Peripheral Arterial Velocity Ratio Criteria

Normal

1. No focal increases in velocity compared to proximal measurements

2. Normal triphasic or biphasic Doppler waveform

Abnormal

1. Mild- 20-49% DR

     a) Elevation without two-fold increase in velocities compared to velocity proximal to obstruction

     b) Normal triphasic or biphasic Doppler waveform

2. Moderate- 50-75% DR

     a) Two-fold increase in velocity

     b) Ratio 2:1

     c) Doppler waveform may become biphasic

3. Severe- 75-90% DR

     a) Three hundred percent increase in velocities

     b) Ratio 3:1

     c) Doppler waveform distally may be abnormal biphasic or monophasic

4. Critical- > 90 % DR

     a) Four hundred percent increase in velocities

     b) End diastolic velocities 2 times ≥ pre-stenotic velocities

     c) Ratio 4:1

     d) Doppler waveform distally will become monophasic

5. Occlusion- No flow noted