title: Patency of infra-inguinal vein grafts--effect of intraoperative Doppler assessment and a graft surveillance program.
abstract: OBJECTIVE
  To assess the value of intraoperative graft flow and resistance measurements and a graft surveillance program to predict at-risk infra-inguinal bypass grafts.
  
  
  METHODS
  Four hundred sixty-eight infra-inguinal bypass procedures performed between 1995-2006 underwent intraoperative measurement of graft flow and resistance using a Scimed OpDop. These data were correlated with graft outcome at six weeks. Two hundred fifty-four (73%) grafts were entered into a graft surveillance program and the effect of this on primary-assisted graft patency was assessed.
  
  
  RESULTS
  Overall primary and primary-assisted graft patency was 81% and 83% at six weeks and 42% and 64% at three years. Grafts failing by six weeks had significantly lower flow (130.5 mL/min vs. 150.5 mL/min, P = .009) and higher resistance (0.67 peripheral resistance units (PRU) vs. 0.57 PRU, P = .004) than those remaining patent. However, OpDop measured flow and resistance was a poor predictor of graft failure in individual cases (area under ROC curve, 0.57). While there was no statistical difference in primary 18-month patency rates between grafts undergoing surveillance and those undergoing clinical follow up (55% vs. 76%, P = .133), primary-assisted 18-month patency rates were significantly higher in the surveillance group (83% vs. 77%, P = .042).
  
  
  CONCLUSIONS
  Intraoperative measurements of graft flow and resistance do not predict graft outcome at six weeks. However, surveillance does identify at-risk grafts and improves mid-term primary-assisted patency.
authors.affiliation: Department of Vascular Surgery, Royal Shrewsbury Hospital, Shrewsbury and Telford NHS Trust, Shrewsbury, United Kingdom. simon@hobbsy.fsworld.co.uk
authors.forename: Simon D
authors.initials: SD
authors.lastname: Hobbs
authors.forename: Thomas
authors.initials: T
authors.lastname: Pinkney
authors.forename: Timothy C F
authors.initials: TC
authors.lastname: Sykes
authors.forename: Antony D
authors.initials: AD
authors.lastname: Fox
authors.forename: Andy D
authors.initials: AD
authors.lastname: Houghton
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D053208:Kaplan-Meier Estimate; D035002:Lower Extremity / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D016491:Peripheral Vascular Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D011237:Predictive Value of Tests; D015397:Program Evaluation; D011446:Prospective Studies; D012039:Regional Blood Flow; D012042:Registries; D018570:Risk Assessment; D013997:Time Factors; D016896:Treatment Outcome; D018608:Ultrasonography, Doppler; D018084:Ultrasonography, Interventional; D014654:Vascular Patency; D014655:Vascular Resistance; D014680:Veins / Q000637:transplantation*