Transient Cortical Blindness and Hemi-Spatial Neglect Following Watchman Device Implantation.

A 66-year-old male with prior right middle cerebral artery stroke status post thrombectomy-as well as right internal carotid artery (ICA) stenting and chronic occlusion, paroxysmal atrial fibrillation, and hypertension-underwent left atrial appendage occlusion with a Watchman device for stroke prevention. Immediately following the procedure, he developed acute bilateral vision loss accompanied by headache and worsening left-sided weakness. Emergent computed tomography (CT) and CT angiography demonstrated no hemorrhagic stroke or new large-vessel occlusion and confirmed the previously known chronic right ICA occlusion. The patient was not a candidate for thrombolysis due to recent heparin exposure during his procedure, and thrombectomy was not pursued given the absence of any new large vessel occlusion. In the context of contrast exposure and negative initial imaging, contrast-induced cortical blindness was considered the leading diagnosis, with embolism, hypoperfusion, and post-stroke recrudescence as alternative considerations. This case highlights the diagnostic complexity of acute cortical blindness and hemispatial neglect following Watchman implantation. Mechanisms may include microembolic shower, transient hypoperfusion, seizure-related cortical dysfunction, post-stroke recrudescence, or contrast induced cortical blindness. Negative initial CT imaging should not preclude suspicion for ischemia, especially in patients with preexisting cerebrovascular compromise. Early magnetic resonance imaging and multidisciplinary coordination are essential.