title: Added prognostic value of ischaemic threshold in radionuclide myocardial perfusion imaging: a common-sense integration of exercise tolerance and ischaemia severity.
abstract: OBJECTIVE
  Reversible ischaemia at radionuclide myocardial perfusion imaging (MPI) accurately predicts risk of cardiac death and nonfatal myocardial infarction (major adverse cardiac events, MACE). This prognostic penetrance might be empowered by accounting for exercise tolerance as an indirect index of ischaemia severity. The present study aimed to verify this hypothesis integrating imaging assessment of ischaemia severity with exercise maximal rate pressure product (RPP) in a large cohort of patients with suspected or known coronary artery disease (CAD).
  
  
  RESULTS
  We analysed 1,502 consecutive patients (1,014 men aged 59 ± 10 years) submitted to exercise stress/rest MPI. To account for exercise tolerance, the summed difference score (SDS) was divided by RPP at tracer injection providing a clinical prognostic index (CPI). Reversible ischaemia was documented in 357 patients (24 %) and was classified by SDS as mild (SDS 2-4) in 180, moderate (SDS 5-7) in 118 and severe (SDS >7) in 59. CPI values of ischaemic patients were clustered into tertiles with lowest and highest values indicating low and high risk, respectively. CPI modified SDS risk prediction in 119/357 (33 %) patients. During a 60-month follow-up, MACE occurred in 68 patients. Kaplan-Meier analysis revealed that CPI significantly improved predictive power for MACE incidence with respect to SDS alone. Multivariate Cox analysis confirmed the additive independent value of CPI-derived information.
  
  
  CONCLUSIONS
  Integration of ischaemic threshold and ischaemia extension and severity can improve accuracy of exercise MPI in predicting long-term outcome in a large cohort of patients with suspected or known CAD.
authors.affiliation: CNR Institute of Bioimaging and Molecular Physiology, Section of Genoa c/o Nuclear Medicine, Pad. Sommariva, IRCCS AOU San Martino-National Institute for Cancer Research, L.go R. Benzi, 10, 16132, Genoa, Italy, Cecilia.Marini@unige.it.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Marini
authors.forename: Wanda
authors.initials: W
authors.lastname: Acampa
authors.forename: Matteo
authors.initials: M
authors.lastname: Bauckneht
authors.forename: Stefania
authors.initials: S
authors.lastname: Daniele
authors.forename: Selene
authors.initials: S
authors.lastname: Capitanio
authors.forename: Valeria
authors.initials: V
authors.lastname: Cantoni
authors.forename: Francesco
authors.initials: F
authors.lastname: Fiz
authors.forename: Emilia
authors.initials: E
authors.lastname: Zampella
authors.forename: Bassam
authors.initials: B
authors.lastname: Dib
authors.forename: Roberta
authors.initials: R
authors.lastname: Assante
authors.forename: Paolo
authors.initials: P
authors.lastname: Bruzzi
authors.forename: Gianmario
authors.initials: G
authors.lastname: Sambuceti
authors.forename: Alberto
authors.initials: A
authors.lastname: Cuocolo
mesh_terms: D000368:Aged; D000465:Algorithms; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging*; D055414:Myocardial Perfusion Imaging; D011237:Predictive Value of Tests