What does high‑resistive biphasic flow in the right posterior tibial, anterior tibial, and peroneal arteries on a pulse‑volume recording ankle‑brachial index study indicate?

High-Resistive Biphasic Flow in Lower Leg Arteries: Interpretation

High-resistive biphasic flow in the right posterior tibial, anterior tibial, and peroneal arteries represents an abnormal finding that indicates early peripheral arterial disease (PAD) or increased downstream vascular resistance, even when the ankle-brachial index (ABI) may still be within normal range.

What This Finding Means

Biphasic waveforms indicate suboptimal arterial perfusion and represent a transition state between normal triphasic flow and severely diseased monophasic flow. 1

• Normal arterial flow is triphasic, consisting of forward systolic flow, brief reverse flow in early diastole, and forward flow again in late diastole 1
• Biphasic flow loses one of these components, typically the late diastolic forward flow, indicating increased peripheral resistance or proximal arterial disease 1
• High-resistive patterns suggest increased downstream vascular resistance or early atherosclerotic changes affecting flow dynamics

Clinical Significance

This finding is clinically important because it can identify early PAD before the ABI becomes abnormal. 1

• In a study of rheumatoid arthritis patients with no cardiovascular history, approximately one-third had biphasic waveforms despite 96% having normal ABI values (≥0.90) 1
• Only 1% progressed to monophasic (severely abnormal) flow, indicating biphasic represents an intermediate disease state 1
• The presence of biphasic flow in all three tibial vessels of the right leg suggests diffuse arterial involvement rather than isolated single-vessel disease 1

Recommended Clinical Approach

Further vascular evaluation with duplex ultrasound is warranted to determine the presence and extent of PAD, even if the ABI is normal. 2

• When arterial flow patterns are abnormal but ABI is normal, additional vascular testing should be performed to avoid missing early PAD 2
• The American Heart Association guidelines specifically state that when ankle artery signals are concerning and the ABI from other arteries is normal, duplex ultrasound is reasonable to determine if PAD is present 2

Key Clinical Pitfalls

Relying solely on ABI measurements can miss early PAD—waveform analysis provides complementary diagnostic information. 1

• Assessment of peripheral arterial perfusion should utilize both ABI and waveform analysis to identify patients with early disease 1
• ABI alone may remain normal (>0.90) despite significant waveform abnormalities indicating early arterial compromise 1
• High-resistive biphasic flow affecting multiple vessels bilaterally would be even more concerning than unilateral involvement, though your case shows right-sided involvement

Cardiovascular Risk Implications

Patients with abnormal lower extremity arterial findings, even with normal ABI, carry increased cardiovascular risk. 2

• PAD identified by ABI <0.90 is associated with significantly increased cardiovascular mortality (hazard ratio 4.2 in men, 3.5 in women compared to normal ABI) 2
• Early identification through waveform analysis allows for cardiovascular risk factor modification before progression to more severe disease 1