- Vascular Noninvasive Physiologic Tests: Ankle-brachial index less than or equal to 0.9 (or abnormal ankle PVR waveform at ankle if arteries are incompressible*) with resting thigh-brachial index (thigh-BI) less than 1.1, and common femoral artery Doppler systolic acceleration time greater than 140 msec [these tests may be ordered for study screening].