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8 — Indirect Assessment of Arterial Disease
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Figure 8-6 Doppler waveforms from the upper extremity showing the right to be normal and the left to be abnormal, suggesting proximal disease. (Image courtesy of Robert Scissons, RVT, FSVU, Toledo, OH.)
classic designations for waveforms that remain in use by most laboratories are as follows:
A. Triphasic
B. Biphasic: bidirectional
C. Biphasic: unidirectional
D. Monophasic: moderate/severe
E. Monophasic: severe/critical
Normal Doppler waveforms are bidirectional and
exhibit a degree of flow reversal in late systole/early diastole (Fig. 8-8A,B).14 Waveform B does not exhibit
a net return to forward flow, but this is seen fre- quently in older patients and those whose feet are cold and is not regarded as abnormal. Waveforms C and D are seen when PAOD progresses from mild/ moderate to severe, and waveform E indicates that it is now at a critical stage; each of these three are unidirectional.
Other than from an artery feeding, a well- functioning dialysis fistula or graft, flow reversal in- dicates the level of peripheral resistance (PR) in the