High internal carotid artery velocity can be a normal finding in which condition?

• A. Anemia
• B. Hypothyroidism
• C. Hypertension
• D. Diabetes mellitus

Answer: (A)

High flow velocity in the internal carotid can occur even without narrowing when the circulation is in a hyperdynamic state. Anemia causes the body to compensate for reduced oxygen-carrying capacity by increasing cardiac output and flow through the arterial tree. This rise in volume flow raises the measured peak systolic velocity in the carotids, so a high ICA velocity can be a normal finding in anemia rather than proof of stenosis. To distinguish from true stenosis, look for signs of focal narrowing or plaque on the vessel wall, as well as abnormal end-diastolic velocities and post-stenotic turbulence; in a hyperdynamic state from anemia, the velocity increase tends to be global rather than localized to a stenotic segment. Other conditions listed do not typically produce benign high carotid velocities in the absence of stenosis.