BACKGROUND: Cardiac troponin is more accurate than creatine kinase (CK) testing for detecting myocardial injury in patients with acute coronary syndromes (ACS), but its effects on clinical care compared with CK testing alone is open to question.
OBJECTIVE: To test the effects of troponin I on medical decisions for patients undergoing cardiac enzyme testing.
DESIGN: Randomized, controlled trial.
SETTING: Urban academic Veterans Affairs medical center.
PATIENTS: Three hundred ninety-two patients presenting to the emergency department (ED) and outpatient settings with symptoms and/or electrocardiograms suggestive but not diagnostic of ACS.
INTERVENTION: Random assignment to linked CK-troponin I (CKTnI) testing or CK testing alone.
MEASUREMENTS: ED discharge and cardiac catheterization incidence (primary); ED medication use, inpatient noninvasive testing, revascularization procedures, discharge medications, and 8-week ED visits, hospitalizations, and procedures (secondary).
RESULTS: Groups were similar in all variables except history of heart failure (CK 26.8% vs CKTnI 17.0%). ACS comprised 12.2% of the cohort. ED discharge incidence was greater in the CKTnI arm (18% vs 9.6%; relative risk [RR], 1.83; 95% CI, 1.08 to 3.31; P=.02; number needed to test=12.6; 95% CI, 4.5 to 130). Troponin testing had no significant effect on catheterization incidence (18.2% vs 14.5%; RR, 1.19; 95% CI, 0.72 to 1.92; P>.20) or other outcomes except follow-up echocardiography (13.4% vs 7.4%; RR, 2.24; 95% CI, 1.11 to 4.69; P=.02).
CONCLUSIONS: In a veterans population undergoing cardiac enzyme testing, CKTnI testing led to more ED discharges than CK testing alone but had no effect on inpatient care and was associated with more echocardiograms in a follow-up period.
Antman EM, Tanasijevic MJ, Thompson B, et al. cardiac-specific troponin I levels to predict the risk of mortality in patients with acute coronary syndromes. N Engl J Med. 1996;335:1342–9.PubMedCrossRefGoogle Scholar
Antman EM, Cohen M, Bernink PJ, et al. The TIMI risk score for unstable angina/non-ST elevation MI: a method for prognostication and therapeutic decision making. JAMA. 2000;284:835–42.PubMedCrossRefGoogle Scholar
Matetzky S, Sharir T, Domingo M, et al. Elevated troponin I level on admission is associated with adverse outcome of primary angioplasty in acute myocardial infarction. Circulation. 2000;102:1611–6.PubMedGoogle Scholar
Newby LK, Ohman EM, Christenson RH, et al. Benefit of glycoprotein IIb/IIIa inhibition in patients with acute coronary syndromes and troponin t-positive status: the paragon-B troponin T substudy. Circulation. 2001;103:2891–6.PubMedGoogle Scholar
Cannon CP, Weintraub WS, Demopoulos LA, et al. Comparison of early invasive and conservative strategies in patients with unstable coronary syndromes treated with the glycoprotein IIb/IIIa inhibitor tirofiban. N Engl J Med. 2001;344:1879–87.PubMedCrossRefGoogle Scholar
Thygeson K, Alpert JSfor the Joint European Society of Cardiology/American College of Cardiology Committee. Myocardial infarction redefined—a consensus document of the Joint European Society of Cardiology/American College of Cardiology Committee for the redefinition of myocardial infarction. J Am Coll Cardiol. 2000;959–69.Google Scholar
Zimmerman J, Fromm R, Meyer D, et al. Diagnostic marker cooperative study for the diagnosis of myocardial infarction. Circulation. 1999;99:1671–7.PubMedGoogle Scholar
Newby LK, Storrow AB, Bibler WB, et al. Bedside multimarker testing for risk stratification in chest pain units: the chest pain evaluation by creatine kinase-MB, myoglobin, and troponin I study. Circulation. 2001;103:1832–37.PubMedGoogle Scholar
Lau J, Ioannidis JP, Balk EM, et al. Diagnosing acute cardiac ischemia in the emergency department: a systematic review of the accuracy and clinical effect of current technologies. Ann Emerg Med. 2001;37:453–60.PubMedCrossRefGoogle Scholar
Balk EM, Ioannidis JP, Salem D, Chew PW, Lau J. Accuracy of biomarkers to diagnose acute cardiac ischemia in the emergency department: a meta-analysis. Ann Emerg Med. 2001;37:478–94.PubMedCrossRefGoogle Scholar
Polanczyk CA, Johnson PA, Cook EF, Lee TH. A proposed strategy for utilization of creatine kinase-MB and troponin I in the evaluation of acute chest pain. Am J Cardiol. 1999;83:1175–9.PubMedCrossRefGoogle Scholar
Polanczyk CA, Kuntz KM, Sacks DB, Johnson PA, Lee TH. Emergency department triage strategies for acute chest pain using creatine kinase-MB and troponin I assays: a cost-effectiveness analysis. Ann Intern Med. 1999;131:909–18.PubMedGoogle Scholar
Dagnone E, Collier C, Pickett W, et al. Chest pain with nondiagnostic electrocardiogram in the emergency department: a randomized controlled trial of two cardiac marker regimens. CMAJ. 2000;162:1561–6.PubMedGoogle Scholar
Bradley K, Seymour J, Mayall I, Gali W, Bernstein LH. Impact of troponin T determinations on hospital resource utilization and costs in the evaluation of patients with suspected myocardial ischemia. Am J Cardiol. 2001;88:732–6.PubMedCrossRefGoogle Scholar
Wu AH, Apple FS, Gibler WB, Jesse RL, Warshaw MM, Valdes R Jr. National Academy of Clinical Biochemistry Standards of Laboratory Practice: recommendations for the use of cardiac markers in coronary artery diseases. Clin Chem. 1999;45:1104–21.PubMedGoogle Scholar
Barboza D. Drug maker accepts a fine over test kits. New York Times. November 3, 1999;A:1.Google Scholar
Centor RM, Allison JJ, Weissman NW, Shaneyfelt T, Heudebert G, Kiefe CI. Early adoption of troponin as a prognostic test is associated with appropriate reductions in catheterization rates for Medicare patients hospitalized with unstable angina. J Gen Intern Med. 2000;15(suppl I):105.Google Scholar
Weingarten SR, Riedinger MS, Conner L, et al. Practice guidelines and reminders to reduce duration of hospital stay for patients with chest pain. An interventional trial. Ann Intern Med. 1994;120:257–63.PubMedGoogle Scholar
Bossuyt PMM, Lijmer JG, Mol BWJ. Randomised comparisons of medical tests: sometimes invalid, not always efficient. Lancet. 2000;356:1844–7.PubMedCrossRefGoogle Scholar
Morrow DA. Evidence-based decision limits for cardiac troponin: low-level elevation and prognosis. Am Heart J. 2004;148:739–42.PubMedCrossRefGoogle Scholar
Sheifer SE, Rathore SS, Gersh BJ, et al. Time to presentation with acute myocardial infarction in the elderly. Circulation. 2000;102:1651–6.PubMedGoogle Scholar
Hollander JE, Todd KH, Heilpern KL, et al. Chest pain associated with cocaine: an assessment of prevalence in suburban and urban emergency departments. Ann Emerg Med. 1995;26:671–6.PubMedCrossRefGoogle Scholar