Correlation between wall-to-lumen ratio of retinal arterioles and clinic and 24 hours blood pressure

Objective: Wall-to-lumen ratio of retinal arterioles might serve as an in-vivo parameter of vascular damage. Previous studies have shown a correlation between retinal arteriolar structure and blood pressure values, measured both in the clinic and during 24 hours ambulatory monitoring. We analyzed the impact of brachial clinic blood pressure (BP), of central BP and of 24 hours BP values on wall-to-lumen ratio of retinal arterioles. Methods: In 267 subjects (129 males, age range 20-72 years; mean 54±7 years) wall-to-lumen ratio of retinal arterioles was assessed in vivo using scanning laser doppler flowmetry (Heidelberg retina flowmeter, Heidelberg Engineering). In addition clinic and 24 hours BP values were measured. Central hemodynamics and augmentation index (Ai) were assessed by pulse wave analysis. Results: In never treated patients with essential hypertension (n=56) a higher wall-to-lumen ratio (0.37±0.19 vs. 0.30±0.13, P=0.05) was observed in comparison with normotensive individuals (n=115); no significant differences were observed between treated (n=96) and untreated hypertensive patients. Wall to lumen ratio and wall cross sectional area of retinal arterioles were significantly related to clinic systolic BP(r=0.23, P=0.005) and PP(r=0.18, P=0.005), to 24 hours systolic BP(r=0.28, P=0.0001) and PP(r=0.19, P=0.003) and to central systolic BP(r=0.20, P=0.01) and central PP(r=0.21, P=0.001). Multiple regression analysis including all BP indices revealed that only mean systolic 24 hours BP is independently associated with an increased wall-to-lumen ratio of retinal arterioles. Conclusion: in this quite large group of hypertensive patients and normotensive individuals 24 hours systolic BP seems to be the strongest determinant of increased WLR of retinal arterioles.