- A Doppler-derived ankle-brachial index (ABI) of < 0.85 in the symptomatic limb after 10 minutes of rest at screening. For subjects with an ABI of >1.3 (non-compressible arteries) a Toe-Brachial Index (TBI) of < 0.70 must be obtained for subject qualification, or if ABI is > 0.85 to 1.0 , and a reduction of 20% in ABI measured within 1 minute of treadmill testing.