[Ischemic optic neuropathy following a dural arteriovenous fistula. Vascular steal phenomenon].

CASE REPORT: We report the case of a 46-year-old patient, with a dural arteriovenous fistula in the left cavernous sinus fed by dural branches of both carotid siphons, by recurrent branches of the left ophthalmic artery (LOA) and by dural branches of the left external carotid artery. Twenty-four hours after arterial embolisation with polyvinyl alcohol particles, the patient suffered visual loss in the left eye. All feeders were embolized except the recurrent branches of the LOA, which became hypertrophied. Fluorescein angiography of the retina was normal. Transocular Doppler ultrasound showed a turbulent, inverted, low resistance flow in the LOA distal part, and a high resistance anterograde flow in the left central artery of the retina, which accounted for an ischemic optic neuropathy.

CONCLUSIONS

The ischemic optic neuropathy resulted from a vascular steal phenomenon. Hypertrophy of recurrent branches of the LOA, after embolization of the remaining feeders, contributed to a low resistance shunt between the LOA proximal part and the left cavernous sinus. This shunt caused the inversion of flow in the distal part of the artery and the subsequent decrease of retrobulbar blood supply.