Emergency department triage strategies for acute chest pain using creatineKinase-MB and troponin I assays: A cost-effectiveness analysis

Background: Evaluation of acute chest pain is highly variable. Objective: To evaluate the cost-effectiveness of strategies using cardiac m arkers and noninvasive tests for myocardial ischemia. Design: Cost-effectiveness analysis. Data Sources: Prospective data from 1066 patients with chest pain and from the published literature. Target Population: Patients admitted with acute chest pain. Time Horizon: Lifetime. Perspective: Societal. Interventions: Creatine kinase (CK)-MB mass assay alone; CK-MB mass assay f ollowed by cardiac troponin assay if the CK-MB value is normal; CK-MB mass assay followed by troponin I assay if the CK-MB value is normal and electro cardiography shows ischemic changes; both CK-MB mass and troponin I assays; and troponin I assay alone. These strategies were evaluated alone or in co mbination with early exercise testing. Outcome Measures: Lifetime cost, life expectancy (in years), and incrementa l cost-effectiveness. Results of Base-Case Analysis: For patients 55 to 64 years of age, measurem ent of CK-MB mass followed by exercise testing in appropriate patients was the most competitive strategy ($43000 per year of life saved). Measurement of CK-MB mass followed by troponin I measurement had an incremental cost-ef fectiveness ratio of $47400 per year of life saved for patients 65 to 74 ye ars of age; it was also the most cost-effective strategy when early exercis e testing could not be performed, CK-MB values were normal, and ischemic ch anges were seen on electrocardiography. Results of Sensitivity Analysis: Results were influenced by age, probabilit y of myocardial infarction, and medical costs. Conclusions: Measurement of CK-MB mass plus early exercise testing is a cos t-effective initial strategy for younger patients and those with a low to m oderate probability of myocardial infarction. Troponin I measurement can be a cost-effective second test in higher-risk subsets of patients if the CK- MB level is normal and early exercise testing is not an option.