No differences observed in Macular Edema Outcomes After Anti-VEGF Therapy between eyes with CRVO and HRVO
Retinal vein occlusions are classified according to the occlusion site as branch retinal vein occlusion (BRVO), central retinal vein occlusion (CRVO), or hemiretinal vein occlusion (HRVO). HRVO may be further classified into hemicentral retinal vein occlusion, in which a dual-trunked central retinal vein persists in the anterior part of the optic nerve as a congenital variant and one of the trunks is occluded, and hemispheric retinal vein occlusion, in which a major branch of the central retinal vein is occluded at or near the optic disc.
Reported risk factors, clinical features, and systemic associations differ among patients with BRVO, CRVO, and HRVO. Further, clinical trials have demonstrated that the response to treatment with thermal laser and to intravitreal triamcinolone acetonide differs between eyes with macular edema associated with CRVO compared with eyes with macular edema associated with BRVO.
The Study of Comparative Treatments for Retinal Vein Occlusion 2 (SCORE2) randomized clinical trial showed that bevacizumab, an anti–vascular endothelial growth factor (VEGF) treatment commonly used off-label, is noninferior to aflibercept, a more expensive anti-VEGF treatment approved by the US Food and Drug Administration, with respect to visual acuity (VA) and patient-reported visual function at 6 months in eyes with macular edema associated with CRVO or HRVO. The purpose of the current study by Ingrid U. Scott and team was to compare the baseline characteristics, treatment response, and treatment burden in participants with HRVO with those of participants with CRVO in the SCORE2 trial.
This post hoc outcome analysis from the Study of Comparative Treatments for Retinal Vein Occlusion 2 randomized clinical trial included 362 participants with macular edema caused by HRVO or CRVO treated at 66 US sites. Randomization began in September 2014, and the last month 24 follow-up visit occurred in February 2018. Data were analyzed from April 2020 to May 2021. Eyes were initially randomized to 6 monthly intravitreal injections of aflibercept or bevacizumab and were treated according to protocol between months 6 to 12 depending on 6-month outcome. After month 12, patients were treated per investigator discretion and observed through month 60.
Of 362 included patients, 157 (43.4%) were female, and the mean (SD) age was 68.9 (12.0) years. Outcome data were analyzed up to month 24 owing to substantial missing data at later visits. A significantly greater proportion of participants with HRVO than those with CRVO were Black (37% vs 11%).
Treatment rates between months 12 to 23 were 0.36 injections per month for patients with CRVO and 0.28 for patients with HRVO (P = .11).
The mean VALS from months 1 to 24 of an HRVO study eye exceeded that of a CRVO study eye by 5.5 (P = .01), consistent with the magnitude of the VALS difference between eyes with CRVO and HRVO at baseline. Eyes with CRVO presented at baseline with more macular edema than eyes with HRVO ( P < .001), with no difference in CST between the groups throughout months 1 to 24.
Eyes with CRVO presented with worse VA and higher CST than did eyes with HRVO, which is not surprising given that CRVO involves a greater portion of the macula than does HRVO. There were CST differences between eyes with CRVO and HRVO observed at baseline but not during months 1 to 24, although the magnitude of the VA differential between the 2 groups remained relatively constant from baseline throughout follow-up. Thus, it appears that although anti-VEGF therapy is similarly effective in CRVO and HRVO with respect to the magnitude of VA improvement and resolving excess central retinal thickness, eyes with CRVO have an overall worse visual prognosis than do eyes with HRVO owing to factors other than macular edema already impairing vision at baseline. Such factors may include damage at the cellular level perhaps due to ischemia. The VALS differences between eyes with CRVO and HRVO do not appear related to treatment, since the magnitude of the difference at baseline between the 2 groups was consistent with the magnitude of the differences throughout follow-up.
The study results also demonstrate that although anti VEGF treatment is effective in improving the VA and reducing the macular edema in most patients with CRVO associated and HRVO-associated macular edema, patients in both groups required 3 to 4 anti-VEGF injections in the second year of follow-up and, by the end of year 2, only 22% to 25% of eyes in each group had achieved complete resolution of macular edema. This suggests that close monitoring and continued treatment as indicated are needed to optimize the long-term visual and anatomic outcomes of patients treated initially with anti-VEGF therapy for CRVO-associated or HRVO associated macular edema.
In summary, although eyes with CRVO presented with worse VA and more macular edema on average than did eyes with HRVO, the magnitude of VALS improvement, the resolution of excess central retinal thickness in response to anti-VEGF therapy, and the treatment burden are similar between the 2 groups.
SOURCE: Ingrid U. Scott, Neal L. Oden, Paul C. VanVeldhuisen, et al; for the SCORE2 Study Investigator Group
JAMA Ophthalmol. doi:10.1001/jamaophthalmol.2022.0352
