-thirds of patients at very low risk of heart attack in the emergency department
text_2: This news release describes the results of a study designed to significantly advance the search for a rapid blood test that can rule out evidence of heart muscle damage in people who come to emergency rooms with chest pain and other symptoms of heart attack. The study, reported in the journal The Lancet, specifically offers compelling evidence that a version of a commonly used blood test may indeed further that quest. For the study, investigators used a highly sensitive version of an existing blood test that detects the protein troponin on more than 6,300 consecutive people presenting to hospital emergency rooms (mostly in Scotland) with suspected acute coronary syndrome. The researchers were able to determine the probability that patients were NOT at risk of heart attack or death from heart attack after 30 days for a range of troponin levels. The release does a generally adequate job of describing how the high-sensitivity test appears to identify very low levels of troponin, in contrast to current troponin tests, thus making it theoretically possible to accurately, relatively quickly, and safely rule out a heart attack in more than 60 percent of such people, at least over the short term. It covers the fact that conventional troponin testing detects only higher levels of the protein, and must be done on serial blood samples over a longer period of time. And the news release puts appropriate emphasis on the potential the new test has for decreasing unnecessary hospitalizations and reducing health care costs. All that said, the release could have done a much better job of making clear earlier in the text that substantially more research will be needed to determine the clinical effectiveness and safety of relying heavily on high-sensitivity troponin testing. Although the release uses qualifiers such as “may have been eligible for early safe discharge,” we think more needed to be said about potential risks, about the potential costs of the more sensitive test; and most of all about the limitations of the study and over-reliance on any single test when people experience heart attack symptoms. Patients arriving at emergency facilities with chest pain is a common and costly situation that is associated with potentially devastating consequences when the evaluation isn’t done in a thorough fashion. The current evaluation of chest pain involves a history focused on the patient’s reported symptoms and past history of heart disease and risk factors as well as tests performed. These include an electrical test of the heart (EKG or electrocardiogram) and blood tests looking for damage to heart muscle. This evaluation has been standard for decades, but better blood tests over time have allowed emergency providers to more accurately and quickly identify patients who may be having a heart attack. At the same time, the use of these newer tests has permitted providers to more quickly identify those who are not having a heart attack, allowing for earlier discharge from the emergency facility or hospital. The study reported in this news release seeks to define the threshold below which a new, more sensitive test identifies people who are at low risk for heart attack or heart related death over the next 30 days. If confirmed, this will be a positive step forward in effectively and efficiently evaluating patients with chest pain in emergency facilities. However, the main limitation of this study is that it is using information previously collected to predict what would have happened if this new test and threshold was used. Only with prospective use and evaluation can we actually determine if this new test and threshold, when applied as part of routine care, leads to improved care and more efficient use of emergency and hospital resources.