A double-blind, multicentered study comparing the accuracy of diagnostic markers to predict short- and long-term clinical events and their utility inpatients presenting with chest pain

Background: Millions of patients present annually with chestpain, but only 10% have myocardial infarction (MI). We recently reported comparative sensi tivity and specificity of available markers in the diagnosis of MI; however , optimum interpretation of marker results requires prognostic follow-up da ta. Hypothesis: The study was undertaken to study the accuracy of CK-MB subform s, troponin I and T, myoglobin, and CK-MB in predicting clinical events at 30 days and 6 months. Methods In all, 955 consecutive patients with chest pain were enrolled in a prospective, multicenter, double-blind study to test the prognostic accura cy of these markers. Results: Myocardial infarction was diagnosed in 119 by CK-MB mass criteria and unstable angina (UA) in 203 patients by clinical criteria. Follow-up at 30 days and 6 months was available in 824 and 724 patients, respectively, with mortalities of 2.8 and 4.14%, respectively Cumulative 6-month mortalit y was 5.6% in MI, 4.4% in UA, and 3.0% in others. Revascularization was rep orted in 9.3% of patients by 6 months. A positive test on each of the marke rs except myoglobin was predictive of revascularization. The composite endp oint of death or revascularization occurred in 107 patients by 6 months and a positive result on each of the markers was predictive of this composite endpoint (p < 0.05). The relative risk of death or revascularization for pa tients who did not have MI but tested positive on each of the markers was > 1.0 but did not reach statistical significance. Conclusions: With the possible exception of myoglobin. each of the diagnost ic markers displayed similar prognostic performance in patients with chest pain presenting to emergency departments. The most appropriate markers to t riage patients with chest pain, which has both adequate early diagnostic se nsitivity and prognostic accuracy, are the CK-MB subforms.