Physiological flow variations in the periorbital arteries in Zambian Africans. A screening with bidirectional Doppler ultrasound

Abstract

Directional Doppler sonography with direct evaluation of the extracranial carotid artery system and scanning of the periorbital arteries has been performed in 49 black Zambian hypertensive patients and in 19 controls without cardiovascular risk factors. Direct evaluation of the extracranial carotid artery system did not show any abnormalities. In contrast to this periorbital Doppler examination revealed positive findings with retrograde flow direction in the supratrochlear artery in 19% and 21% of all examined carotids in the hypertension and control group, respectively. Compared to direct carotid angiography, 66% of the positive supratrochlear and 13% of the positive supraorbital findings in the hypertensive patient group could be shown to be false positive results. As a possible explanation of this high incidence of a retrograde flow direction in periorbital arteries a different flow physiology in the ophthalmic artery of black Zambians compared to Caucasians is discussed.