The limited utility of routine cardiac stress testing in emergency department chest pain patients younger than 40 years.

STUDY
OBJECTIVE: This is a study designed to evaluate the utility of routine provocative cardiac testing in low-risk young adult (younger than 40 years) patients evaluated for an acute coronary syndrome in an emergency department (ED) setting.
METHODS: This was a retrospective observational study of patients aged 23 to 40 years who were evaluated for acute coronary syndrome in an ED-based chest pain unit from March 2004 to September 2007. All patients had serial cardiac biomarker testing to rule out myocardial infarction and then underwent provocative cardiac testing to identify the presence of myocardial ischemia. Patients were excluded from the study if they had known coronary artery disease, had ECG findings diagnostic of myocardial infarction or ischemia, or self-admitted, or tested positive for cocaine use.
RESULTS: Of the 220 patients who met inclusion criteria, 6 patients (2.7%; 95% confidence interval 1% to 5.8%) had positive stress test results. Among these 6 patients, 4 underwent subsequent coronary angiography that demonstrated no obstructive coronary disease, suggesting the initial provocative study was falsely positive. For the remaining 2 patients, no diagnostic angiography was performed. Discounting the patients who had negative angiography results, only 2 of 220 study patients (0.9%; 95% confidence interval 0.1% to 3.2%) had a provocative test result that was positive for myocardial ischemia.
CONCLUSION: In our study, a combination of age younger than 40 years, nondiagnostic ECG result, and 2 sets of negative cardiac biomarker results at least 6 hours apart identified a patient group with a very low rate of true-positive provocative testing. Routine stress testing added little to the diagnostic evaluation of this patient group and was falsely positive in all patients who consented to diagnostic coronary angiography (4 of 6 cases).