title: Comparison of arterial and venous coronary artery bypass flow measurements using 3-T magnetic resonance phase contrast imaging.
abstract: OBJECTIVE
  Comparison of arterial and venous coronary artery bypass flow measurements using 3-T magnetic resonance (MR) phase contrast in correlation with intraoperative Doppler flow measurements.
  
  
  METHODS
  Fifty-six coronary bypasses (right coronary artery n=18, left internal mammary artery to left anterior descending artery n=16, marginal artery n=7, circumflex artery n=7, diagonal artery n=6, left anterior descending artery n=1, and right internal mammary artery to right coronary artery n=1) were studied in 27 asymptomatic patients. In this prospective study, each bypass was studied intra-operatively using Doppler flow measurement. Within one week post surgery, patients were studied using a 3-T MR scanner (Magnetom Verio, Siemens, Erlangen, Germany) using velocity encoded phase-contrast flow measurements.
  
  
  RESULTS
  Intraoperative Doppler flow measurements demonstrated regular flow patterns in all vascular territories supplied. All bypasses were patent on MRI and flow measurement results were as follows: median flow 60ml/min (interquartile range (IQR): 37.5-78.5ml/min). For comparison, the corresponding median intraoperative flow was 58ml/min (IQR: 41-80ml/min) (p<0.001; R=0.44). Linear regression analysis demonstrated a significant correlation for venous bypasses (p=0.0002; R=0.48), but not for arterial bypasses (p=0.09; R=0.24).
  
  
  CONCLUSIONS
  This study demonstrated that MR flow measurements of venous bypass grafts agreed more with Doppler than arterial bypass grafts. However, bypass patency was confirmed for all patients. In the future, this technique may be used for non invasive coronary bypass graft follow-up.
authors.affiliation: Cardiovascular Surgery, University Hospital Bern, Switzerland.
authors.forename: David
authors.initials: D
authors.lastname: Reineke
authors.forename: Michael
authors.initials: M
authors.lastname: Ith
authors.forename: Volkhard
authors.initials: V
authors.lastname: Goeber
authors.forename: Andrea Bianca
authors.initials: AB
authors.lastname: Rosskopf
authors.forename: Otto
authors.initials: O
authors.lastname: Hess
authors.forename: Thierry
authors.initials: T
authors.lastname: Carrel
authors.forename: Martin
authors.initials: M
authors.lastname: Czerny
authors.forename: Hanno
authors.initials: H
authors.lastname: Hoppe
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001158:Arteries / Q000637:transplantation*; D001783:Blood Flow Velocity; D001026:Coronary Artery Bypass / Q000379:methods*; D003324:Coronary Artery Disease / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery*; D003326:Coronary Circulation; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012501:Saphenous Vein / Q000503:physiopathology / Q000637:transplantation*; D016896:Treatment Outcome