title: Variations in the referral patterns to stress nuclear imaging and stress echocardiography scans.
abstract: BACKGROUND
  Stress myocardial perfusion imaging (MPI) and stress echocardiography (Echo) are commonly used for the noninvasive evaluation of patients with suspected coronary artery disease (CAD). Very few studies have compared the referral patterns to these imaging modalities in terms of the clinical profile of patients, reasons for referral, and type of referring physicians.
  
  
  RESULTS
  This was a prospective study of 1,020 consecutive patients who were referred for stress MPI (429 patients) or stress Echo (591 patients) at the American University of Beirut Medical Center in the year of 2008. Patients referred to MPI were older and had a higher prevalence of diabetes, hypertension, hypercholesterolemia, smoking, and previous myocardial infarction, coronary angioplasty, or bypass surgery. There were more abnormal scans in the stress MPI group (24% vs 15%, P < 0.001), as well as a higher prevalence of ischemia (15% vs 7.6%, P < 0.001) and impaired left ventricular function with an ejection fraction <50% (11% vs 1.7%, P < 0.001). A higher percentage of stress Echo studies were self-referred by physicians who themselves interpret the scans (31% vs 19%, P < 0.001).
  
  
  CONCLUSIONS
  Patients referred for stress MPI are at a higher risk than those referred for stress Echo having more CAD risk factors, more prior history of coronary events, and an older age. These findings have important implications in the interpretation of studies that compare the diagnostic and prognostic power of these two imaging modalities.
authors.affiliation: Department of Internal Medicine, American University of Beirut, Beirut, Lebanon.
authors.forename: Salam
authors.initials: S
authors.lastname: Itani
authors.forename: Walid
authors.initials: W
authors.lastname: Gharzuddine
authors.forename: Samir
authors.initials: S
authors.lastname: Arnaout
authors.forename: Mukbil
authors.initials: M
authors.lastname: Hourani
authors.forename: Samir
authors.initials: S
authors.lastname: Alam
authors.forename: Habib A
authors.initials: HA
authors.lastname: Dakik
mesh_terms: D000328:Adult; D000368:Aged; D002309:Cardiology / Q000295:instrumentation / Q000379:methods; D003324:Coronary Artery Disease / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D025401:Echocardiography, Stress / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D011379:Prognosis; D011446:Prospective Studies; D012017:Referral and Consultation; D012306:Risk; D012737:Sex Factors