MyVisionTest News Archive
Oct 25, 2009
Edaravone for macular edema due to branch retinal vein occlusion
Patients given edaravone (Radicut, Mitsubishi Pharma Co, Japan) during arteriovenous sheathotomy for macular edema associated with branch retinal vein occlusion (BRVO) had beter post-operative visual acuity than patients that did not receive edarvone.
Vitrectomy is effective in reducing the macular edema associated with BRVO. It has been proposed that the reduction of macular edema by vitrectomy was due to the release of vitreal traction on the retina.
An adjunctive procedure used during the vitrectomy is arteriovenous sheathotomy. The rationale for this procedure is that it reduces or eliminates the pressure on the retinal vein at the arteriovenous crossing caused by the BRVO thus improving venous blood flow.
Free radicals are often produced in patients with a cerebral infarction, and the free radicals can then damage endothelial cells and neurocytes during the reperfusion. A recent study showed that hydroxyl radicals were generated in the retina during an ischaemic episode and remained elevated during the reperfusion period.
Edaravone, a free radical scavenger, was developed in Japan as a neuroprotective agent against the free radicals generated by ischaemia. Arteriovenous sheathotomy for the treatment of BRVO generates free radicals during the reperfusion that may damage the retinal cells and affect the postoperative visual acuity.
This study was performed to determine whether systemic administration of edaravone during vitrectomy would enhance the recovery of vision after arteriovenous sheathotomy for the treatment of macular oedema associated with BRVO.
Methods and Results
Forty-seven eyes of 47 consecutive patients with a BRVO who were treated with arteriovenous sheathotomy were studied. The patients were assigned prospectively to either Group R who received 30 mg of edaravone (Radicut) systemically during the vitrectomy or Group N who did not receive any drugs. The postoperative visual acuity was measured before and 12 months after the operation.
At 12 months postoperatively, the best-corrected visual acuity (BCVA) in logarithm of the minimum angle of resolution (logMAR) units improved significantly from 0.22 logMAR to 0.56 logMAR units in Group R and from 0.20 logMAR to 0.27 logMARin Group N (p = 0.016). Twenty-three of 27 cases (85%) in Group R and four of 15 cases (27%) in Group N showed an improvement in BCVA of >0.2 logMAR units (p = 0.0025).
Discussion and Conclusions
There are conflicting results on the effectiveness of vitrectomy against the macular edema in eyes with a BRVO. This may be because even if surgery does improve venous blood flow, two factors additional can limit post-operative visual acuity improvement. First, the photoreceptor and neural cells in the inner retina could have been irreversibly damaged during the period of occlusion. Second, reperfusion can generate free radicals that can damage neuronal and vascular endothelial cells. These factors need to be considered when assessing the efficacy of arteriovenous sheathotomy.
In this study, the preoperative visual acuity, estimated duration of the BRVO and degree of macular edema between the two groups were not significantly different. These preoperative findings indicate that the physiological condition of the photoreceptors and other retinal neurons was probably similar in the two groups. However, the improvements in both visual acuity and macular edema were significantly better in patients that received edaravone (Radicut) pre-operatively. This suggests that the decrease post-operative visual acuity in Group N was due to the effects of free radicals produced during the reperfusion.
It is possible that combined use of edaravone with conventional anticoagulants, platelet-aggregation inhibitors or anti-VEGF treatments might have additive and synergistic effects.
The investigators conclude that vitrectomy combined with arteriovenous sheathotomy in eyes with macular edema due to BRVO lead to better results then when edaravone was given intravenously at the time of the vitrectomy. The researchers state that edaravone should be given as early as possible to prevent irreversible change to photoreceptors and retinal neurons.
Read more...
Br J Ophthalmol 2009;93:1479-1482
Tags: macular edema, retinal vein occlusion, surgery, edaravone
Patients given edaravone (Radicut, Mitsubishi Pharma Co, Japan) during arteriovenous sheathotomy for macular edema associated with branch retinal vein occlusion (BRVO) had beter post-operative visual acuity than patients that did not receive edarvone.Vitrectomy is effective in reducing the macular edema associated with BRVO. It has been proposed that the reduction of macular edema by vitrectomy was due to the release of vitreal traction on the retina.
Free radicals are often produced in patients with a cerebral infarction, and the free radicals can then damage endothelial cells and neurocytes during the reperfusion. A recent study showed that hydroxyl radicals were generated in the retina during an ischaemic episode and remained elevated during the reperfusion period.
Edaravone, a free radical scavenger, was developed in Japan as a neuroprotective agent against the free radicals generated by ischaemia. Arteriovenous sheathotomy for the treatment of BRVO generates free radicals during the reperfusion that may damage the retinal cells and affect the postoperative visual acuity.
This study was performed to determine whether systemic administration of edaravone during vitrectomy would enhance the recovery of vision after arteriovenous sheathotomy for the treatment of macular oedema associated with BRVO.
Methods and Results
Forty-seven eyes of 47 consecutive patients with a BRVO who were treated with arteriovenous sheathotomy were studied. The patients were assigned prospectively to either Group R who received 30 mg of edaravone (Radicut) systemically during the vitrectomy or Group N who did not receive any drugs. The postoperative visual acuity was measured before and 12 months after the operation.
At 12 months postoperatively, the best-corrected visual acuity (BCVA) in logarithm of the minimum angle of resolution (logMAR) units improved significantly from 0.22 logMAR to 0.56 logMAR units in Group R and from 0.20 logMAR to 0.27 logMARin Group N (p = 0.016). Twenty-three of 27 cases (85%) in Group R and four of 15 cases (27%) in Group N showed an improvement in BCVA of >0.2 logMAR units (p = 0.0025).Discussion and Conclusions
There are conflicting results on the effectiveness of vitrectomy against the macular edema in eyes with a BRVO. This may be because even if surgery does improve venous blood flow, two factors additional can limit post-operative visual acuity improvement. First, the photoreceptor and neural cells in the inner retina could have been irreversibly damaged during the period of occlusion. Second, reperfusion can generate free radicals that can damage neuronal and vascular endothelial cells. These factors need to be considered when assessing the efficacy of arteriovenous sheathotomy.
In this study, the preoperative visual acuity, estimated duration of the BRVO and degree of macular edema between the two groups were not significantly different. These preoperative findings indicate that the physiological condition of the photoreceptors and other retinal neurons was probably similar in the two groups. However, the improvements in both visual acuity and macular edema were significantly better in patients that received edaravone (Radicut) pre-operatively. This suggests that the decrease post-operative visual acuity in Group N was due to the effects of free radicals produced during the reperfusion.
It is possible that combined use of edaravone with conventional anticoagulants, platelet-aggregation inhibitors or anti-VEGF treatments might have additive and synergistic effects.
The investigators conclude that vitrectomy combined with arteriovenous sheathotomy in eyes with macular edema due to BRVO lead to better results then when edaravone was given intravenously at the time of the vitrectomy. The researchers state that edaravone should be given as early as possible to prevent irreversible change to photoreceptors and retinal neurons.
Read more...
Br J Ophthalmol 2009;93:1479-1482
