Mature vessel occlusion after anti-VEGF treatment in a retinal arteriovenous malformation

Background: To report engorged vessel occlusion after repeated intravitreal injections of bevacizumab to treat the macular oedema in a case of arteriovenous malformation. Case presentation. A 37-year-old woman presented with a sudden, painless loss of vision in her left eye. Her visual acuity was 20/200 in the left eye, and 20/20 in the right eye. Ophthalmoscopic examination revealed an abnormal tangle of vessels and enlarged draining veins. A fluorescence angiogram revealed fluorescence leakage at a turn near the fovea. Horizontally oriented optical coherence tomography revealed an increased macular thickness and an accumulation of intraretinal fluid, indicating macular oedema. After three intravitreal injections of 1.25 mg bevacizumab, her vision improved to 20/20. Ophthalmoscopic examination revealed a decreased calibre of the previously engorged draining veins and ghost vessels. Repeated horizontally oriented optical coherence tomography revealed a decreased macular thickness and the absence of an intraretinal cyst. At the 2-year follow-up visit, the vision of the patient was stable. Conclusion: This finding implies that certain middle-size vessels can become occluded during anti- vascular endothelium growth factor (anti-VEGF) therapy, which could induce fatal complications if it occurred in the heart or brain. Clinicians should be cautious of the potential thrombotic effects on systemic blood vessels when administering anti-VEGF treatment.