EFFECT OF RECENT COCAINE USE ON THE SPECIFICITY OF CARDIAC MARKERS FOR DIAGNOSIS OF ACUTE MYOCARDIAL-INFARCTION

We evaluated whether recent cocaine use alters the specificity of CK-M B, myoglobin, and cardiac troponin I for acute myocardial infarction ( AMI) in patients who are seen in the emergency department for chest pa in. Patients <60 years old with potential myocardial ischemia underwen t a standardized history and physical examination and routine CK-MB as says every 8 to 12 hours and had study serum obtained at presentation for CK-MB, myoglobin, and cardiac troponin I immunoassays, as well as benzoylecgonine, cocaine's main metabolite. We enrolled 97 patients, 1 9 (20%) of whom had recent used cocaine. Patients with and without coc aine use were similar with regards to sex, race, renal and muscular di sease, diabetes, family history, and hypertension and rate of AMI (12% vs 11%, p = 1.0). In patients without MI, the mean myoglobin level wa s higher in cocaine users than noncocaine users (179 vs 74 ng/ml; Mann -Whitney p = 0.003), but the mean values were similar For CK-MB (2.2 v s 2.1 ng/ml; Mann-Whitney p = 0.58) and for cardiac troponin-1 (0.02 v s 0.02 ng/ml; Mann-Whitney p = 0.87). The specificities of the markers in patients with and without cocaine use were as follows: cardiac tro ponin I, 94% vs 94%, (p = 1.0); CK-MB, 75% vs 88% (p = 0.24); and myog lobin, 50% vs 82%, (p = 0.02), respectively Our data demonstrate that the specificity of myoglobin was altered by recent cocaine use. The sp ecificity of CK-MB was affected less and the specificity of cardiac tr oponin I was not affected by recent cocaine use.