The association of ocular blood flow with haemorheological parameters in primary open-angle and exfoliative glaucoma

Abstract

ABSTRACT.Purpose: To evaluate the ocular blood flow velocities and haemorheological parameters in patients with primary open-angle glaucoma (POAG), exfoliative glaucoma (XFG) and exfoliation syndrome (XFS) and to compare their results with those of healthy controls. Methods: Twenty-five patients with POAG (group 1), 25 patients with XFG (group 2), 25 patients with XFS (group 3) and 25 healthy controls (group 4) were included in the study. Ocular blood flow velocities of ophthalmic artery (OA), central retinal artery (CRA) and short posterior ciliary arteries (SPCAs) were measured using colour Doppler imaging (CDI). Haemorheological parameters (erythrocyte elongation and aggregation index, aggregation amplitude, aggregation half-life, plasma viscosity, haematocrit) were measured in venous blood samples of all patients. Results: The peak systolic velocity (PSV) and end-diastolic velocity (EDV) values were lower and resistive indices (RI) were higher for the OA, CRA and SPCA of glaucomatous (groups 1 and 2) patients compared with those of controls (group 4) (PSV: OA, 40.4 ± 11.3 versus 52.6 ± 12.8 cm ⁄ second, p < 0.001; CRA, 12.9 ± 2.9 versus 15.3 ± 4.2 cm ⁄ second, p = 0.02; SPCA, 21.7 ± 6.6 versus 26.6 ± 8.3 cm ⁄ second, p = 0.013) (EDV: OA, 10.3 ± 4.3 versus 14.2 ± 5.1 cm ⁄ second, p < 0.001; CRA, 3.7 ± 1.1 versus 4.5 ± 1.3 cm ⁄ second, p = 0.025; SPCA, 5.2 ± 1.8 versus 7.7 ± 3.2 cm ⁄ second, p = 0.001) (RI: OA, 0.75 ± 0.05 versus 0.66 ± 0.07, p < 0.001; CRA, 0.73 ± 0.08 versus 0.68 ± 0.10, p = 0.223; SPCA, 0.70 ± 0.10 versus 0.63 ± 0.11, p = 0.004). There were no statistically significant differences between the haemorheological parameters of glaucomatous and non-glaucomatous patients. The reduction in ocular blood flow velocities in groups 1, 2 and 3 were not associated with changes in haemorheological parameters. Conclusion: Our results suggest that impairment of the retrobulbar blood flow in POAG and XFG is not associated with alterations in haemorheological parameters.

Increased erythrocyte aggregation in patients with primary open angle glaucoma

“…This means that RBC deformability was measured at high shear stresses, which actually do not match with the wall shear stress values of retinal vessels in these studies. On the other hand, Sekeroglu et al measured RBC deformability of POAG patients at shear stresses of 3 and 30 Pa and found no difference. In the present study, RBC deformability was measured using LORCA but in a wider range of shear stresses between 0.30 and 30 Pa covering the average wall shear stress values of retinal vessels.…”

“…19 Only a few studies evaluated erythrocyte aggregation and deformability in glaucoma patients and these studies used different laboratory techniques and patient selection criteria. 2,5,[15][16][17][19][20][21] Cheng et al 15 and Vetrugno et al 19 using ektacytometry, demonstrated a lower index of erythrocyte deformability in patients with normal tension glaucoma (NTG). Ates et al 5 found no difference in RBC deformability in normal tension glaucoma and high tension glaucoma using the Cell Transit Analyser.…”

“…18 Previous literature comprises conflicting results from a number of studies investigating haemorrheological characteristics of patients with glaucoma based on different patient selection criteria (sample size, exclusion criteria, guidelines for the diagnosis of glaucoma, different stages of glaucoma and presence of hypertension) and methods used for determination of RBC deformability and aggregation. 2,5,[15][16][17][19][20][21] Furthermore, the relationship between haemorrheological parameters and optic nerve head morphology in patients with primary open angle glaucoma (POAG) is unclear. Hence, the present study aims to determine alterations in erythrocyte mechanical properties (erythrocyte aggregation and deformability) and the association between rheological alterations and OCT measurements (ONH and RNFL parameters) in patients with POAG.…”

Subfoveal choroidal blood flow and central retinal function in early glaucoma

“…The influence of factors such as age, gender, menopausal status and systemic disease or drugs on the ocular blood flow has been widely investigated in many reports (Kavroulaki et al. 2010; Sekeroglu et al. 2011; Shoshani et al.…”

Effects of blood flow properties on ocular hemodynamics

“…Оценка степени взаимосвязи показателей офтальмогемодинамики и реологических свойств крови при глаукоме является непростой задачей и нуждается в дальнейшей детализации и уточнении. Это обусловлено тем, что при ПОУГ часто выявляют изменения показателей гемодинамики (снижение скоростных показателей и повышение индексов периферического сопротивления по данным ЦДК), которые могут не зависеть от вязкости крови, но совпадать с подобными изменениями по форме проявления [9].…”