Left atrial appendage occlusion (LAAO) has become a preferred alternative for ischemic stroke prophylaxis in patients with a high risk of cardioembolic stroke but who are contraindicated for long-term anticoagulation. While the intervention has been successful in reducing bleeding events when compared to using anticoagulation, some stroke risk still persists. We present a case of stroke related to the failure of a left atrial appendage occluder, which was found to have a peri-device leak and incomplete endothelialization. In our case, we also believe these may have been exacerbated by comorbid severe mitral regurgitation. While current post-procedural protocols do address management of specific findings predictive of device failure, our patient still suffered from ischemic stroke despite following guidelines. Based on current outcome studies on LAAO, he may have been at higher risk than appreciated. His surveillance imaging at post-operative day 45 revealed a small peri-device leak of < 5 mm, which is now found to be associated with a higher embolic stroke risk than larger leaks of > 5 mm. Moreover, his mitral regurgitation, which was severe and borderline symptomatic, remained undertreated for a prolonged period. In cases of similar comorbidities, one might consider exploring the role of concomitant endovascular mitral repair and LAAO to optimize outcomes.