RELATIONSHIPS BETWEEN CHOROIDAL THICKNESS AND 24 H PULSE PRESSURE IN HYPERTENSIVE PATIENTS

Abstract

Objective: The choroid is a pure vascular structure and its thinning may reflect a microvascular damage, that may be the local expression of a more generalised vascular injury. Choroid may be easily damaged directly by acute and chronic severe elevation of blood pressure (BP). However, all the studies exploring the association of BP values with choroidal thickness yielded conflicting results. Our study was aimed to assess in hypertensive patients the relationships between choroidal thickness and “office” and 24-hour BP readings. Design and method: We enrolled 158 consecutive hypertensive subjects (age: 48 ± 13 years) attending our Hypertension Centre. All the patients underwent clinic BP measurements, 24-h ambulatory BP monitoring (ABPM) and morphological evaluation of the retino-choroidal district by SS-OCT. OCT measurements were performed according to the ETDRS protocol whose map divides the macula into 9 subfields. The circular grid is centred over the fovea and consists of 3 concentric rings,the inner and outer rings are further divided into quadrants: temporal, nasal, superior, and inferior. The retinal and choroidal thicknesses were automatically calculated by the OCT mapping software and only one eye of each subject was randomly selected for analysis and for sake of brevity we show only the data referring to the mean choroidal thickness. (MCT). Results: MCT (250 ± 62 m) showed significant correlations with: mean 24-h DBP (r = 0.18; p = 0.02) and diurnal (r = 0.21; p = 0.009), mean 24-h pulse pressure (PP) (r = - 0.30; p < 0.001), of the day (r = - 0.19; p = 0.02) and of the night (r = - 0.25; p = 0.002). The correlation between the 24-hour PP and the SCM remains significant even after accounting for confounders in the multiple linear regression (r = - 0.18; p = 0.02). Conclusions: Our results, highlighting an inverse association between choroid thickness and 24-hour PP (possible index of arterial stiffness) seem to reinforce the hypothesis that choroidal thinning may be the expression of systemic vascular damage.