title: Transit-time flow measurement as a predictor of coronary bypass graft failure at one year angiographic follow-up.
abstract: BACKGROUND
  Transit-time flow measurement (TTFM) is a commonly used intraoperative method for evaluation of coronary artery bypass graft (CABG) anastomoses. This study was undertaken to determine whether TTFM can also be used to predict graft patency at one year postsurgery.
  
  
  METHODS
  Three hundred forty-five CABG patients with intraoperative graft flow measurements and one year angiographic follow-up were analyzed. Graft failure was defined as more than 50% stenosis including the "string sign." Logistic regression analysis was used to analyze the risk of graft failure after one year based on graft vessel type, anastomatic configuration, and coronary artery size.
  
  
  RESULTS
  Nine hundred eighty-two coronary anastomoses were performed of which 12% had signs of graft failure at one year angiographic follow-up. In internal mammary arteries (IMAs), analysis showed a 4% decrease in graft failure odds for every 1 mL/min increase in TTFM (OR = 0.96, CI = [0.93; 0.99], p = 0.005). ROC analysis showed good discriminative ability for TTFM alone AUC = 69.5% in IMA grafts. For single-vein grafts the decrease in graft failure odds was 2% for every 1 mL/min increase in TTFM (OR = 0.98; CI = [0.97; 1.00], p = 0.059) and AUC of 59.9%. There were no significant relationships between TTFM and graft failure in other graft types or graft configurations.
  
  
  CONCLUSIONS
  The TTFM method has good discriminative ability for assessing the risk of graft failure in certain graft types within the first year after CABG surgery and is a valuable instrument for intraoperative quality assessment of bypass grafts.
authors.affiliation: Department of Cardiothoracic Surgery, Rigshospitalet, Copenhagen University Hospital, Denmark.
authors.forename: Per
authors.initials: P
authors.lastname: Lehnert
authors.forename: Christian H
authors.initials: CH
authors.lastname: Møller
authors.forename: Sune
authors.initials: S
authors.lastname: Damgaard
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Gerds
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Steinbrüchel
mesh_terms: D000368:Aged; D000714:Anastomosis, Surgical; D017023:Coronary Angiography; D001026:Coronary Artery Bypass; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006083:Graft Occlusion, Vascular / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D016015:Logistic Models; D008297:Male; D008323:Mammary Arteries / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000637:transplantation; D016343:Monitoring, Intraoperative / Q000379:methods*; D011237:Predictive Value of Tests; D063177:Pulse Wave Analysis / Q000379:methods*; D013997:Time Factors; D017211:Treatment Failure; D014654:Vascular Patency