CW Doppler waveform for multilevel arterial disease?

• A. Normal triphasic waveform throughout
• B. High-resistance, sharp systolic peak with no damping
• C. Abnormal damped monophasic waveform with degradation progressing distally
• D. Normal monophasic waveform

Answer: (C)

In CW Doppler, the shape of the arterial waveform reflects both upstream blockage and the resistance downstream. Normal peripheral arteries typically show a triphasic pattern with a sharp forward systolic peak, a brief early diastolic reversal, and continued forward flow in late diastole. When disease is present at multiple levels, the transmitted pulse loses pulsatility as it travels downstream because each level of obstruction adds resistance and blunts the energy of the pulse. This results in a damped, monophasic waveform that becomes progressively more diminished as you move distally through the limb.

This is why the abnormal damped monophasic waveform with degradation progressing distally is the best fit for multilevel arterial disease. It captures the expected loss of phasicity and the tendency toward monophasic flow that worsens with distance from the proximal disease. The other patterns—normal triphasic throughout, a high-resistance sharp peak with no damping, or a normal monophasic waveform—do not align with the characteristic progressive dampening seen when disease exists at multiple arterial levels.