title: Clinical role of the Duke Activity Status Index in the selection of the optimal type of stress myocardial perfusion imaging study in patients with known or suspected ischemic heart disease.
abstract: BACKGROUND
  Exercise treadmill stress myocardial perfusion imaging (MPI) with single photon emission computed tomography is commonly used to evaluate the extent and severity of inducible ischemia as well as to risk stratify patients with suspected and known coronary artery disease (CAD). Failure to reach adequate stress, defined as not attaining age-appropriate metabolic equivalents (METs), can underestimate the extent and severity of ischemic heart disease, resulting in false negative results. This study evaluates the efficacy of the Duke Activity Status Index (DASI), a simple self-administered 12-item questionnaire, as a predictor of METs achieved by treadmill stress testing.
  
  
  METHODS
  The DASI was prospectively administered to 200 randomly selected men and women referred to the nuclear cardiology laboratory at New York University Langone Medical Center for stress MPI. Each patient was asked to complete the 12-item DASI questionnaire independently. 136 patients underwent treadmill exercise with MPI and 64 had pharmacologic stress with MPI. The association between exercise capacity in METs as estimated by the DASI questionnaire and performance on the Bruce treadmill protocol in METS was compared using chi-square statistics.
  
  
  RESULTS
  Over 70% of those patients whose DASI score predicted the ability to perform <10 METs were unable to exercise beyond stage 2 of the Bruce protocol (7 METs). For those whose DASI score predicted ability to perform >12.5 METs, over 80% of patients reached >stage 2 of the Bruce protocol with 40% reaching beyond stage 3 (10 METs). When patient age was incorporated into the calculation, a more linear relationship was observed between predicted and obtained METs.
  
  
  CONCLUSIONS
  The DASI is a simple self-administered questionnaire which is a useful pretest tool to determine a patient's ability to achieve appropriate METs. In the nuclear cardiology laboratory, the DASI has the potential to guide selection of exercise treadmill vs pharmacologic stress and ultimately improve laboratory efficiency.
authors.affiliation: Division of Cardiology, Department of Medicine, New York University Langone Medical Center, 530 First Avenue, SKI-9U, New York, NY 10016, USA. Lawrence.Phillips@NYUMC.org
authors.forename: Lawrence
authors.initials: L
authors.lastname: Phillips
authors.forename: Jing Wa
authors.initials: JW
authors.lastname: Wang
authors.forename: Brad
authors.initials: B
authors.lastname: Pfeffer
authors.forename: Eugenia
authors.initials: E
authors.lastname: Gianos
authors.forename: Daniel
authors.initials: D
authors.lastname: Fisher
authors.forename: Leslee J
authors.initials: LJ
authors.lastname: Shaw
authors.forename: Jennifer H
authors.initials: JH
authors.lastname: Mieres
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D059026:Diagnostic Self Evaluation; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000175:diagnosis*; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D018579:Patient Selection; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires