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Interpreting Troponin Tests: Coming to a New Consensus

Interpreting Troponin Tests: Coming to a New Consensus

Since its introduction in the early 1990s, cardiac troponin testing has been predominantly used to diagnose or rule out myocardial infarction (MI) in patients with possible symptoms of MI. However, it has become clear that a positive troponin indicates that cardiac injury has occurred, but it is not specific for the etiology of the injury. “Experience with troponin testing has also showed that higher levels identify patients at greater risk for adverse events, regardless of the clinical setting (eg, MI, heart failure, or non-cardiac etiologies),” explains L. Kristin Newby, MD, MHS, FACC, FAHA. “However, more recent studies have raised questions about cardiac troponin cutoffs that should be used for diagnostic and prognostic interpretations and the particular importance of the clinical context in making those interpretations.” In the Journal of the American College of Cardiology, Dr. Newby and colleagues from seven professional societies, led by the American College of Cardiology, released a consensus statement to help clinicians determine when to order troponin testing and how to interpret results. The document provides a framework for clinicians to interpret results of troponin testing in a useful mechanism-based construct. Key Recommendations on Troponin Testing According to the consensus statement, physicians should adopt the definition of MI that was recently updated in order to fully understand the implications of elevated troponin levels. “The universal definition of MI, which was updated in 2012, is important because it provides a standard framework in which to apply troponin testing for a diagnosis of MI and emphasizes not only troponin levels, but also the importance of clinical symptoms of MI,” Dr. Newby says. In addition, the consensus statement...

Revascularizing Occluded Arteries: Assessing the Influence of Guidelines

The Occluded Artery Trial (OAT) was a large, randomized controlled study funded by the National Heart, Lung, and Blood Institute that tested routine percutaneous recanalization of persistently totally occluded infarct-related arteries identified a minimum of 24 hours after myocardial infarction (MI) in stable patients who did not have triple vessel disease or severe inducible ischemia. In 2006, results from OAT were released, showing that there appears to be no benefit to routinely using PCI for persistently totally occluded infarct-related arteries in this patient population. Routine PCI for these arteries did not reduce mortality, reinfarction, or class IV heart failure. These results subsequently led to updates of guidelines from the American College of Cardiology (ACC) and American Heart Association (AHA) on unstable angina/non-STEMI, STEMI, and PCI in 2007. The revised guidelines recommended that PCI not be performed in this context. Prior to OAT data being released, clinicians tended to favor using PCI for persistent infarct-related artery occlusions largely because of experimental and observational data. “OAT results demonstrated that use of PCI did not lead to a reduction in clinical events,” explains Judith S. Hochman, MD. “The beneficial effect on angina and quality of life was small and not durable. OAT also suggested that PCI was more costly than optimal medical therapy alone. As a result, these findings should have discouraged routine PCI in this setting.” Assessing the Impact of the OAT Study In the October 10, 2011 Archives of Internal Medicine, Dr. Hochman and colleagues had a study published in which they examined whether PCI use for treating occluded infarct-related arteries after an MI decreased following the publication of OAT...

Can Hypothermia Benefit Post-MI Patients?

A small American study suggests that systemic therapeutic hypothermia can decrease morbidity and mortality in post-myocardial infarction (MI) patients with cardiogenic shock. Although more research is needed, the investigators noted that the approach may offer advances in treatment and outcomes in individuals with post-MI cardiogenic shock. Abstract: Journal of the American College of Cardiology, February 14,...
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