title: Incremental utility of iodine-123 meta-iodobenzylguanidine imaging beyond established heart failure risk models.
abstract: BACKGROUND
  Nuclear myocardial imaging with iodine-123 meta-iodobenzylguanidine ((123)I-mIBG) is approved for risk stratification of patients with systolic heart failure (HF). Whether (123)I-mIBG imaging provides incremental prognostic utility beyond established risk models remains unclear.
  
  
  RESULTS
  In a multicenter study, 961 patients with moderate systolic HF underwent (123)I-mIBG imaging and were followed for cardiac death, progressive HF, or life-threatening arrhythmias over 2 years. We constructed 4 multivariable models, using variables from each of 4 published HF risk models, and patient-level scores were calculated both before and after adding the heart-to-mediastinum ratio (H/M) from (123)I-mIBG imaging. Incremental utility was evaluated by calculating integrated discrimination improvement (IDI), which quantifies the increase in probability of experiencing the primary end point after adding H/M to each model. The composite end point occurred in 25% of patients. After adding H/M, absolute IDI ranged from 2.1% to 3.0%, representing 33%-59% relative improvements in risk stratification. Of note, hazard ratios for H/M were remarkably similar between risk models (0.40-0.44 for predicting the composite end point, 0.10-0.18 for mortality; all P < .001).
  
  
  CONCLUSIONS
  Despite notable differences in predictor variables, patient populations, and analytic techniques from which each model was initially derived, adding (123)I-mIBG data to HF risk models consistently identified patients at lower risk of experiencing adverse events.
authors.affiliation: Division of Cardiology, Saint Louis University, St. Louis, Missouri.
authors.forename: Kaushik K
authors.initials: KK
authors.lastname: Jain
authors.affiliation: Division of Cardiology, Saint Louis University, St. Louis, Missouri.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Hauptman
authors.affiliation: Saint Luke's Mid America Heart Institute, Kansas City, Missouri.
authors.forename: John A
authors.initials: JA
authors.lastname: Spertus
authors.affiliation: Saint Luke's Mid America Heart Institute, Kansas City, Missouri.
authors.forename: Kevin F
authors.initials: KF
authors.lastname: Kennedy
authors.affiliation: Saint Luke's Mid America Heart Institute, Kansas City, Missouri.
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Bateman
authors.affiliation: GE Healthcare, Princeton, New Jersey.
authors.forename: Arnold F
authors.initials: AF
authors.lastname: Jacobson
authors.affiliation: Division of Cardiology, Saint Louis University, St. Louis, Missouri. Electronic address: jstolker@yahoo.com.
authors.forename: Joshua M
authors.initials: JM
authors.lastname: Stolker
mesh_terms: D000368:Aged; D003909:Dexetimide / Q000031:analogs & derivatives*; D003952:Diagnostic Imaging / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000000981:diagnostic imaging* / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011877:Radionuclide Imaging; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D014481:United States
chemical_list: D007457:Iodine Radioisotopes; C094599:N-methyl-4-iododexetimide; D003909:Dexetimide
keywords: Risk model; heart failure; prognosis; radionuclide imaging