Incidence of carotid artery insufficiency in patients with proliferative diabetic retinopathy

Purpose
The aim of this work is to study the prevalence of carotid artery insufficiency by
ultrasonography parameters in patients with proliferative diabetic retinopathy in
Alexandria, Egypt, and also to study common carotid artery (CCA) diameter as a
newly suggested marker of early carotid insufficiency.
Design
This is a descriptive cross-sectional study.
Patients and methods
The study included 100 eyes of 50 diabetic patients with proliferative diabetic
retinopathy. All were apparently healthy individuals, had nonoperated eyes, and
were free of renal insufficiency.
Results
Diabetic retinopathy correlated with lower CCA-peak systolic velocity, having a
mean of 59.4±15.9 cm/s (P=0.020, r=−0.048); higher CCA diameter, having a
mean of 7.2±0.09mm(P=0.000, r=0.434); and higher CCA-intima-media thickness
(IMT), having a mean of 0.69±0.19mm (P=0.033, r=0.204). Diabetic retinopathy
also correlated with higher plaque score (P=0.020) and higher carotid artery
stenosis ranging from 4 to 50% (P=0.033). Regarding the symmetry of diabetic
retinopathy, 70% of the patients (N=35) had some degree of carotid artery
insufficiency (IMT>0.8mm or carotid plaques). Asymmetric diabetic retinopathy
was detected in 28 of the 50 patients. We studied the relationship among CCA
diameter, CCA-IMT, and symmetry of diabetic retinopathy. Approximately half of
the cases in this study (N=24) had larger CCA diameter in the worse eye and 87.5%
in asymmetric diabetic retinopathy (P=0.000). Regarding CCA-IMT and symmetry,
40% of the cases in this study (N=20) had larger CCA-IMT in the worse eye and
80% in asymmetric diabetic retinopathy (P=0.005).
Conclusion
Diabetes seems to be an independent risk factor of carotid artery insufficiency,
leading to worsening of diabetic retinopathy even in the absence of other known risk
factors of atherosclerosis.