title: Mortality risk associated with ejection fraction differs across resting nuclear perfusion findings.
abstract: BACKGROUND
  Left ventricular ejection fraction (LVEF) is a significant predictor of morbidity and death. The nuclear summed rest score (SRS) measures myocardial perfusion defects and provides prognostic information, but its effects on long-term outcomes are not fully established. Moreover, information regarding the potential interaction between these 2 covariates is limited. The purpose of this study was to determine whether the mortality risk associated with LVEF is the same across all values of SRS in a population undergoing evaluation for ischemic heart disease.
  
  
  RESULTS
  We examined 3,187 patients who underwent cardiac catheterization and perfusion single photon emission computed tomography imaging with a maximum follow-up of 8.1 years and median follow-up of 3.1 years. Cox proportional hazards modeling showed that increasing nuclear SRS and decreasing LVEF were independently associated with a higher long-term mortality rate, with a clinically significant interaction between them (P = .032). Patients with a normal LVEF and a high SRS (greater perfusion abnormality) have a prognosis similar to those with a reduced LVEF.
  
  
  CONCLUSIONS
  Resting perfusion studies provide prognostic information for long-term survival and significantly impact the interpretation of mortality risk associated with changes in LVEF. Patient prognostication, risk stratification, and future research using these variables should take this interaction into account.
authors: Division of Cardiology, Department of Internal Medicine, Duke University Health System, Durham, NC, USA. jamieson2@gmail.com
authors: Jamieson M
authors: JM
authors: Bourque
authors: Eric J
authors: EJ
authors: Velazquez
authors: Robert H
authors: RH
authors: Tuttle
authors: Linda K
authors: LK
authors: Shaw
authors: Christopher M
authors: CM
authors: O'Connor
authors: Salvador
authors: S
authors: Borges-Neto
mesh_terms: D000368:Aged; D015331:Cohort Studies; D015897:Comorbidity; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000401:mortality*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000401:mortality*; D009657:North Carolina / Q000453:epidemiology; D010477:Perfusion / Q000379:methods; D011877:Radionuclide Imaging; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D013223:Statistics as Topic; D013318:Stroke Volume; D016019:Survival Analysis; D015996:Survival Rate; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000401:mortality*