Predischarge duplex imaging of infrainguinal vein grafts does not predict the development of stenoses

Abstract

Background - The aim of this study was to determine whether predischarge duplex imaging of an infrainguinal vein graft could predict the subsequent development of graft stenosis. Methods - Patients with infrainguinal vein grafts underwent a duplex scan of the entire graft before discharge from hospital. Grafts were classified as abnormal or normal based on the presence or absence of now abnormalities (peak velocity ratio 1.5 or greater). All grafts were re-examined 1 month after surgery, at 3-monthly intervals for the first year and then every 6 months thereafter. A significant stenosis requiring correction was defined by a duplex-derived peak systolic velocity ratio of 3.0 or more. The relationship between the predischarge scan and subsequent development of stenosis was examined. Results - Forty-four grafts were recruited. Two occluded soon after a normal predischarge scan and were excluded from subsequent analysis. Predischarge abnormalities were found in 16 grafts. The abnormality in one graft required immediate correction. A further four grafts subsequently developed significant stenoses and required angioplasty. Of the 26 grafts with no predischarge abnormalities, 11 developed significant stenoses and underwent angioplasty. Abnormal predischarge duplex scans had a sensitivity and specificity of 31 and 58 per cent respectively for the development of stenoses. The positive and negative predictive values were 31 and 58 per cent respectively. Conclusion - Predischarge duplex imaging cannot be used to predict the development of stenoses in infrainguinal vein grafts.