What is the arterial Doppler pattern characteristic of hyperemic flow?

• A. Reversed diastolic flow
• B. Persistent forward diastolic flow with fast systolic upstroke
• C. No diastolic flow
• D. High-resistance pattern

Answer: (B)

Doppler waveforms reflect distal vascular resistance; when arterioles dilate in hyperemia, resistance drops and the bed behaves as low-resistance. That produces a low-resistance waveform with a brisk systolic upstroke and forward flow that continues through diastole. In this context, diastolic flow remains forward rather than reversing or stopping, which is why persistent forward diastolic flow with a fast systolic upstroke best describes hyperemic flow. High-resistance patterns show little or reversed diastolic flow, and no diastolic flow is also a high-resistance pattern, so they don’t fit hyperemia as well.