Reference values for vertebral artery flow volume by duplex sonography in young and elderly adults

Area of Science:

• Neurology
• Vascular Medicine
• Medical Imaging

Background:

• Vertebrobasilar ischemia is linked to reduced vertebral artery flow volume.
• Duplex sonography can determine vertebral artery flow volume.
• Reference values for vertebral artery flow volume are lacking in relevant age groups.

Purpose of the Study:

• Establish reference values for vertebral artery flow volume.
• Investigate age and sex differences in vertebral artery flow.
• Provide a basis for reevaluating the association between reduced flow and ischemia.

Main Methods:

• Duplex sonography was used to measure flow velocities and vessel diameters in 50 nonvascular neurological patients (mean age 55.8 years).
• Vertebral artery flow volume was calculated using two distinct equations.
• Measurements were taken bilaterally in the intertransverse (V2) segments.

Main Results:

• Net vertebral artery flow volume was 182.0+/-56.0 mL/min, with no significant side-to-side differences.
• Flow volumes calculated by both equations showed no significant difference.
• Vessel diameters and net flow volumes were significantly lower in women than in men; age dependence was not observed.
• The 5th to 95th percentile range for net vertebral artery flow volume is 102.4–301.0 mL/min, indicating high interindividual variability.

Conclusions:

• The established reference values necessitate a reevaluation of the association between decreased vertebral artery flow volume and vertebrobasilar ischemia.
• Further research should explore collateral flow in vertebral arteries in carotid artery disease.
• Quantifying the contribution of vertebral arteries to overall cerebral blood flow is recommended.