title: Impaired coronary flow reserve is the most important marker of viable myocardium in the myocardial segment-based analysis of dual-isotope gated myocardial perfusion single-photon emission computed tomography.
abstract: OBJECTIVE
  The aim of this study was to investigate the most robust predictor of myocardial viability among stress/rest reversibility (coronary flow reserve [CFR] impairment), (201)Tl perfusion status at rest, (201)Tl 24 hours redistribution and systolic wall thickening of (99m)Tc-methoxyisobutylisonitrile using a dual isotope gated myocardial perfusion single-photon emission computed tomography (SPECT) in patients with coronary artery disease (CAD) who were re-vascularized with a coronary artery bypass graft (CABG) surgery.
  
  
  METHODS
  A total of 39 patients with CAD was enrolled (34 men and 5 women), aged between 36 and 72 years (mean 58 ± 8 standard in years) who underwent both pre- and 3 months post-CABG myocardial SPECT. We analyzed 17 myocardial segments per patient. Perfusion status and wall motion were semi-quantitatively evaluated using a 4-point grading system. Viable myocardium was defined as dysfunctional myocardium which showed wall motion improvement after CABG.
  
  
  RESULTS
  The left ventricular ejection fraction (LVEF) significantly increased from 37.8 ± 9.0% to 45.5 ± 12.3% (p < 0.001) in 22 patients who had a pre-CABG LVEF lower than 50%. Among 590 myocardial segments in the re-vascularized area, 115 showed abnormal wall motion before CABG and 73.9% (85 of 115) had wall motion improvement after CABG. In the univariate analysis (n = 115 segments), stress/rest reversibility (p < 0.001) and (201)Tl rest perfusion status (p = 0.024) were significant predictors of wall motion improvement. However, in multiple logistic regression analysis, stress/rest reversibility alone was a significant predictor for post-CABG wall motion improvement (p < 0.001).
  
  
  CONCLUSIONS
  Stress/rest reversibility (impaired CFR) during dual-isotope gated myocardial perfusion SPECT was the single most important predictor of wall motion improvement after CABG.
authors.affiliation: Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam 463-707, Korea. ; Institute of Radiation Medicine, Medical Research Center, Seoul National University, Seoul 110-744, Korea.
authors.forename: Won Woo
authors.initials: WW
authors.lastname: Lee
authors.affiliation: Department of Nuclear Medicine, Konkuk University School of Medicine, Seoul 143-729, Korea.
authors.forename: Young
authors.initials: Y
authors.lastname: So
authors.affiliation: Department of Thoracic & Cardiovascular Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul 110-744, Korea.
authors.forename: Ki-Bong
authors.initials: KB
authors.lastname: Kim
authors.affiliation: Institute of Radiation Medicine, Medical Research Center, Seoul National University, Seoul 110-744, Korea. ; Department of Nuclear Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul 110-744, Korea.
authors.forename: Dong Soo
authors.initials: DS
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D055426:Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography / Q000379:methods*; D001026:Coronary Artery Bypass; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D003326:Coronary Circulation / Q000502:physiology*; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology; D009206:Myocardium; D009570:Nitriles; D013318:Stroke Volume / Q000502:physiology; D013667:Technetium; D016277:Ventricular Function, Left / Q000502:physiology
chemical_list: D009570:Nitriles; C055887:2-methoxyisobutylisonitrile; D013667:Technetium
keywords: Coronary artery bypass grafting; Ischemia; Myocardium; Single-photon emission-computed tomography; Tissue viability