title: Risk factors for occlusion of infrainguinal bypass grafts.
abstract: OBJECTIVE
  to identify risk factors for infrainguinal bypass occlusion and quantify the predictive value of data available before and after surgery.
  
  
  METHODS
  prospective study of 2650 patients who participated in a randomised trial of oral anticoagulants or aspirin after infrainguinal bypass surgery.
  
  
  METHODS
  risk factors were determined by univariate Cox regression analysis, and entered in multivariate analyses which distinguished two models: analysis of factors available from history and clinical examination, completed by radiological and surgical data in the second model. To compare the information content of the two models, receiver-operator characteristic (ROC) curves were computed.
  
  
  RESULTS
  in all patients female gender, critical ischaemia, femorocrural bypass grafting and non-venous graft material were independent risk factors. In patients with femoropopliteal bypasses female gender, critical ischaemia, poor run-off and non-venous graft material, the latter even in patients with supragenicular bypasses, were independent risk factors. The only significant risk factor in patients with femorocrural bypass grafts was use of a non-venous graft. The information contained in the first model was poor, whereas the second model had a higher predictive value.
  
  
  CONCLUSIONS
  the major risk factor, even in above-knee bypasses, is non-venous graft material. The venous bypass graft should be offered to patients whenever possible.
authors.affiliation: Department of Vascular Surgery, University Hospital Utrecht, Utrecht, The Netherlands.
authors.forename: M J
authors.initials: MJ
authors.lastname: Tangelder
authors.forename: A
authors.initials: A
authors.lastname: Algra
authors.forename: J A
authors.initials: JA
authors.lastname: Lawson
authors.forename: B C
authors.initials: BC
authors.lastname: Eikelboom
mesh_terms: D000368:Aged; D001807:Blood Vessel Prosthesis / Q000009:adverse effects; D005260:Female; D005263:Femoral Artery / Q000601:surgery*; D005268:Femoral Vein / Q000601:surgery*; D006083:Graft Occlusion, Vascular / Q000175:diagnosis / Q000209:etiology* / Q000517:prevention & control; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016491:Peripheral Vascular Diseases / Q000601:surgery*; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012372:ROC Curve; D015203:Reproducibility of Results; D012307:Risk Factors; D012501:Saphenous Vein / Q000637:transplantation; D012737:Sex Factors