Risk factors for occlusion of infrainguinal bypass grafts

Objectives: to identify risk factors fro infrainguinal bypass occlusion and quantify the predictive value of data available before and after surgery. Design: prospective study of 2650 patients who participated in a randomized trial of oral anticoagulants or aspirin after infrainguinal bypass surgery . Materials and methods: risk factors were determined by univariate Cox regre ssion analysis, and entered in multivariate analyses which distinguished tw o models: analysis of factors available from history and clinical examinati on, completed by radiological and surgical data in the second model. To com pare the information content of the two models, receiver-operator character istic (ROC) curves were computed. Results: in all patients female gender, critical ischaemia, femorocrural by pass grafting and non-venous graft material were independent risk factors. In patients wit femoropopliteal bypasses female gender, critical ischaemia, poor run-off and non-venous graft material, the latter even in patients wi th supragenicular bypasses, were independent risk factors. The only signifi cant risk factor in patients with femorocrural bypass grafts was use of a n on-venous graft. The information contained in the first model was poor, whereas the second m odel had a higher predictive value. Conclusions: the major risk factor, even in above-knee bypasses, is non-ven ous graft material. The venous bypass graft should be offered to patients w henever possible.