title: Stress-only Tc-99m myocardial perfusion imaging in an emergency department chest pain unit.
abstract: BACKGROUND
  Stress-only myocardial perfusion imaging (MPI) saves time by eliminating rest imaging, which is important for emergency department (ED) throughput but has not been studied in an ED population.
  
  
  OBJECTIVE
  To determine the prognosis of a normal stress-only MPI study compared to a normal rest-stress MPI and establish its effectiveness in an ED setting.
  
  
  METHODS
  All patients evaluated in the ED over 6.5 years who underwent a stress-only technetium-99m gated MPI were compared to those who had a rest-stress study. All-cause mortality was determined using the Social Security Death Index. Survival was analyzed in patients with normal and abnormal MPI results.
  
  
  RESULTS
  A total of 4145 studies (2340 stress-only, 1805 rest-stress) were performed. Patients' average age was 57.9 years, 38.5% were male, and most had an intermediate or low pretest risk of coronary artery disease (87.7%). Average follow-up was 35.9 ± 20.9 months. In patients with normal perfusion, at 1 year of follow-up there were 11 deaths in the stress-only group (0.5% 1-year mortality), and 13 deaths in the rest-stress cohort (1.1% 1-year mortality). At the end of follow-up, the stress-only group had a lower all-cause mortality (p < 0.0001) and similar risk adjusted all-cause mortality (p = 0.10) than the rest-stress cohort. Patients with abnormal perfusion demonstrated the expected differential prognosis based on total perfusion deficits in both groups.
  
  
  CONCLUSIONS
  A normal stress-only MPI study has a benign 1-year prognosis similar to a rest-stress study when performed in the ED. The ability to triage patients more rapidly and reduce radiation exposure represents an attractive alternative for low-risk patients.
authors.affiliation: Department of Cardiology (Mount Sinai Heart), Mount Sinai Medical Center, New York, New York 10029, USA.
authors.forename: William L
authors.initials: WL
authors.lastname: Duvall
authors.forename: Melanie N
authors.initials: MN
authors.lastname: Wijetunga
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Klein
authors.forename: Rittu
authors.initials: R
authors.lastname: Hingorani
authors.forename: Benoit
authors.initials: B
authors.lastname: Bewley
authors.forename: Shahid M
authors.initials: SM
authors.lastname: Khan
authors.forename: Luke K
authors.initials: LK
authors.lastname: Hermann
authors.forename: Milena J
authors.initials: MJ
authors.lastname: Henzlova
mesh_terms: D000368:Aged; D002316:Cardiotonic Agents / Q000008:administration & dosage; D002423:Cause of Death; D002637:Chest Pain / Q000000981:diagnostic imaging* / Q000401:mortality; D004176:Dipyridamole / Q000008:administration & dosage; D004298:Dopamine / Q000008:administration & dosage; D004636:Emergency Service, Hospital; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D011379:Prognosis; D013312:Stress, Physiological / Q000502:physiology; D016019:Survival Analysis; D013667:Technetium; D014665:Vasodilator Agents / Q000008:administration & dosage
chemical_list: D002316:Cardiotonic Agents; D014665:Vasodilator Agents; D004176:Dipyridamole; D013667:Technetium; D004298:Dopamine