Relationship between the Parameters of Retinal Circulation Measured by Laser Doppler Velocimetry and a Marker of Early Systemic Atherosclerosis

Abstract

To examine the relation between intima-media thickness (IMT) in the common carotid artery, which is generally recognized as a marker of early atherosclerosis, and retinal circulatory parameters. The vessel diameter and blood velocity of retinal arterioles were measured with laser Doppler velocimetry (LDV) in 33 patients with coronary artery disease (CAD), because they were thought to have general atherosclerosis. The retinal blood flow (RBF) and wall shear rate (WSR), an index of wall shear stress in retinal vessels, were calculated from the two parameters. The carotid IMT was evaluated with B-mode ultrasonography. The patients were divided into two groups: those with an IMT >0.70 mm and those with an IMT < or =0.70 mm. The blood velocity, WSR, and upstroke time in the retinal arterioles were significantly higher in the group with an IMT >0.70 mm compared with the group with an IMT < or =0.70 mm. There were no significant differences in vessel diameter and RBF between the groups. Positive correlations were found between the carotid IMT and blood velocity (r = 0.51, P = 0.002) and WSR (r = 0.60, P = 0.0001). Multiple regression analysis showed that the retinal WSR and blood velocity correlated independently with the IMT in patients with CAD. The present findings from this pilot study suggest that the retinal circulatory parameters measured by LDV may be associated with systemic atherosclerosis. These results support recent studies showing an association between retinal microvascular changes and cardiovascular disease.