Analysis of agreement between Duplex ultrasound scanning and arteriography in patients with lower limb artery disease.

BACKGROUND: Angiography is the gold standard for therapeutic decision-making in lower limb artery disease. However, both the potentiality and safety of Duplex ultrasound scanning suggest that it may become the main diagnostic tool. The present study aimed to investigate the agreement between Duplex scanning and angiography in the diagnosis of stenosis in lower limb artery disease. METHODS: Forty-nine patients with lower limb artery disease (24 claudication, 12 critical ischemia, 13 skin lesions) underwent angiography and Duplex scanning. The lower limb arterial axis was divided into 15 segments and graded on the basis of the degree of stenosis (0-49%, 50-69%, 70-99% and occlusion). Agreement between angiography and Duplex scanning was assessed by Cohen's kappa statistics (kappa). The sensitivity and specificity of Duplex scanning in detecting significant stenosis at angiography (>/= 70%) were also calculated. RESULTS: Good diagnostic agreement (kappa = 0.70; 95% CI 0.588-0.825) was achieved in the whole arterial axis. Agreement was good for the aorto-iliac district (kappa = 0.63) with a sensitivity of 63% and a specificity of 96%, and for the femoro-popliteal district (kappa = 0.70) with a sensitivity of 74% and a specificity of 83%. In infrapopliteal arteries, kappa showed a poor agreement, but Duplex scanning detected 28 patent tibial arteries in limbs that were not opacified on arteriography. CONCLUSIONS: Duplex scanning shows good agreement with angiography in lower limb artery disease on the whole, but poor agreement in infrapopliteal districts, with a low sensitivity and high specificity in detecting significant stenoses or occlusions.