Does the impression match the waveforms in the carotid artery Doppler study?

Waveform Analysis Does Not Match the Stenosis Impression

The impression does not match the waveforms because monophasic flow patterns throughout both carotid systems indicate hemodynamically significant proximal disease or cardiac dysfunction, which contradicts the reported moderate stenosis classifications.

Critical Waveform Abnormalities

The most concerning finding is the universal monophasic flow pattern documented bilaterally in:

• Internal carotid arteries 1
• Carotid bifurcations 1
• Mid common carotid arteries 1

Normal carotid arteries should demonstrate multiphasic (triphasic) waveforms, particularly in the common carotid and external carotid arteries 1. The internal carotid artery typically shows a more pulsatile flow pattern with continuous diastolic flow 1.

Why This Matters Clinically

Monophasic Waveforms Indicate:

• Severe proximal stenosis (aortic arch or innominate/subclavian disease) causing dampened flow distally 1
• Cardiac dysfunction with reduced stroke volume affecting all vessels 2
• Diffuse atherosclerotic disease more extensive than focal stenosis measurements suggest 1

The Velocity Data Contradicts Monophasic Patterns:

Right ICA Analysis:

• PSV 167 cm/s at distal ICA suggests 50-69% stenosis by velocity criteria 1
• ICA/CCA ratio of 1.81 is below the threshold of 2.0 for even 50% stenosis 1
• This ratio actually suggests less than 50% stenosis, not the reported 16-49% 1

Left ICA Analysis:

• PSV 187 cm/s at mid ICA falls within 50-69% stenosis range (125-230 cm/s) 1
• ICA/CCA ratio of 2.16 confirms 50-69% stenosis (ratio 2-4) 1
• EDV 27 cm/s is well below 40 cm/s, the lower threshold for 50-69% stenosis 1

Specific Discrepancies

Right Side Issues:

The report states 16-49% stenosis, but:

• The PSV of 167 cm/s exceeds 130 cm/s, which by guideline criteria indicates at least 50% stenosis 1, 3
• The ICA/CCA ratio of 1.81 contradicts significant stenosis 1
• Monophasic waveforms should not occur with only mild-moderate focal stenosis 1

Left Side Issues:

The velocities support 50-69% stenosis classification, but:

• EDV of 27 cm/s is too low (should be 40-100 cm/s for this category) 1
• Monophasic waveforms throughout suggest more extensive disease than focal stenosis 1

Critical Pitfalls Present

Technical Factors Affecting Accuracy:

• Contralateral disease can elevate velocities in the less-diseased artery through compensatory flow 1, 2
• Cardiac output abnormalities may reduce all velocities, causing underestimation of stenosis severity 1
• The universal monophasic pattern suggests inflow disease that invalidates standard velocity criteria 1

Quality Assurance Concerns:

The American Heart Association emphasizes that every vascular laboratory should have quality assurance programs comparing ultrasound findings with other imaging modalities 1. This study demonstrates internal inconsistencies requiring:

• Correlation with additional imaging (CTA or MRA) to resolve discrepancies 1
• Evaluation for aortic arch disease or cardiac dysfunction 2
• Assessment of vertebral artery flow patterns for posterior circulation compensation 2

Recommended Action

This patient requires:

1. Cardiac evaluation to assess for reduced ejection fraction or valvular disease causing dampened waveforms 2
2. Arch vessel imaging (CTA or MRA) to identify proximal stenoses affecting all cervical vessels 1
3. Repeat duplex with cardiac gating if cardiac dysfunction is confirmed 1
4. Do not rely on these velocity measurements alone for clinical decision-making regarding intervention 1

The combination of monophasic waveforms throughout both carotid systems with velocity measurements suggesting only moderate stenosis represents a fundamental mismatch that indicates either significant proximal disease, cardiac pathology, or technical error in the examination 1.