PS-BPC03-8: MORNING BLOOD PRESSURE SURGE AND THE VASCULATURE: A COMPARISON BETWEEN YOUNG DIPPERS AND NON-DIPPERS FROM THE AFRICAN-PREDICT STUDY

Abstract

Background and aim: Adverse changes in large arteries and retinal microvascular calibres are predictors for hypertension and stroke. These adverse changes were reported in response to the suppressed night-time dipping as well as in hypertensive individuals with exaggerated morning surge. However, it is unknown whether young healthy individuals with normal morning surge, but with non-dipping night-time blood pressure profile, will already present with early onset of micro and macrovascular changes. We investigated the relationship of morning surge with retinal vessel calibres and large artery stiffness in healthy young dippers and non-dippers. Methods: We included black and white participants (N = 323), aged 20–30 years, determined sleep-trough surge. We determined central retinal artery and vein equivalents from fundus images, as well as carotid-femoral pulse wave velocity. Results: Dippers had a greater morning surge (within normal range) (p < 0.001) and a greater proportion of individuals with exaggerated morning surge (p < 0.001). In dippers only, we found a positive relationship between central retinal artery equivalent and morning surge (p = 0.040). In sensitivity analysis, the association between central retinal artery equivalent and morning surge in dippers lost significance (p = 0.09) when 24-hour diastolic blood pressure was replaced with night-time diastolic blood pressure. However, an independent negative association between central retinal artery equivalent and night-time diastolic blood pressure (p < 0.001) emerged. Normal morning surge of dippers was positively associated with central retinal artery equivalent (dependent on night-time dipping). Conclusion: Normal night-time dipping may therefore be involved in preserving retinal arteriolar diameter of dippers, which may reflect a lower vascular resistance.