Influence of hemorheological factors on the development of retinal vein occlusion

Effect of a Dexamethasone Implant on Rheological Blood Parameters in Patients Treated for Retinal Vein Thrombosis

Purpose

To assess the effect of the prolonged-release dexamethasone implant (Ozurdex) in patients with retinal venous thrombosis on blood rheological parameters and evaluate the impact on morphological and functional parameters.

Methods

Prospective cross-sectional study involved 35 subjects treated with central retinal vein and vein branch occlusion with intravitreal dexamethasone implant and 35 healthy subjects in control group. Hematocrit, blood and plasma viscosity, erythrocyte aggregation amplitude (EAA), index (EAI), aggregation half-life time (EAT1/2), and erythrocyte deformability (ED) were evaluated. The best-corrected visual acuity (BCVA), central retinal thickness (CRT) and visual field (VF) were examined. All the parameters were examined at the baseline, 7 and 30 days after the treatment. The results were analyzed with correlation and regression and compared to the baseline values.

Results

In the studied group, three hemorheological parameters improved as early as on the 7th day after the drug administration, and this improvement remained at a similar level on the 30th day. The EAA increased by 21.26% on day 7 and by 19.78% on day 30, the EAI decreased by 10.55% on day 7 and by 9.14% on day 30 and the EAT1/2 time increased by 38.50% on day 7 and by 31.02% on day 30. On day 7, the BCVA was improved by 1 row, CRT was reduced by 170.77 µm (24.49%), and the VF was improved by 9.8 dB (49.92%) compared to baseline parameters. On day 30, the BCVA was improved by three rows, CRT reduced by 244.68 µm (35.09%), and VF improved by 12.09 dB (61.59%).

Conclusion

The intravitreal dexamethasone implant used in treating macular oedema in patients with RVO has a statistically significant effect on some rheological parameters of blood, reduction of CRT and clinical improvement in BCVA and VF.

Comparison of systemic conditions at diagnosis between central retinal vein occlusion and branch retinal vein occlusion

Objective

To compare systemic conditions at the time of diagnosis between patients with central retinal vein occlusion (CRVO) and branch retinal vein occlusion (BRVO).

Design

This study included patients diagnosed with CRVO or BRVO between February 2009 and August 2017 at three branch hospitals of Hallym University Medical Center. Demographic and anthropometric variables, systemic comorbidity profiles, and laboratory findings at diagnosis were collected from a clinical data warehouse system, and were compared between the CRVO and BRVO groups.

Result

Four hundred and seventeen patients with CRVO and 1,511 patients with BRVO were included. The mean age was 61.8 ± 13.9 years, which was comparable between two groups (P = .332). Female proportion was higher in the BRVO group (55.0%) than in the CRVO group (48.0%; P = .013). Diabetes mellitus (P = .017) and chronic kidney disease (P = .004) were more prevalent in the CRVO group. Serum homocysteine level was abnormally high in 23.5% of CRVO patients and in 8.4% of BRVO patients (P < .001). Blood urea nitrogen and serum creatinine levels were abnormally elevated in more subjects with CRVO (P = .002).

Conclusion

CRVO is associated with higher prevalence of diabetes mellitus and chronic kidney disease, as well as with elevated serum homocysteine level. These results might suggest a difference between the pathophysiologies of CRVO and BRVO.