title: Safety of a rapid diagnostic protocol with accelerated stress testing.
abstract: BACKGROUND
  Most patients at low to intermediate risk for an acute coronary syndrome (ACS) receive a 12- to 24-hour "rule out." Recently, trials have found that a coronary computed tomographic angiography-based strategy is more efficient. If stress testing were performed within the same time frame as coronary computed tomographic angiography, the 2 strategies would be more similar. We tested the hypothesis that stress testing can safely be performed within several hours of presentation.
  
  
  METHODS
  We performed a retrospective cohort study of patients presenting to a university hospital from January 1, 2009, to December 31, 2011, with potential ACS. Patients placed in a clinical pathway that performed stress testing after 2 negative troponin values 2 hours apart were included. We excluded patients with ST-elevation myocardial infarction or with an elevated initial troponin. The main outcome was safety of immediate stress testing defined as the absence of death or acute myocardial infarction (defined as elevated troponin within 24 hours after the test).
  
  
  RESULTS
  A total of 856 patients who presented with potential ACS were enrolled in the clinical pathway and included in this study. Patients had a median age of 55.0 (interquartile range, 48-62) years. Chest pain was the chief concern in 86%, and pain was present on arrival in 73% of the patients. There were no complications observed during the stress test. There were 0 deaths (95% confidence interval, 0%-0.46%) and 4 acute myocardial infarctions within 24 hours (0.5%; 95% confidence interval, 0.14%-1.27%). The peak troponins were small (0.06, 0.07, 0.07, and 0.19 ng/mL).
  
  
  CONCLUSIONS
  Patients who present to the ED with potential ACS can safely undergo a rapid diagnostic protocol with stress testing.
authors.affiliation: Department of Emergency Medicine, University of Pennsylvania, Philadelphia, PA. Electronic address: olanmd@gmail.com.
authors.forename: Olan A
authors.initials: OA
authors.lastname: Soremekun
authors.affiliation: Division of Emergency Medicine, University of Wisconsin, Madison, WI.
authors.forename: Azita
authors.initials: A
authors.lastname: Hamedani
authors.affiliation: Department of Emergency Medicine, University of Pennsylvania, Philadelphia, PA.
authors.forename: Frances S
authors.initials: FS
authors.lastname: Shofer
authors.affiliation: Department of Emergency Medicine, University of Pennsylvania, Philadelphia, PA.
authors.forename: Katie J
authors.initials: KJ
authors.lastname: O'Conor
authors.affiliation: Division of Emergency Medicine, University of Wisconsin, Madison, WI.
authors.forename: James
authors.initials: J
authors.lastname: Svenson
authors.affiliation: Department of Emergency Medicine, University of Pennsylvania, Philadelphia, PA.
authors.forename: Judd E
authors.initials: JE
authors.lastname: Hollander
mesh_terms: D054058:Acute Coronary Syndrome / Q000175:diagnosis*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017023:Coronary Angiography / Q000379:methods; D019091:Critical Pathways; D004636:Emergency Service, Hospital; D005080:Exercise Test / Q000009:adverse effects / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis; D061214:Patient Safety; D012189:Retrospective Studies; D013997:Time Factors