Blood flow reversal from the external into the internal carotid artery-New insights into the hemodynamics at the carotid bifurcation.

Abstract

BackgroundComplex blood flow patterns are a well‐known phenomenon at the carotid bifurcation. However, unlike for the descending aorta, a blood flow reversal has not been detected at the carotid bifurcation, so far.MethodsIn 17 subjects, flow patterns with focus on blood flow reversal were examined at the carotid bifurcation with vector flow imaging.ResultsWe found a blood flow reversal from the external carotid artery (ECA) into the internal carotid artery (ICA) in 13 of 25 (52%) carotid bifurcations. The blood flow reversal ranged 5.3 ± 1.7 mm (range 2.6–8.3 mm) distally to the beginning of the ECA and lasted 105 ± 59 ms (range 32–225 ms). The mean peak systolic velocity within the blood flow reversal was 12.5 ± 4.6 cm/s (range 5–18 cm/s).ConclusionA blood flow reversal from the ECA into the ICA during the systole is a frequent finding at the carotid bifurcation. Considering ischemic stroke, retrograde embolism from plaques in the proximal ECA into the ICA might play a role.