Interobserver variation of colour duplex scanning of the popliteal,tibial and pedal arteries

OBJECTIVES: to determine interobserver variation in the measurement of Peak Systolic Velocity (PSV) and grading of disease by means of Duplex scanning (DS) in the popliteal, tibial and pedal arteries. DESIGN: prospective validation study. MATERIALS: twenty-four consecutive patients with severe claudication (n=6), ischaemic rest pain (n=11) and tissue loss (n=7). METHODS: two vascular technologists independently examined the popliteal, tibial and pedal arteries. The PSV was recorded in 15 arterial segments that were graded with B-mode and Doppler parameters as fully patent, severely diseased or occluded. Concordance in PSV recordings was expressed as intraclass correlation coefficients (ICC). Agreement in artery assessment was expressed as weighted kappa-values. RESULTS: the ICC for PSV measurements was 0.90 (95% CI, 0.86 to 0.93) within the popliteal and tibial arteries and 0.64 (95% CI, 0.37 to 0.81) within the pedal arteries. Agreement for grading disease was good within the popliteal and tibial arteries (kappa 0.66, 95% CI, 0.58 to 0.74), and moderate within the pedal arteries (kappa 0.54, 95% CI 0.33 to 0.74). The presence of diabetes or stage of disease did not influence interobserver agreement. CONCLUSION: interobserver agreement of DS is good within the popliteal and tibial arteries and moderate within the pedal arteries