title: Validation of a Decision Tree to Streamline Infrainguinal Vein Graft Surveillance.
abstract: BACKGROUND
  Duplex ultrasound (DU)-based graft surveillance remains controversial. The aim of this study was to assess the ability of a recently proposed decision tree in identifying high-risk grafts which would benefit from DU-based surveillance.
  
  
  METHODS
  Consecutive patients undergoing infrainguinal vein graft bypass from January 2008 to December 2015 were identified from the National Vascular registry and enrolled in a duplex surveillance program. An early postoperative DU was performed at a median of 6 weeks (range: 4-9 weeks). Grafts were classified into high risk or low risk based on the findings of the earliest postoperative scan and 4 established risk factors for graft failure (diabetes, smoking, infragenicular distal anastomosis, and revision bypass surgery) using a classification and regression tree (CRT). The accuracy of the CRT model was evaluated using area under receiver operator characteristic (AROC) curve.
  
  
  RESULTS
  About 278 vein graft bypasses were performed; 29 grafts had occluded by the first surveillance visit; 249 vein grafts were entered into surveillance. Sixty-four (23%) developed critical stenosis. Overall 30-month primary patency, primary-assisted patency, and secondary patency rates were 71.2%, 77.2%, and 80.1%, respectively. AROC for prediction of graft stenosis or occlusion was 83% (95% confidence interval [CI]: 78-87%). The sensitivity and specificity of the CRT model for prediction of graft stenosis or occlusion were 95% (95% CI: 88-98%) and 52.2% (95% CI: 45-60%).
  
  
  CONCLUSIONS
  A prediction model based on commonly recorded clinical variables and early postoperative DU scan is accurate at identifying grafts which are at high risk of failure. These high-risk grafts may benefit from DU-based surveillance.
authors.affiliation: Department of Vascular Surgery, The James Cook University Hospital, Middlesbrough, UK. Electronic address: rezamofidi@nhs.net.
authors.forename: Reza
authors.initials: R
authors.lastname: Mofidi
authors.affiliation: Department of Vascular Surgery, Royal Infirmary of Edinburgh, Edinburgh, UK.
authors.forename: Olivia M B
authors.initials: OMB
authors.lastname: McBride
authors.affiliation: Department of Vascular Surgery, The James Cook University Hospital, Middlesbrough, UK.
authors.forename: Barnabas R
authors.initials: BR
authors.lastname: Green
authors.affiliation: Department of Vascular Surgery, The James Cook University Hospital, Middlesbrough, UK.
authors.forename: Tracey
authors.initials: T
authors.lastname: Gatenby
authors.affiliation: Department of Interventional Radiology, The James Cook University Hospital, Middlesbrough, UK.
authors.forename: Paul
authors.initials: P
authors.lastname: Walker
authors.affiliation: Department of Interventional Radiology, The James Cook University Hospital, Middlesbrough, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Milburn
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography; D000800:Angioplasty, Balloon / Q000295:instrumentation; D019540:Area Under Curve; D003661:Decision Support Techniques; D003663:Decision Trees; D005260:Female; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology / Q000628:therapy; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D058729:Peripheral Arterial Disease / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D011237:Predictive Value of Tests; D012372:ROC Curve; D012042:Registries; D015203:Reproducibility of Results; D018570:Risk Assessment; D012307:Risk Factors; D012501:Saphenous Vein / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000637:transplantation*; D015607:Stents; D062606:Tertiary Care Centers; D013997:Time Factors; D016896:Treatment Outcome; D018616:Ultrasonography, Doppler, Duplex; D006113:United Kingdom; D058017:Vascular Grafting / Q000009:adverse effects*; D014654:Vascular Patency