Patent foramen ovale (PFO) is frequently identified in young patients with ischemic stroke. Randomized controlled trials provide robust evidence supporting PFO closure in selected patients with cryptogenic ischemic stroke; however, several questions remain unanswered. This report summarizes current knowledge on the epidemiology of PFO-associated stroke, the role of PFO as a cause of stroke, and anatomic high-risk features. We also comment on breakthrough developments in patient selection algorithms for PFO closure in relation to the PFO-associated stroke causal likelihood risk stratification system. We further highlight areas for future research in PFO-associated stroke including the efficacy and safety of PFO closure in the elderly population, incidence, and long-term consequences of atrial fibrillation post-PFO closure, generalizability of the results of clinical trials in the real world, and the need for assessing the effect of neurocardiology teams on adherence to international recommendations. Other important knowledge gaps such as sex, race/ethnicity, and regional disparities in access to diagnostic technologies, PFO closure devices, and clinical outcomes in the real world are also discussed as priority research topics.
Keywords: algorithm; atrial fibrillation; ethnicity; ischemic stroke; patent foramen ovale.