The potential of duplex scanning to replace aorto-iliac and femoro-popliteal angiography.

The ability of duplex scanning to assess haemodynamically significant lesions in the aorto-iliac and femoro-popliteal arteries was studied. Duplex scanning was prospectively and independently compared to intra-arterial digital subtraction angiography (ia. DSA) of the aorto-iliac and femoro-popliteal arteries and intra-arterial pressure measurements of the aorto-iliac tract before and after the administration of papaverine. In 40 patients 629 arterial segments were evaluated. A greater than 150% increase in peak systolic velocity had a sensitivity of 92% and a specificity of 98% in detecting greater than 50% diameter reducing lesions in the aorto-iliac arteries as compared to ia. DSA. The numbers for the femoro-popliteal arteries are 88% and 98% respectively. Detection of occlusion in the aorto-iliac arteries had a sensitivity and specificity of 100% and in the femoro-popliteal arteries 90% and 100% respectively. There was a poorer correlation between intra-arterial pressure measurements and duplex scanning or ia. DSA as compared to the correlation between ia. DSA and duplex scanning. Retrospective spectral analysis showed that an end diastolic velocity (EDV) of greater than 40 cm/s seems to be a valuable parameter to differentiate between 50% to 74% and 75% to 99% diameter reduction. It is concluded that duplex scanning can reliably differentiate between haemodynamically significant and insignificant lesions in the aorto-iliac and femoro-popliteal arteries and has the potential to replace angiography.