Search
Close
Search
Advanced Search
Search Menu
AI Discovery Assistant

Abstract

Early retinal changes in hypertension (HT) are difficult to assess. The aim of this analysis was to assess whether topological indices of the retinal vascular tree may provide sensitive measures of retinal vascular disease in HT. Retinal images from 10 normo- (Norm: Age = 44±4yrs, BP=122±2/73±2) and 10 age and sex matched hypertensive (HT: Age = 41±4yrs, BP=160±6/97±4) were image processed and analysed as binary rooted trees. Six topological indices were examined: the total number of external (or terminal) edges (NT), the maximum tree exterior path length or altitude (A), the total exterior path length (Pe), the number of external-internal edges (EI), the asymmetry (As), where As = (N+1-2A)/(2A -2A), and the Strahler branching ratio (R). All topological indices were calculated for both arterial and venous trees with NT >4 and, for comparison of trees of different sizes, A, Pe and EI were normalised by NT. Table 1 shows the normalised data for arterial trees. There were marked significant differences in A, Pe and EI when normal and HT were compared, despite minimal clinical evidence of retinal vascular changes. There were no significant difference for any index for venous trees. Comparing R for different Strahler orders showed that neither arterial nor venous trees were self-similar. Topological analysis of the retinal microvasculature may have potential value in the evaluation of hypertensive target organ damage, and in monitoring response to therapy.

Table 1.
Open in new tab

Normalised topological indices for retinal arterial trees, mean± SD. p values were calculated by Student's t-test.

IndexNorm (n=12)HT (n=9)p
NT - number of terminals12.1±4.507.60± 2.500.014
A/NT - altitude0.67± 0.190.75± 0.100.246
Pe/NT - total ext. path5.39± 1.094.42± 0.990.050
EI /NT - ext.-int. edges0.43± 0.140.30± 0.130.044
As - asymmetry0.06± 0.050.17± 0.220.103
IndexNorm (n=12)HT (n=9)p
NT - number of terminals12.1±4.507.60± 2.500.014
A/NT - altitude0.67± 0.190.75± 0.100.246
Pe/NT - total ext. path5.39± 1.094.42± 0.990.050
EI /NT - ext.-int. edges0.43± 0.140.30± 0.130.044
As - asymmetry0.06± 0.050.17± 0.220.103
Table 1.
Open in new tab

Normalised topological indices for retinal arterial trees, mean± SD. p values were calculated by Student's t-test.

IndexNorm (n=12)HT (n=9)p
NT - number of terminals12.1±4.507.60± 2.500.014
A/NT - altitude0.67± 0.190.75± 0.100.246
Pe/NT - total ext. path5.39± 1.094.42± 0.990.050
EI /NT - ext.-int. edges0.43± 0.140.30± 0.130.044
As - asymmetry0.06± 0.050.17± 0.220.103
IndexNorm (n=12)HT (n=9)p
NT - number of terminals12.1±4.507.60± 2.500.014
A/NT - altitude0.67± 0.190.75± 0.100.246
Pe/NT - total ext. path5.39± 1.094.42± 0.990.050
EI /NT - ext.-int. edges0.43± 0.140.30± 0.130.044
As - asymmetry0.06± 0.050.17± 0.220.103

retinal vasculature, vessel topology, branching topology
This content is only available as a PDF.
© American Journal of Hypertension, Ltd. 2001
Topic:
Issue Section:
Abstracts
You do not currently have access to this article.
Download all slides