Many PCI referrals due to false-positive myocardial infarction diagnoses
MedWire News: Researchers have identified the prevalence of and factors associated with false-positive ST-segment-elevation myocardial infarction (STEMI) diagnoses at percutaneous coronary intervention (PCI) centers.
James McCabe (Brigham and Women's Hospital, Boston, Massachusetts, USA) and colleagues found that over a third of patients referred for primary PCI from an emergency department (ED) do not have STEMI.
"While a certain percentage of false-positive STEMI activations are essential to ensuring adequate diagnostic sensitivity, the point of equipoise between necessary diagnostic sensitivity and patient safety requires further investigation, particularly in light of increasing resource limitations," they comment.
McCabe and team analyzed the data of 411 consecutive patients who were referred for primary PCI due to possible STEMI between October 2008 and April 2011. False-positive STEMI diagnosis was defined as a lack of a culprit lesion on angiography or by assessment of clinical, electrocardiographic, and biomarker data in the absence of angiography.
The findings, reported in the Archives of Internal Medicine, show that 146 (36%) of STEMI diagnoses by emergency physicians were deemed to be false-positive.
Structural heart disease and heart failure were the most common diagnoses among these false-positive cases.
Factors that increased the odds for false-positive STEMI diagnoses were electrocardiographic left ventricular hypertrophy, history of coronary artery disease, and prior illicit drug abuse, at adjusted odds ratios of 3.15, 1.93, and 2.67, respectively (p<0.04 for all).
By contrast, increasing body mass index (BMI) decreased the chances of a false-positive diagnosis by an adjusted odds ratio of 0.91 per unit/for each 1 kg/m2 increase in BMI. In addition, angina at presentation decreased the risk for a false-positive diagnosis by 72% (p<0.001).
In a related commentary, Fouad Bachour and Richard Asinger, both from the University of Minnesota in Minneapolis, USA, point out that the false-positive STEMI diagnoses made in the study "could have been the result of an absolutely appropriate cardiac catheterization laboratory (CCL) activation."
They say that in this case, a lower percentage of the series in study would have been classified as false.
The editorialists add: "The discrepancy between the study by McCabe et al and other reports for CCL activation for STEMI highlight the variability of definitions and need for further guidance in establishing measures for quality of reperfusion programs."
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By Piriya Mahendra