Impact of Intravitreal Dexamethasone Implant on Vessel Diameters in Patients with Retinal Vein Occlusion

Abstract

Purpose. To investigate the vasomotor responses and diameter of retinal vessels in patients with macular edema secondary to retinal vein occlusion (RVO) who were treated with intravitreal dexamethasone implant. Methods. We enrolled 17 eyes of 17 patients with macular edema secondary to RVO. All patients were evaluated through optical coherence tomography and dynamic and static retinal vessel analysis, using the Dynamic Vessel Analyzer (Imedos, Jena, Germany) before administration (baseline) and 1 week, 1 month, and 2 months after administration of intravitreal dexamethasone. Measurements of patients were compared to those of 17 eyes of age- and sex-matched control subjects. Results. In static analysis, arteriovenous ratio (AVR) in control subjects was 0.86 (0.80–0.88). In RVO patients, baseline AVR was 0.71 (0.54–0.84) and significantly lower than that in control subjects (p=0.016). Baseline AVR in the RVO group was significantly lower than AVR at month 1 and month 2 (p=0.001 and p<0.001, respectively). CRVE in healthy control subjects was 183.59 ± 21.79 measurement units (MU) which was significantly different from CRVE of RVO eyes at baseline (207.00 ± 26.35 MU) (p=0.008). Static analysis showed a significant decrease of central retinal vein equivalent (CRVE) from baseline to 1 week, 1 month, and 2 months (p<0.001, p<0.001, and p<0.001, respectively). CRAE in the control group was 176.24 ± 22.45 MU. CRAE in the RVO group was significantly lower at baseline, week 1, month 1, and month 2 compared to that in the control group (p=0.008, p=0.003, p=0.013, and p=0.011, respectively). Dynamic analysis showed that maximum venous and arterial dilations did not statistically differ from baseline to 1 week, 1 month, or 2 months. Conclusion. Using the Dynamic Vessel Analyzer, we found that retinal veins in patients with RVO were significantly larger compared to those in the control group, and intravitreal dexamethasone treatment reduced the diameters of these veins.

Alterations in Retinal Vessel Diameters in Patients with Retinal Vein Occlusion before and after Treatment with Intravitreal Ranibizumab

“…Apart from laser photocoagulation and intravitreal anti-VEGF agents, intravitreal steroids have been used in the treatment of macular edema secondary to RVO. Two studies that investigated the effect of an intravitreal injection of a sustained-release intravitreal dexamethasone implant (Ozurdex; Allergan, Irvine, CA, USA) in 17 and 40 eyes with RVO, respectively, found that retinal venular diameters were narrower after treatment, whereas retinal arterioles showed no response [ 20 , 21 ]. Furthermore, Eibenberger et al reported a significant decrease in retinal venules only in CRVO and not in the studied BRVO population [ 21 ], whereas Yilmaz Tugan et al demonstrated the vasoconstriction of venules in both CRVO and BRVO patients [ 20 ], showing controversial results.…”

“…Two studies that investigated the effect of an intravitreal injection of a sustained-release intravitreal dexamethasone implant (Ozurdex; Allergan, Irvine, CA, USA) in 17 and 40 eyes with RVO, respectively, found that retinal venular diameters were narrower after treatment, whereas retinal arterioles showed no response [ 20 , 21 ]. Furthermore, Eibenberger et al reported a significant decrease in retinal venules only in CRVO and not in the studied BRVO population [ 21 ], whereas Yilmaz Tugan et al demonstrated the vasoconstriction of venules in both CRVO and BRVO patients [ 20 ], showing controversial results. These findings could be attributed to the fact that intravitreal dexamethasone acts by stabilizing the endothelial cell tight junctions and reducing intraocular cytokine production [ 7 ].…”

“…So far, few studies have examined the effect of therapeutic procedures such as laser photocoagulation [ 13 , 16 ], intravitreal ranibizumab [ 17 , 18 ], bevacizumab [ 19 ] and dexamethasone implant [ 20 , 21 ] on retinal vessel calibers in patients with macular edema due to RVO. The majority of previous studies reported that there was vasoconstriction of arterioles and venules after intravitreal anti-VEGF or laser treatment in RVO patients.…”

Changes in venous calibre during intra-vitreal therapy for central retinal vein occlusion

“…Much of the reduction was observed within the first 12 months, with 29% and 6% in the first and second 12month periods, respectively. Mean CRAE in treated eyes reduced by 10.6% to month 24 [2,3].…”