Diagnostic Value of Peripheral Fractional Flow Reserve in Isolated Iliac Artery Stenosis: A Comparison With the Post-Exercise Ankle-Brachial Index

PURPOSE: To examine in claudicant patients with aortoiliac lesions the relationship between the post-exercise ankle-brachial index (ABI) and the peripheral fractional flow reserve (p-FFR), a physiological test that has heretofore been used to assess coronary and renal artery stenosis. METHODS: Sixteen male patients (mean age 68.1±7.5 years) with isolated iliac artery lesions detected by ultrasound in 17 limbs were enrolled in this study. Resting ABI was measured and a treadmill test was administered to measure the post-exercise ABI. During angiography, the p-FFR was measured using a pressure guidewire after administration of papaverine to induce hyperemia. Changes in the ABI during exercise and p-FFR at hyperemia were calculated. RESULTS: The mean resting ABI and post-exercise ABI were 0.87±0.12 and 0.65±0.24, respectively. There was no complication during the measurement of p-FFR. The mean p-FFR at hyperemia was 0.71±0.14. A significant linear correlation was observed between post-exercise ABI and p-FFR at hyperemia (r=0.857, p<0.001), which was stronger than the correlation between post-exercise ABI and peak-to-peak pressure gradient at hyperemia (r= -0.626, p=0.013). CONCLUSIONS: Measuring p-FFR appears to be a feasible and safe procedure, and there is a significant linear correlation between post-exercise ABI and p-FFR in aortoiliac lesions. The p-FFR was more accurate than a peak-to-peak pressure gradient in assessing the physiological significance of a stenosis. Though larger studies are required, p-FFR might be used to physiologically assess stenosis in PAD patients with isolated aortoiliac lesions.