WASHINGTON – Patients presenting with chest pain with a negative ECG and an undetectable blood level of cardiac troponin T on a high-sensitivity assay had virtually no risk of a myocardial infarction during the following 30 days, in a retrospective review of more than 8,900 patients at one Swedish medical center.
Applying a high-sensitivity cardiac troponin T screen to rule out a possible MI in patients who present to emergency departments with chest pain could substantially reduce the rate of unnecessary hospitalizations such patients, Dr. Martin Holzmann said at the annual meeting of the American College of Cardiology.
During December 2010–December 2012, a total of 8,907 patients older than 25 years who presented to the emergency department at one large European medical center with chest pain, no identifiable ST-segment elevation, or depression on their ECG, and a blood level of cardiac troponin T that was undetectable at less than 5 ng/L on a high-sensitivity assay. From this group of patients, 15 subsequently developed an MI during the next 30 days of follow-up.
This finding showed that an undetectable level of high-sensitivity cardiac troponin T had a negative predictive accuracy of 99.8%, said Dr. Holzmann, an emergency medicine physician at Karolinska University Hospital in Stockholm. The researchers used an Elecsys 2010 device marketed by Roche for high-sensitivity measurement of cardiac troponin T.
But this finding, while consistent with prior reports suggesting that high-sensitivity measurement of cardiac troponin T could detect or rule out MI, came from a study that was not rigorously enough designed to justify routine high-sensitivity screening for cardiac troponin T in chest-pain patients in emergency departments, commented Dr. Allan S. Jaffe, a cardiologist and professor of medicine and laboratory medicine at the Mayo Clinic in Rochester, Minn. He also noted that the device used in the study is not approved for U.S. marketing.
"This is a strategy that has been hinted at since a paper in 2009 by Dr. Tobias Reichlin (N. Engl. J. Med. 2009;361:858-67)," but Dr. Jaffe questioned whether all patients in the new, Swedish study underwent adequate assessment for new-onset MIs during follow-up.
"I agree that in the long-term this strategy will likely work for low-risk people, but I have concerns" whether adequate proof is now in hand. "I want to see it tested in a study with all the ‘I’s dotted and ‘T’s crossed," including two or three serial measures of high-sensitivity cardiac troponin T, Dr. Jaffe said in an interview.
The study had no commercial funding, and Dr. Holzmann and his associates had no disclosures. Dr. Jaffe said that he has received research support and had consulted for several companies developing devices to measure cardiac troponin T.
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