Purpose
The retinal vascular endothelial dysfunction may play a role in the breakdown of the blood-retinal barrier and leakage of plasma from retinal vessels and capillaries, resulting in diabetic macular edema (DME). To determine if the vascular endothelial function is involved in the pathogenesis of DME, we measured brachial artery flow-mediated vasodilation (FMD) in patients with diabetes.
Methods
Twenty-three patients with type 2 diabetes mellitus (DM) and nonproliferative diabetic retinopathy were enrolled. Based on optical coherence tomography and fluorescein angiography findings, the patients were divided into 2 groups: the DME(+) group (n=12; mean age, 65.9 ± 7.6 years) and the DME(-) group (n=11; mean age, 64.1 ± 10.3 years). We evaluated the logarithm of the minimum angle of resolution visual acuity (logMAR VA) and central macular thickness (CMT). Using high-resolution ultrasonographic imaging, we evaluated the FMD by measuring changes in the brachial artery diameter during reperfusion after arterial occlusion.
Results
The mean CMTs ± standard deviations (SDs) were 410.2 ± 131.1 μm and 229.9 ± 33.5 μm in DME(+) and DME(-) groups, respectively. The mean logMAR VAs ± SDs were 0.42 ± 0.38 and 0.10 ± 0.07 respectively. There were significant differences in the CMT and logMAR VA between the two groups (p<0.001 for both comparisons). The group-averaged FMD values were significantly lower in the DME(+) group (3.1 ± 1.5%) compared with the DME(-) group (5.4 ± 2.7%, p = 0.035). In the DME(+) group, the FMD value was not significantly correlated with the CMT and logMAR VA.
Conclusions
The current results showed that the FMD in patients with DME with type 2 DM was lower than in patients without DME, suggesting that impaired systemic vascular endothelial function might be associated with the pathogenesis of DME.
Keywords: 499 diabetic retinopathy •
505 edema