title: Assessment of coronary artery bypass graft disease using cardiovascular magnetic resonance determination of flow reserve.
abstract: OBJECTIVE
  The purpose of this study was to assess the value of cardiovascular magnetic resonance (CMR)-determined graft flow and flow reserve in differentiating significant from non-significant vein graft disease.
  
  
  BACKGROUND
  In patients after coronary artery bypass grafting (CABG), non-invasive testing may be helpful in the detection of recurrent graft disease.
  
  
  METHODS
  Randomly selected patients (n = 21) scheduled for X-ray angiography because of recurrent chest complaints after CABG were included for evaluation of vein grafts (n = 40) by CMR. Three-dimensional contrast-enhanced CMR angiography was performed and followed by flow measurements at rest and during hyperemia in patent grafts only. Flow reserve was calculated when resting flow exceeded 20 ml/min. Analysis was based on four categories defined by X-ray angiography: occluded grafts (n = 3), grafts with stenosis >50% (n = 19), grafts with stenosis <50% with diseased graft run-off (n = 8), and grafts with stenosis <50% and normal run-off (n = 10).
  
  
  RESULTS
  The CMR angiography demonstrated occlusion of three grafts. In nine of the 37 patent grafts, basal blood flow was <20 ml/min, all demonstrating significant stenosis at X-ray angiography. In grafts with resting flow >20 ml/min (n = 28), flow reserve significantly differed between grafts without stenosis and grafts with significant stenosis or with diseased run-off (2.5 +/- 0.7 vs. 1.8 +/- 0.9, p = 0.04). An algorithm combining basal volume flow <20 ml/min and graft flow reserve <2 had a sensitivity and specificity of 78% and 80% respectively for detecting grafts with significant stenosis or diseased run-off.
  
  
  CONCLUSIONS
  This feasibility study showed that quantification of flow and flow reserve by CMR may serve as a non-invasive adjunct to differentiate between vein grafts without stenosis and grafts with significant stenosis or diseased run-off.
authors.affiliation: Department of Cardiology, VU University Medical Center Amsterdam, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands. wlf.bedaux@VUmc.nl
authors.forename: Willemijn L F
authors.initials: WL
authors.lastname: Bedaux
authors.forename: Mark B M
authors.initials: MB
authors.lastname: Hofman
authors.forename: Stefan L A
authors.initials: SL
authors.lastname: Vyt
authors.forename: Jean G F
authors.initials: JG
authors.lastname: Bronzwaer
authors.forename: Cees A
authors.initials: CA
authors.lastname: Visser
authors.forename: Albert C
authors.initials: AC
authors.lastname: van Rossum
mesh_terms: D000328:Adult; D000368:Aged; D000714:Anastomosis, Surgical; D001158:Arteries / Q000503:physiopathology / Q000601:surgery; D001783:Blood Flow Velocity / Q000502:physiology*; D017023:Coronary Angiography; D001026:Coronary Artery Bypass; D023921:Coronary Stenosis / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery; D003331:Coronary Vessels / Q000503:physiopathology / Q000601:surgery; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012501:Saphenous Vein / Q000000981:diagnostic imaging / Q000601:surgery; D012680:Sensitivity and Specificity; D014463:Ultrasonography