Conversion from nonischemic to ischemic retinal vein occlusion: prediction by venous velocity on color Doppler imaging

Abstract

To identify color Doppler imaging (CDI) parameters and other prognostic factors of a conversion from nonischemic to ischemic retinal vein occlusion (RVO) in a large population with a long follow-up. This was a retrospective observational study. Data were collected for patients who had been admitted to the ophthalmologic department of the Hospital of Tours because of nonischemic central RVO (CRVO) or branch RVO (BRVO). We analyzed the relation between time until conversion into ischemic RVO and several prognostic factors of conversion, mainly vein velocities as measured by CDI. Analyses involved 162 patients. One year after inclusion, conversion into ischemic RVO occurred in 25.0% of the 113 CRVO and in 28.6% of the 49 BRVO cases. For CRVO, an increase of the minimal central retinal venous velocity (CRV), measured by CDI before and after treatment by hemodilution, diminished the risk of conversion into an ischemic form (p=0.048). For BRVO, an elevated maximal CRV on diagnosis was a protector (p=0.004). Age was associated with a high risk of ischemic evolution for CRVO (p=0.023) but not BRVO. Initial visual acuity was not associated with the conversion, for BRVO or CRVO. Increased retinal hemorrhages highly increased the risk of conversion both for CRVO (p<0.0001) and BRVO (p=0.010). Risk of ischemic evolution for BRVO and CRVO treated by isovolemic hemodilution was associated with central venous velocities. CDI might be useful for identifying risk of ischemic conversion and individualizing the follow-up of patients.