Abstract 15220: Myocardial Biomarker Testing With Troponin I: Are We Ordering Too Many Studies?
Background: Myocardial biomarker testing with some form of troponin assay has become standard of care for diagnosing acute myocardial infarction (AMI) among patients presenting with symptoms consistent with acute coronary syndrome. However, in order to “not miss anyone,” troponin assays may be ordered on patients presenting with non-cardiac diagnoses, but the frequency, justification and outcome of this practice are unknown.
Methods: During the year 2007, in a large multi-hospital integrated health system, all patients with a troponin-I (trpI) measurement obtained were studied. Baseline clinical characteristics, primary and secondary admit and discharge diagnoses, as well as maximum trpI were collected and analyzed. A trpI level >0.4 was considered consistent with AMI. Independent predictors of a positive trpI were determined by logistic regression analysis.
Results: At least one trpI test was obtained in a total of 22,410 unique encounters in 18,730 unique patients (age=67±16 years, males=52%, diabetes=38%; history of AMI, coronary artery disease without prior AMI (CAD), heart failure (HF), atrial fibrillation (AF), stroke or renal failure history = 19.8%, 33.6%, 39.5%, 28.9%, 5.7% and 24.1% respectively). Of these, the admit diagnosis was CAD-related in 1,896 (8.5%), other cardiac-related in 6,883 (30.7%) and non-cardiac related in 13,631 (60.8%) patients. Of the patients with a non-cardiac related admit diagnosis, trpI level was >0.4 in 1,238 (9.1%) of cases. Of these, a primary or secondary discharge diagnosis of AMI was given in only 375 (30.3%) of cases. Independent predictors of trpI>0.4 in patients with a non-cardiac admit diagnosis included only a prior history of AMI (OR=6.80, p<0.0001) and renal failure (OR=1.86, p<0.0001).
Conclusions: In a large integrated health system, nearly two thirds of troponin assays are ordered on patients without a cardiac-related admit diagnosis, who had a positive trpI rate of <10%, of which less than a third ultimately were given the diagnosis of AMI. The potential risks, benefits, costs and decision algorithms associated with trpI testing in these patients deserves reassessment.
- © 2013 by American Heart Association, Inc.