Abstract
Purpose:
Morphological changes affecting the wall of small retinal arteries are observable using adaptive optics (AO) imaging (Koch et al, J Hypertens. 2014). Here, we prospectively and quantitatively investigated the changes of the inner diameter (ID) and wall-to-lumen ratio (WLR) of retinal arterioles in hypertensive humans during treatment.
Methods:
In a group of hypertensive subjects (n = 21; mean age 50 years [32;71]) the ID and the WLR of the superotemporal artery from AO images (rtx1; ImagineEyes, France) was measured using a dedicated software. Two groups of hypertensive subjects were followed and analysed : the first group of naïve patients (n=9) before and after initiation of hypotensive treatment, the second group of treated patients (n=12).
Results:
The mean follow-up was 234 days [range, 42-552]. The ID increased within three months of initiation of hypotensive treatment (69μm [60-83] before versus 73μm [range, 57-87] after), and remained stable thereafter. Accordingly, the WLR was smaller after initiation of hypotensive treatment patients (0.35 [0.17-0.51] before versus 0.32 [0.17-0.47] after initiation of hypotensive treatment). In the group of treated patients the WLR and ID did not change over time (0.35 [0.23-0.5] versus 0.34 [0.27-0.45], 69.5 [59-90] versus 70.24 [61.4-83.8]. These modifications were not significantly correlated to changes in arterial pressure.
Conclusions:
Initiation of hypotensive treatment induces vasodilation of arteries, independantly of the changes of arterial pressure. This suggests that microvascular changes may provide additional medical information, in particular regarding cerebral perfusion given the functional similarities between the retina and the brain microcirculations. For instance, arterial pressure drop without change in microvascular resistances may decrease downstream perfusion. Additional studies are needed to identify drug-specific effects.