title: Safe discharge from the cardiac emergency room with a rapid rule-out myocardial infarction protocol using serial CK-MB(mass).
abstract: OBJECTIVE
  To determine whether a new protocol, using a rapid and sensitive CK-MB(mass) assay and serial sampling, can rule out myocardial infarction in patients with chest pain and decrease their length of stay in the cardiac emergency room without increasing risk.
  
  
  METHODS
  The combined incidence of cardiac death and acute myocardial infarction at 30 days, six months, and 24 months of follow up were compared between patients discharged home from the cardiac emergency room after ruling out myocardial infarction with a CK-MB(activity) assay in 1994 and those discharged home after a rapid CK-MB(mass) assay in 1996.
  
  
  METHODS
  Cardiac emergency room of a large university hospital.
  
  
  METHODS
  In 1994 and 1996, 230 and 423 chest pain patients, respectively, were discharged home from the cardiac emergency room with a normal CK-MB and an uneventful observation period.
  
  
  RESULTS
  The median length of stay in the cardiac emergency room was significantly reduced, from 16.0 hours in 1994 to 9.0 hours in 1996 (p < 0.0001). Mean event rates in patients from the 1994 and 1996 cohorts, respectively, were 0.9% (95% confidence interval (CI) -0.3% to 2.1%) v 0.7% (95% CI -0.1% to 1. 5%) at 30 days, 3.0% (95% CI 0.8% to 5.2%) v 2.8% (95% CI 1.2% to 4. 4%) at six months, and 7.0% (95% CI 3.7% to 10.3%) v 5.7% (95% CI 3. 5% to 7.9%) at 24 months. Kaplan-Meier survival analysis showed no difference in mean event-free survival at 30 days, six months, and 24 months of follow up.
  
  
  CONCLUSIONS
  Using a rule-out myocardial infarction protocol with a rapid and sensitive CK-MB(mass) assay and serial sampling, the length of stay of patients with chest pain in the cardiac emergency room can be reduced without compromising safety.
authors.affiliation: Department of Cardiology, Academic Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, Netherlands. r.bholasingh@amc.uva.nl
authors.forename: R
authors.initials: R
authors.lastname: Bholasingh
authors.forename: R J
authors.initials: RJ
authors.lastname: de Winter
authors.forename: J C
authors.initials: JC
authors.lastname: Fischer
authors.forename: R W
authors.initials: RW
authors.lastname: Koster
authors.forename: R J
authors.initials: RJ
authors.lastname: Peters
authors.forename: G T
authors.initials: GT
authors.lastname: Sanders
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D002637:Chest Pain / Q000209:etiology*; D004796:Clinical Enzyme Tests / Q000379:methods*; D002985:Clinical Protocols; D003402:Creatine Kinase / Q000097:blood*; D052279:Creatine Kinase, MB Form; D018572:Disease-Free Survival; D004636:Emergency Service, Hospital; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007527:Isoenzymes / Q000097:blood*; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis*; D010351:Patient Discharge; D011446:Prospective Studies; D014218:Triage / Q000379:methods
chemical_list: D015415:Biomarkers; D007527:Isoenzymes; D003402:Creatine Kinase; D052279:Creatine Kinase, MB Form