Risk stratification of patients in an emergency department chest pain unit: prognostic value of exercise treadmill testing using the Duke score

BACKGROUND: Exercise treadmill testing (ETT) has been standard for evaluating outpatients at risk for cardiovascular events. Few studies have demonstrated its prognostic usefulness in emergency department chest pain units or have used the Duke score [(exercise duration in minutes) - (5 x ST-segment deviation in millimeters) - (4 x treadmill angina index)] to grade its performance. AIMS: Our objective was to assess the usefulness of this score in a chest pain unit to predict cardiovascular events. METHODS: From November 2000 to October 2001, we retrospectively studied consecutive patients in the chest pain unit. Those undergoing ETT were stratified into "low" (Duke score > or = 5) and "moderate/high" risk groups (< 5). Cardiovascular events defined as death, myocardial infarction > 24 h after presentation, revascularization, acute congestive heart failure, stroke or arrhythmia were identified within 1 year after presentation. Differences in risk of having a cardiovascular event among low-risk and moderate/high-risk groups are presented. RESULTS: During the study period, 1,048 patients entered the chest pain unit; 800 met inclusion criteria. Of these, 599 received ETT and 201 had contraindications or a positive finding in the chest pain unit protocol before ETT. Cardiovascular event rates were 0.7% (3/454), 15.2% (22/145) and 14.9% (30/201) after 1 month of follow-up for low-risk, moderate/high-risk and no-ETT groups, respectively. CONCLUSIONS: According to the Duke score, the low-risk group developed minimal cardiovascular events compared with the moderate/high-risk group. The Duke score appears effective for risk stratification of chest pain patients in chest pain units.