The aim of the study was to test the hypothesis if arterial stiffness is linked to reduction of retinal capillary blood flow and development of retinal microvascular remodelling.
Design and method:
The study group comprised of 88 patients with essential hypertension (n = 88, 54.3 ± 8.3 years, 44.3% were female) and 32 healthy controls. Inclusion criteria were: essential hypertension, age of 40–70 years old. Exclusion criteria were: secondary hypertension, any cardiovascular disease including heart failure, coronary artery disease, arrhythmia, moderate or severe valve disease, history of stroke or transient ischemic attack, chronic kidney disease with eGFR < 60 mml/min/1.73 m2, diabetes mellitus, eye disease, pregnancy. Retinal microcirculation was evaluated by scanning laser Doppler flowmetry. Macrovascular changes were assessed on the basis of measurement of arterial stiffness (by carotid-femoral pulse wave velocity, central pulse pressure, augmentation pressure and augmentation index) and intima media thickness of common carotid artery. Diastolic dysfunction and left ventricular hypertrophy were analysed by echocardiography.
Pulse wave velocity was inversely correlated with mean retinal capillary blood flow in a group of hypertensive patients (R = −0.32, p < 0.01). This relationship remained significant in multivariate regression analysis even after adjustment for age, systolic blood pressure and waist to hip ratio (β = −40.275, p < 0.001). Central pulse pressure was positively correlated with retinal wall thickness (R = 0.44, p < 0.05), wall cross sectional area (R = 0.44, p < 0.05) and wall to lumen ratio (R = 0.43, p < 0.05). Brachial pulse pressure was positively correlated with wall thickness (R = 0.43, p < 0.05), wall cross sectional area (R = 0.41, p < 0.05) and wall to lumen ratio (R = 0.47, p < 0.05). In contrast, the relationship between augmentation pressure or augmentation index and structural indicators of retinal remodelling was not observed.
In conclusion, the study provides an evidence that microcirculation is coupled with macrocirculation not only in terms of structural but also functional parameters. Pulse wave velocity was independently associated with retinal capilary flow. Central and brachial pulse pressure were significantly related to retinal wall thickness, wall cross sectional area and wall to lumen ratio.