Interobserver agreement in duplex scanning for vein grafts

Background: although the precision of duplex scanning is of utmost importan ce in vein-graft surveillance, it has not been properly assessed. This stud y aims to analyse interobserver agreement on duplex scanning. Methods: a blinded comparative trial of 69 infrainguinal vein bypass recons tructions. Two consecutive duplex scans were performed by different examine rs and duplex ultrasound machines on the same patient. The duplex examinati ons were also compared with angiography, when available, and clinical follo w-up. Results: interobserver agreement in Kappa statistics was 0.69, signifying " good" agreement between the examinations in detecting haemodynamically sign ificant changes in the grafts. The sensitivity, specificity and accuracy fi gures compared with a combination of angiography and follow-up data for the two scans were 80%, 91%, 88% and 85%, 93%, 91%, respectively. The limits o f agreement were, however, wide for Doppler-derived velocity characteristic s. Conclusion: duplex scanning is an accurate and reproducible method for dete cting haemodynamically significant changes in infrainguinal vein grafts.