Adaptive common carotid arteries remodeling after unilateral internal carotid artery occlusion in adult patients.

OBJECTIVE

This study was undertaken in human adults to examine modifications in common carotid internal diameter (ID), intima-media thickness (IMT), cross-sectional area (CSA) and wall shear stress (WSS) occurring both on the ipsilateral side of an internal carotid artery (ICA) occlusion and on the non-occluded contralateral side.

METHODS

Seventeen patients with unilateral ICA occlusion had repeated echo-Doppler examinations during 1 year and were compared to 12 volunteers with control non-occluded common carotid arteries (CCA).

RESULTS

The cause of ICA occlusion was atherosclerosis in nine patients, dissection in five, and undetermined in three. The results showed a significant reduction in ID on the occluded side (5.15 +/- 0.30 mm) compared with the non-occluded side (5.96 +/- 0.20 mm, P < 0.05) and with control arteries (5.55 +/- 0.10, P < 0.05). A significant reduction in blood flow was observed on the occluded side (404 +/- 58 ml/min) compared with the non-occluded side (703 +/- 51 ml/min, P < 0.0001) and with controls (567 +/- 27 ml/min, P < 0.0001). Wall cross-sectional area was found to be positively correlated to blood flow (r = 0.35, P < 0.01), without any significant difference in mean CSA between both sides. Interestingly, wall shear stress values were identical on both sides whatever the cause of ICA occlusion, and did not differ from those in controls.

CONCLUSIONS

Our results suggest that in humans, the internal diameter of the common carotid artery decreases in response to chronic decrease in blood flow, in order to maintain a constant wall shear stress even in pathological arteries.