title: Prediction of graft flow impairment by intraoperative transit time flow measurement in off-pump coronary artery bypass using arterial grafts.
abstract: BACKGROUND
  We assessed the validity of intraoperative transit time flow measurement (TTFM) in predicting graft flow abnormalities.
  
  
  METHODS
  Intraoperative graft flow measurement using TTFM and early postoperative coronary angiography was performed in 58 patients who underwent total arterial off-pump coronary artery bypass. Five variables (flow pattern, mean flow, pulsatility index, insufficiency ratio, and fast Fourier transformation ratio) were measured and compared between 103 normal and 14 abnormal (occluded or competitive) grafts.
  
  
  RESULTS
  The grafts anastomosed to the right coronary territories showed significantly less diastolic dominant pattern, lower mean flow and fast Fourier transformation ratio, and higher pulsatility index than grafts to the left coronary artery territories (p < 0.05). None of the abnormal grafts showed a diastolic dominant flow pattern. The abnormal grafts demonstrated significantly lower mean flow and fast Fourier transformation ratio and higher pulsatility index and insufficiency ratio than normal grafts (p < 0.05). When our criteria for detection of abnormal graft flow, [(1) systolic dominant or balanced pattern of the flow curve in the left coronary territories, systolic dominant pattern of the flow curve in the right coronary territories; (2) mean flow < 15 mL/min; (3) pulsatility index > 3 in the left coronary territories and > 5 in the right coronary territories; and (4) insufficiency ratio > 2%] were applied, the sensitivity and specificity of TTFM to detect the graft flow abnormality were 96.2% and 76.9%, respectively.
  
  
  CONCLUSIONS
  Our data suggest that TTFM is a reliable intraoperative tool to predict graft flow impairment.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital, Seoul, Korea. kimkb@snu.ac.kr
authors.forename: Ki-Bong
authors.initials: KB
authors.lastname: Kim
authors.forename: Chang Hyun
authors.initials: CH
authors.lastname: Kang
authors.forename: Cheong
authors.initials: C
authors.lastname: Lim
mesh_terms: D017023:Coronary Angiography; D047549:Coronary Artery Bypass, Off-Pump; D003324:Coronary Artery Disease / Q000175:diagnosis / Q000601:surgery; D003326:Coronary Circulation; D006801:Humans; D007432:Intraoperative Period; D011237:Predictive Value of Tests; D013997:Time Factors; D014654:Vascular Patency