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Redefining MI After Revascularization

Redefining MI After Revascularization

Numerous definitions for diagnosing myocardial infarction (MI) after coronary revasculariza­tion are currently being used by clinicians. In 2013, the Society for Cardiovascular Angiography and Interven­tions (SCAI) convened an expert panel that proposed new, more meaningful cri­teria for diagnosing MI after PCI or CABG. “Having a standardized MI definition can help clinicians better identify patients with true complications after PCI or CABG who require urgent action,” says Issam D. Moussa, MD, FSCAI, lead author of the SCAI consensus document. “It would also better reflect the quality of coronary revascularization procedures and assist in the design of research trials aimed at developing effective prevention strategies.” New Criteria The new definition of MI differs from existing definitions in several ways, according to Dr. Moussa. “Both diagnose MI by detecting proteins in the blood that are released when the heart muscle is damaged,” he says. “The universal definition calls for a relatively small increase in cardiac troponin (up to five times the normal level), plus confirmation by an ECG, an imaging test, or symptoms. On the other hand, the new SCAI definition calls for a large increase in CK-MB (up to at least 10 times the normal level) in most cases.” If CK-MB is unavailable, SCAI’s new definition calls for a troponin level that is 70 times the normal level. If an ECG provides strong evidence of an MI, then the new definition allows for blood levels of CK-MB that are five times normal and troponin that is 35 times normal. “When patients are diagnosed with an MI, there are important implications to consider,” Dr. Moussa. “These diagnoses could lead to longer hospitalizations,...
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...

Conference Highlights: ASE 2012

New research was presented at ASE 2012, the American Society of Echocardiography’s 23rd Annual Scientific Sessions, from June 30 to July 3 in Maryland. The features below highlight just some of the studies that emerged from the conference. Echocardiograms for Diagnosing Pulmonary Hypertension The Particulars: Patients with stable heart failure who have high pulmonary artery systolic pressure are at increased risk for adverse outcomes. A reliable method is needed for measuring pulmonary artery systolic pressure in this patient population. Data Breakdown: Emory University researchers used echocardiography to diagnose pulmonary hypertension— defined as pulmonary artery systolic pressure higher than 45 mm Hg—in stable outpatients with heart failure. Echocardiography was found to strongly predict higher risk of clinical events. The testing also helped determine which patients would have higher hospitalization rates. Take Home Pearl: Pulmonary artery systolic pressure as measured by echocardiography appears to provide important prognostic information for patients with stable heart failure. Ultrasonography Helps Predict Atherosclerosis The Particulars: The incidence of peripheral arterial disease is rising throughout the United States. However, data from large population-based samples on the prevalence of subclinical atherosclerosis in the peripheral arteries are lacking. Data Breakdown: Investigators in a study used ultrasound exams to look for the presence and degree of popliteal arterial plaque as a predictor of atherosclerosis. Popliteal artery atherosclerosis was prevalent among patients aged 40 or younger who were at risk for becoming obese and/ or having diabetes. Popliteal artery atherosclerosis was independently associated with older age and albuminuria. Urinary albuminuria was also linked with the severity of atherosclerotic plaque burden in the popliteal arteries. Take Home Pearl: Among younger patients with...
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