Safety and efficiency of a chest pain diagnostic algorithm with selective outpatient stress testing for emergency department patients with potential ischemic chest pain.

Study objective: Chest pain units have been used to monitor and investigate emergency department (ED) patients with potential ischemic chest pain to reduce the possibility of missed acute coronary syndrome. We seek to optimize the use of hospital resources by implementing a chest pain diagnostic algorithm. Methods: This was a prospective cohort study of ED patients with potential ischemic chest pain. High-risk patients were referred to cardiology, and patients without ECG or biomarker evidence of ischemia were discharged home after 2 to 6 hours of observation. Emergency physicians scheduled discharged patients for outpatient stress ECGs or radionuclide scans at the hospital within 48 hours. Patients with positive provocative test results were immediately referred back to the ED. The primary outcome was the rate of missed diagnosis of acute coronary syndrome at 30 days. Results: We prospectively followed 1,116 consecutive patients who went through the chest pain diagnostic algorithm, of whom 197 (17.7%) were admitted at the index visit and 254 (22.8%) received outpatient testing on discharge. The 30-day acute coronary syndrome event rate was 10.8%, and the 30-day missed acute coronary syndrome rate was 0% (95% confidence interval 0% to 2.4%). Of the 120 acute coronary syndrome cases, 99 (82.5%) were diagnosed at the index ED visit, and 21 patients (17.5%) received the diagnosis during outpatient stress testing. Conclusion: In ED patients with chest pain, a structured diagnostic approach with time-focused ED decision points, brief observation, and selective application of early outpatient provocative testing appears both safe and diagnostically efficient, even though some patients with acute coronary syndrome may be discharged for outpatient stress testing on the index ED visit. [Ann Emerg Med. 2012;59:256-264.]