Objective: To test the concept that diabetic patients with microangiopathy of the retinal microcirculation would also show an involvement of the carotid adventitial microcirculation, we aimed to assess the status of the vasa vasorum (VV) signal, measured by contrast-enhanced carotid ultrasound imaging, in type 2 diabetic patients with and without retinopathy.
Methods and results: Using contrast-enhanced ultrasound imaging, we quantified the signal of the VV of the common carotid artery. We investigated two subgroups of type 2 diabetic patients who did not have previous cardiovascular disease: 51 with retinopathy and 56 without retinopathy. The reference VV signal was measured in a group of 65 healthy volunteers as the ratio of the contrast agent signal of the VV and that of the lumen of the artery. Patients and volunteers also underwent a clinical evaluation. The reference VV signal in the group of 65 healthy volunteers was 0.562 (SD = 0.142). Patients with diabetic retinopathy showed a higher mean adventitial VV signal (0.700; SD = 0.150) than those without retinopathy (0.621; SD = 0.120) (P < 0.0039). This difference remained highly significant after adjusting for cardiovascular risk factors. Common carotid intima-media thickness and carotid plaque prevalence were not different between diabetic subgroups.
Conclusions: Type 2 diabetic patients with retinopathy show increased angiogenesis of the VV of the common carotid artery. This suggests the existence of a diabetic microangiopathic complication affecting the wall of the large arteries that may be an important contributor to the cardiovascular disease burden in diabetes mellitus.
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